| Message ID | 20190215222217.133213-1-mortonm@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] LSM: SafeSetID: gate setgid transitions | expand |
On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote: > From: Micah Morton <mortonm@chromium.org> > > This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the > existing 'task_fix_setuid' LSM hook, and calls this new hook from the > setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to > govern setgid transitions in addition to setuid transitions. This change > also makes sure the setgid functions in kernel/sys.c call > security_capable_setid rather than the ordinary security_capable Sorry, where security_capable_setid this defined? I assume it was in a recent patchset, but google and grep are failing me. > function, so that the security_capable hook in the SafeSetID LSM knows > it is being invoked from a setid function. > > Signed-off-by: Micah Morton <mortonm@chromium.org> > --- > Tested with slight mod to test in tools/testing/selftests/safesetid for > testing setgid as well as setuid. > > include/linux/lsm_hooks.h | 12 ++++++++++++ > include/linux/security.h | 10 ++++++++++ > kernel/sys.c | 27 +++++++++++++++++++++------ > security/security.c | 6 ++++++ > 4 files changed, 49 insertions(+), 6 deletions(-) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index 22fc786d723a..f252ed3e95ef 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -603,6 +603,15 @@ > * @old is the set of credentials that are being replaces > * @flags contains one of the LSM_SETID_* values. > * Return 0 on success. > + * @task_fix_setgid: > + * Update the module's state after setting one or more of the group > + * identity attributes of the current process. The @flags parameter > + * indicates which of the set*gid system calls invoked this hook. > + * @new is the set of credentials that will be installed. Modifications > + * should be made to this rather than to @current->cred. > + * @old is the set of credentials that are being replaced > + * @flags contains one of the LSM_SETID_* values. > + * Return 0 on success. > * @task_setpgid: > * Check permission before setting the process group identifier of the > * process @p to @pgid. > @@ -1596,6 +1605,8 @@ union security_list_options { > enum kernel_read_file_id id); > int (*task_fix_setuid)(struct cred *new, const struct cred *old, > int flags); > + int (*task_fix_setgid)(struct cred *new, const struct cred *old, > + int flags); > int (*task_setpgid)(struct task_struct *p, pid_t pgid); > int (*task_getpgid)(struct task_struct *p); > int (*task_getsid)(struct task_struct *p); > @@ -1887,6 +1898,7 @@ struct security_hook_heads { > struct hlist_head kernel_post_read_file; > struct hlist_head kernel_module_request; > struct hlist_head task_fix_setuid; > + struct hlist_head task_fix_setgid; > struct hlist_head task_setpgid; > struct hlist_head task_getpgid; > struct hlist_head task_getsid; > diff --git a/include/linux/security.h b/include/linux/security.h > index 13537a49ae97..f3d095e8dfc1 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr); > extern int cap_mmap_file(struct file *file, unsigned long reqprot, > unsigned long prot, unsigned long flags); > extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags); > +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags); > extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, > unsigned long arg4, unsigned long arg5); > extern int cap_task_setscheduler(struct task_struct *p); > @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, > enum kernel_read_file_id id); > int security_task_fix_setuid(struct cred *new, const struct cred *old, > int flags); > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > + int flags); > int security_task_setpgid(struct task_struct *p, pid_t pgid); > int security_task_getpgid(struct task_struct *p); > int security_task_getsid(struct task_struct *p); > @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new, > return cap_task_fix_setuid(new, old, flags); > } > > +static inline int security_task_fix_setgid(struct cred *new, > + const struct cred *old, > + int flags) > +{ > + return cap_task_fix_setgid(new, old, flags); > +} > + > static inline int