| Message ID | 20210722004758.12371-23-casey@schaufler-ca.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | None | expand |
On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > > Create a new audit record type to contain the subject information > when there are multiple security modules that require such data. > This record is linked with the same timestamp and serial number > using the audit_alloc_local() mechanism. > The record is produced only in cases where there is more than one > security module with a process "context". > In cases where this record is produced the subj= fields of > other records in the audit event will be set to "subj=?". > > An example of the MAC_TASK_CONTEXTS (1420) record is: > > type=UNKNOWN[1420] > msg=audit(1600880931.832:113) > subj_apparmor="=unconfined" > subj_smack="_" > > There will be a subj_$LSM= entry for each security module > LSM that supports the secid_to_secctx and secctx_to_secid > hooks. The BPF security module implements secid/secctx > translation hooks, so it has to be considered to provide a > secctx even though it may not actually do so. > > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > To: paul@paul-moore.com > To: linux-audit@redhat.com > To: rgb@redhat.com > Cc: netdev@vger.kernel.org > --- > drivers/android/binder.c | 2 +- > include/linux/audit.h | 16 +++++ > include/linux/security.h | 16 ++++- > include/net/netlabel.h | 2 +- > include/net/scm.h | 2 +- > include/net/xfrm.h | 13 +++- > include/uapi/linux/audit.h | 1 + > kernel/audit.c | 90 +++++++++++++++++++------ > kernel/auditfilter.c | 5 +- > kernel/auditsc.c | 27 ++++++-- > net/ipv4/ip_sockglue.c | 2 +- > net/netfilter/nf_conntrack_netlink.c | 4 +- > net/netfilter/nf_conntrack_standalone.c | 2 +- > net/netfilter/nfnetlink_queue.c | 2 +- > net/netlabel/netlabel_unlabeled.c | 21 +++--- > net/netlabel/netlabel_user.c | 14 ++-- > net/netlabel/netlabel_user.h | 6 +- > net/xfrm/xfrm_policy.c | 8 ++- > net/xfrm/xfrm_state.c | 18 +++-- > security/integrity/ima/ima_api.c | 6 +- > security/integrity/integrity_audit.c | 5 +- > security/security.c | 46 ++++++++----- > security/smack/smackfs.c | 3 +- > 23 files changed, 221 insertions(+), 90 deletions(-) > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index 2c3a2348a144..3520caa0260c 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -2722,7 +2722,7 @@ static void binder_transaction(struct binder_proc *proc, > * case well anyway. > */ > security_task_getsecid_obj(proc->tsk, &blob); > - ret = security_secid_to_secctx(&blob, &lsmctx); > + ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY); > if (ret) { > return_error = BR_FAILED_REPLY; > return_error_param = ret; > diff --git a/include/linux/audit.h b/include/linux/audit.h > index 97cd7471e572..85eb87f6f92d 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -291,6 +291,7 @@ extern int audit_alloc(struct task_struct *task); > extern void __audit_free(struct task_struct *task); > extern struct audit_context *audit_alloc_local(gfp_t gfpflags); > extern void audit_free_context(struct audit_context *context); > +extern void audit_free_local(struct audit_context *context); > extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, > unsigned long a2, unsigned long a3); > extern void __audit_syscall_exit(int ret_success, long ret_value); > @@ -386,6 +387,19 @@ static inline void audit_ptrace(struct task_struct *t) > __audit_ptrace(t); > } > > +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp) > +{ > + struct audit_context *context = audit_context(); > + > + if (context) > + return context; > + > + if (lsm_multiple_contexts()) > + return audit_alloc_local(gfp); > + > + return NULL; > +} We don't want to do this, at least not as it is written above. We shouldn't have a function which abstracts away the creation of a local audit_context. Usage of a local audit_context should be explicit in the caller, and if the caller's execution context is ambiguous enough that it can require both a task_struct audit_context and a local audit_context then we need to handle that on a case-by-case basis. Hiding it like this is guaranteed to cause problems later. I probably did a poor job of explaining what a local context is during the last patchset; I'll try to do a better job here but also let me say this as clear as I can ... if the "current" task struct is valid for a given code path, *never* use a local audit context. The local audit context is a hack that is made necessary by the fact that we have to audit things which happen outside the scope of an executing task, e.g. the netfilter audit hooks, it should *never* be used when there is a valid task_struct. It's the audit_context which helps bind multiple audit records into a single event, creating a new, "local" audit_context destroys that binding as audit records created using that local audit_context have a different timestamp from those records created using the current task_struct's audit_context. Hopefully that makes sense? > /* Private API (for audit.c only) */ > extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); > extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); > @@ -560,6 +574,8 @@ extern int audit_signals; > } > static inline void audit_free_context(struct audit_context *context) > { } > +static inline void audit_free_local(struct audit_context *context) > +{ } > static inline int audit_alloc(struct task_struct *task) > { > return 0; > diff --git a/include/linux/security.h b/include/linux/security.h > index 3e9743118fb9..b3cf68cf2bd6 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -182,6 +182,8 @@ struct lsmblob { > #define LSMBLOB_INVALID -1 /* Not a valid LSM slot number */ > #define LSMBLOB_NEEDED -2 /* Slot requested on initialization */ > #define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */ > +#define LSMBLOB_DISPLAY -4 /* Use the "display" slot */ > +#define LSMBLOB_FIRST -5 /* Use the default "display" slot */ > > /** > * lsmblob_init - initialize an lsmblob structure > @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob) > return 0; > } > > +static inline bool lsm_multiple_contexts(void) > +{ > +#ifdef CONFIG_SECURITY > + return lsm_slot_to_name(1) != NULL; > +#else > + return false; > +#endif > +} > + > /* These functions are in security/commoncap.c */ > extern int cap_capable(const struct cred *cred, struct user_namespace *ns, > int cap, unsigned int opts); > @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value, > size_t size); > int security_netlink_send(struct sock *sk, struct sk_buff *skb); > int security_ismaclabel(const char *name); > -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp); > +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp, > + int display); > int security_secctx_to_secid(const char *secdata, u32 seclen, > struct lsmblob *blob); > void security_release_secctx(struct lsmcontext *cp); > @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name) > } > > static inline int security_secid_to_secctx(struct lsmblob *blob, > - struct lsmcontext *cp) > + struct lsmcontext *cp, int display) > { > return -EOPNOTSUPP; > } > diff --git a/include/net/netlabel.h b/include/net/netlabel.h > index 73fc25b4042b..216cb1ffc8f0 100644 > --- a/include/net/netlabel.h > +++ b/include/net/netlabel.h > @@ -97,7 +97,7 @@ struct calipso_doi; > > /* NetLabel audit information */ > struct netlbl_audit { > - u32 secid; > + struct lsmblob lsmdata; > kuid_t loginuid; > unsigned int sessionid; > }; This chunk seems lost here, does it belong in another patch? > diff --git a/include/net/scm.h b/include/net/scm.h > index b77a52f93389..f4d567d4885e 100644 > --- a/include/net/scm.h > +++ b/include/net/scm.h > @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc > * and the infrastructure will know which it is. > */ > lsmblob_init(&lb, scm->secid); > - err = security_secid_to_secctx(&lb, &context); > + err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY); Misplaced code change? > if (!err) { > put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len, > diff --git a/include/net/xfrm.h b/include/net/xfrm.h > index cbff7c2a9724..a10fa01f7bf4 100644 > --- a/include/net/xfrm.h > +++ b/include/net/xfrm.h > @@ -660,13 +660,22 @@ struct xfrm_spi_skb_cb { > #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0])) > > #ifdef CONFIG_AUDITSYSCALL > -static inline struct audit_buffer *xfrm_audit_start(const char *op) > +static inline struct audit_buffer *xfrm_audit_start(const char *op, > + struct audit_context **lac) > { > + struct audit_context *context; > struct audit_buffer *audit_buf = NULL; > > if (audit_enabled == AUDIT_OFF) > return NULL; > - audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, > + context = audit_context(); > + if (lac != NULL) { > + if (lsm_multiple_contexts() && context == NULL) > + context = audit_alloc_local(GFP_ATOMIC); > + *lac = context; > + } > + > + audit_buf = audit_log_start(context, GFP_ATOMIC, > AUDIT_MAC_IPSEC_EVENT); > if (audit_buf == NULL) > return NULL; Related to the other comments around local audit_contexts, we don't want to do this; use the existing audit_context, @lac in this case, so that this audit record is bound to the other associated records into a single audit event (all have the same timestamp). > diff --git a/kernel/audit.c b/kernel/audit.c > index 841123390d41..cba63789a164 100644 > --- a/kernel/audit.c > +++ b/kernel/audit.c > @@ -386,10 +386,12 @@ void audit_log_lost(const char *message) > static int audit_log_config_change(char *function_name, u32 new, u32 old, > int allow_changes) > { > + struct audit_context *context; > struct audit_buffer *ab; > int rc = 0; > > - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); > + context = audit_alloc_for_lsm(GFP_KERNEL); > + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE); We shouldn't need to do this for the reasons discussed up near the top of this email (and elsewhere as well). I'm going to refrain from commenting on the other uses of audit_alloc_for_lsm() in this patch unless there is something unique to the code path, so if you don't see me comment about a use of audit_alloc_for_lsm() you can assume it should be removed and the existing audit_context used instead. > @@ -399,6 +401,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old, > allow_changes = 0; /* Something weird, deny request */ > audit_log_format(ab, " res=%d", allow_changes); > audit_log_end(ab); > + audit_free_local(context); See my comment directly above regarding usage of audit_alloc_for_lsm(), it obviously applies here too. > @@ -2128,6 +2136,36 @@ void audit_log_key(struct audit_buffer *ab, char *key) > audit_log_format(ab, "(null)"); > } > > +static void audit_log_lsm(struct audit_context *context, struct lsmblob *blob) See my note below about moving this into audit_log_task_context(), but if we really need to keep this as a separate function, let's consider changing the name to something which indicates that it logs the LSM data as *subject* fields. How about audit_log_lsm_subj()? > +{ > + struct audit_buffer *ab; > + struct lsmcontext lsmdata; > + bool sep = false; > + int error; > + int i; > + > + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS); > + if (!ab) > + return; /* audit_panic or being filtered */ > + > + for (i = 0; i < LSMBLOB_ENTRIES; i++) { > + if (blob->secid[i] == 0) > + continue; > + error = security_secid_to_secctx(blob, &lsmdata, i); > + if (error && error != -EINVAL) { > + audit_panic("error in audit_log_lsm"); > + return; > + } > + > + audit_log_format(ab, "%ssubj_%s=\"%s\"", sep ? " " : "", > + lsm_slot_to_name(i), lsmdata.context); > + sep = true; Since @i starts at zero, you can get rid of @sep by replacing it with @i: audit_log_format(ab, ..., (i ? " " : ""), ...); > + security_release_secctx(&lsmdata); > + } > + audit_log_end(ab); > +} > @@ -2138,7 +2176,18 @@ int audit_log_task_context(struct audit_buffer *ab) > if (!lsmblob_is_set(&blob)) > return 0; > > - error = security_secid_to_secctx(&blob, &context); > + /* > + * If there is more than one security module that has a > + * subject "context" it's necessary to put the subject data > + * into a separate record to maintain compatibility. > + */ > + if (lsm_multiple_contexts()) { > + audit_log_format(ab, " subj=?"); > + audit_log_lsm(ab->ctx, &blob); > + return 0; > + } > + > + error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST); Instead of the lsm_multiple_contexts() case bailing on the rest of the function with a return inside the if-block, let's made the code a bit more robust by organizing it like this: int audit_log_task_context(ab) { /* common stuff at the start */ if (lsm_multiple_contexts()) { /* multi-LSM stuff */ } else { /* single LSM stuff */ } /* common stuff at the end */ } ... it also may make sense to just move the body of audit_log_lsm() into audit_log_task_context() and do away with audit_log_lsm() entirely; is it ever going to be called from anywhere else? > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 0e58a3ab56f5..01fdcbf468c0 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -993,12 +993,11 @@ struct audit_context *audit_alloc_local(gfp_t gfpflags) > context = audit_alloc_context(AUDIT_STATE_BUILD, gfpflags); > if (!context) { > audit_log_lost("out of memory in audit_alloc_local"); > - goto out; > + return NULL; > } > context->serial = audit_serial(); > ktime_get_coarse_real_ts64(&context->ctime); > context->local = true; > -out: > return context; > } This chunk should be moved to 21/25 when audit_alloc_local() is first defined. > @@ -1019,6 +1018,13 @@ void audit_free_context(struct audit_context *context) > } > EXPORT_SYMBOL(audit_free_context); > > +void audit_free_local(struct audit_context *context) > +{ > + if (context && context->local) > + audit_free_context(context); > +} > +EXPORT_SYMBOL(audit_free_local); If this is strictly necessary, and I don't think it is, it should also be moved to patch 21/25 with the original definition of a local audit_context. However, there really should be no reason why we have to distinguish between a proper and local audtit_context when it comes to free'ing the memory, just call audit_free_context() in both cases. > @@ -1036,7 +1042,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, > from_kuid(&init_user_ns, auid), > from_kuid(&init_user_ns, uid), sessionid); > if (lsmblob_is_set(blob)) { > - if (security_secid_to_secctx(blob, &lsmctx)) { > + if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) { Misplaced code change? Actually, there are a lot of these below, I'm not going to comment on all of them as I think you get the idea ... and I very well may be wrong so I'll save you all of my wrongness in that case :) > diff --git a/security/security.c b/security/security.c > index cb359e185d1a..5d7fd982f84a 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2309,7 +2309,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, > hlist_for_each_entry(hp, &security_hook_heads.setprocattr, > list) { > rc = hp->hook.setprocattr(name, value, size); > - if (rc < 0) > + if (rc < 0 && rc != -EINVAL) > return rc; > } This really looks misplaced ... ?
