| Message ID | 1706654228-17180-9-git-send-email-wufan@linux.microsoft.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | Integrity Policy Enforcement LSM (IPE) | expand |
On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: > > As is typical with LSMs, IPE uses securityfs as its interface with > userspace. for a complete list of the interfaces and the respective > inputs/outputs, please see the documentation under > admin-guide/LSM/ipe.rst > > Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> > Signed-off-by: Fan Wu <wufan@linux.microsoft.com> > --- > v2: > + Split evaluation loop, access control hooks, > and evaluation loop from policy parser and userspace > interface to pass mailing list character limit > > v3: > + Move policy load and activation audit event to 03/12 > + Fix a potential panic when a policy failed to load. > + use pr_warn for a failure to parse instead of an > audit record > + Remove comments from headers > + Add lockdep assertions to ipe_update_active_policy and > ipe_activate_policy > + Fix up warnings with checkpatch --strict > + Use file_ns_capable for CAP_MAC_ADMIN for securityfs > nodes. > + Use memdup_user instead of kzalloc+simple_write_to_buffer. > + Remove strict_parse command line parameter, as it is added > by the sysctl command line. > + Prefix extern variables with ipe_ > > v4: > + Remove securityfs to reverse-dependency > + Add SHA1 reverse dependency. > + Add versioning scheme for IPE properties, and associated > interface to query the versioning scheme. > + Cause a parser to always return an error on unknown syntax. > + Remove strict_parse option > + Change active_policy interface from sysctl, to securityfs, > and change scheme. > > v5: > + Cause an error if a default action is not defined for each > operation. > + Minor function renames > > v6: > + No changes > > v7: > + Propagating changes to support the new ipe_context structure in the > evaluation loop. > > + Further split the parser and userspace interface changes into > separate commits. > > + "raw" was renamed to "pkcs7" and made read only > + "raw"'s write functionality (update a policy) moved to "update" > + introduced "version", "policy_name" nodes. > + "content" renamed to "policy" > + changes to allow the compiled-in policy to be treated > identical to deployed-after-the-fact policies. > > v8: > + Prevent securityfs initialization if the LSM is disabled > > v9: > + Switch to securityfs_recursive_remove for policy folder deletion > > v10: > + Simplify and correct concurrency > + Fix typos > > v11: > + Correct code comments > > v12: > + Correct locking and remove redundant code > --- > security/ipe/Makefile | 2 + > security/ipe/fs.c | 101 +++++++++ > security/ipe/fs.h | 16 ++ > security/ipe/ipe.c | 3 + > security/ipe/ipe.h | 2 + > security/ipe/policy.c | 123 ++++++++++ > security/ipe/policy.h | 9 + > security/ipe/policy_fs.c | 469 +++++++++++++++++++++++++++++++++++++++ > 8 files changed, 725 insertions(+) > create mode 100644 security/ipe/fs.c > create mode 100644 security/ipe/fs.h > create mode 100644 security/ipe/policy_fs.c ... > diff --git a/security/ipe/policy.c b/security/ipe/policy.c > index f22a576a6d68..61fea3e38e11 100644 > --- a/security/ipe/policy.c > +++ b/security/ipe/policy.c > @@ -43,6 +71,68 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, > return 0; > } > > +/** > + * ipe_update_policy - parse a new policy and replace old with it. > + * @root: Supplies a pointer to the securityfs inode saved the policy. > + * @text: Supplies a pointer to the plain text policy. > + * @textlen: Supplies the length of @text. > + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. > + * @pkcs7len: Supplies the length of @pkcs7len. > + * > + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see > + * ipe_new_policy. > + * > + * Context: Requires root->i_rwsem to be held. > + * Return: > + * * !IS_ERR - The existing policy saved in the inode before update > + * * -ENOENT - Policy doesn't exist > + * * -EINVAL - New policy is invalid > + */ > +struct ipe_policy *ipe_update_policy(struct inode *root, > + const char *text, size_t textlen, > + const char *pkcs7, size_t pkcs7len) > +{ > + int rc = 0; > + struct ipe_policy *old, *ap, *new = NULL; > + > + old = (struct ipe_policy *)root->i_private; > + if (!old) > + return ERR_PTR(-ENOENT); > + > + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); > + if (IS_ERR(new)) > + return new; > + > + if (strcmp(new->parsed->name, old->parsed->name)) { > + rc = -EINVAL; > + goto err; > + } > + > + if (ver_to_u64(old) > ver_to_u64(new)) { > + rc = -EINVAL; > + goto err; > + } > + > + root->i_private = new; > + swap(new->policyfs, old->policyfs); Should the swap() take place with @ipe_policy_lock held? > + mutex_lock(&ipe_policy_lock); > + ap = rcu_dereference_protected(ipe_active_policy, > + lockdep_is_held(&ipe_policy_lock)); > + if (old == ap) { > + rcu_assign_pointer(ipe_active_policy, new); > + mutex_unlock(&ipe_policy_lock); > + synchronize_rcu(); I'm guessing you are forcing a synchronize_rcu() here because you are free()'ing @old in the caller, yes? Looking at the code, I only see one caller, update_policy(). With only one caller, why not free @old directly in ipe_update_policy()? Do you see others callers that would do something different? > + } else { > + mutex_unlock(&ipe_policy_lock); > + } > + > + return