security_task_setpgid(struct task_struct *p, pid_t pgid) > { > return 0; > diff --git a/kernel/sys.c b/kernel/sys.c > index c5f875048aef..76f1c46ac66f 100644 > --- a/kernel/sys.c > +++ b/kernel/sys.c > @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > if (rgid != (gid_t) -1) { > if (gid_eq(old->gid, krgid) || > gid_eq(old->egid, krgid) || > - ns_capable(old->user_ns, CAP_SETGID)) > + ns_capable_setid(old->user_ns, CAP_SETGID)) > new->gid = krgid; > else > goto error; > @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > if (gid_eq(old->gid, kegid) || > gid_eq(old->egid, kegid) || > gid_eq(old->sgid, kegid) || > - ns_capable(old->user_ns, CAP_SETGID)) > + ns_capable_setid(old->user_ns, CAP_SETGID)) > new->egid = kegid; > else > goto error; > @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid) > new->sgid = new->egid; > new->fsgid = new->egid; > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RE); > + if (retval < 0) > + goto error; > + > return commit_creds(new); > > error: > @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid) > old = current_cred(); > > retval = -EPERM; > - if (ns_capable(old->user_ns, CAP_SETGID)) > + if (ns_capable_setid(old->user_ns, CAP_SETGID)) > new->gid = new->egid = new->sgid = new->fsgid = kgid; > else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) > new->egid = new->fsgid = kgid; > else > goto error; > > + retval = security_task_fix_setgid(new, old, LSM_SETID_ID); > + if (retval < 0) > + goto error; > + > return commit_creds(new); > > error: > @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > old = current_cred(); > > retval = -EPERM; > - if (!ns_capable(old->user_ns, CAP_SETGID)) { > + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) { > if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && > !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) > goto error; > @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > new->sgid = ksgid; > new->fsgid = new->egid; > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RES); > + if (retval < 0) > + goto error; > + > return commit_creds(new); > > error: > @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid) > > if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || > gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || > - ns_capable(old->user_ns, CAP_SETGID)) { > + ns_capable_setid(old->user_ns, CAP_SETGID)) { > if (!gid_eq(kgid, old->fsgid)) { > new->fsgid = kgid; > - goto change_okay; > + if (security_task_fix_setgid(new, > + old, > + LSM_SETID_FS) == 0) > + goto change_okay; > } > } > > diff --git a/security/security.c b/security/security.c > index b6bff646d373..4264a1e77ce8 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old, > return call_int_hook(task_fix_setuid, 0, new, old, flags); > } > > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > + int flags) > +{ > + return call_int_hook(task_fix_setgid, 0, new, old, flags); > +} > + > int security_task_setpgid(struct task_struct *p, pid_t pgid) > { > return call_int_hook(task_setpgid, 0, p, pgid); > -- > 2.21.0.rc0.258.g878e2cd30e-goog
On Sat, Feb 16, 2019 at 8:43 AM Serge E. Hallyn <serge@hallyn.com> wrote: > > On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote: > > From: Micah Morton <mortonm@chromium.org> > > > > This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the > > existing 'task_fix_setuid' LSM hook, and calls this new hook from the > > setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to > > govern setgid transitions in addition to setuid transitions. This change > > also makes sure the setgid functions in kernel/sys.c call > > security_capable_setid rather than the ordinary security_capable > > Sorry, where security_capable_setid this defined? I assume it was in a recent > patchset, but google and grep are failing me. It was defined in commit 40852275a94afb3e836be9248399e036982d1a79 on the origin/next-general branch of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git. > > > function, so that the security_capable hook in the SafeSetID LSM knows > > it is being invoked from a setid function. > > > > Signed-off-by: Micah Morton <mortonm@chromium.org> > > --- > > Tested with slight mod to test in tools/testing/selftests/safesetid