linux-stable.git/security/apparmor, branch v6.12.109 Linux kernel stable tree apparmor: fix out-of-bounds write when null terminating a label vec 2026-09-07T15:17:58+00:00 Hyunwoo Kim imv4bel@gmail.com 2026-08-10T09:51:33+00:00 9124e078ea2250d8d01d2162a550acb01ef5bf48 commit 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123 upstream. aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE is passed. If the components are all distinct no duplicates are dropped, dups is 0 and the terminator goes to vec[n], so the caller has to provide room for n + 1 entries. aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len, gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it allocates exactly len pointers. The terminator therefore lands one entry past the end of the local array when len is LOCAL_VEC_ENTRIES, and one entry past the end of the allocation when len is larger. len comes from the number of "//&" separated components in the label name and label_count_strn_entries() does not bound it. An unprivileged task reaches the parse by writing to /proc/self/attr/apparmor/current or through lsm_set_self_attr(2), both of which go through do_setattr(), and the name is parsed before the change_profile permission is checked. The query_label() path behind the securityfs .access file, which is mode 0666, performs no permission check at all. Every component has to resolve to a loaded profile, so a system with policy loaded is required. The other two VEC_FLAG_TERMINATE users work on a label vec that aa_label_alloc() has already sized with "+ 1 for null terminator entry on vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of the local array and into kzalloc(). Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123 upstream.

aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE
is passed. If the components are all distinct no duplicates are dropped,
dups is 0 and the terminator goes to vec[n], so the caller has to provide
room for n + 1 entries.

aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,
gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but
vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES
it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it
allocates exactly len pointers. The terminator therefore lands one entry
past the end of the local array when len is LOCAL_VEC_ENTRIES, and one
entry past the end of the allocation when len is larger.

len comes from the number of "//&" separated components in the label name
and label_count_strn_entries() does not bound it. An unprivileged task
reaches the parse by writing to /proc/self/attr/apparmor/current or through
lsm_set_self_attr(2), both of which go through do_setattr(), and the name
is parsed before the change_profile permission is checked.
The query_label() path behind the securityfs .access file, which is
mode 0666, performs no permission check at all. Every component has to
resolve to a loaded profile, so a system with policy loaded is required.

The other two VEC_FLAG_TERMINATE users work on a label vec that
aa_label_alloc() has already sized with "+ 1 for null terminator entry on
vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing
len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of
the local array and into kzalloc().

Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels")
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
apparmor: fix cred UAF caused by begin_current_label_crit_section() 2026-09-07T15:17:58+00:00 Jann Horn jannh@google.com 2026-08-06T15:55:02+00:00 361488984d668235438faac28635f3632351407f commit 3f4ae5fab613dca01d6a2a8210dd832e009fcf47 upstream. AppArmor's begin_current_label_crit_section() is a scary function called from lots of LSM hooks (in particular VFS/socket-related ones) that checks if the label referenced by the current creds is marked FLAG_STALE, and if so, attempts to use aa_replace_current_label() to replace the creds with an updated version that uses a new label. The first problem with this is that it would directly lead to UAF of `struct cred` if anything in the kernel takes a pointer to the current creds and accesses these past a security hook invocation that replaces creds, like so: ``` const struct cred *cred = current_cred(); alloc_file_pseudo(...); uid_t uid = cred->euid; ``` I don't know if anything in the kernel actually does this, but I think it is very surprising that this pattern could lead to UAF. The second problem is that things go wrong when aa_replace_current_label() runs with overridden credentials. aa_replace_current_label() bails out if `current_cred() != current_real_cred()` (mirroring the check in proc_pid_attr_write()), but this check can't actually reliably detect overridden credentials because the overridden creds can be the same as the objective creds. So in approximately the following scenario, things go wrong: 1. task begins with <creds A> (as both objective and subjective creds), with refcount=2 2. task grabs an extra reference on <creds A> for overriding 3. task calls override_creds(<creds A>), which returns a pointer to the old subjective creds (<creds A>) 4. task enters AppArmor LSM hook 5. AppArmor checks that objective/subjective creds are equal 6. AppArmor replaces both cred pointers with <creds B> and drops 2 refs on <creds A> 7. task leaves AppArmor LSM hook 8. task calls revert_creds(<creds A>) 9. now task->cred is <creds A> while task->real_cred is <creds B>, but the task_struct logically holds two references to <creds B> 10. another task drops the extra reference on <creds A> that was used for overriding, refcount drops to 0 11. now task->real_cred points to freed creds At this point, any access to current_cred() will be UAF. I have a test case where I run aa-disable on a profile while a process using that profile is blocked on splice() from a FUSE passthrough file into a full pipe; after the profile update, the pipe becomes empty, splice() resumes, the credentials go out of sync, and a subsequent getuid() syscall results in a KASAN UAF splat. To fix this, instead of directly replacing creds, do it via task_work that will run at the end of the current syscall. (The point in time at which the cred replacement happens should have no correctness impact; it is just a performance optimization to avoid unnecessarily touching the refcount of the new label.) Note that AppArmor still performs direct cred replacements in the sb_pivotroot LSM hook after this change, and that direct cred replacements can still happen in VFS ->write() callbacks via proc_pid_attr_write(). There are two options for what to do with aa_dup_task_ctx(): Either explicitly reset new->label_replacement_pending after the entire aa_task_ctx has been copied, or switch to manually copying members over. I am switching to manually copying members over because that should make bugs more obvious. Cc: stable@vger.kernel.org Fixes: c75afcd153f6 ("AppArmor: contexts used in attaching policy to system objects") Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3f4ae5fab613dca01d6a2a8210dd832e009fcf47 upstream.

AppArmor's begin_current_label_crit_section() is a scary function called
from lots of LSM hooks (in particular VFS/socket-related ones) that checks
if the label referenced by the current creds is marked FLAG_STALE, and if
so, attempts to use aa_replace_current_label() to replace the creds with an
updated version that uses a new label.

The first problem with this is that it would directly lead to UAF of
`struct cred` if anything in the kernel takes a pointer to the current
creds and accesses these past a security hook invocation that replaces
creds, like so:
```
const struct cred *cred = current_cred();
alloc_file_pseudo(...);
uid_t uid = cred->euid;
```
I don't know if anything in the kernel actually does this, but I think it
is very surprising that this pattern could lead to UAF.

The second problem is that things go wrong when aa_replace_current_label()
runs with overridden credentials. aa_replace_current_label() bails out if
`current_cred() != current_real_cred()` (mirroring the check in
proc_pid_attr_write()), but this check can't actually reliably detect
overridden credentials because the overridden creds can be the same as the
objective creds.

So in approximately the following scenario, things go wrong:

1. task begins with <creds A> (as both objective and subjective creds),
   with refcount=2
2. task grabs an extra reference on <creds A> for overriding
3. task calls override_creds(<creds A>), which returns a pointer to the old
   subjective creds (<creds A>)
4. task enters AppArmor LSM hook
5. AppArmor checks that objective/subjective creds are equal
6. AppArmor replaces both cred pointers with <creds B> and drops 2 refs on
   <creds A>
7. task leaves AppArmor LSM hook
8. task calls revert_creds(<creds A>)
9. now task->cred is <creds A> while task->real_cred is <creds B>, but the
   task_struct logically holds two references to <creds B>
10. another task drops the extra reference on <creds A> that was used for
    overriding, refcount drops to 0
11. now task->real_cred points to freed creds

At this point, any access to current_cred() will be UAF.

I have a test case where I run aa-disable on a profile while a process
using that profile is blocked on splice() from a FUSE passthrough file into
a full pipe; after the profile update, the pipe becomes empty, splice()
resumes, the credentials go out of sync, and a subsequent getuid() syscall
results in a KASAN UAF splat.