On 8/12/2021 1:59 PM, Paul Moore wrote: > On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >> Create a new audit record type to contain the subject information >> when there are multiple security modules that require such data. >> This record is linked with the same timestamp and serial number >> using the audit_alloc_local() mechanism. >> The record is produced only in cases where there is more than one >> security module with a process "context". >> In cases where this record is produced the subj= fields of >> other records in the audit event will be set to "subj=?". >> >> An example of the MAC_TASK_CONTEXTS (1420) record is: >> >> type=UNKNOWN[1420] >> msg=audit(1600880931.832:113) >> subj_apparmor="=unconfined" >> subj_smack="_" >> >> There will be a subj_$LSM= entry for each security module >> LSM that supports the secid_to_secctx and secctx_to_secid >> hooks. The BPF security module implements secid/secctx >> translation hooks, so it has to be considered to provide a >> secctx even though it may not actually do so. >> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> >> To: paul@paul-moore.com >> To: linux-audit@redhat.com >> To: rgb@redhat.com >> Cc: netdev@vger.kernel.org >> --- >> drivers/android/binder.c | 2 +- >> include/linux/audit.h | 16 +++++ >> include/linux/security.h | 16 ++++- >> include/net/netlabel.h | 2 +- >> include/net/scm.h | 2 +- >> include/net/xfrm.h | 13 +++- >> include/uapi/linux/audit.h | 1 + >> kernel/audit.c | 90 +++++++++++++++++++------ >> kernel/auditfilter.c | 5 +- >> kernel/auditsc.c | 27 ++++++-- >> net/ipv4/ip_sockglue.c | 2 +- >> net/netfilter/nf_conntrack_netlink.c | 4 +- >> net/netfilter/nf_conntrack_standalone.c | 2 +- >> net/netfilter/nfnetlink_queue.c | 2 +- >> net/netlabel/netlabel_unlabeled.c | 21 +++--- >> net/netlabel/netlabel_user.c | 14 ++-- >> net/netlabel/netlabel_user.h | 6 +- >> net/xfrm/xfrm_policy.c | 8 ++- >> net/xfrm/xfrm_state.c | 18 +++-- >> security/integrity/ima/ima_api.c | 6 +- >> security/integrity/integrity_audit.c | 5 +- >> security/security.c | 46 ++++++++----- >> security/smack/smackfs.c | 3 +- >> 23 files changed, 221 insertions(+), 90 deletions(-) >> >> diff --git a/drivers/android/binder.c b/drivers/android/binder.c >> index 2c3a2348a144..3520caa0260c 100644 >> --- a/drivers/android/binder.c >> +++ b/drivers/android/binder.c >> @@ -2722,7 +2722,7 @@ static void binder_transaction(struct binder_proc *proc, >> * case well anyway. >> */ >> security_task_getsecid_obj(proc->tsk, &blob); >> - ret = security_secid_to_secctx(&blob, &lsmctx); >> + ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY); >> if (ret) { >> return_error = BR_FAILED_REPLY; >> return_error_param = ret; >> diff --git a/include/linux/audit.h b/include/linux/audit.h >> index 97cd7471e572..85eb87f6f92d 100644 >> --- a/include/linux/audit.h >> +++ b/include/linux/audit.h >> @@ -291,6 +291,7 @@ extern int audit_alloc(struct task_struct *task); >> extern void __audit_free(struct task_struct *task); >> extern struct audit_context *audit_alloc_local(gfp_t gfpflags); >> extern void audit_free_context(struct audit_context *context); >> +extern void audit_free_local(struct audit_context *context); >> extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, >> unsigned long a2, unsigned long a3); >> extern void __audit_syscall_exit(int ret_success, long ret_value); >> @@ -386,6 +387,19 @@ static inline void audit_ptrace(struct task_struct *t) >> __audit_ptrace(t); >> } >> >> +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp) >> +{ >> + struct audit_context *context = audit_context(); >> + >> + if (context) >> + return context; >> + >> + if (lsm_multiple_contexts()) >> + return audit_alloc_local(gfp); >> + >> + return NULL; >> +} > We don't want to do this, at least not as it is written above. We > shouldn't have a function which abstracts away the creation of a local > audit_context. Usage of a local audit_context should be explicit in > the caller, and if the caller's execution context is ambiguous enough > that it can require both a task_struct audit_context and a local > audit_context then we need to handle that on a case-by-case basis. > Hiding it like this is guaranteed to cause problems later. OK. Please understand that *every case* where I've used audit_alloc_for_lsm() is a case where I have *verified* that context may be NULL. I will make the change. > I probably did a poor job of explaining what a local context is during > the last patchset; I'll try to do a better job here but also let me > say this as clear as I can ... if the "current" task struct is valid > for a given code path, *never* use a local audit context. I probably did a poor job of demonstrating that I never use a local context where there's a valid current context. > The local > audit context is a hack that is made necessary by the fact that we > have to audit things which happen outside the scope of an executing > task, e.g. the netfilter audit hooks, it should *never* be used when > there is a valid task_struct. In the existing audit code a "current context" is only needed for syscall events, so that's the only case where it's allocated. Would you suggest that I track down the non-syscall events that include subj= fields and add allocate a "current context" for them? I looked into doing that, and it wouldn't be simple. > It's the audit_context which helps bind multiple audit records into a > single event, creating a new, "local" audit_context destroys that > binding ... if there's a current context. There often isn't. That's why I'm using a local context. There is not a "current" context available. > as audit records created using that local audit_context have a > different timestamp from those records created using the current > task_struct's audit_context. (Weeps) I only introduce a local context where there is no current context available, so this is never a problem. > Hopefully that makes sense? Yes, it makes sense. Methinks you may believe that the current context is available more regularly than it actually is. I instrumented the audit event functions with: WARN_ONCE(audit_context, "%s has context\n", __func__); WARN_ONCE(!audit_context, "%s lacks context\n", __func__); I only used local contexts where the 2nd WARN_ONCE was hit. >> /* Private API (for audit.c only) */ >> extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); >> extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); >> @@ -560,6 +574,8 @@ extern int audit_signals; >> } >> static inline void audit_free_context(struct audit_context *context) >> { } >> +static inline void audit_free_local(struct audit_context *context) >> +{ } >> static inline int audit_alloc(struct task_struct *task) >> { >> return 0; >> diff --git a/include/linux/security.h b/include/linux/security.h >> index 3e9743118fb9..b3cf68cf2bd6 100644 >> --- a/include/linux/security.h >> +++ b/include/linux/security.h >> @@ -182,6 +182,8 @@ struct lsmblob { >> #define LSMBLOB_INVALID -1 /* Not a valid LSM slot number */ >> #define LSMBLOB_NEEDED -2 /* Slot requested on initialization */ >> #define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */ >> +#define LSMBLOB_DISPLAY -4 /* Use the "display" slot */ >> +#define LSMBLOB_FIRST -5 /* Use the default "display" slot */ >> >> /** >> * lsmblob_init - initialize an lsmblob structure >> @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob) >> return 0; >> } >> >> +static inline bool lsm_multiple_contexts(void) >> +{ >> +#ifdef CONFIG_SECURITY >> + return lsm_slot_to_name(1) != NULL; >> +#else >> + return false; >> +#endif >> +} >> + >> /* These functions are in security/commoncap.c */ >> extern int cap_capable(const struct cred *cred, struct user_namespace *ns, >> int cap, unsigned int opts); >> @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value, >> size_t size); >> int security_netlink_send(struct sock *sk, struct sk_buff *skb); >> int security_ismaclabel(const char *name); >> -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp); >> +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp, >> + int display); >> int security_secctx_to_secid(const char *secdata, u32 seclen, >> struct lsmblob *blob); >> void security_release_secctx(struct lsmcontext *cp); >> @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name) >> } >> >> static inline int security_secid_to_secctx(struct lsmblob *blob, >> - struct lsmcontext *cp) >> + struct lsmcontext *cp, int display) >> { >> return -EOPNOTSUPP; >> } >> diff --git a/include/net/netlabel.h b/include/net/netlabel.h >> index 73fc25b4042b..216cb1ffc8f0 100644 >> --- a/include/net/netlabel.h >> +++ b/include/net/netlabel.h >> @@ -97,7 +97,7 @@ struct calipso_doi; >> >> /* NetLabel audit information */ >> struct netlbl_audit { >> - u32 secid; >> + struct lsmblob lsmdata; >> kuid_t loginuid; >> unsigned int sessionid; >> }; > This chunk seems lost here, does it belong in another patch? Probably. I am getting a touch of patch-rot showing up. >> diff --git a/include/net/scm.h b/include/net/scm.h >> index b77a52f93389..f4d567d4885e 100644 >> --- a/include/net/scm.h >> +++ b/include/net/scm.h >> @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc >> * and the infrastructure will know which it is. >> */ >> lsmblob_init(&lb, scm->secid); >> - err = security_secid_to_secctx(&lb, &context); >> + err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY); > Misplaced code change? Same here. >> if (!err) { >> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len, >> diff --git a/include/net/xfrm.h b/include/net/xfrm.h >> index cbff7c2a9724..a10fa01f7bf4 100644 >> --- a/include/net/xfrm.h >> +++ b/include/net/xfrm.h >> @@ -660,13 +660,22 @@ struct xfrm_spi_skb_cb { >> #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0])) >> >> #ifdef CONFIG_AUDITSYSCALL >> -static inline struct audit_buffer *xfrm_audit_start(const char *op) >> +static inline struct audit_buffer *xfrm_audit_start(const char *op, >> + struct audit_context **lac) >> { >> + struct audit_context *context; >> struct audit_buffer *audit_buf = NULL; >> >> if (audit_enabled == AUDIT_OFF) >> return NULL; >> - audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, >> + context = audit_context(); >> + if (lac != NULL) { >> + if (lsm_multiple_contexts() && context == NULL) >> + context = audit_alloc_local(GFP_ATOMIC); >> + *lac = context; >> + } >> + >> + audit_buf = audit_log_start(context, GFP_ATOMIC, >> AUDIT_MAC_IPSEC_EVENT); >> if (audit_buf == NULL) >> return NULL; > Related to the other comments around local audit_contexts, we don't > want to do this; use the existing audit_context, @lac in this case, so > that this audit record is bound to the other associated records into a > single audit event (all have the same