for > > testing setgid as well as setuid. > > > > include/linux/lsm_hooks.h | 12 ++++++++++++ > > include/linux/security.h | 10 ++++++++++ > > kernel/sys.c | 27 +++++++++++++++++++++------ > > security/security.c | 6 ++++++ > > 4 files changed, 49 insertions(+), 6 deletions(-) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index 22fc786d723a..f252ed3e95ef 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -603,6 +603,15 @@ > > * @old is the set of credentials that are being replaces > > * @flags contains one of the LSM_SETID_* values. > > * Return 0 on success. > > + * @task_fix_setgid: > > + * Update the module's state after setting one or more of the group > > + * identity attributes of the current process. The @flags parameter > > + * indicates which of the set*gid system calls invoked this hook. > > + * @new is the set of credentials that will be installed. Modifications > > + * should be made to this rather than to @current->cred. > > + * @old is the set of credentials that are being replaced > > + * @flags contains one of the LSM_SETID_* values. > > + * Return 0 on success. > > * @task_setpgid: > > * Check permission before setting the process group identifier of the > > * process @p to @pgid. > > @@ -1596,6 +1605,8 @@ union security_list_options { > > enum kernel_read_file_id id); > > int (*task_fix_setuid)(struct cred *new, const struct cred *old, > > int flags); > > + int (*task_fix_setgid)(struct cred *new, const struct cred *old, > > + int flags); > > int (*task_setpgid)(struct task_struct *p, pid_t pgid); > > int (*task_getpgid)(struct task_struct *p); > > int (*task_getsid)(struct task_struct *p); > > @@ -1887,6 +1898,7 @@ struct security_hook_heads { > > struct hlist_head kernel_post_read_file; > > struct hlist_head kernel_module_request; > > struct hlist_head task_fix_setuid; > > + struct hlist_head task_fix_setgid; > > struct hlist_head task_setpgid; > > struct hlist_head task_getpgid; > > struct hlist_head task_getsid; > > diff --git a/include/linux/security.h b/include/linux/security.h > > index 13537a49ae97..f3d095e8dfc1 100644 > > --- a/include/linux/security.h > > +++ b/include/linux/security.h > > @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr); > > extern int cap_mmap_file(struct file *file, unsigned long reqprot, > > unsigned long prot, unsigned long flags); > > extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags); > > +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags); > > extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, > > unsigned long arg4, unsigned long arg5); > > extern int cap_task_setscheduler(struct task_struct *p); > > @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, > > enum kernel_read_file_id id); > > int security_task_fix_setuid(struct cred *new, const struct cred *old, > > int flags); > > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > > + int flags); > > int security_task_setpgid(struct task_struct *p, pid_t pgid); > > int security_task_getpgid(struct task_struct *p); > > int security_task_getsid(struct task_struct *p); > > @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new, > > return cap_task_fix_setuid(new, old, flags); > > } > > > > +static inline int security_task_fix_setgid(struct cred *new, > > + const struct cred *old, > > + int flags) > > +{ > > + return cap_task_fix_setgid(new, old, flags); > > +} > > + > > static inline int security_task_setpgid(struct task_struct *p, pid_t pgid) > > { > > return 0; > > diff --git a/kernel/sys.c b/kernel/sys.c > > index c5f875048aef..76f1c46ac66f 100644 > > --- a/kernel/sys.c > > +++ b/kernel/sys.c > > @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > if (rgid != (gid_t) -1) { > > if (gid_eq(old->gid, krgid) || > > gid_eq(old->egid, krgid) || > > - ns_capable(old->user_ns, CAP_SETGID)) > > + ns_capable_setid(old->user_ns, CAP_SETGID)) > > new->gid = krgid; > > else > > goto error; > > @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > if (gid_eq(old->gid, kegid) || > > gid_eq(old->egid, kegid) || > > gid_eq(old->sgid, kegid) || > > - ns_capable(old->user_ns, CAP_SETGID)) > > + ns_capable_setid(old->user_ns, CAP_SETGID)) > > new->egid = kegid; > > else > > goto