old; > +err: > + ipe_free_policy(new); > + return ERR_PTR(rc); > +} > + > /** > * ipe_new_policy - Allocate and parse an ipe_policy structure. > * > @@ -99,3 +189,36 @@ struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, > ipe_free_policy(new); > return ERR_PTR(rc); > } > + > +/** > + * ipe_set_active_pol - Make @p the active policy. > + * @p: Supplies a pointer to the policy to make active. > + * > + * Context: Requires root->i_rwsem, which i_private has the policy, to be held. > + * Return: > + * * !IS_ERR - Success > + * * -EINVAL - New active policy version is invalid > + */ > +int ipe_set_active_pol(const struct ipe_policy *p) > +{ > + struct ipe_policy *ap = NULL; > + > + mutex_lock(&ipe_policy_lock); > + > + ap = rcu_dereference_protected(ipe_active_policy, > + lockdep_is_held(&ipe_policy_lock)); > + if (ap == p) { > + mutex_unlock(&ipe_policy_lock); > + return 0; > + } > + if (ap && ver_to_u64(ap) > ver_to_u64(p)) { > + mutex_unlock(&ipe_policy_lock); > + return -EINVAL; > + } > + > + rcu_assign_pointer(ipe_active_policy, p); > + mutex_unlock(&ipe_policy_lock); > + synchronize_rcu(); Why do you need the synchronize_rcu() call here? > + return 0; > +} -- paul-moore.com
On 2/3/2024 2:25 PM, Paul Moore wrote: > On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: >> >> As is typical with LSMs, IPE uses securityfs as its interface with >> userspace. for a complete list of the interfaces and the respective >> inputs/outputs, please see the documentation under >> admin-guide/LSM/ipe.rst >> >> Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> >> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> >> --- >> v2: >> + Split evaluation loop, access control hooks, >> and evaluation loop from policy parser and userspace >> interface to pass mailing list character limit >> >> v3: >> + Move policy load and activation audit event to 03/12 >> + Fix a potential panic when a policy failed to load. >> + use pr_warn for a failure to parse instead of an >> audit record >> + Remove comments from headers >> + Add lockdep assertions to ipe_update_active_policy and >> ipe_activate_policy >> + Fix up warnings with checkpatch --strict >> + Use file_ns_capable for CAP_MAC_ADMIN for securityfs >> nodes. >> + Use memdup_user instead of kzalloc+simple_write_to_buffer. >> + Remove strict_parse command line parameter, as it is added >> by the sysctl command line. >> + Prefix extern variables with ipe_ >> >> v4: >> + Remove securityfs to reverse-dependency >> + Add SHA1 reverse dependency. >> + Add versioning scheme for IPE properties, and associated >> interface to query the versioning scheme. >> + Cause a parser to always return an error on unknown syntax. >> + Remove strict_parse option >> + Change active_policy interface from sysctl, to securityfs, >> and change scheme. >> >> v5: >> + Cause an error if a default action is not defined for each >> operation. >> + Minor function renames >> >> v6: >> + No changes >> >> v7: >> + Propagating changes to support the new ipe_context structure in the >> evaluation loop. >> >> + Further split the parser and userspace interface changes into >> separate commits. >> >> + "raw" was renamed to "pkcs7" and made read only >> + "raw"'s write functionality (update a policy) moved to "update" >> + introduced "version", "policy_name" nodes. >> + "content" renamed to "policy" >> + changes to allow the compiled-in policy to be treated >> identical to deployed-after-the-fact policies. >> >> v8: >> + Prevent securityfs initialization if the LSM is disabled >> >> v9: >> + Switch to securityfs_recursive_remove for policy folder deletion >> >> v10: >> + Simplify and correct concurrency >> + Fix typos >> >> v11: >> + Correct code comments >> >> v12: >> + Correct locking and remove redundant code >> --- >> security/ipe/Makefile | 2 + >> security/ipe/fs.c | 101 +++++++++ >> security/ipe/fs.h | 16 ++ >> security/ipe/ipe.c | 3 + >> security/ipe/ipe.h | 2 + >> security/ipe/policy.c | 123 ++++++++++ >> security/ipe/policy.h | 9 + >> security/ipe/policy_fs.c | 469 +++++++++++++++++++++++++++++++++++++++ >> 8 files changed, 725 insertions(+) >> create mode 100644 security/ipe/fs.c >> create mode 100644 security/ipe/fs.h >> create mode 100644 security/ipe/policy_fs.c > > ... > >> diff --git a/security/ipe/policy.c b/security/ipe/policy.c >> index f22a576a6d68..61fea3e38e11 100644 >> --- a/security/ipe/policy.c >> +++ b/security/ipe/policy.c >> @@ -43,6 +71,68 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, >> return 0; >> } >> >> +/** >> + * ipe_update_policy - parse a new policy and replace old with it. >> + * @root: Supplies a pointer to the securityfs inode saved the policy. >> + * @text: Supplies a pointer to the plain text policy. >> + * @textlen: Supplies the length of @text. >> + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. >> + * @pkcs7len: Supplies the length of @pkcs7len. >> + * >> + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see >> + * ipe_new_policy. >> + * >> + * Context: Requires root->i_rwsem to be held. >> + * Return: >> + * * !IS_ERR - The existing policy saved in the inode before update >> + * * -ENOENT - Policy doesn't exist >> + * * -EINVAL - New policy is invalid >> + */ >> +struct ipe_policy *ipe_update_policy(struct inode *root, >> + const char *text, size_t textlen, >> + const char *pkcs7, size_t