timestamp). Hmm. This is clearly a problem. Looks like a change came in that I didn't see. >> diff --git a/kernel/audit.c b/kernel/audit.c >> index 841123390d41..cba63789a164 100644 >> --- a/kernel/audit.c >> +++ b/kernel/audit.c >> @@ -386,10 +386,12 @@ void audit_log_lost(const char *message) >> static int audit_log_config_change(char *function_name, u32 new, u32 old, >> int allow_changes) >> { >> + struct audit_context *context; >> struct audit_buffer *ab; >> int rc = 0; >> >> - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); >> + context = audit_alloc_for_lsm(GFP_KERNEL); >> + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE); > We shouldn't need to do this for the reasons discussed up near the top > of this email (and elsewhere as well). Here and elsewhere, I only put audit_alloc_for_lsm() in because there are cases where audit_context() returns NULL. Really. > > I'm going to refrain from commenting on the other uses of > audit_alloc_for_lsm() in this patch unless there is something unique > to the code path, so if you don't see me comment about a use of > audit_alloc_for_lsm() you can assume it should be removed and the > existing audit_context used instead. > >> @@ -399,6 +401,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old, >> allow_changes = 0; /* Something weird, deny request */ >> audit_log_format(ab, " res=%d", allow_changes); >> audit_log_end(ab); >> + audit_free_local(context); > See my comment directly above regarding usage of > audit_alloc_for_lsm(), it obviously applies here too. > >> @@ -2128,6 +2136,36 @@ void audit_log_key(struct audit_buffer *ab, char *key) >> audit_log_format(ab, "(null)"); >> } >> >> +static void audit_log_lsm(struct audit_context *context, struct lsmblob *blob) > See my note below about moving this into audit_log_task_context(), Either works for me. This seemed consistent with the rest of the audit code, but I'm happy to change it if you like that better. > but > if we really need to keep this as a separate function, let's consider > changing the name to something which indicates that it logs the LSM > data as *subject* fields. How about audit_log_lsm_subj()? > >> +{ >> + struct audit_buffer *ab; >> + struct lsmcontext lsmdata; >> + bool sep = false; >> + int error; >> + int i; >> + >> + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS); >> + if (!ab) >> + return; /* audit_panic or being filtered */ >> + >> + for (i = 0; i < LSMBLOB_ENTRIES; i++) { >> + if (blob->secid[i] == 0) >> + continue; >> + error = security_secid_to_secctx(blob, &lsmdata, i); >> + if (error && error != -EINVAL) { >> + audit_panic("error in audit_log_lsm"); >> + return; >> + } >> + >> + audit_log_format(ab, "%ssubj_%s=\"%s\"", sep ? " " : "", >> + lsm_slot_to_name(i), lsmdata.context); >> + sep = true; > Since @i starts at zero, you can get rid of @sep by replacing it with @i: > > audit_log_format(ab, ..., (i ? " " : ""), ...); Clever. > >> + security_release_secctx(&lsmdata); >> + } >> + audit_log_end(ab); >> +} >> @@ -2138,7 +2176,18 @@ int audit_log_task_context(struct audit_buffer *ab) >> if (!lsmblob_is_set(&blob)) >> return 0; >> >> - error = security_secid_to_secctx(&blob, &context); >> + /* >> + * If there is more than one security module that has a >> + * subject "context" it's necessary to put the subject data >> + * into a separate record to maintain compatibility. >> + */ >> + if (lsm_multiple_contexts()) { >> + audit_log_format(ab, " subj=?"); >> + audit_log_lsm(ab->ctx, &blob); >> + return 0; >> + } >> + >> + error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST); > Instead of the lsm_multiple_contexts() case bailing on the rest of the > function with a return inside the if-block, let's made the code a bit > more robust by organizing it like this: Sure, why not? > > int audit_log_task_context(ab) > { > /* common stuff at the start */ > > if (lsm_multiple_contexts()) { > /* multi-LSM stuff */ > } else { > /* single LSM stuff */ > } > > /* common stuff at the end */ > } > > ... it also may make sense to just move the body of audit_log_lsm() > into audit_log_task_context() and do away with audit_log_lsm() > entirely; is it ever going to be called from anywhere else? > >> diff --git a/kernel/auditsc.c b/kernel/auditsc.c >> index 0e58a3ab56f5..01fdcbf468c0 100644 >> --- a/kernel/auditsc.c >> +++ b/kernel/auditsc.c >> @@ -993,12 +993,11 @@ struct audit_context *audit_alloc_local(gfp_t gfpflags) >> context = audit_alloc_context(AUDIT_STATE_BUILD, gfpflags); >> if (!context) { >> audit_log_lost("out of memory in audit_alloc_local"); >> - goto out; >> + return NULL; >> } >> context->serial = audit_serial(); >> ktime_get_coarse_real_ts64(&context->ctime); >> context->local = true; >> -out: >> return context; >> } > This chunk should be moved to 21/25 when audit_alloc_local() is first defined. True. I was trying to minimize the change to the original audit_alloc_local() patch on the assumption that it was coming in for other reasons, but that hasn't happened. >> @@ -1019,6 +1018,13 @@ void audit_free_context(struct audit_context *context) >> } >> EXPORT_SYMBOL(audit_free_context); >> >> +void audit_free_local(struct audit_context *context) >> +{ >> + if (context && context->local) >> + audit_free_context(context); >> +} >> +EXPORT_SYMBOL(audit_free_local); > If this is strictly necessary, and I don't think it is, it should also > be moved to patch 21/25 with the original definition of a local > audit_context. However, there really should be no reason why we have > to distinguish between a proper and local audtit_context when it comes > to free'ing the memory, just call audit_free_context() in both cases. > >> @@ -1036,7 +1042,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, >> from_kuid(&init_user_ns, auid), >> from_kuid(&init_user_ns, uid), sessionid); >> if (lsmblob_is_set(blob)) { >> - if (security_secid_to_secctx(blob, &lsmctx)) { >> + if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) { > Misplaced code change? > > Actually, there are a lot of these below, I'm not going to comment on > all of them as I think you get the idea ... and I very well may be > wrong so I'll save you all of my wrongness in that case :) > >> diff --git a/security/security.c b/security/security.c >> index cb359e185d1a..5d7fd982f84a 100644 >> --- a/security/security.c >> +++ b/security/security.c >> @@ -2309,7 +2309,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, >> hlist_for_each_entry(hp, &security_hook_heads.setprocattr, >> list) { >> rc = hp->hook.setprocattr(name, value, size); >> - if (rc < 0) >> + if (rc < 0 && rc != -EINVAL) >> return rc; >> } > This really looks misplaced ... ? Yeah, you're not the first person to notice these bits of patch-rot. I have some clean-up to do. Thank you for the review.
On Thu, Aug 12, 2021 at 6:38 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > On 8/12/2021 1:59 PM, Paul Moore wrote: > > On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >> Create a new audit record type to contain the subject information > >> when there are multiple security modules that require such data. ... > > The local > > audit context is a hack that is made necessary by the fact that we > > have to audit things which happen outside the scope of an executing > > task, e.g. the netfilter audit hooks, it should *never* be used when > > there is a valid task_struct. > > In the existing audit code a "current context" is only needed for > syscall events, so that's the only case where it's allocated. Would > you suggest that I track down the non-syscall events that include > subj= fields and add allocate a "current context" for them? I looked > into doing that, and it wouldn't be simple. This is why the "local context" was created. Prior to these stacking additions, and the audit container ID work, we never needed to group multiple audit records outside of a syscall context into a single audit event so passing a NULL context into audit_log_start() was reasonable. The local context was designed as a way to generate a context for use in a local function scope to group multiple records, however, for reasons I'll get to below I'm now wondering if the local context approach is really workable ... > > Hopefully that makes sense? > > Yes, it makes sense. Methinks you may believe that the current context > is available more regularly than it actually is. > > I instrumented the audit event functions with: > > WARN_ONCE(audit_context, "%s has context\n", __func__); > WARN_ONCE(!audit_context, "%s lacks context\n", __func__); > > I only used local contexts where the 2nd WARN_ONCE was hit. What does your audit config look like? Both the kernel command line and the output of 'auditctl -l' would be helpful. I'm beginning to suspect that you have the default we-build-audit-into-the-kernel-because-product-management-said-we-have-to-but-we-don't-actually-enable-it-at-runtime audit configuration that is de rigueur for many distros these days. If that is the case, there are many cases where you would not see a NULL current->audit_context simply because the config never allocated one, see kernel/auditsc.c:audit_alloc(). If that is the case, I'm honestly a little surprised we didn't realize that earlier, especially given all the work/testing that Richard has done with the audit container ID bits, but then again he surely had a proper audit config during his testing so it wouldn't have appeared. Good times. Regardless, assuming that is the case we probably need to find an alternative to the local context approach as it currently works. For reasons we already talked about, we don't want to use a local audit_context if there is the possibility for a proper current->audit_context, but we need to do *something* so that we can group these multiple events into a single record. Since this is just occurring to me now I need a bit more time to think on possible solutions - all good ideas are welcome - but the first thing that pops into my head is that we need to augment audit_log_end() to potentially generated additional, associated records similar to what we do on syscall exit in audit_log_exit(). Of course the audit_log_end() changes would be much more limited than audit_log_exit(), just the LSM subject and audit container ID info, and even then we might want to limit that to cases where the ab->ctx value is NULL and let audit_log_exit() handle it otherwise. We may need to store the event type in the audit_buffer during audit_log_start() so that we can later use that in audit_log_end() to determine what additional records are needed. Regardless, let's figure out why all your current->audit_context values are NULL first (report back on your audit config please), I may be worrying about a hypothetical that isn't real.