error; > > @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > new->sgid = new->egid; > > new->fsgid = new->egid; > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RE); > > + if (retval < 0) > > + goto error; > > + > > return commit_creds(new); > > > > error: > > @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid) > > old = current_cred(); > > > > retval = -EPERM; > > - if (ns_capable(old->user_ns, CAP_SETGID)) > > + if (ns_capable_setid(old->user_ns, CAP_SETGID)) > > new->gid = new->egid = new->sgid = new->fsgid = kgid; > > else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) > > new->egid = new->fsgid = kgid; > > else > > goto error; > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_ID); > > + if (retval < 0) > > + goto error; > > + > > return commit_creds(new); > > > > error: > > @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > > old = current_cred(); > > > > retval = -EPERM; > > - if (!ns_capable(old->user_ns, CAP_SETGID)) { > > + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) { > > if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && > > !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) > > goto error; > > @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > > new->sgid = ksgid; > > new->fsgid = new->egid; > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RES); > > + if (retval < 0) > > + goto error; > > + > > return commit_creds(new); > > > > error: > > @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid) > > > > if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || > > gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || > > - ns_capable(old->user_ns, CAP_SETGID)) { > > + ns_capable_setid(old->user_ns, CAP_SETGID)) { > > if (!gid_eq(kgid, old->fsgid)) { > > new->fsgid = kgid; > > - goto change_okay; > > + if (security_task_fix_setgid(new, > > + old, > > + LSM_SETID_FS) == 0) > > + goto change_okay; > > } > > } > > > > diff --git a/security/security.c b/security/security.c > > index b6bff646d373..4264a1e77ce8 100644 > > --- a/security/security.c > > +++ b/security/security.c > > @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old, > > return call_int_hook(task_fix_setuid, 0, new, old, flags); > > } > > > > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > > + int flags) > > +{ > > + return call_int_hook(task_fix_setgid, 0, new, old, flags); > > +} > > + > > int security_task_setpgid(struct task_struct *p, pid_t pgid) > > { > > return call_int_hook(task_setpgid, 0, p, pgid); > > -- > > 2.21.0.rc0.258.g878e2cd30e-goog
On Tue, Feb 19, 2019 at 09:00:13AM -0800, Micah Morton wrote: > On Sat, Feb 16, 2019 at 8:43 AM Serge E. Hallyn <serge@hallyn.com> wrote: > > > > On Fri, Feb 15, 2019 at 02:22:17PM -0800, mortonm@chromium.org wrote: > > > From: Micah Morton <mortonm@chromium.org> > > > > > > This patch adds a 'task_fix_setgid' LSM hook, which is analogous to the > > > existing 'task_fix_setuid' LSM hook, and calls this new hook from the > > > setgid functions in kernel/sys.c. This will allow the SafeSetID LSM to > > > govern setgid transitions in addition to setuid transitions. This change > > > also makes sure the setgid functions in kernel/sys.c call > > > security_capable_setid rather than the ordinary security_capable > > > > Sorry, where security_capable_setid this defined? I assume it was in a recent > > patchset, but google and grep are failing me. > > It was defined in commit 40852275a94afb3e836be9248399e036982d1a79 on > the origin/next-general branch of > git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git. Thanks. > > > function, so that the security_capable hook in the SafeSetID LSM knows > > > it is being invoked from a setid function. > > > > > > Signed-off-by: Micah Morton <mortonm@chromium.org> Acked-by: Serge Hallyn <serge@hallyn.com> > > > --- > > > Tested with slight mod to test in tools/testing/selftests/safesetid for > > > testing setgid as well as setuid. > > > > > > include/linux/lsm_hooks.h | 12 ++++++++++++ > > > include/linux/security.h | 10 ++++++++++ > > > kernel/sys.c | 27 +++++++++++++++++++++------ > > > security/security.c | 6 ++++++ > > > 4 files changed, 49 insertions(+), 6 deletions(-) > > > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > > index 