To fix this, instead of directly replacing creds, do it via task_work that
will run at the end of the current syscall. (The point in time at which the
cred replacement happens should have no correctness impact; it is just a
performance optimization to avoid unnecessarily touching the refcount of
the new label.)

Note that AppArmor still performs direct cred replacements in the
sb_pivotroot LSM hook after this change, and that direct cred replacements
can still happen in VFS ->write() callbacks via proc_pid_attr_write().

There are two options for what to do with aa_dup_task_ctx(): Either
explicitly reset new->label_replacement_pending after the entire
aa_task_ctx has been copied, or switch to manually copying members over.
I am switching to manually copying members over because that should make
bugs more obvious.

Cc: stable@vger.kernel.org
Fixes: c75afcd153f6 ("AppArmor: contexts used in attaching policy to system objects")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
apparmor: fix label can not be immediately before a declaration 2026-07-24T14:11:10+00:00 John Johansen john.johansen@canonical.com 2026-06-14T23:16:59+00:00 dc6c3e658e713cc44dee6bf128fd6002ae3a5025 [ Upstream commit 1ed40bd525c00d22af666016af9aef7167f8085f ] Fix error reported by kernel test robot security/apparmor/policy.c:1381:2: error: a label can only be part of a statement and a declaration is not a statement All errors (new ones prefixed by >>): security/apparmor/policy.c: In function 'aa_replace_profiles': >> security/apparmor/policy.c:1381:2: error: a label can only be part of a statement and a declaration is not a statement ssize_t udata_sz = udata->size; ^~~~~ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202606150525.npax8WiH-lkp@intel.com/ Fixes: 7b42f95813dc9 ("apparmor: fix potential UAF in aa_replace_profiles") Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1ed40bd525c00d22af666016af9aef7167f8085f ]

Fix error reported by kernel test robot

security/apparmor/policy.c:1381:2: error: a label can only be part of
a statement and a declaration is not a statement

All errors (new ones prefixed by >>):

   security/apparmor/policy.c: In function 'aa_replace_profiles':
>> security/apparmor/policy.c:1381:2: error: a label can only be part
   of a statement and a declaration is not a statement
     ssize_t udata_sz = udata->size;
     ^~~~~

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202606150525.npax8WiH-lkp@intel.com/
Fixes: 7b42f95813dc9 ("apparmor: fix potential UAF in aa_replace_profiles")
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: put secmark label after secid lookup 2026-07-24T14:11:09+00:00 Zygmunt Krynicki me@zygoon.pl 2026-05-05T03:40:53+00:00 f96d9e9104b5fcecb521bde174cad98aaed1c1d0 [ Upstream commit 340372688bb87da45ff8d4e2f82ccfd1b64c65ff ] apparmor_secmark_init() parses a configured secmark label to obtain its secid. aa_label_strn_parse() returns a refcounted label, but the success path kept that reference after copying the secid. Fixes: ab9f2115081a ("apparmor: Allow filtering based on secmark policy") Signed-off-by: Zygmunt Krynicki <me@zygoon.pl> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 340372688bb87da45ff8d4e2f82ccfd1b64c65ff ]

apparmor_secmark_init() parses a configured secmark label to obtain its
secid.  aa_label_strn_parse() returns a refcounted label, but the success
path kept that reference after copying the secid.