pkcs7len) >> +{ >> + int rc = 0; >> + struct ipe_policy *old, *ap, *new = NULL; >> + >> + old = (struct ipe_policy *)root->i_private; >> + if (!old) >> + return ERR_PTR(-ENOENT); >> + >> + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); >> + if (IS_ERR(new)) >> + return new; >> + >> + if (strcmp(new->parsed->name, old->parsed->name)) { >> + rc = -EINVAL; >> + goto err; >> + } >> + >> + if (ver_to_u64(old) > ver_to_u64(new)) { >> + rc = -EINVAL; >> + goto err; >> + } >> + >> + root->i_private = new; >> + swap(new->policyfs, old->policyfs); > > Should the swap() take place with @ipe_policy_lock held? > I think we are safe here because root->i_rwsem is held. Other two operations set_active and delete are also depending on the inode lock. >> + mutex_lock(&ipe_policy_lock); >> + ap = rcu_dereference_protected(ipe_active_policy, >> + lockdep_is_held(&ipe_policy_lock)); >> + if (old == ap) { >> + rcu_assign_pointer(ipe_active_policy, new); >> + mutex_unlock(&ipe_policy_lock); >> + synchronize_rcu(); > > I'm guessing you are forcing a synchronize_rcu() here because you are > free()'ing @old in the caller, yes? Looking at the code, I only see > one caller, update_policy(). With only one caller, why not free @old > directly in ipe_update_policy()? Do you see others callers that would > do something different? > The call of synchronize_rcu() is because we are updating the current active policy so we need to set the new policy as active. I do agree we can free the old inside this function. >> + } else { >> + mutex_unlock(&ipe_policy_lock); >> + } >> + >> + return old; >> +err: >> + ipe_free_policy(new); >> + return ERR_PTR(rc); >> +} >> + >> /** >> * ipe_new_policy - Allocate and parse an ipe_policy structure. >> * >> @@ -99,3 +189,36 @@ struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, >> ipe_free_policy(new); >> return ERR_PTR(rc); >> } >> + >> +/** >> + * ipe_set_active_pol - Make @p the active policy. >> + * @p: Supplies a pointer to the policy to make active. >> + * >> + * Context: Requires root->i_rwsem, which i_private has the policy, to be held. >> + * Return: >> + * * !IS_ERR - Success >> + * * -EINVAL - New active policy version is invalid >> + */ >> +int ipe_set_active_pol(const struct ipe_policy *p) >> +{ >> + struct ipe_policy *ap = NULL; >> + >> + mutex_lock(&ipe_policy_lock); >> + >> + ap = rcu_dereference_protected(ipe_active_policy, >> + lockdep_is_held(&ipe_policy_lock)); >> + if (ap == p) { >> + mutex_unlock(&ipe_policy_lock); >> + return 0; >> + } >> + if (ap && ver_to_u64(ap) > ver_to_u64(p)) { >> + mutex_unlock(&ipe_policy_lock); >> + return -EINVAL; >> + } >> + >> + rcu_assign_pointer(ipe_active_policy, p); >> + mutex_unlock(&ipe_policy_lock); >> + synchronize_rcu(); > > Why do you need the synchronize_rcu() call here? > >> + return 0; >> +} > > > -- > paul-moore.com
On Mon, Feb 5, 2024 at 6:01 PM Fan Wu <wufan@linux.microsoft.com> wrote: > On 2/3/2024 2:25 PM, Paul Moore wrote: > > On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: > >> > >> As is typical with LSMs, IPE uses securityfs as its interface with > >> userspace. for a complete list of the interfaces and the respective > >> inputs/outputs, please see the documentation under > >> admin-guide/LSM/ipe.rst > >> > >> Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> > >> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> > >> --- > >> v2: > >> + Split evaluation loop, access control hooks, > >> and evaluation loop from policy parser and userspace > >> interface to pass mailing list character limit > >> > >> v3: > >> + Move policy load and activation audit event to 03/12 > >> + Fix a potential panic when a policy failed to load. > >> + use pr_warn for a failure to parse instead of an > >> audit record > >> + Remove comments from headers > >> + Add lockdep assertions to ipe_update_active_policy and > >> ipe_activate_policy > >> + Fix up warnings with checkpatch --strict > >> + Use file_ns_capable for CAP_MAC_ADMIN for securityfs > >> nodes. > >> + Use memdup_user instead of kzalloc+simple_write_to_buffer. > >> + Remove strict_parse command line parameter, as it is added > >> by the sysctl command line. > >> + Prefix extern variables with ipe_ > >> > >> v4: > >> + Remove securityfs to reverse-dependency > >> + Add SHA1 reverse dependency. > >> + Add versioning scheme for IPE properties, and associated > >> interface to query the versioning scheme. > >> + Cause a parser to always return an error on unknown syntax. > >> + Remove strict_parse option > >> + Change active_policy interface from sysctl, to securityfs, > >> and change scheme. > >> > >> v5: > >> + Cause an error if a default action is not defined for each > >> operation. > >> + Minor function renames > >> > >> v6: > >> + No changes > >> > >> v7: > >> + Propagating changes to support the new ipe_context structure in the > >> evaluation loop. > >> > >> + Further split the parser and userspace interface changes into > >> separate commits. > >> > >> + "raw" was renamed to "pkcs7" and made read only > >> + "raw"'s write functionality (update a policy) moved to "update" > >> + introduced "version", "policy_name" nodes. > >> + "content" renamed to "policy" > >> + changes to allow the compiled-in policy to be treated > >> identical to deployed-after-the-fact policies. > >> > >> v8: > >> + Prevent securityfs initialization if the