22fc786d723a..f252ed3e95ef 100644 > > > --- a/include/linux/lsm_hooks.h > > > +++ b/include/linux/lsm_hooks.h > > > @@ -603,6 +603,15 @@ > > > * @old is the set of credentials that are being replaces > > > * @flags contains one of the LSM_SETID_* values. > > > * Return 0 on success. > > > + * @task_fix_setgid: > > > + * Update the module's state after setting one or more of the group > > > + * identity attributes of the current process. The @flags parameter > > > + * indicates which of the set*gid system calls invoked this hook. > > > + * @new is the set of credentials that will be installed. Modifications > > > + * should be made to this rather than to @current->cred. > > > + * @old is the set of credentials that are being replaced > > > + * @flags contains one of the LSM_SETID_* values. > > > + * Return 0 on success. > > > * @task_setpgid: > > > * Check permission before setting the process group identifier of the > > > * process @p to @pgid. > > > @@ -1596,6 +1605,8 @@ union security_list_options { > > > enum kernel_read_file_id id); > > > int (*task_fix_setuid)(struct cred *new, const struct cred *old, > > > int flags); > > > + int (*task_fix_setgid)(struct cred *new, const struct cred *old, > > > + int flags); > > > int (*task_setpgid)(struct task_struct *p, pid_t pgid); > > > int (*task_getpgid)(struct task_struct *p); > > > int (*task_getsid)(struct task_struct *p); > > > @@ -1887,6 +1898,7 @@ struct security_hook_heads { > > > struct hlist_head kernel_post_read_file; > > > struct hlist_head kernel_module_request; > > > struct hlist_head task_fix_setuid; > > > + struct hlist_head task_fix_setgid; > > > struct hlist_head task_setpgid; > > > struct hlist_head task_getpgid; > > > struct hlist_head task_getsid; > > > diff --git a/include/linux/security.h b/include/linux/security.h > > > index 13537a49ae97..f3d095e8dfc1 100644 > > > --- a/include/linux/security.h > > > +++ b/include/linux/security.h > > > @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr); > > > extern int cap_mmap_file(struct file *file, unsigned long reqprot, > > > unsigned long prot, unsigned long flags); > > > extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags); > > > +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags); > > > extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, > > > unsigned long arg4, unsigned long arg5); > > > extern int cap_task_setscheduler(struct task_struct *p); > > > @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, > > > enum kernel_read_file_id id); > > > int security_task_fix_setuid(struct cred *new, const struct cred *old, > > > int flags); > > > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > > > + int flags); > > > int security_task_setpgid(struct task_struct *p, pid_t pgid); > > > int security_task_getpgid(struct task_struct *p); > > > int security_task_getsid(struct task_struct *p); > > > @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new, > > > return cap_task_fix_setuid(new, old, flags); > > > } > > > > > > +static inline int security_task_fix_setgid(struct cred *new, > > > + const struct cred *old, > > > + int flags) > > > +{ > > > + return cap_task_fix_setgid(new, old, flags); > > > +} > > > + > > > static inline int security_task_setpgid(struct task_struct *p, pid_t pgid) > > > { > > > return 0; > > > diff --git a/kernel/sys.c b/kernel/sys.c > > > index c5f875048aef..76f1c46ac66f 100644 > > > --- a/kernel/sys.c > > > +++ b/kernel/sys.c > > > @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > > if (rgid != (gid_t) -1) { > > > if (gid_eq(old->gid, krgid) || > > > gid_eq(old->egid, krgid) || > > > - ns_capable(old->user_ns, CAP_SETGID)) > > > + ns_capable_setid(old->user_ns, CAP_SETGID)) > > > new->gid = krgid; > > > else > > > goto error; > > > @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > > if (gid_eq(old->gid, kegid) || > > > gid_eq(old->egid, kegid) || > > > gid_eq(old->sgid, kegid) || > > > - ns_capable(old->user_ns, CAP_SETGID)) > > > + ns_capable_setid(old->user_ns, CAP_SETGID)) > > > new->egid = kegid; > > > else > > > goto error; > > > @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid) > > > new->sgid = new->egid; > > > new->fsgid = new->egid; > > > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RE); > > > + if (retval < 0) > > > + goto error; > > > + > > > return commit_creds(new); > > > > > > error: > > > @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid) > > > old = current_cred(); > > > > > > retval = -EPERM; > > > - if (ns_capable(old->user_ns, CAP_SETGID)) > > > + if (ns_capable_setid(old->user_ns, CAP_SETGID)) > > > new->gid = new->egid = new->sgid = new->fsgid = kgid; > > > else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) > > > new->egid = new->fsgid = kgid; > > > else > > > goto error; > > > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_ID); > > > + if (retval < 0) > > > + goto error; > > > + > > > return commit_creds(new); > > > > > > error: > > > @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > > > old = current_cred(); > > > > > > retval = -EPERM; > > > - if (!ns_capable(old->user_ns, CAP_SETGID)) { > > > + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) { > > > if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && > > > !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) > > > goto error; > > > @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) > > > new->sgid = ksgid; > > > new->fsgid = new->egid; > > > > > > + retval = security_task_fix_setgid(new, old, LSM_SETID_RES); > > > + if (retval < 0) > > > + goto error; > > > + > > > return commit_creds(new); > > > > > > error: > > > @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid) > > > > > > if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || > > > gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || > > > - ns_capable(old->user_ns, CAP_SETGID)) { > > > + ns_capable_setid(old->user_ns, CAP_SETGID)) { > > > if (!gid_eq(kgid, old->fsgid)) { > > > new->fsgid = kgid; > > > - goto change_okay; > > > + if (security_task_fix_setgid(new, > > > + old, > > > + LSM_SETID_FS) == 0) > > > + goto change_okay; > > > } > > > } > > > > > > diff --git a/security/security.c b/security/security.c > > > index b6bff646d373..4264a1e77ce8 100644 > > > --- a/security/security.c > > > +++ b/security/security.c > > > @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old, > > > return call_int_hook(task_fix_setuid, 0, new, old, flags); > > > } > > > > > > +int security_task_fix_setgid(struct cred *new, const struct cred *old, > > > + int flags) > > > +{ > > > + return call_int_hook(task_fix_setgid, 0, new, old, flags); > > > +} > > > + > > > int security_task_setpgid(struct task_struct *p, pid_t pgid) > > > { > > > return call_int_hook(task_setpgid, 0, p, pgid); > > > -- > > > 2.21.0.rc0.258.g878e2cd30e-goog
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 22fc786d723a..f252ed3e95ef 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -603,6 +603,15 @@ * @old is the set of credentials that are being replaces * @flags contains one of the LSM_SETID_* values. * Return 0 on success. + * @task_fix_setgid: + * Update the module's state after setting one or more of the group + * identity attributes of the current process. The @flags parameter + * indicates which of the set*gid system calls invoked this hook. + * @new is the set of credentials that will be installed. Modifications + * should be made to this rather than to @current->cred. + * @old is the set of credentials that are being replaced + * @flags contains one of the LSM_SETID_* values. + * Return 0 on success. * @task_setpgid: * Check permission before setting the process group identifier of the * process @p to @pgid. @@ -1596,6 +1605,8 @@ union security_list_options { enum kernel_read_file_id id); int (*task_fix_setuid)(struct cred *new, const struct cred *old, int flags); + int (*task_fix_setgid)(struct cred *new, const struct cred *old, + int flags); int (*task_setpgid)(struct task_struct *p, pid_t pgid); int (*task_getpgid)(struct task_struct *p); int (*task_getsid)(struct task_struct *p); @@ -1887,6 +1898,7 @@ struct security_hook_heads { struct hlist_head kernel_post_read_file; struct hlist_head kernel_module_request; struct hlist_head task_fix_setuid; + struct hlist_head task_fix_setgid; struct hlist_head task_setpgid; struct hlist_head task_getpgid; struct hlist_head task_getsid; diff --git