Fixes: ab9f2115081a ("apparmor: Allow filtering based on secmark policy")
Signed-off-by: Zygmunt Krynicki <me@zygoon.pl>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: aa_getprocattr free procattr leak on format failure 2026-07-24T14:11:09+00:00 Zygmunt Krynicki me@zygoon.pl 2026-05-02T11:37:14+00:00 9493fa5b7542823317cffcbb80e6bd478834f1c3 [ Upstream commit fea23bf73f0cae8ccb1d0684e4a3003874771f41 ] aa_getprocattr() allocates the output string before rendering the label into it. If the second aa_label_snxprint() call fails, the function returned without freeing that allocation. Free and clear the output pointer on the uncommon formatting failure path before dropping the namespace reference. Fixes: 76a1d263aba3 ("apparmor: switch getprocattr to using label_print fns()") Reviewed-by: Tyler Hicks <code@thicks.com> Reviewed-by: Ryan Lee <ryan.lee@canonical.com> Signed-off-by: Zygmunt Krynicki <me@zygoon.pl> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit fea23bf73f0cae8ccb1d0684e4a3003874771f41 ]

aa_getprocattr() allocates the output string before rendering the label
into it. If the second aa_label_snxprint() call fails, the function
returned without freeing that allocation.

Free and clear the output pointer on the uncommon formatting failure path
before dropping the namespace reference.

Fixes: 76a1d263aba3 ("apparmor: switch getprocattr to using label_print fns()")
Reviewed-by: Tyler Hicks <code@thicks.com>
Reviewed-by: Ryan Lee <ryan.lee@canonical.com>
Signed-off-by: Zygmunt Krynicki <me@zygoon.pl>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: remove or add symlinks to rawdata according to export_binary 2026-07-24T14:11:09+00:00 Georgia Garcia georgia.garcia@canonical.com 2026-01-29T18:39:42+00:00 6fd4fd40edc0c07197c2bb8edf159fe50b19f6c7 [ Upstream commit 59fe6fbc4cd45582bc8893de0a382a36562317b3 ] When the export_binary parameter is set, then rawdata is available and there should be a symbolic link for the rawdata in the profile directory in apparmorfs. If the parameter is unset, then the symlinks should not exist. The issue arises when changing the value of export_binary on runtime and replacing profiles. If export_binary was set when the profile was originally loaded, then changed to 0 and the profile was reloaded, then the symbolic links would still exist but would return ENOENT because the rawdata no longer exists. On the opposite side, if export_binary was unset when the profile was originally loaded, then changed to 1 and the profile was reloaded, then the symbolic links would not exist, even though the rawdata does. Fixes: d61c57fde8191 ("apparmor: make export of raw binary profile to userspace optional") Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 59fe6fbc4cd45582bc8893de0a382a36562317b3 ]

When the export_binary parameter is set, then rawdata is available and
there should be a symbolic link for the rawdata in the profile
directory in apparmorfs. If the parameter is unset, then the symlinks
should not exist.

The issue arises when changing the value of export_binary on runtime
and replacing profiles. If export_binary was set when the profile was
originally loaded, then changed to 0 and the profile was reloaded,
then the symbolic links would still exist but would return ENOENT
because the rawdata no longer exists.

On the opposite side, if export_binary was unset when the profile was
originally loaded, then changed to 1 and the profile was reloaded,
then the symbolic links would not exist, even though the rawdata does.

Fixes: d61c57fde8191 ("apparmor: make export of raw binary profile to userspace optional")
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: fix potential UAF in aa_replace_profiles 2026-07-24T14:11:09+00:00 Maxime Bélair maxime.belair@canonical.com 2026-02-18T09:27:34+00:00 c44de0880b7ccc15c70a6352b5e107677d32b061 [ Upstream commit 7b42f95813dc9ceb6bda35afcf914630909a19f9 ] The function aa_replace_profiles was accessing udata->size after calling aa_put_loaddata(udata), causing a potential UAF. Fixed this by saving the size to a local variable before dropping the reference. Fixes: 5ac8c355ae001 ("apparmor: allow introspecting the loaded policy pre internal transform") Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com> Signed-off-by: Maxime Bélair <maxime.belair@canonical.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7b42f95813dc9ceb6bda35afcf914630909a19f9 ]

The function aa_replace_profiles was accessing udata->size after calling
aa_put_loaddata(udata), causing a potential UAF.