LSM is disabled > >> > >> v9: > >> + Switch to securityfs_recursive_remove for policy folder deletion > >> > >> v10: > >> + Simplify and correct concurrency > >> + Fix typos > >> > >> v11: > >> + Correct code comments > >> > >> v12: > >> + Correct locking and remove redundant code > >> --- > >> security/ipe/Makefile | 2 + > >> security/ipe/fs.c | 101 +++++++++ > >> security/ipe/fs.h | 16 ++ > >> security/ipe/ipe.c | 3 + > >> security/ipe/ipe.h | 2 + > >> security/ipe/policy.c | 123 ++++++++++ > >> security/ipe/policy.h | 9 + > >> security/ipe/policy_fs.c | 469 +++++++++++++++++++++++++++++++++++++++ > >> 8 files changed, 725 insertions(+) > >> create mode 100644 security/ipe/fs.c > >> create mode 100644 security/ipe/fs.h > >> create mode 100644 security/ipe/policy_fs.c > > > > ... > > > >> diff --git a/security/ipe/policy.c b/security/ipe/policy.c > >> index f22a576a6d68..61fea3e38e11 100644 > >> --- a/security/ipe/policy.c > >> +++ b/security/ipe/policy.c > >> @@ -43,6 +71,68 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, > >> return 0; > >> } > >> > >> +/** > >> + * ipe_update_policy - parse a new policy and replace old with it. > >> + * @root: Supplies a pointer to the securityfs inode saved the policy. > >> + * @text: Supplies a pointer to the plain text policy. > >> + * @textlen: Supplies the length of @text. > >> + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. > >> + * @pkcs7len: Supplies the length of @pkcs7len. > >> + * > >> + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see > >> + * ipe_new_policy. > >> + * > >> + * Context: Requires root->i_rwsem to be held. > >> + * Return: > >> + * * !IS_ERR - The existing policy saved in the inode before update > >> + * * -ENOENT - Policy doesn't exist > >> + * * -EINVAL - New policy is invalid > >> + */ > >> +struct ipe_policy *ipe_update_policy(struct inode *root, > >> + const char *text, size_t textlen, > >> + const char *pkcs7, size_t pkcs7len) > >> +{ > >> + int rc = 0; > >> + struct ipe_policy *old, *ap, *new = NULL; > >> + > >> + old = (struct ipe_policy *)root->i_private; > >> + if (!old) > >> + return ERR_PTR(-ENOENT); > >> + > >> + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); > >> + if (IS_ERR(new)) > >> + return new; > >> + > >> + if (strcmp(new->parsed->name, old->parsed->name)) { > >> + rc = -EINVAL; > >> + goto err; > >> + } > >> + > >> + if (ver_to_u64(old) > ver_to_u64(new)) { > >> + rc = -EINVAL; > >> + goto err; > >> + } > >> + > >> + root->i_private = new; > >> + swap(new->policyfs, old->policyfs); > > > > Should the swap() take place with @ipe_policy_lock held? > > > I think we are safe here because root->i_rwsem is held. Other two > operations set_active and delete are also depending on the inode lock. > >> + mutex_lock(&ipe_policy_lock); > >> + ap = rcu_dereference_protected(ipe_active_policy, > >> + lockdep_is_held(&ipe_policy_lock)); > >> + if (old == ap) { > >> + rcu_assign_pointer(ipe_active_policy, new); > >> + mutex_unlock(&ipe_policy_lock); > >> + synchronize_rcu(); > > > > I'm guessing you are forcing a synchronize_rcu() here because you are > > free()'ing @old in the caller, yes? Looking at the code, I only see > > one caller, update_policy(). With only one caller, why not free @old > > directly in ipe_update_policy()? Do you see others callers that would > > do something different? > > > The call of synchronize_rcu() is because we are updating the current > active policy so we need to set the new policy as active. Unless I'm mistaken, a syncronize_rcu() call only ensures that the current task will see the updated value by waiting until all current RCU critical sections have finished. Given the mutex involved here I don't believe this is necessary, but please correct me if I'm wrong.
On 2/5/2024 3:10 PM, Paul Moore wrote: > On Mon, Feb 5, 2024 at 6:01 PM Fan Wu <wufan@linux.microsoft.com> wrote: >> On 2/3/2024 2:25 PM, Paul Moore wrote: >>> On Jan 30, 2024 Fan Wu <wufan@linux.microsoft.com> wrote: >>>> >>>> As is typical with LSMs, IPE uses securityfs as its interface with >>>> userspace. for a complete list of the interfaces and the respective >>>> inputs/outputs, please see the documentation under >>>> admin-guide/LSM/ipe.rst >>>> >>>> Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com> >>>> Signed-off-by: Fan Wu <wufan@linux.microsoft.com> >>>> --- >>>> v2: >>>> + Split evaluation loop, access control hooks, >>>> and evaluation loop from policy parser and userspace >>>> interface to pass mailing list character limit >>>> >>>> v3: >>>> + Move policy load and activation audit event to 03/12 >>>> + Fix a potential panic when a policy failed to load. >>>> + use pr_warn for a failure to parse instead of an >>>> audit record >>>> + Remove comments from headers >>>> + Add lockdep assertions to ipe_update_active_policy and >>>> ipe_activate_policy >>>> + Fix up warnings with checkpatch --strict >>>> + Use file_ns_capable for CAP_MAC_ADMIN for securityfs >>>> nodes. >>>> + Use memdup_user instead of kzalloc+simple_write_to_buffer. >>>> + Remove strict_parse command line parameter, as it is added >>>> by the sysctl command line. >>>> + Prefix extern variables with ipe_ >>>> >>>> v4: >>>> + Remove securityfs to reverse-dependency >>>> + Add SHA1 reverse dependency. >>>> + Add versioning scheme for IPE properties, and associated >>>> interface to query the