On 8/13/2021 8:31 AM, Paul Moore wrote: > On Thu, Aug 12, 2021 at 6:38 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >> On 8/12/2021 1:59 PM, Paul Moore wrote: >>> On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >>>> Create a new audit record type to contain the subject information >>>> when there are multiple security modules that require such data. > ... > >>> The local >>> audit context is a hack that is made necessary by the fact that we >>> have to audit things which happen outside the scope of an executing >>> task, e.g. the netfilter audit hooks, it should *never* be used when >>> there is a valid task_struct. >> In the existing audit code a "current context" is only needed for >> syscall events, so that's the only case where it's allocated. Would >> you suggest that I track down the non-syscall events that include >> subj= fields and add allocate a "current context" for them? I looked >> into doing that, and it wouldn't be simple. > This is why the "local context" was created. Prior to these stacking > additions, and the audit container ID work, we never needed to group > multiple audit records outside of a syscall context into a single > audit event so passing a NULL context into audit_log_start() was > reasonable. The local context was designed as a way to generate a > context for use in a local function scope to group multiple records, > however, for reasons I'll get to below I'm now wondering if the local > context approach is really workable ... I haven't found a place where it didn't work. What is the concern? >>> Hopefully that makes sense? >> Yes, it makes sense. Methinks you may believe that the current context >> is available more regularly than it actually is. >> >> I instrumented the audit event functions with: >> >> WARN_ONCE(audit_context, "%s has context\n", __func__); >> WARN_ONCE(!audit_context, "%s lacks context\n", __func__); >> >> I only used local contexts where the 2nd WARN_ONCE was hit. > What does your audit config look like? Both the kernel command line > and the output of 'auditctl -l' would be helpful. On the fedora system: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.14.0-rc5stack+ root=/dev/mapper/fedora-root ro resume=/dev/mapper/fedora-swap rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap lsm.debug -a always,exit -F arch=b64 -S bpf -F key=testsuite-1628714321-EtlWIphW On the Ubuntu system: BOOT_IMAGE=/boot/vmlinuz-5.14.0-rc1stack+ root=UUID=39c25777-d413-4c2e-948c-dfa2bf259049 ro lsm.debug No rules > I'm beginning to suspect that you have the default > we-build-audit-into-the-kernel-because-product-management-said-we-have-to-but-we-don't-actually-enable-it-at-runtime > audit configuration that is de rigueur for many distros these days. Yes, but I've also fiddled about with it so as to get better event coverage. I've run the audit-testsuite, which has got to fiddle about with the audit configuration. > If that is the case, there are many cases where you would not see a > NULL current->audit_context simply because the config never allocated > one, see kernel/auditsc.c:audit_alloc(). I assume you mean that I *would* see a NULL current->audit_context in the "event not enabled" case. Â > If that is the case, I'm > honestly a little surprised we didn't realize that earlier, especially > given all the work/testing that Richard has done with the audit > container ID bits, but then again he surely had a proper audit config > during his testing so it wouldn't have appeared. > > Good times. Indeed. > Regardless, assuming that is the case we probably need to find an > alternative to the local context approach as it currently works. For > reasons we already talked about, we don't want to use a local > audit_context if there is the possibility for a proper > current->audit_context, but we need to do *something* so that we can > group these multiple events into a single record. I tried a couple things, but neither was satisfactory. > Since this is just occurring to me now I need a bit more time to think > on possible solutions - all good ideas are welcome - but the first > thing that pops into my head is that we need to augment > audit_log_end() to potentially generated additional, associated > records similar to what we do on syscall exit in audit_log_exit(). I looked into that. You need a place to save the timestamp that doesn't disappear. That's the role the audit_context plays now. > Of > course the audit_log_end() changes would be much more limited than > audit_log_exit(), just the LSM subject and audit container ID info, > and even then we might want to limit that to cases where the ab->ctx > value is NULL and let audit_log_exit() handle it otherwise. We may > need to store the event type in the audit_buffer during > audit_log_start() so that we can later use that in audit_log_end() to > determine what additional records are needed. > > Regardless, let's figure out why all your current->audit_context > values are NULL That's what's maddening, and why I implemented audit_alloc_for_lsm(). They aren't all NULL. Sometimes current->audit_context is NULL, sometimes it isn't, for the same event. I thought it might be a question of the netlink interface being treated specially, but that doesn't explain all the cases. > first (report back on your audit config please), I may > be worrying about a hypothetical that isn't real. >
On Fri, Aug 13, 2021 at 2:48 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > On 8/13/2021 8:31 AM, Paul Moore wrote: > > On Thu, Aug 12, 2021 at 6:38 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >> On 8/12/2021 1:59 PM, Paul Moore wrote: > >>> On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >>>> Create a new audit record type to contain the subject information > >>>> when there are multiple security modules that require such data. > > ... > > > >>> The local > >>> audit context is a hack that is made necessary by the fact that we > >>> have to audit things which happen outside the scope of an executing > >>> task, e.g. the netfilter audit hooks, it should *never* be used when > >>> there is a valid task_struct. > >> In the existing audit code a "current context" is only needed for > >> syscall events, so that's the only case where it's allocated. Would > >> you suggest that I track down the non-syscall events that include > >> subj= fields and add allocate a "current context" for them? I looked > >> into doing that, and it wouldn't be simple. > > > > This is why the "local context" was created. Prior to these stacking > > additions, and the audit container ID work, we never needed to group > > multiple audit records outside of a syscall context into a single > > audit event so passing a NULL context into audit_log_start() was > > reasonable. The local context was designed as a way to generate a > > context for use in a local function scope to group multiple records, > > however, for reasons I'll get to below I'm now wondering if the local > > context approach is really workable ... > > I haven't found a place where it didn't work. What is the concern? The concern is that use of a local context can destroy any hopes of linking with other related records, e.g. SYSCALL and PATH records, to form a single cohesive event. If the current task_struct is valid for a given function invocation then we *really* should be using current's audit_context. However, based on our discussion here it would seem that we may have some issues where current->audit_context is not being managed correctly. I'm not surprised, but I will admit to being disappointed. > > What does your audit config look like? Both the kernel command line > > and the output of 'auditctl -l' would be helpful. > > On the fedora system: > > BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.14.0-rc5stack+ > root=/dev/mapper/fedora-root ro resume=/dev/mapper/fedora-swap > rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap lsm.debug > > -a always,exit -F arch=b64 -S bpf -F key=testsuite-1628714321-EtlWIphW > > On the Ubuntu system: > > BOOT_IMAGE=/boot/vmlinuz-5.14.0-rc1stack+ > root=UUID=39c25777-d413-4c2e-948c-dfa2bf259049 ro lsm.debug > > No rules The Fedora system looks to have some audit-testsuite leftovers, but that shouldn't have an impact on what we are discussing; in both cases I would expect current->audit_context to be allocated and non-NULL. > > I'm beginning to suspect that you have the default > > we-build-audit-into-the-kernel-because-product-management-said-we-have-to-but-we-don't-actually-enable-it-at-runtime > > audit configuration that is de rigueur for many distros these days. > > Yes, but I've also fiddled about with it so as to get better event coverage. > I've run the audit-testsuite, which has got to fiddle about with the audit > configuration. Yes, it looks like my hunch was wrong. > > If that is the case, there are many cases where you would not see a > > NULL current->audit_context simply because the config never allocated > > one, see kernel/auditsc.c:audit_alloc(). > > I assume you mean that I *would* see a NULL current->audit_context > in the "event not enabled" case. Yep, typo. > > Regardless, assuming that is the case we probably need to find an > > alternative to the local context approach as it currently works. For > > reasons we already talked about, we don't want to use a local > > audit_context if there is the possibility for a proper > > current->audit_context, but we need to do *something* so that we can > > group these multiple events into a single record. > > I tried a couple things, but neither was satisfactory. > > > Since this is just occurring to me now I need a bit more time to think > > on possible solutions - all good ideas are welcome - but the first > > thing that pops into my head is that we need to augment > > audit_log_end() to potentially generated additional, associated > > records similar to what we do on syscall exit in audit_log_exit(). > > I looked into that. You need a place to save the timestamp > that doesn't disappear. That's the role the audit_context plays > now. Yes, I've spent a few hours staring at the poorly planned struct that is audit_context ;) Regardless, the obvious place for such a thing is audit_buffer; we can stash whatever we need in there. > > Of > > course the audit_log_end() changes would be much more limited than > > audit_log_exit(), just the LSM subject and audit container ID info, > > and even then we might want to limit that to cases where the ab->ctx > > value is NULL and let audit_log_exit() handle it otherwise. We may > > need to store the event type in the audit_buffer during > > audit_log_start() so that we can later use that in audit_log_end() to > > determine what additional records are needed. > > > > Regardless, let's figure out why all your current->audit_context > > values are NULL > > That's what's maddening, and why I implemented audit_alloc_for_lsm(). > They aren't all NULL. Sometimes current->audit_context is NULL, > sometimes it isn't, for the same event. I thought it might be a > question of the netlink interface being treated specially, but > that doesn't explain all the cases. Your netlink changes are exactly what made me think, "this is obviously wrong", but now I'm wondering if a previously held assumption of "current is valid and points to the calling process" in the case of the kernel servicing netlink messages sent from userspace. Or rather, perhaps that assumption is still true but something is causing current->audit_context to be NULL in that case. Friday the 13th indeed.