Fixed this by saving the size to a local variable before dropping the
reference.

Fixes: 5ac8c355ae001 ("apparmor: allow introspecting the loaded policy pre internal transform")
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: Maxime Bélair <maxime.belair@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: grab ns lock and refresh when looking up changehat child profiles 2026-07-24T14:11:09+00:00 Ryan Lee ryan.lee@canonical.com 2026-02-13T19:29:38+00:00 6446dbe02f4a3592bf062b4d12105927993086af [ Upstream commit 32e92764d6f8d251c1bca62be33793287b453a81 ] There was a race condition involving change_hat and profile replacement in which replacement of the parent profile during a changehat operation could result in the list of children becoming empty and the changehat operation failing. To prevent this: - grab the namespace lock until we've built the hat transition, and - use aa_get_newest_profile to avoid using stale profile objects. Link: https://bugs.launchpad.net/bugs/2139664 Fixes: 89dbf1962aa63 ("apparmor: move change_hat mediation to using labels") Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com> Signed-off-by: Ryan Lee <ryan.lee@canonical.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 32e92764d6f8d251c1bca62be33793287b453a81 ]

There was a race condition involving change_hat and profile replacement in
which replacement of the parent profile during a changehat operation could
result in the list of children becoming empty and the changehat operation
failing. To prevent this:
 - grab the namespace lock until we've built the hat transition, and
 - use aa_get_newest_profile to avoid using stale profile objects.

Link: https://bugs.launchpad.net/bugs/2139664
Fixes: 89dbf1962aa63 ("apparmor: move change_hat mediation to using labels")
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: Ryan Lee <ryan.lee@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: fix rawdata_f_data implicit flex array 2026-07-24T14:11:09+00:00 John Johansen john.johansen@canonical.com 2026-03-01T20:24:06+00:00 8453803d2c2fa0bd3f9ae125573583db27805f90 [ Upstream commit ad213bbbc0e3e270ce7df2d9d80d4ce3826993d7 ] rawdata_f_data has a blob of data that is allocated at its end but not explicitly declared. Makes sure it is correctly declared as a flex_rray. Fixes: 63c16c3a76085 ("apparmor: Initial implementation of raw policy blob compression") Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ad213bbbc0e3e270ce7df2d9d80d4ce3826993d7 ]

rawdata_f_data has a blob of data that is allocated at its end but
not explicitly declared. Makes sure it is correctly declared as a
flex_rray.

Fixes: 63c16c3a76085 ("apparmor: Initial implementation of raw policy blob compression")
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
apparmor: aa_label_alloc use aa_label_free on alloc failure 2026-07-24T14:11:09+00:00 Zygmunt Krynicki me@zygoon.pl 2026-05-02T11:21:33+00:00 bf310b044e85d4de670c94295c5d8e4c5bc5e7bc [ Upstream commit 654fe7505dc6889724d4094fa64f89991afabfc3 ] aa_label_alloc() allocates a secid before allocating or taking the label proxy. If the later proxy step fails, the error path only freed the label memory, leaking any resources initialized by aa_label_init(). Use aa_label_free() on the failure path so partially initialized labels release their secid and other label resources before the backing memory is freed. Fixes: f1bd904175e81 ("apparmor: add the base fns() for domain labels") Signed-off-by: Zygmunt Krynicki <me@zygoon.pl> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 654fe7505dc6889724d4094fa64f89991afabfc3 ]

aa_label_alloc() allocates a secid before allocating or taking the label
proxy. If the later proxy step fails, the error path only freed the label
memory, leaking any resources initialized by aa_label_init().

Use aa_label_free() on the failure path so partially initialized labels
release their secid and other label resources before the backing memory is
freed.

Fixes: f1bd904175e81 ("apparmor: add the base fns() for domain labels")
Signed-off-by: Zygmunt Krynicki <me@zygoon.pl>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>