versioning scheme. >>>> + Cause a parser to always return an error on unknown syntax. >>>> + Remove strict_parse option >>>> + Change active_policy interface from sysctl, to securityfs, >>>> and change scheme. >>>> >>>> v5: >>>> + Cause an error if a default action is not defined for each >>>> operation. >>>> + Minor function renames >>>> >>>> v6: >>>> + No changes >>>> >>>> v7: >>>> + Propagating changes to support the new ipe_context structure in the >>>> evaluation loop. >>>> >>>> + Further split the parser and userspace interface changes into >>>> separate commits. >>>> >>>> + "raw" was renamed to "pkcs7" and made read only >>>> + "raw"'s write functionality (update a policy) moved to "update" >>>> + introduced "version", "policy_name" nodes. >>>> + "content" renamed to "policy" >>>> + changes to allow the compiled-in policy to be treated >>>> identical to deployed-after-the-fact policies. >>>> >>>> v8: >>>> + Prevent securityfs initialization if the LSM is disabled >>>> >>>> v9: >>>> + Switch to securityfs_recursive_remove for policy folder deletion >>>> >>>> v10: >>>> + Simplify and correct concurrency >>>> + Fix typos >>>> >>>> v11: >>>> + Correct code comments >>>> >>>> v12: >>>> + Correct locking and remove redundant code >>>> --- >>>> security/ipe/Makefile | 2 + >>>> security/ipe/fs.c | 101 +++++++++ >>>> security/ipe/fs.h | 16 ++ >>>> security/ipe/ipe.c | 3 + >>>> security/ipe/ipe.h | 2 + >>>> security/ipe/policy.c | 123 ++++++++++ >>>> security/ipe/policy.h | 9 + >>>> security/ipe/policy_fs.c | 469 +++++++++++++++++++++++++++++++++++++++ >>>> 8 files changed, 725 insertions(+) >>>> create mode 100644 security/ipe/fs.c >>>> create mode 100644 security/ipe/fs.h >>>> create mode 100644 security/ipe/policy_fs.c >>> >>> ... >>> >>>> diff --git a/security/ipe/policy.c b/security/ipe/policy.c >>>> index f22a576a6d68..61fea3e38e11 100644 >>>> --- a/security/ipe/policy.c >>>> +++ b/security/ipe/policy.c >>>> @@ -43,6 +71,68 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, >>>> return 0; >>>> } >>>> >>>> +/** >>>> + * ipe_update_policy - parse a new policy and replace old with it. >>>> + * @root: Supplies a pointer to the securityfs inode saved the policy. >>>> + * @text: Supplies a pointer to the plain text policy. >>>> + * @textlen: Supplies the length of @text. >>>> + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. >>>> + * @pkcs7len: Supplies the length of @pkcs7len. >>>> + * >>>> + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see >>>> + * ipe_new_policy. >>>> + * >>>> + * Context: Requires root->i_rwsem to be held. >>>> + * Return: >>>> + * * !IS_ERR - The existing policy saved in the inode before update >>>> + * * -ENOENT - Policy doesn't exist >>>> + * * -EINVAL - New policy is invalid >>>> + */ >>>> +struct ipe_policy *ipe_update_policy(struct inode *root, >>>> + const char *text, size_t textlen, >>>> + const char *pkcs7, size_t pkcs7len) >>>> +{ >>>> + int rc = 0; >>>> + struct ipe_policy *old, *ap, *new = NULL; >>>> + >>>> + old = (struct ipe_policy *)root->i_private; >>>> + if (!old) >>>> + return ERR_PTR(-ENOENT); >>>> + >>>> + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); >>>> + if (IS_ERR(new)) >>>> + return new; >>>> + >>>> + if (strcmp(new->parsed->name, old->parsed->name)) { >>>> + rc = -EINVAL; >>>> + goto err; >>>> + } >>>> + >>>> + if (ver_to_u64(old) > ver_to_u64(new)) { >>>> + rc = -EINVAL; >>>> + goto err; >>>> + } >>>> + >>>> + root->i_private = new; >>>> + swap(new->policyfs, old->policyfs); >>> >>> Should the swap() take place with @ipe_policy_lock held? >>> >> I think we are safe here because root->i_rwsem is held. Other two >> operations set_active and delete are also depending on the inode lock. >>>> + mutex_lock(&ipe_policy_lock); >>>> + ap = rcu_dereference_protected(ipe_active_policy, >>>> + lockdep_is_held(&ipe_policy_lock)); >>>> + if (old == ap) { >>>> + rcu_assign_pointer(ipe_active_policy, new); >>>> + mutex_unlock(&ipe_policy_lock); >>>> + synchronize_rcu(); >>> >>> I'm guessing you are forcing a synchronize_rcu() here because you are >>> free()'ing @old in the caller, yes? Looking at the code, I only see >>> one caller, update_policy(). With only one caller, why not free @old >>> directly in ipe_update_policy()? Do you see others callers that would >>> do something different? >>> >> The call of synchronize_rcu() is because we are updating the current >> active policy so we need to set the new policy as active. > > Unless I'm mistaken, a syncronize_rcu() call only ensures that the > current task will see the updated value by waiting until all current > RCU critical sections have finished. Given the mutex involved here I > don't believe this is necessary, but please correct me if I'm wrong. > Sorry for the confusion. I think your previous comment was right, the call of synchronize_rcu() is to free the old one. And I should put the free of old just after the synchronize_rcu() call. Thanks, Fan