On 8/13/2021 1:43 PM, Paul Moore wrote: > On Fri, Aug 13, 2021 at 2:48 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >> On 8/13/2021 8:31 AM, Paul Moore wrote: >>> On Thu, Aug 12, 2021 at 6:38 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >>>> On 8/12/2021 1:59 PM, Paul Moore wrote: >>>>> On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: >>>>>> Create a new audit record type to contain the subject information >>>>>> when there are multiple security modules that require such data. >>> ... >>> >>>>> The local >>>>> audit context is a hack that is made necessary by the fact that we >>>>> have to audit things which happen outside the scope of an executing >>>>> task, e.g. the netfilter audit hooks, it should *never* be used when >>>>> there is a valid task_struct. >>>> In the existing audit code a "current context" is only needed for >>>> syscall events, so that's the only case where it's allocated. Would >>>> you suggest that I track down the non-syscall events that include >>>> subj= fields and add allocate a "current context" for them? I looked >>>> into doing that, and it wouldn't be simple. >>> This is why the "local context" was created. Prior to these stacking >>> additions, and the audit container ID work, we never needed to group >>> multiple audit records outside of a syscall context into a single >>> audit event so passing a NULL context into audit_log_start() was >>> reasonable. The local context was designed as a way to generate a >>> context for use in a local function scope to group multiple records, >>> however, for reasons I'll get to below I'm now wondering if the local >>> context approach is really workable ... >> I haven't found a place where it didn't work. What is the concern? > The concern is that use of a local context can destroy any hopes of > linking with other related records, e.g. SYSCALL and PATH records, to > form a single cohesive event. If the current task_struct is valid for > a given function invocation then we *really* should be using current's > audit_context. > > However, based on our discussion here it would seem that we may have > some issues where current->audit_context is not being managed > correctly. I'm not surprised, but I will admit to being disappointed. I'd believe that with syscall audit being a special case for other reasons the multiple record situation got taken care of on a case-by-case basis and no one really paid much attention to generality. It's understandable. >>> What does your audit config look like? Both the kernel command line >>> and the output of 'auditctl -l' would be helpful. >> On the fedora system: >> >> BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.14.0-rc5stack+ >> root=/dev/mapper/fedora-root ro resume=/dev/mapper/fedora-swap >> rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap lsm.debug >> >> -a always,exit -F arch=b64 -S bpf -F key=testsuite-1628714321-EtlWIphW >> >> On the Ubuntu system: >> >> BOOT_IMAGE=/boot/vmlinuz-5.14.0-rc1stack+ >> root=UUID=39c25777-d413-4c2e-948c-dfa2bf259049 ro lsm.debug >> >> No rules > The Fedora system looks to have some audit-testsuite leftovers, but > that shouldn't have an impact on what we are discussing; in both cases > I would expect current->audit_context to be allocated and non-NULL. As would I. >>> I'm beginning to suspect that you have the default >>> we-build-audit-into-the-kernel-because-product-management-said-we-have-to-but-we-don't-actually-enable-it-at-runtime >>> audit configuration that is de rigueur for many distros these days. >> Yes, but I've also fiddled about with it so as to get better event coverage. >> I've run the audit-testsuite, which has got to fiddle about with the audit >> configuration. > Yes, it looks like my hunch was wrong. > >>> If that is the case, there are many cases where you would not see a >>> NULL current->audit_context simply because the config never allocated >>> one, see kernel/auditsc.c:audit_alloc(). >> I assume you mean that I *would* see a NULL current->audit_context >> in the "event not enabled" case. > Yep, typo. > >>> Regardless, assuming that is the case we probably need to find an >>> alternative to the local context approach as it currently works. For >>> reasons we already talked about, we don't want to use a local >>> audit_context if there is the possibility for a proper >>> current->audit_context, but we need to do *something* so that we can >>> group these multiple events into a single record. >> I tried a couple things, but neither was satisfactory. >> >>> Since this is just occurring to me now I need a bit more time to think >>> on possible solutions - all good ideas are welcome - but the first >>> thing that pops into my head is that we need to augment >>> audit_log_end() to potentially generated additional, associated >>> records similar to what we do on syscall exit in audit_log_exit(). >> I looked into that. You need a place to save the timestamp >> that doesn't disappear. That's the role the audit_context plays >> now. > Yes, I've spent a few hours staring at the poorly planned struct that > is audit_context ;) > > Regardless, the obvious place for such a thing is audit_buffer; we can > stash whatever we need in there. I had considered doing that, but was afraid that moving the timestamp out of the audit_context might have dire consequences. >>> Of >>> course the audit_log_end() changes would be much more limited than >>> audit_log_exit(), just the LSM subject and audit container ID info, >>> and even then we might want to limit that to cases where the ab->ctx >>> value is NULL and let audit_log_exit() handle it otherwise. We may >>> need to store the event type in the audit_buffer during >>> audit_log_start() so that we can later use that in audit_log_end() to >>> determine what additional records are needed. >>> >>> Regardless, let's figure out why all your current->audit_context >>> values are NULL >> That's what's maddening, and why I implemented audit_alloc_for_lsm(). >> They aren't all NULL. Sometimes current->audit_context is NULL, >> sometimes it isn't, for the same event. I thought it might be a >> question of the netlink interface being treated specially, but >> that doesn't explain all the cases. > Your netlink changes are exactly what made me think, "this is > obviously wrong", but now I'm wondering if a previously held > assumption of "current is valid and points to the calling process" in > the case of the kernel servicing netlink messages sent from userspace. If that's the case the subject data in the audit record is going to be bogus. From what I've seen that data appears to be correct. > Or rather, perhaps that assumption is still true but something is > causing current->audit_context to be NULL in that case. I can imagine someone deciding not to set up audit_context in situations like netlink because they knew that nothing following that would be a syscall event. I've been looking into the audit userspace and there are assumptions like that all over the place. > Friday the 13th indeed. I've been banging my head against this for a couple months. My biggest fear is that I may have learned enough about the audit system to make useful contributions.
On Fri, Aug 13, 2021 at 5:47 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > On 8/13/2021 1:43 PM, Paul Moore wrote: > > On Fri, Aug 13, 2021 at 2:48 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >> On 8/13/2021 8:31 AM, Paul Moore wrote: > >>> On Thu, Aug 12, 2021 at 6:38 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >>>> On 8/12/2021 1:59 PM, Paul Moore wrote: > >>>>> On Wed, Jul 21, 2021 at 9:12 PM Casey Schaufler <casey@schaufler-ca.com> wrote: > >>>>>> Create a new audit record type to contain the subject information > >>>>>> when there are multiple security modules that require such data. > >>> ... > >>> > >>>>> The local > >>>>> audit context is a hack that is made necessary by the fact that we > >>>>> have to audit things which happen outside the scope of an executing > >>>>> task, e.g. the netfilter audit hooks, it should *never* be used when > >>>>> there is a valid task_struct. > >>>> In the existing audit code a "current context" is only needed for > >>>> syscall events, so that's the only case where it's allocated. Would > >>>> you suggest that I track down the non-syscall events that include > >>>> subj= fields and add allocate a "current context" for them? I looked > >>>> into doing that, and it wouldn't be simple. > >>> This is why the "local context" was created. Prior to these stacking > >>> additions, and the audit container ID work, we never needed to group > >>> multiple audit records outside of a syscall context into a single > >>> audit event so passing a NULL context into audit_log_start() was > >>> reasonable. The local context was designed as a way to generate a > >>> context for use in a local function scope to group multiple records, > >>> however, for reasons I'll get to below I'm now wondering if the local > >>> context approach is really workable ... > >> I haven't found a place where it didn't work. What is the concern? > > The concern is that use of a local context can destroy any hopes of > > linking with other related records, e.g. SYSCALL and PATH records, to > > form a single cohesive event. If the current task_struct is valid for > > a given function invocation then we *really* should be using current's > > audit_context. > > > > However, based on our discussion here it would seem that we may have > > some issues where current->audit_context is not being managed > > correctly. I'm not surprised, but I will admit to being disappointed. > > I'd believe that with syscall audit being a special case for other reasons > the multiple record situation got taken care of on a case-by-case basis > and no one really paid much attention to generality. It's understandable. > > >>> What does your audit config look like? Both the kernel command line > >>> and the output of 'auditctl -l' would be helpful. > >> On the fedora system: > >> > >> BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.14.0-rc5stack+ > >> root=/dev/mapper/fedora-root ro resume=/dev/mapper/fedora-swap > >> rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap lsm.debug > >> > >> -a always,exit -F arch=b64 -S bpf -F key=testsuite-1628714321-EtlWIphW > >> > >> On the Ubuntu system: > >> > >> BOOT_IMAGE=/boot/vmlinuz-5.14.0-rc1stack+ > >> root=UUID=39c25777-d413-4c2e-948c-dfa2bf259049 ro lsm.debug > >> > >> No rules > > The Fedora system looks to have some audit-testsuite leftovers, but > > that shouldn't have an impact on what we are discussing; in both cases > > I would expect current->audit_context to be allocated and non-NULL. > > As would I. > > > >>> I'm beginning to suspect that you have the default > >>> we-build-audit-into-the-kernel-because-product-management-said-we-have-to-but-we-don't-actually-enable-it-at-runtime > >>> audit configuration that is de rigueur for many distros these days. > >> Yes, but I've also fiddled about with it so as to get better event coverage. > >> I've run the audit-testsuite, which has got to fiddle about with the audit > >> configuration. > > Yes, it looks like my hunch was wrong. > > > >>> If that is the case, there are many cases where you would not see a > >>> NULL current->audit_context simply because the config never allocated > >>> one, see kernel/auditsc.c:audit_alloc(). > >> I assume you mean that I *would* see a NULL current->audit_context > >> in the "event not enabled" case. > > Yep, typo. > > > >>> Regardless, assuming that is the case we probably need to find an > >>> alternative to the local context approach as it currently works. For > >>> reasons we already talked about, we don't want to use a local > >>> audit_context if there is the possibility for a proper > >>> current->audit_context, but we need to do *something* so that we can > >>> group these multiple events into a single record. > >> I tried a couple things, but neither was satisfactory. > >> > >>> Since this is just occurring to me now I need a bit more time to think > >>> on possible solutions - all good ideas are welcome - but the first > >>> thing that pops into my head is that we need to augment > >>> audit_log_end() to potentially generated additional, associated > >>> records similar to what we do on syscall exit in audit_log_exit(). > >> I looked into that. You need a place to save the timestamp > >> that doesn't disappear. That's the role the audit_context plays > >> now. > > Yes, I've spent a few hours staring at the poorly planned struct that > > is audit_context ;) > > > > Regardless, the obvious place for such a thing is audit_buffer; we can > > stash whatever we need in there. > > I had considered doing that, but was afraid that moving the timestamp > out of the audit_context might have dire consequences. Don't move, copy. If there is a valid context one would stash the timestamp there, if not, we stash it in the audit_buffer. However, before we start messing with that too much I would like to better understand why we aren't seeing a valid audit_context in the netlink case at the very least. > >>> Of > >>> course the audit_log_end() changes would be much more limited than > >>> audit_log_exit(), just the LSM subject and audit container ID info, > >>> and even then we might want to limit that to cases where the ab->ctx > >>> value is NULL and let audit_log_exit() handle it otherwise. We may > >>> need to store the event type in the audit_buffer during > >>> audit_log_start() so that we can later use that in audit_log_end() to > >>> determine what additional records are needed. > >>> > >>> Regardless, let's figure out why all your current->audit_context > >>> values are NULL > >> That's what's maddening, and why I implemented audit_alloc_for_lsm(). > >> They aren't all NULL. Sometimes current->audit_context is NULL, > >> sometimes it isn't, for the same event. I thought it might be a > >> question of the netlink interface being treated specially, but > >> that doesn't explain all the cases. > > > > Your netlink changes are exactly what made me think, "this is > > obviously wrong", but now I'm wondering if a previously held > > assumption of "current is valid and points to the calling process" in > > the case of the kernel servicing netlink messages sent from userspace. > > If that's the case the subject data in the audit record is going > to be bogus. From what I've seen that data appears to be correct. Yeah, the thought occurred to me, but we are clearly already in the maybe-the-assumptions-are-wrong stage so I'm not going to rely on that being 100%. We definitely need to track this down before we start making to many more guesses about what is working and what is not. > > Or rather, perhaps that assumption is still true but something is > > causing current->audit_context to be NULL in that case. > > I can imagine someone deciding not to set up audit_context in > situations like netlink because they knew that nothing following > that would be a syscall event. *If* the user/kernel transition happens as part of the netlink socket send/write/etc. syscall then it *should* have all of the audit syscall setup already done ... however, see my earlier comments about assumptions :/ > I've been looking into the audit > userspace and there are assumptions like that all over the place. I've made my feelings about audit's design known quite a bit already so I'm not going to drag all of that back up, all I'll say is that I believe the audit design was tragically and inherently flawed in many ways. We've been working to resolve some of those issues in the kernel for a little while now, but the audit userspace remains rooted in some of those original design decisions. Of course, these are just my opinions, others clearly feel differently. Regardless, and somewhat independent of our discussion here, now that I am back to being able to dedicate a good chunk of my time to upstream efforts, one of my priorities is to start repairing audit ... however, I need to get past the io_uring mess first. > > Friday the 13th indeed. > > I've been banging my head against this for a couple months. > My biggest fear is that I may have learned enough about the > audit system to make useful contributions. As the usual refrain goes, "patches are always welcome" ... and I say that with equal parts honesty and warning :) Even if you aren't comfortable putting together a patch, simply root-causing the missing audit_context setup in the netlink case would be helpful.