a/include/linux/security.h b/include/linux/security.h index 13537a49ae97..f3d095e8dfc1 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -96,6 +96,7 @@ extern int cap_mmap_addr(unsigned long addr); extern int cap_mmap_file(struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags); extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags); +extern int cap_task_fix_setgid(struct cred *new, const struct cred *old, int flags); extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4, unsigned long arg5); extern int cap_task_setscheduler(struct task_struct *p); @@ -326,6 +327,8 @@ int security_kernel_post_read_file(struct file *file, char *buf, loff_t size, enum kernel_read_file_id id); int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags); +int security_task_fix_setgid(struct cred *new, const struct cred *old, + int flags); int security_task_setpgid(struct task_struct *p, pid_t pgid); int security_task_getpgid(struct task_struct *p); int security_task_getsid(struct task_struct *p); @@ -930,6 +933,13 @@ static inline int security_task_fix_setuid(struct cred *new, return cap_task_fix_setuid(new, old, flags); } +static inline int security_task_fix_setgid(struct cred *new, + const struct cred *old, + int flags) +{ + return cap_task_fix_setgid(new, old, flags); +} + static inline int security_task_setpgid(struct task_struct *p, pid_t pgid) { return 0; diff --git a/kernel/sys.c b/kernel/sys.c index c5f875048aef..76f1c46ac66f 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -372,7 +372,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) if (rgid != (gid_t) -1) { if (gid_eq(old->gid, krgid) || gid_eq(old->egid, krgid) || - ns_capable(old->user_ns, CAP_SETGID)) + ns_capable_setid(old->user_ns, CAP_SETGID)) new->gid = krgid; else goto error; @@ -381,7 +381,7 @@ long __sys_setregid(gid_t rgid, gid_t egid) if (gid_eq(old->gid, kegid) || gid_eq(old->egid, kegid) || gid_eq(old->sgid, kegid) || - ns_capable(old->user_ns, CAP_SETGID)) + ns_capable_setid(old->user_ns, CAP_SETGID)) new->egid = kegid; else goto error; @@ -392,6 +392,10 @@ long __sys_setregid(gid_t rgid, gid_t egid) new->sgid = new->egid; new->fsgid = new->egid; + retval = security_task_fix_setgid(new, old, LSM_SETID_RE); + if (retval < 0) + goto error; + return commit_creds(new); error: @@ -427,13 +431,17 @@ long __sys_setgid(gid_t gid) old = current_cred(); retval = -EPERM; - if (ns_capable(old->user_ns, CAP_SETGID)) + if (ns_capable_setid(old->user_ns, CAP_SETGID)) new->gid = new->egid = new->sgid = new->fsgid = kgid; else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) new->egid = new->fsgid = kgid; else goto error; + retval = security_task_fix_setgid(new, old, LSM_SETID_ID); + if (retval < 0) + goto error; + return commit_creds(new); error: @@ -735,7 +743,7 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) old = current_cred(); retval = -EPERM; - if (!ns_capable(old->user_ns, CAP_SETGID)) { + if (!ns_capable_setid(old->user_ns, CAP_SETGID)) { if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) goto error; @@ -755,6 +763,10 @@ long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) new->sgid = ksgid; new->fsgid = new->egid; + retval = security_task_fix_setgid(new, old, LSM_SETID_RES); + if (retval < 0) + goto error; + return commit_creds(new); error: @@ -858,10 +870,13 @@ long __sys_setfsgid(gid_t gid) if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || - ns_capable(old->user_ns, CAP_SETGID)) { + ns_capable_setid(old->user_ns, CAP_SETGID)) { if (!gid_eq(kgid, old->fsgid)) { new->fsgid = kgid; - goto change_okay; + if (security_task_fix_setgid(new, + old, + LSM_SETID_FS) == 0) + goto change_okay; } } diff --git a/security/security.c b/security/security.c index b6bff646d373..4264a1e77ce8 100644 --- a/security/security.c +++ b/security/security.c @@ -1570,6 +1570,12 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old, return call_int_hook(task_fix_setuid, 0, new, old, flags); } +int security_task_fix_setgid(struct cred *new, const struct cred *old, + int flags) +{ + return call_int_hook(task_fix_setgid, 0, new, old, flags); +} + int security_task_setpgid(struct task_struct *p, pid_t pgid) { return call_int_hook(task_setpgid, 0, p, pgid);