diff --git a/security/ipe/Makefile b/security/ipe/Makefile index d7f2870d7c09..cfbed03a8885 100644 --- a/security/ipe/Makefile +++ b/security/ipe/Makefile @@ -8,6 +8,8 @@ obj-$(CONFIG_SECURITY_IPE) += \ eval.o \ hooks.o \ + fs.o \ ipe.o \ policy.o \ + policy_fs.o \ policy_parser.o \ diff --git a/security/ipe/fs.c b/security/ipe/fs.c new file mode 100644 index 000000000000..4949296caeb5 --- /dev/null +++ b/security/ipe/fs.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ + +#include <linux/dcache.h> +#include <linux/security.h> + +#include "ipe.h" +#include "fs.h" +#include "policy.h" + +static struct dentry *np __ro_after_init; +static struct dentry *root __ro_after_init; +struct dentry *policy_root __ro_after_init; + +/** + * new_policy - Write handler for the securityfs node, "ipe/new_policy". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t new_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + char *copy = NULL; + struct ipe_policy *p = NULL; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + copy = memdup_user_nul(data, len); + if (IS_ERR(copy)) + return PTR_ERR(copy); + + p = ipe_new_policy(NULL, 0, copy, len); + if (IS_ERR(p)) { + rc = PTR_ERR(p); + goto out; + } + + rc = ipe_new_policyfs_node(p); + +out: + if (rc < 0) + ipe_free_policy(p); + kfree(copy); + return (rc < 0) ? rc : len; +} + +static const struct file_operations np_fops = { + .write = new_policy, +}; + +/** + * ipe_init_securityfs - Initialize IPE's securityfs tree at fsinit. + * + * Return: + * * !0 - Error + * * 0 - OK + */ +static int __init ipe_init_securityfs(void) +{ + int rc = 0; + + if (!ipe_enabled) + return -EOPNOTSUPP; + + root = securityfs_create_dir("ipe", NULL); + if (IS_ERR(root)) { + rc = PTR_ERR(root); + goto err; + } + + policy_root = securityfs_create_dir("policies", root); + if (IS_ERR(policy_root)) { + rc = PTR_ERR(policy_root); + goto err; + } + + np = securityfs_create_file("new_policy", 0200, root, NULL, &np_fops); + if (IS_ERR(np)) { + rc = PTR_ERR(np); + goto err; + } + + return 0; +err: + securityfs_remove(np); + securityfs_remove(policy_root); + securityfs_remove(root); + return rc; +} + +fs_initcall(ipe_init_securityfs); diff --git a/security/ipe/fs.h b/security/ipe/fs.h new file mode 100644 index 000000000000..c1fc0ca4ae93 --- /dev/null +++ b/security/ipe/fs.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ + +#ifndef _IPE_FS_H +#define _IPE_FS_H + +#include "policy.h" + +extern struct dentry *policy_root __ro_after_init; + +int ipe_new_policyfs_node(struct ipe_policy *p); +void ipe_del_policyfs_node(struct ipe_policy *p); + +#endif /* _IPE_FS_H */ diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c index ed3acf6174d8..034ee8cd6802 100644 --- a/security/ipe/ipe.c +++ b/security/ipe/ipe.c @@ -8,6 +8,8 @@ #include "eval.h" #include "hooks.h" +bool ipe_enabled; + static struct lsm_blob_sizes ipe_blobs __ro_after_init = { #ifdef CONFIG_BLK_DEV_INITRD .lbs_superblock = sizeof(struct ipe_sb), @@ -50,6 +52,7 @@ static struct security_hook_list ipe_hooks[] __ro_after_init = { static int __init ipe_init(void) { security_add_hooks(ipe_hooks, ARRAY_SIZE(ipe_hooks), &ipe_lsmid); + ipe_enabled = true; return 0; } diff --git a/security/ipe/ipe.h b/security/ipe/ipe.h index f1e7c3222b6d..1862c710dab8 100644 --- a/security/ipe/ipe.h +++ b/security/ipe/ipe.h @@ -16,4 +16,6 @@ struct ipe_sb *ipe_sb(const struct super_block *sb); #endif /* CONFIG_BLK_DEV_INITRD */ +extern bool ipe_enabled; + #endif /* _IPE_H */ diff --git a/security/ipe/policy.c b/security/ipe/policy.c index f22a576a6d68..61fea3e38e11 100644 --- a/security/ipe/policy.c +++ b/security/ipe/policy.c @@ -7,9 +7,36 @@ #include <linux/verification.h> #include "ipe.h" +#include "eval.h" +#include "fs.h" #include "policy.h" #include "policy_parser.h" +/* lock for synchronizing writers across ipe policy */ +DEFINE_MUTEX(ipe_policy_lock); + +/** + * ver_to_u64 - Convert an internal ipe_policy_version to a u64. + * @p: Policy to extract the version from. + * + * Bits (LSB is index 0): + * [48,32] -> Major + * [32,16] -> Minor + * [16, 0] -> Revision + * + * Return: u64 version of the embedded version structure. + */ +static inline u64 ver_to_u64(const struct ipe_policy *const p) +{ + u64 r; + + r = (((u64)p->parsed->version.major) << 32) + | (((u64)p->parsed->version.minor) << 16) + | ((u64)(p->parsed->version.rev)); + + return r; +} + /** * ipe_free_policy - Deallocate a given IPE policy. * @p: Supplies the policy to free. @@ -21,6 +48,7 @@ void ipe_free_policy(struct ipe_policy *p) if (IS_ERR_OR_NULL(p)) return; + ipe_del_policyfs_node(p); free_parsed_policy(p->parsed); /* * p->text is allocated only when p->pkcs7 is not NULL @@ -43,6 +71,68 @@ static int set_pkcs7_data(void *ctx, const void *data, size_t len, return 0; } +/** + * ipe_update_policy - parse a new policy and replace old with it. + * @root: Supplies a pointer to the securityfs inode saved the policy. + * @text: Supplies a pointer to the plain text policy. + * @textlen: Supplies the length of @text. + * @pkcs7: Supplies a pointer to a buffer containing a pkcs7 message. + * @pkcs7len: Supplies the length of @pkcs7len. + * + * @text/@textlen is mutually exclusive with @pkcs7/@pkcs7len - see + * ipe_new_policy. + * + * Context: Requires root->i_rwsem to be held. + * Return: + * * !IS_ERR - The existing policy saved in the inode before update + * * -ENOENT - Policy doesn't exist + * * -EINVAL - New policy is invalid + */ +struct ipe_policy *ipe_update_policy(struct inode *root, + const char *text, size_t textlen, + const char *pkcs7, size_t pkcs7len) +{ + int rc = 0; + struct ipe_policy *old, *ap, *new = NULL; + + old = (struct ipe_policy *)root->i_private; + if (!old) + return ERR_PTR(-ENOENT); + + new = ipe_new_policy(text, textlen, pkcs7, pkcs7len); + if (IS_ERR(new)) + return new; + + if (strcmp(new->parsed->name, old->parsed->name)) { + rc = -EINVAL; + goto err; + } + + if (ver_to_u64(old) > ver_to_u64(new)) { + rc = -EINVAL; + goto err; + } + + root->i_private = new; + swap(new->policyfs, old->policyfs); + + mutex_lock(&ipe_policy_lock); + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (old == ap) { + rcu_assign_pointer(ipe_active_policy, new); + mutex_unlock(&ipe_policy_lock); + synchronize_rcu(); + } else { + mutex_unlock(&ipe_policy_lock); + } + + return old; +err: + ipe_free_policy(new); + return ERR_PTR(rc); +} + /** * ipe_new_policy - Allocate and parse an ipe_policy structure. * @@ -99,3 +189,36 @@ struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, ipe_free_policy(new); return ERR_PTR(rc); } + +/** + * ipe_set_active_pol - Make @p the active policy. + * @p: Supplies a pointer to the policy to make active. + * + * Context: Requires root->i_rwsem, which i_private has the policy, to be held. + * Return: + * * !IS_ERR - Success + * * -EINVAL - New active policy version is invalid + */ +int ipe_set_active_pol(const struct ipe_policy *p) +{ + struct ipe_policy *ap = NULL; + + mutex_lock(&ipe_policy_lock); + + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (ap == p) { + mutex_unlock(&ipe_policy_lock); + return 0; + } + if (ap && ver_to_u64(ap) > ver_to_u64(p)) { + mutex_unlock(&ipe_policy_lock); + return -EINVAL; + } + + rcu_assign_pointer(ipe_active_policy, p); + mutex_unlock(&ipe_policy_lock); + synchronize_rcu(); + + return 0; +} diff --git a/security/ipe/policy.h b/security/ipe/policy.h index fb48024bb63e..060ffdbc62d6 100644 --- a/security/ipe/policy.h +++ b/security/ipe/policy.h @@ -7,6 +7,7 @@ #include <linux/list.h> #include <linux/types.h> +#include <linux/fs.h> enum ipe_op_type { IPE_OP_EXEC = 0, @@ -76,10 +77,18 @@ struct ipe_policy { size_t textlen; struct ipe_parsed_policy *parsed; + + struct dentry *policyfs; }; struct ipe_policy *ipe_new_policy(const char *text, size_t textlen, const char *pkcs7, size_t pkcs7len); void ipe_free_policy(struct ipe_policy *pol); +struct ipe_policy *ipe_update_policy(struct inode *root, + const char *text, + size_t textlen, const char *pkcs7, + size_t pkcs7len); +int ipe_set_active_pol(const struct ipe_policy *p); +extern struct mutex ipe_policy_lock; #endif /* _IPE_POLICY_H */ diff --git a/security/ipe/policy_fs.c b/security/ipe/policy_fs.c new file mode 100644 index 000000000000..abdf1ad843e0 --- /dev/null +++ b/security/ipe/policy_fs.c @@ -0,0 +1,469 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) Microsoft Corporation. All rights reserved. + */ +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/types.h> +#include <linux/dcache.h> +#include <linux/security.h> + +#include "ipe.h" +#include "policy.h" +#include "eval.h" +#include "fs.h" + +#define MAX_VERSION_SIZE ARRAY_SIZE("65535.65535.65535") + +/** + * ipefs_file - defines a file in securityfs. + */ +struct ipefs_file { + const char *name; + umode_t access; + const struct file_operations *fops; +}; + +/** + * read_pkcs7 - Read handler for "ipe/policies/$name/pkcs7". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the pkcs7 blob representing the policy + * on success. If the policy is unsigned (like the boot policy), this + * will return -ENOENT. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t read_pkcs7(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + if (!p->pkcs7) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->pkcs7, p->pkcs7len); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_policy - Read handler for "ipe/policies/$name/policy". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the plain-text version of the policy + * on success. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t read_policy(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->text, p->textlen); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_name: Read handler for "ipe/policies/$name/name". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the policy_name attribute on success. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t read_name(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = simple_read_from_buffer(data, len, offset, p->parsed->name, + strlen(p->parsed->name)); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * read_version - Read handler for "ipe/policies/$name/version". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the version string on success. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t read_version(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + ssize_t rc = 0; + size_t strsize = 0; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + char buffer[MAX_VERSION_SIZE] = { 0 }; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + strsize = scnprintf(buffer, ARRAY_SIZE(buffer), "%hu.%hu.%hu", + p->parsed->version.major, p->parsed->version.minor, + p->parsed->version.rev); + + rc = simple_read_from_buffer(data, len, offset, buffer, strsize); + +out: + inode_unlock_shared(root); + + return rc; +} + +/** + * setactive - Write handler for "ipe/policies/$name/active". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t setactive(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + bool value = false; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + rc = kstrtobool_from_user(data, len, &value); + if (rc) + return rc; + + if (!value) + return -EINVAL; + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + + p = (struct ipe_policy *)root->i_private; + if (!p) { + rc = -ENOENT; + goto out; + } + + rc = ipe_set_active_pol(p); + +out: + inode_unlock(root); + return (rc < 0) ? rc : len; +} + +/** + * getactive - Read handler for "ipe/policies/$name/active". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * @data will be populated with the 1 or 0 depending on if the + * corresponding policy is active. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t getactive(struct file *f, char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + const char *str; + struct inode *root = NULL; + const struct ipe_policy *p = NULL; + + root = d_inode(f->f_path.dentry->d_parent); + + inode_lock_shared(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + inode_unlock_shared(root); + return -ENOENT; + } + inode_unlock_shared(root); + + str = (p == rcu_access_pointer(ipe_active_policy)) ? "1" : "0"; + rc = simple_read_from_buffer(data, len, offset, str, 1); + + return rc; +} + +/** + * update_policy - Write handler for "ipe/policies/$name/update". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * On success this updates the policy represented by $name, + * in-place. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t update_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + char *copy = NULL; + struct inode *root = NULL; + struct ipe_policy *old = NULL; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + copy = memdup_user(data, len); + if (IS_ERR(copy)) + return PTR_ERR(copy); + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + old = ipe_update_policy(root, NULL, 0, copy, len); + inode_unlock(root); + + kfree(copy); + if (IS_ERR(old)) + return PTR_ERR(old); + ipe_free_policy(old); + + return len; +} + +/** + * delete_policy - write handler for "ipe/policies/$name/delete". + * @f: Supplies a file structure representing the securityfs node. + * @data: Supplies a buffer passed to the write syscall. + * @len: Supplies the length of @data. + * @offset: unused. + * + * On success this deletes the policy represented by $name. + * + * Return: + * * >0 - Success, Length of buffer written + * * <0 - Error + */ +static ssize_t delete_policy(struct file *f, const char __user *data, + size_t len, loff_t *offset) +{ + int rc = 0; + bool value = false; + struct inode *root = NULL; + struct ipe_policy *p = NULL; + struct ipe_policy *ap = NULL; + + if (!file_ns_capable(f, &init_user_ns, CAP_MAC_ADMIN)) + return -EPERM; + + rc = kstrtobool_from_user(data, len, &value); + if (rc) + return rc; + + if (!value) + return -EINVAL; + + root = d_inode(f->f_path.dentry->d_parent); + inode_lock(root); + p = (struct ipe_policy *)root->i_private; + if (!p) { + inode_unlock(root); + return -ENOENT; + } + + mutex_lock(&ipe_policy_lock); + ap = rcu_dereference_protected(ipe_active_policy, + lockdep_is_held(&ipe_policy_lock)); + if (p == ap) { + mutex_unlock(&ipe_policy_lock); + inode_unlock(root); + return -EPERM; + } + mutex_unlock(&ipe_policy_lock); + + root->i_private = NULL; + inode_unlock(root); + + ipe_free_policy(p); + return len; +} + +static const struct file_operations content_fops = { + .read = read_policy, +}; + +static const struct file_operations pkcs7_fops = { + .read = read_pkcs7, +}; + +static const struct file_operations name_fops = { + .read = read_name, +}; + +static const struct file_operations ver_fops = { + .read = read_version, +}; + +static const struct file_operations active_fops = { + .write = setactive, + .read = getactive, +}; + +static const struct file_operations update_fops = { + .write = update_policy, +}; + +static const struct file_operations delete_fops = { + .write = delete_policy, +}; + +/** + * policy_subdir - files under a policy subdirectory + */ +static const struct ipefs_file policy_subdir[] = { + { "pkcs7", 0444, &pkcs7_fops }, + { "policy", 0444, &content_fops }, + { "name", 0444, &name_fops }, + { "version", 0444, &ver_fops }, + { "active", 0600, &active_fops }, + { "update", 0200, &update_fops }, + { "delete", 0200, &delete_fops }, +}; + +/** + * ipe_del_policyfs_node - Delete a securityfs entry for @p. + * @p: Supplies a pointer to the policy to delete a securityfs entry for. + */ +void ipe_del_policyfs_node(struct ipe_policy *p) +{ + securityfs_recursive_remove(p->policyfs); + p->policyfs = NULL; +} + +/** + * ipe_new_policyfs_node - Create a securityfs entry for @p. + * @p: Supplies a pointer to the policy to create a securityfs entry for. + * + * Return: + * * 0 - OK + * * !0 - Error + */ +int ipe_new_policyfs_node(struct ipe_policy *p) +{ + int rc = 0; + size_t i = 0; + struct dentry *d = NULL; + struct dentry *policyfs = NULL; + struct inode *root = NULL; + const struct ipefs_file *f = NULL; + + if (p->policyfs) + return 0; + + policyfs = securityfs_create_dir(p->parsed->name, policy_root); + if (IS_ERR(policyfs)) + return PTR_ERR(policyfs); + + root = d_inode(policyfs); + + for (i = 0; i < ARRAY_SIZE(policy_subdir); ++i) { + f = &policy_subdir[i]; + + d = securityfs_create_file(f->name, f->access, policyfs, + NULL, f->fops); + if (IS_ERR(d)) { + rc = PTR_ERR(d); + goto err; + } + } + + inode_lock(root); + p->policyfs = policyfs; + root->i_private = p; + inode_unlock(root); + + return 0; +err: + securityfs_recursive_remove(policyfs); + return rc; +}