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 2c3a2348a144..3520caa0260c 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2722,7 +2722,7 @@ static void binder_transaction(struct binder_proc *proc, * case well anyway. */ security_task_getsecid_obj(proc->tsk, &blob); - ret = security_secid_to_secctx(&blob, &lsmctx); + ret = security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_DISPLAY); if (ret) { return_error = BR_FAILED_REPLY; return_error_param = ret; diff --git a/include/linux/audit.h b/include/linux/audit.h index 97cd7471e572..85eb87f6f92d 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -291,6 +291,7 @@ extern int audit_alloc(struct task_struct *task); extern void __audit_free(struct task_struct *task); extern struct audit_context *audit_alloc_local(gfp_t gfpflags); extern void audit_free_context(struct audit_context *context); +extern void audit_free_local(struct audit_context *context); extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1, unsigned long a2, unsigned long a3); extern void __audit_syscall_exit(int ret_success, long ret_value); @@ -386,6 +387,19 @@ static inline void audit_ptrace(struct task_struct *t) __audit_ptrace(t); } +static inline struct audit_context *audit_alloc_for_lsm(gfp_t gfp) +{ + struct audit_context *context = audit_context(); + + if (context) + return context; + + if (lsm_multiple_contexts()) + return audit_alloc_local(gfp); + + return NULL; +} + /* Private API (for audit.c only) */ extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); @@ -560,6 +574,8 @@ extern int audit_signals; } static inline void audit_free_context(struct audit_context *context) { } +static inline void audit_free_local(struct audit_context *context) +{ } static inline int audit_alloc(struct task_struct *task) { return 0; diff --git a/include/linux/security.h b/include/linux/security.h index 3e9743118fb9..b3cf68cf2bd6 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -182,6 +182,8 @@ struct lsmblob { #define LSMBLOB_INVALID -1 /* Not a valid LSM slot number */ #define LSMBLOB_NEEDED -2 /* Slot requested on initialization */ #define LSMBLOB_NOT_NEEDED -3 /* Slot not requested */ +#define LSMBLOB_DISPLAY -4 /* Use the "display" slot */ +#define LSMBLOB_FIRST -5 /* Use the default "display" slot */ /** * lsmblob_init - initialize an lsmblob structure @@ -248,6 +250,15 @@ static inline u32 lsmblob_value(const struct lsmblob *blob) return 0; } +static inline bool lsm_multiple_contexts(void) +{ +#ifdef CONFIG_SECURITY + return lsm_slot_to_name(1) != NULL; +#else + return false; +#endif +} + /* These functions are in security/commoncap.c */ extern int cap_capable(const struct cred *cred, struct user_namespace *ns, int cap, unsigned int opts); @@ -578,7 +589,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value, size_t size); int security_netlink_send(struct sock *sk, struct sk_buff *skb); int security_ismaclabel(const char *name); -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp); +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp, + int display); int security_secctx_to_secid(const char *secdata, u32 seclen, struct lsmblob *blob); void security_release_secctx(struct lsmcontext *cp); @@ -1433,7 +1445,7 @@ static inline int security_ismaclabel(const char *name) } static inline int security_secid_to_secctx(struct lsmblob *blob, - struct lsmcontext *cp) + struct lsmcontext *cp, int display) { return -EOPNOTSUPP; } diff --git a/include/net/netlabel.h b/include/net/netlabel.h index 73fc25b4042b..216cb1ffc8f0 100644 --- a/include/net/netlabel.h +++ b/include/net/netlabel.h @@ -97,7 +97,7 @@ struct calipso_doi; /* NetLabel audit information */ struct netlbl_audit { - u32 secid; + struct lsmblob lsmdata; kuid_t loginuid; unsigned int sessionid; }; diff --git a/include/net/scm.h b/include/net/scm.h index b77a52f93389..f4d567d4885e 100644 --- a/include/net/scm.h +++ b/include/net/scm.h @@ -101,7 +101,7 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc * and the infrastructure will know which it is. */ lsmblob_init(&lb, scm->secid); - err = security_secid_to_secctx(&lb, &context); + err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY); if (!err) { put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, context.len, diff --git a/include/net/xfrm.h b/include/net/xfrm.h index cbff7c2a9724..a10fa01f7bf4 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -660,13 +660,22 @@ struct xfrm_spi_skb_cb { #define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0])) #ifdef CONFIG_AUDITSYSCALL -static inline struct audit_buffer *xfrm_audit_start(const char *op) +static inline struct audit_buffer *xfrm_audit_start(const char *op, + struct audit_context **lac) { + struct audit_context *context; struct audit_buffer *audit_buf = NULL; if (audit_enabled == AUDIT_OFF) return NULL; - audit_buf = audit_log_start(audit_context(), GFP_ATOMIC, + context = audit_context(); + if (lac != NULL) { + if (lsm_multiple_contexts() && context == NULL) + context = audit_alloc_local(GFP_ATOMIC); + *lac = context; + } + + audit_buf = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_IPSEC_EVENT); if (audit_buf == NULL) return NULL; diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index daa481729e9b..4432a8bed8e0 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -139,6 +139,7 @@ #define AUDIT_MAC_UNLBL_STCDEL 1417 /* NetLabel: del a static label */ #define AUDIT_MAC_CALIPSO_ADD 1418 /* NetLabel: add CALIPSO DOI entry */ #define AUDIT_MAC_CALIPSO_DEL 1419 /* NetLabel: del CALIPSO DOI entry */ +#define AUDIT_MAC_TASK_CONTEXTS 1420 /* Multiple LSM contexts */ #define AUDIT_FIRST_KERN_ANOM_MSG 1700 #define AUDIT_LAST_KERN_ANOM_MSG 1799 diff --git a/kernel/audit.c b/kernel/audit.c index 841123390d41..cba63789a164 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -386,10 +386,12 @@ void audit_log_lost(const char *message) static int audit_log_config_change(char *function_name, u32 new, u32 old, int allow_changes) { + struct audit_context *context; struct audit_buffer *ab; int rc = 0; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return rc; audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old); @@ -399,6 +401,7 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old, allow_changes = 0; /* Something weird, deny request */ audit_log_format(ab, " res=%d", allow_changes); audit_log_end(ab); + audit_free_local(context); return rc; } @@ -1072,12 +1075,6 @@ static void audit_log_common_recv_msg(struct audit_context *context, audit_log_task_context(*ab); } -static inline void audit_log_user_recv_msg(struct audit_buffer **ab, - u16 msg_type) -{ - audit_log_common_recv_msg(NULL, ab, msg_type); -} - int is_audit_feature_set(int i) { return af.features & AUDIT_FEATURE_TO_MASK(i); @@ -1190,6 +1187,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; struct audit_sig_info *sig_data; + struct audit_context *lcontext; err = audit_netlink_ok(skb, msg_type); if (err) @@ -1357,7 +1355,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (err) break; } - audit_log_user_recv_msg(&ab, msg_type); + lcontext = audit_alloc_for_lsm(GFP_KERNEL); + audit_log_common_recv_msg(lcontext, &ab, msg_type); if (msg_type != AUDIT_USER_TTY) { /* ensure NULL termination */ str[data_len - 1] = '\0'; @@ -1371,6 +1370,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) audit_log_n_untrustedstring(ab, str, data_len); } audit_log_end(ab); + audit_free_local(lcontext); } break; case AUDIT_ADD_RULE: @@ -1378,13 +1378,15 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (data_len < sizeof(struct audit_rule_data)) return -EINVAL; if (audit_enabled == AUDIT_LOCKED) { - audit_log_common_recv_msg(audit_context(), &ab, + lcontext = audit_alloc_for_lsm(GFP_KERNEL); + audit_log_common_recv_msg(lcontext, &ab, AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=%s audit_enabled=%d res=0", msg_type == AUDIT_ADD_RULE ? "add_rule" : "remove_rule", audit_enabled); audit_log_end(ab); + audit_free_local(lcontext); return -EPERM; } err = audit_rule_change(msg_type, seq, data, data_len); @@ -1394,10 +1396,11 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) break; case AUDIT_TRIM: audit_trim_trees(); - audit_log_common_recv_msg(audit_context(), &ab, - AUDIT_CONFIG_CHANGE); + lcontext = audit_alloc_for_lsm(GFP_KERNEL); + audit_log_common_recv_msg(lcontext, &ab, AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=trim res=1"); audit_log_end(ab); + audit_free_local(lcontext); break; case AUDIT_MAKE_EQUIV: { void *bufp = data; @@ -1425,14 +1428,15 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) /* OK, here comes... */ err = audit_tag_tree(old, new); - audit_log_common_recv_msg(audit_context(), &ab, - AUDIT_CONFIG_CHANGE); + lcontext = audit_alloc_for_lsm(GFP_KERNEL); + audit_log_common_recv_msg(lcontext, &ab, AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=make_equiv old="); audit_log_untrustedstring(ab, old); audit_log_format(ab, " new="); audit_log_untrustedstring(ab, new); audit_log_format(ab, " res=%d", !err); audit_log_end(ab); + audit_free_local(lcontext); kfree(old); kfree(new); break; @@ -1443,7 +1447,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (lsmblob_is_set(&audit_sig_lsm)) { err = security_secid_to_secctx(&audit_sig_lsm, - &context); + &context, LSMBLOB_FIRST); if (err) return err; } @@ -1498,13 +1502,14 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) old.enabled = t & AUDIT_TTY_ENABLE; old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); - audit_log_common_recv_msg(audit_context(), &ab, - AUDIT_CONFIG_CHANGE); + lcontext = audit_alloc_for_lsm(GFP_KERNEL); + audit_log_common_recv_msg(lcontext, &ab, AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" " old-log_passwd=%d new-log_passwd=%d res=%d", old.enabled, s.enabled, old.log_passwd, s.log_passwd, !err); audit_log_end(ab); + audit_free_local(lcontext); break; } default: @@ -1550,6 +1555,7 @@ static void audit_receive(struct sk_buff *skb) /* Log information about who is connecting to the audit multicast socket */ static void audit_log_multicast(int group, const char *op, int err) { + struct audit_context *context; const struct cred *cred; struct tty_struct *tty; char comm[sizeof(current->comm)]; @@ -1558,7 +1564,8 @@ static void audit_log_multicast(int group, const char *op, int err) if (!audit_enabled) return; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_EVENT_LISTENER); if (!ab) return; @@ -1577,6 +1584,7 @@ static void audit_log_multicast(int group, const char *op, int err) audit_log_d_path_exe(ab, current->mm); /* exe= */ audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err); audit_log_end(ab); + audit_free_local(context); } /* Run custom bind function on netlink socket group connect or bind requests. */ @@ -2128,6 +2136,36 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } +static void audit_log_lsm(struct audit_context *context, struct lsmblob *blob) +{ + struct audit_buffer *ab; + struct lsmcontext lsmdata; + bool sep = false; + int error; + int i; + + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_MAC_TASK_CONTEXTS); + if (!ab) + return; /* audit_panic or being filtered */ + + for (i = 0; i < LSMBLOB_ENTRIES; i++) { + if (blob->secid[i] == 0) + continue; + error = security_secid_to_secctx(blob, &lsmdata, i); + if (error && error != -EINVAL) { + audit_panic("error in audit_log_lsm"); + return; + } + + audit_log_format(ab, "%ssubj_%s=\"%s\"", sep ? " " : "", + lsm_slot_to_name(i), lsmdata.context); + sep = true; + + security_release_secctx(&lsmdata); + } + audit_log_end(ab); +} + int audit_log_task_context(struct audit_buffer *ab) { int error; @@ -2138,7 +2176,18 @@ int audit_log_task_context(struct audit_buffer *ab) if (!lsmblob_is_set(&blob)) return 0; - error = security_secid_to_secctx(&blob, &context); + /* + * If there is more than one security module that has a + * subject "context" it's necessary to put the subject data + * into a separate record to maintain compatibility. + */ + if (lsm_multiple_contexts()) { + audit_log_format(ab, " subj=?"); + audit_log_lsm(ab->ctx, &blob); + return 0; + } + + error = security_secid_to_secctx(&blob, &context, LSMBLOB_FIRST); if (error) { if (error != -EINVAL) goto error_path; @@ -2274,6 +2323,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, unsigned int oldsessionid, unsigned int sessionid, int rc) { + struct audit_context *context; struct audit_buffer *ab; uid_t uid, oldloginuid, loginuid; struct tty_struct *tty; @@ -2281,7 +2331,8 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, if (!audit_enabled) return; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_LOGIN); if (!ab) return; @@ -2297,6 +2348,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, oldsessionid, sessionid, !rc); audit_put_tty(tty); audit_log_end(ab); + audit_free_local(context); } /** diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index 1ba14a7a38f7..fd71c6bac200 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1098,12 +1098,14 @@ static void audit_list_rules(int seq, struct sk_buff_head *q) /* Log rule additions and removals */ static void audit_log_rule_change(char *action, struct audit_krule *rule, int res) { + struct audit_context *context; struct audit_buffer *ab; if (!audit_enabled) return; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (!ab) return; audit_log_session_info(ab); @@ -1112,6 +1114,7 @@ static void audit_log_rule_change(char *action, struct audit_krule *rule, int re audit_log_key(ab, rule->filterkey); audit_log_format(ab, " list=%d res=%d", rule->listnr, res); audit_log_end(ab); + audit_free_local(context); } /** diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 0e58a3ab56f5..01fdcbf468c0 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -993,12 +993,11 @@ struct audit_context *audit_alloc_local(gfp_t gfpflags) context = audit_alloc_context(AUDIT_STATE_BUILD, gfpflags); if (!context) { audit_log_lost("out of memory in audit_alloc_local"); - goto out; + return NULL; } context->serial = audit_serial(); ktime_get_coarse_real_ts64(&context->ctime); context->local = true; -out: return context; } EXPORT_SYMBOL(audit_alloc_local); @@ -1019,6 +1018,13 @@ void audit_free_context(struct audit_context *context) } EXPORT_SYMBOL(audit_free_context); +void audit_free_local(struct audit_context *context) +{ + if (context && context->local) + audit_free_context(context); +} +EXPORT_SYMBOL(audit_free_local); + static int audit_log_pid_context(struct audit_context *context, pid_t pid, kuid_t auid, kuid_t uid, unsigned int sessionid, @@ -1036,7 +1042,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid, from_kuid(&init_user_ns, auid), from_kuid(&init_user_ns, uid), sessionid); if (lsmblob_is_set(blob)) { - if (security_secid_to_secctx(blob, &lsmctx)) { + if (security_secid_to_secctx(blob, &lsmctx, LSMBLOB_FIRST)) { audit_log_format(ab, " obj=(none)"); rc = 1; } else { @@ -1282,7 +1288,8 @@ static void show_special(struct audit_context *context, int *call_panic) struct lsmblob blob; lsmblob_init(&blob, osid); - if (security_secid_to_secctx(&blob, &lsmcxt)) { + if (security_secid_to_secctx(&blob, &lsmcxt, + LSMBLOB_FIRST)) { audit_log_format(ab, " osid=%u", osid); *call_panic = 1; } else { @@ -1439,7 +1446,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n, struct lsmcontext lsmctx; lsmblob_init(&blob, n->osid); - if (security_secid_to_secctx(&blob, &lsmctx)) { + if (security_secid_to_secctx(&blob, &lsmctx, LSMBLOB_FIRST)) { audit_log_format(ab, " osid=%u", n->osid); if (call_panic) *call_panic = 2; @@ -2637,10 +2644,12 @@ void __audit_ntp_log(const struct audit_ntp_data *ad) void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, enum audit_nfcfgop op, gfp_t gfp) { + struct audit_context *context; struct audit_buffer *ab; char comm[sizeof(current->comm)]; - ab = audit_log_start(audit_context(), gfp, AUDIT_NETFILTER_CFG); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, gfp, AUDIT_NETFILTER_CFG); if (!ab) return; audit_log_format(ab, "table=%s family=%u entries=%u op=%s", @@ -2651,6 +2660,7 @@ void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, audit_log_format(ab, " comm="); audit_log_untrustedstring(ab, get_task_comm(comm, current)); audit_log_end(ab); + audit_free_local(context); } EXPORT_SYMBOL_GPL(__audit_log_nfcfg); @@ -2685,6 +2695,7 @@ static void audit_log_task(struct audit_buffer *ab) */ void audit_core_dumps(long signr) { + struct audit_context *context; struct audit_buffer *ab; if (!audit_enabled) @@ -2693,12 +2704,14 @@ void audit_core_dumps(long signr) if (signr == SIGQUIT) /* don't care for those */ return; - ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_ABEND); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_ANOM_ABEND); if (unlikely(!ab)) return; audit_log_task(ab); audit_log_format(ab, " sig=%ld res=1", signr); audit_log_end(ab); + audit_free_local(context); } /** diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index ae073b642fa7..5c0029a3a595 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -140,7 +140,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb) return; lsmblob_init(&lb, secid); - err = security_secid_to_secctx(&lb, &context); + err = security_secid_to_secctx(&lb, &context, LSMBLOB_DISPLAY); if (err) return; diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 668b31ecd638..05bdbb942499 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -347,7 +347,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct) * security_secid_to_secctx() will know which security module * to use to create the secctx. */ lsmblob_init(&blob, ct->secmark); - ret = security_secid_to_secctx(&blob, &context); + ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY); if (ret) return 0; @@ -658,7 +658,7 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct) struct lsmblob blob; struct lsmcontext context; - ret = security_secid_to_secctx(&blob, &context); + ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY); if (ret) return 0; diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c index b5796a8e5e90..3da3770e9739 100644 --- a/net/netfilter/nf_conntrack_standalone.c +++ b/net/netfilter/nf_conntrack_standalone.c @@ -177,7 +177,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct) struct lsmcontext context; lsmblob_init(&blob, ct->secmark); - ret = security_secid_to_secctx(&blob, &context); + ret = security_secid_to_secctx(&blob, &context, LSMBLOB_DISPLAY); if (ret) return; diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index cffb04baf7b8..9bef0bddf7d6 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -316,7 +316,7 @@ static void nfqnl_get_sk_secctx(struct sk_buff *skb, struct lsmcontext *context) * blob. security_secid_to_secctx() will know which security * module to use to create the secctx. */ lsmblob_init(&blob, skb->secmark); - security_secid_to_secctx(&blob, context); + security_secid_to_secctx(&blob, context, LSMBLOB_DISPLAY); } read_unlock_bh(&skb->sk->sk_callback_lock); diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c index 289602835b75..245f63f5773a 100644 --- a/net/netlabel/netlabel_unlabeled.c +++ b/net/netlabel/netlabel_unlabeled.c @@ -437,7 +437,8 @@ int netlbl_unlhsh_add(struct net *net, unlhsh_add_return: rcu_read_unlock(); if (audit_buf != NULL) { - if (security_secid_to_secctx(lsmblob, &context) == 0) { + if (security_secid_to_secctx(lsmblob, &context, + LSMBLOB_FIRST) == 0) { audit_log_format(audit_buf, " sec_obj=%s", context.context); security_release_secctx(&context); @@ -492,7 +493,8 @@ static int netlbl_unlhsh_remove_addr4(struct net *net, if (dev != NULL) dev_put(dev); if (entry != NULL && - security_secid_to_secctx(&entry->lsmblob, &context) == 0) { + security_secid_to_secctx(&entry->lsmblob, &context, + LSMBLOB_FIRST) == 0) { audit_log_format(audit_buf, " sec_obj=%s", context.context); security_release_secctx(&context); @@ -552,7 +554,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net, if (dev != NULL) dev_put(dev); if (entry != NULL && - security_secid_to_secctx(&entry->lsmblob, &context) == 0) { + security_secid_to_secctx(&entry->lsmblob, &context, + LSMBLOB_FIRST) == 0) { audit_log_format(audit_buf, " sec_obj=%s", context.context); security_release_secctx(&context); @@ -738,11 +741,10 @@ static void netlbl_unlabel_acceptflg_set(u8 value, netlabel_unlabel_acceptflg = value; audit_buf = netlbl_audit_start_common(AUDIT_MAC_UNLBL_ALLOW, audit_info); - if (audit_buf != NULL) { + if (audit_buf != NULL) audit_log_format(audit_buf, " unlbl_accept=%u old=%u", value, old_val); - audit_log_end(audit_buf); - } + audit_log_end(audit_buf); } /** @@ -1122,7 +1124,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd, lsmb = (struct lsmblob *)&addr6->lsmblob; } - ret_val = security_secid_to_secctx(lsmb, &context); + ret_val = security_secid_to_secctx(lsmb, &context, LSMBLOB_FIRST); if (ret_val != 0) goto list_cb_failure; ret_val = nla_put(cb_arg->skb, @@ -1528,14 +1530,11 @@ int __init netlbl_unlabel_defconf(void) int ret_val; struct netlbl_dom_map *entry; struct netlbl_audit audit_info; - struct lsmblob blob; /* Only the kernel is allowed to call this function and the only time * it is called is at bootup before the audit subsystem is reporting * messages so don't worry to much about these values. */ - security_task_getsecid_subj(current, &blob); - /* scaffolding until audit_info.secid is converted */ - audit_info.secid = blob.secid[0]; + security_task_getsecid_subj(current, &audit_info.lsmdata); audit_info.loginuid = GLOBAL_ROOT_UID; audit_info.sessionid = 0; diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c index 951ba0639d20..9c43c3cb2088 100644 --- a/net/netlabel/netlabel_user.c +++ b/net/netlabel/netlabel_user.c @@ -85,7 +85,6 @@ struct audit_buffer *netlbl_audit_start_common(int type, { struct audit_buffer *audit_buf; struct lsmcontext context; - struct lsmblob blob; if (audit_enabled == AUDIT_OFF) return NULL; @@ -98,11 +97,14 @@ struct audit_buffer *netlbl_audit_start_common(int type, from_kuid(&init_user_ns, audit_info->loginuid), audit_info->sessionid); - lsmblob_init(&blob, audit_info->secid); - if (audit_info->secid != 0 && - security_secid_to_secctx(&blob, &context) == 0) { - audit_log_format(audit_buf, " subj=%s", context.context); - security_release_secctx(&context); + if (lsmblob_is_set(&audit_info->lsmdata)) { + if (!lsm_multiple_contexts() && + security_secid_to_secctx(&audit_info->lsmdata, &context, + LSMBLOB_FIRST) == 0) { + audit_log_format(audit_buf, " subj=%s", + context.context); + security_release_secctx(&context); + } } return audit_buf; diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h index aa31f7bf79ee..e5b15ad41df7 100644 --- a/net/netlabel/netlabel_user.h +++ b/net/netlabel/netlabel_user.h @@ -32,11 +32,7 @@ */ static inline void netlbl_netlink_auditinfo(struct netlbl_audit *audit_info) { - struct lsmblob blob; - - security_task_getsecid_subj(current, &blob); - /* scaffolding until secid is converted */ - audit_info->secid = blob.secid[0]; + security_task_getsecid_subj(current, &audit_info->lsmdata); audit_info->loginuid = audit_get_loginuid(current); audit_info->sessionid = audit_get_sessionid(current); } diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 827d84255021..2152e319951d 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -4178,30 +4178,34 @@ static void xfrm_audit_common_policyinfo(struct xfrm_policy *xp, void xfrm_audit_policy_add(struct xfrm_policy *xp, int result, bool task_valid) { + struct audit_context *context; struct audit_buffer *audit_buf; - audit_buf = xfrm_audit_start("SPD-add"); + audit_buf = xfrm_audit_start("SPD-add", &context); if (audit_buf == NULL) return; xfrm_audit_helper_usrinfo(task_valid, audit_buf); audit_log_format(audit_buf, " res=%u", result); xfrm_audit_common_policyinfo(xp, audit_buf); audit_log_end(audit_buf); + audit_free_local(context); } EXPORT_SYMBOL_GPL(xfrm_audit_policy_add); void xfrm_audit_policy_delete(struct xfrm_policy *xp, int result, bool task_valid) { + struct audit_context *context; struct audit_buffer *audit_buf; - audit_buf = xfrm_audit_start("SPD-delete"); + audit_buf = xfrm_audit_start("SPD-delete", &context); if (audit_buf == NULL) return; xfrm_audit_helper_usrinfo(task_valid, audit_buf); audit_log_format(audit_buf, " res=%u", result); xfrm_audit_common_policyinfo(xp, audit_buf); audit_log_end(audit_buf); + audit_free_local(context); } EXPORT_SYMBOL_GPL(xfrm_audit_policy_delete); #endif diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index a2f4001221d1..4d174f42eb60 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2796,29 +2796,33 @@ static void xfrm_audit_helper_pktinfo(struct sk_buff *skb, u16 family, void xfrm_audit_state_add(struct xfrm_state *x, int result, bool task_valid) { + struct audit_context *context; struct audit_buffer *audit_buf; - audit_buf = xfrm_audit_start("SAD-add"); + audit_buf = xfrm_audit_start("SAD-add", &context); if (audit_buf == NULL) return; xfrm_audit_helper_usrinfo(task_valid, audit_buf); xfrm_audit_helper_sainfo(x, audit_buf); audit_log_format(audit_buf, " res=%u", result); audit_log_end(audit_buf); + audit_free_local(context); } EXPORT_SYMBOL_GPL(xfrm_audit_state_add); void xfrm_audit_state_delete(struct xfrm_state *x, int result, bool task_valid) { + struct audit_context *context; struct audit_buffer *audit_buf; - audit_buf = xfrm_audit_start("SAD-delete"); + audit_buf = xfrm_audit_start("SAD-delete", &context); if (audit_buf == NULL) return; xfrm_audit_helper_usrinfo(task_valid, audit_buf); xfrm_audit_helper_sainfo(x, audit_buf); audit_log_format(audit_buf, " res=%u", result); audit_log_end(audit_buf); + audit_free_local(context); } EXPORT_SYMBOL_GPL(xfrm_audit_state_delete); @@ -2828,7 +2832,7 @@ void xfrm_audit_state_replay_overflow(struct xfrm_state *x, struct audit_buffer *audit_buf; u32 spi; - audit_buf = xfrm_audit_start("SA-replay-overflow"); + audit_buf = xfrm_audit_start("SA-replay-overflow", NULL); if (audit_buf == NULL) return; xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf); @@ -2846,7 +2850,7 @@ void xfrm_audit_state_replay(struct xfrm_state *x, struct audit_buffer *audit_buf; u32 spi; - audit_buf = xfrm_audit_start("SA-replayed-pkt"); + audit_buf = xfrm_audit_start("SA-replayed-pkt", NULL); if (audit_buf == NULL) return; xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf); @@ -2861,7 +2865,7 @@ void xfrm_audit_state_notfound_simple(struct sk_buff *skb, u16 family) { struct audit_buffer *audit_buf; - audit_buf = xfrm_audit_start("SA-notfound"); + audit_buf = xfrm_audit_start("SA-notfound", NULL); if (audit_buf == NULL) return; xfrm_audit_helper_pktinfo(skb, family, audit_buf); @@ -2875,7 +2879,7 @@ void xfrm_audit_state_notfound(struct sk_buff *skb, u16 family, struct audit_buffer *audit_buf; u32 spi; - audit_buf = xfrm_audit_start("SA-notfound"); + audit_buf = xfrm_audit_start("SA-notfound", NULL); if (audit_buf == NULL) return; xfrm_audit_helper_pktinfo(skb, family, audit_buf); @@ -2893,7 +2897,7 @@ void xfrm_audit_state_icvfail(struct xfrm_state *x, __be32 net_spi; __be32 net_seq; - audit_buf = xfrm_audit_start("SA-icv-failure"); + audit_buf = xfrm_audit_start("SA-icv-failure", NULL); if (audit_buf == NULL) return; xfrm_audit_helper_pktinfo(skb, x->props.family, audit_buf); diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c index 691f68d478f1..3481990a25a6 100644 --- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -342,6 +342,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, void ima_audit_measurement(struct integrity_iint_cache *iint, const unsigned char *filename) { + struct audit_context *context; struct audit_buffer *ab; char *hash; const char *algo_name = hash_algo_name[iint->ima_hash->algo]; @@ -358,8 +359,8 @@ void ima_audit_measurement(struct integrity_iint_cache *iint, hex_byte_pack(hash + (i * 2), iint->ima_hash->digest[i]); hash[i * 2] = '\0'; - ab = audit_log_start(audit_context(), GFP_KERNEL, - AUDIT_INTEGRITY_RULE); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, AUDIT_INTEGRITY_RULE); if (!ab) goto out; @@ -369,6 +370,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint, audit_log_task_info(ab); audit_log_end(ab); + audit_free_local(context); iint->flags |= IMA_AUDITED; out: diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c index 29220056207f..c3b313886e15 100644 --- a/security/integrity/integrity_audit.c +++ b/security/integrity/integrity_audit.c @@ -38,13 +38,15 @@ void integrity_audit_message(int audit_msgno, struct inode *inode, const char *cause, int result, int audit_info, int errno) { + struct audit_context *context; struct audit_buffer *ab; char name[TASK_COMM_LEN]; if (!integrity_audit_info && audit_info == 1) /* Skip info messages */ return; - ab = audit_log_start(audit_context(), GFP_KERNEL, audit_msgno); + context = audit_alloc_for_lsm(GFP_KERNEL); + ab = audit_log_start(context, GFP_KERNEL, audit_msgno); audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u", task_pid_nr(current), from_kuid(&init_user_ns, current_uid()), @@ -64,4 +66,5 @@ void integrity_audit_message(int audit_msgno, struct inode *inode, } audit_log_format(ab, " res=%d errno=%d", !result, errno); audit_log_end(ab); + audit_free_local(context); } diff --git a/security/security.c b/security/security.c index cb359e185d1a..5d7fd982f84a 100644 --- a/security/security.c +++ b/security/security.c @@ -2309,7 +2309,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value, hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { rc = hp->hook.setprocattr(name, value, size); - if (rc < 0) + if (rc < 0 && rc != -EINVAL) return rc; } @@ -2354,13 +2354,31 @@ int security_ismaclabel(const char *name) } EXPORT_SYMBOL(security_ismaclabel); -int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp) +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp, + int ilsm) { struct security_hook_list *hp; - int ilsm = lsm_task_ilsm(current); memset(cp, 0, sizeof(*cp)); + /* + * ilsm either is the slot number use for formatting + * or an instruction on which relative slot to use. + */ + if (ilsm == LSMBLOB_DISPLAY) + ilsm = lsm_task_ilsm(current); + else if (ilsm == LSMBLOB_FIRST) + ilsm = LSMBLOB_INVALID; + else if (ilsm < 0) { + WARN_ONCE(true, + "LSM: %s unknown interface LSM\n", __func__); + ilsm = LSMBLOB_INVALID; + } else if (ilsm >= lsm_slot) { + WARN_ONCE(true, + "LSM: %s invalid interface LSM\n", __func__); + ilsm = LSMBLOB_INVALID; + } + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) { if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot)) continue; @@ -2390,7 +2408,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen, return hp->hook.secctx_to_secid(secdata, seclen, &blob->secid[hp->lsmid->slot]); } - return 0; + return -EOPNOTSUPP; } EXPORT_SYMBOL(security_secctx_to_secid); @@ -2884,23 +2902,17 @@ int security_key_getsecurity(struct key *key, char **_buffer) int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule) { struct security_hook_list *hp; - bool one_is_good = false; - int rc = 0; - int trc; + int ilsm = lsm_task_ilsm(current); hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) { if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot)) continue; - trc = hp->hook.audit_rule_init(field, op, rulestr, - &lsmrule[hp->lsmid->slot]); - if (trc == 0) - one_is_good = true; - else - rc = trc; + if (ilsm != LSMBLOB_INVALID && ilsm != hp->lsmid->slot) + continue; + return hp->hook.audit_rule_init(field, op, rulestr, + &lsmrule[hp->lsmid->slot]); } - if (one_is_good) - return 0; - return rc; + return 0; } int security_audit_rule_known(struct audit_krule *krule) @@ -2932,6 +2944,8 @@ int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op, continue; if (lsmrule[hp->lsmid->slot] == NULL) continue; + if (lsmrule[hp->lsmid->slot] == NULL) + continue; rc = hp->hook.audit_rule_match(blob->secid[hp->lsmid->slot], field, op, &lsmrule[hp->lsmid->slot]); diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 9cda52f2ec31..2f0f412fc403 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -185,7 +185,8 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap) nap->loginuid = audit_get_loginuid(current); nap->sessionid = audit_get_sessionid(current); - nap->secid = skp->smk_secid; + lsmblob_init(&nap->lsmdata, 0); + nap->lsmdata.secid[smack_lsmid.slot] = skp->smk_secid; } /*
Create a new audit record type to contain the subject information when there are multiple security modules that require such data. This record is linked with the same timestamp and serial number using the audit_alloc_local() mechanism. The record is produced only in cases where there is more than one security module with a process "context". In cases where this record is produced the subj= fields of other records in the audit event will be set to "subj=?". An example of the MAC_TASK_CONTEXTS (1420) record is: type=UNKNOWN[1420] msg=audit(1600880931.832:113) subj_apparmor="=unconfined" subj_smack="_" There will be a subj_$LSM= entry for each security module LSM that supports the secid_to_secctx and secctx_to_secid hooks. The BPF security module implements secid/secctx translation hooks, so it has to be considered to provide a secctx even though it may not actually do so. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> To: paul@paul-moore.com To: linux-audit@redhat.com To: rgb@redhat.com Cc: netdev@vger.kernel.org --- drivers/android/binder.c | 2 +- include/linux/audit.h | 16 +++++ include/linux/security.h | 16 ++++- include/net/netlabel.h | 2 +- include/net/scm.h | 2 +- include/net/xfrm.h | 13 +++- include/uapi/linux/audit.h | 1 + kernel/audit.c | 90 +++++++++++++++++++------ kernel/auditfilter.c | 5 +- kernel/auditsc.c | 27 ++++++-- net/ipv4/ip_sockglue.c | 2 +- net/netfilter/nf_conntrack_netlink.c | 4 +- net/netfilter/nf_conntrack_standalone.c | 2 +- net/netfilter/nfnetlink_queue.c | 2 +- net/netlabel/netlabel_unlabeled.c | 21 +++--- net/netlabel/netlabel_user.c | 14 ++-- net/netlabel/netlabel_user.h | 6 +- net/xfrm/xfrm_policy.c | 8 ++- net/xfrm/xfrm_state.c | 18 +++-- security/integrity/ima/ima_api.c | 6 +- security/integrity/integrity_audit.c | 5 +- security/security.c | 46 ++++++++----- security/smack/smackfs.c | 3 +- 23 files changed, 221 insertions(+), 90 deletions(-)