| 6f060496 | 26-May-2026 |
Ruslan Valiyev <linuxoid@gmail.com> |
apparmor: fix use-after-free in rawdata dedup loop
aa_replace_profiles() walks ns->rawdata_list to dedup the incoming
policy blob against entries already attached to existing profiles.
Per the kerne
apparmor: fix use-after-free in rawdata dedup loop
aa_replace_profiles() walks ns->rawdata_list to dedup the incoming
policy blob against entries already attached to existing profiles.
Per the kernel-doc on struct aa_loaddata, list membership does not
hold a reference: profiles hold pcount, and when the last pcount
drops, do_ploaddata_rmfs() is queued on a workqueue that takes
ns->lock and removes the entry. Between dropping the last pcount
and the workqueue running, an entry remains on the list with
pcount == 0.
aa_get_profile_loaddata() is an unconditional kref_get() on
pcount, so when the dedup loop hits such an entry, refcount
hardening reports
refcount_t: addition on 0; use-after-free.
inside aa_replace_profiles(), and the poisoned counter then
trips "saturated" and "underflow" warnings on the subsequent
uses of the same loaddata.
Before commit a0b7091c4de4 ("apparmor: fix race on rawdata
dereference") the dedup path used a get_unless_zero-style helper
on a single counter, so the existing "if (tmp)" guard was
meaningful. The split-refcount refactor introduced
aa_get_profile_loaddata(), which has plain kref_get() semantics,
and the guard quietly became a no-op.
Introduce aa_get_profile_loaddata_not0(), matching the existing
_not0 convention used by aa_get_profile_not0(), and use it for
the rawdata_list dedup lookup so dying entries are skipped.
Reproduced on x86_64 with v7.1-rc5 in QEMU+KVM running Ubuntu
24.04 + stress-ng 0.17.06:
stress-ng --apparmor 1 --klog-check --timeout 60s
Without this patch the three refcount_t warnings fire within a
few seconds. With it the same 60 s run is clean. Coverage is a
smoke-test only; a longer soak with CONFIG_KASAN, CONFIG_KCSAN
and CONFIG_PROVE_LOCKING would be welcome from anyone with the
cycles.
Fixes: a0b7091c4de4 ("apparmor: fix race on rawdata dereference")
Reported-by: Colin Ian King <colin.i.king@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221513
Cc: stable@vger.kernel.org
Signed-off-by: Ruslan Valiyev <linuxoid@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 59fe6fbc | 29-Jan-2026 |
Georgia Garcia <georgia.garcia@canonical.com> |
apparmor: remove or add symlinks to rawdata according to export_binary
When the export_binary parameter is set, then rawdata is available and
there should be a symbolic link for the rawdata in the p
apparmor: remove or add symlinks to rawdata according to export_binary
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>
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| 716d384a | 24-Feb-2026 |
John Johansen <john.johansen@canonical.com> |
apparmor: make fn_label_build() capable of handling not supported
Currently fn_label_build() callback fns must provide a transition or
failure. Change this so that a callback can indicate it should
apparmor: make fn_label_build() capable of handling not supported
Currently fn_label_build() callback fns must provide a transition or
failure. Change this so that a callback can indicate it should be
skipped/not be involved in the label being built.
This will be useful when building object labels based on mediation
flags, as to whether the label should be set.
Existing callers can keep treating NULL return as an error because
none of those callback fns support skipping, but instead of the old
error handling replace with AA_BUG.
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 8e135b8a | 02-Mar-2026 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix race between freeing data and fs accessing it
AppArmor was putting the reference to i_private data on its end after
removing the original entry from the file system. However the inode
apparmor: fix race between freeing data and fs accessing it
AppArmor was putting the reference to i_private data on its end after
removing the original entry from the file system. However the inode
can aand does live beyond that point and it is possible that some of
the fs call back functions will be invoked after the reference has
been put, which results in a race between freeing the data and
accessing it through the fs.
While the rawdata/loaddata is the most likely candidate to fail the
race, as it has the fewest references. If properly crafted it might be
possible to trigger a race for the other types stored in i_private.
Fix this by moving the put of i_private referenced data to the correct
place which is during inode eviction.
Fixes: c961ee5f21b20 ("apparmor: convert from securityfs to apparmorfs for policy ns files")
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Reviewed-by: Maxime Bélair <maxime.belair@canonical.com>
Reviewed-by: Cengiz Can <cengiz.can@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| a0b7091c | 24-Feb-2026 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix race on rawdata dereference
There is a race condition that leads to a use-after-free situation:
because the rawdata inodes are not refcounted, an attacker can start
open()ing one of th
apparmor: fix race on rawdata dereference
There is a race condition that leads to a use-after-free situation:
because the rawdata inodes are not refcounted, an attacker can start
open()ing one of the rawdata files, and at the same time remove the
last reference to this rawdata (by removing the corresponding profile,
for example), which frees its struct aa_loaddata; as a result, when
seq_rawdata_open() is reached, i_private is a dangling pointer and
freed memory is accessed.
The rawdata inodes weren't refcounted to avoid a circular refcount and
were supposed to be held by the profile rawdata reference. However
during profile removal there is a window where the vfs and profile
destruction race, resulting in the use after free.
Fix this by moving to a double refcount scheme. Where the profile
refcount on rawdata is used to break the circular dependency. Allowing
for freeing of the rawdata once all inode references to the rawdata
are put.
Fixes: 5d5182cae401 ("apparmor: move to per loaddata files, instead of replicating in profiles")
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Reviewed-by: Maxime Bélair <maxime.belair@canonical.com>
Reviewed-by: Cengiz Can <cengiz.can@canonical.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 39440b13 | 17-Oct-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix differential encoding verification
Differential encoding allows loops to be created if it is abused. To
prevent this the unpack should verify that a diff-encode chain
terminates.
Unfo
apparmor: fix differential encoding verification
Differential encoding allows loops to be created if it is abused. To
prevent this the unpack should verify that a diff-encode chain
terminates.
Unfortunately the differential encode verification had two bugs.
1. it conflated states that had gone through check and already been
marked, with states that were currently being checked and marked.
This means that loops in the current chain being verified are treated
as a chain that has already been verified.
2. the order bailout on already checked states compared current chain
check iterators j,k instead of using the outer loop iterator i.
Meaning a step backwards in states in the current chain verification
was being mistaken for moving to an already verified state.
Move to a double mark scheme where already verified states get a
different mark, than the current chain being kept. This enables us
to also drop the backwards verification check that was the cause of
the second error as any already verified state is already marked.
Fixes: 031dcc8f4e84 ("apparmor: dfa add support for state differential encoding")
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Reviewed-by: Cengiz Can <cengiz.can@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 6601e13e | 07-Nov-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix unprivileged local user can do privileged policy management
An unprivileged local user can load, replace, and remove profiles by
opening the apparmorfs interfaces, via a confused deput
apparmor: fix unprivileged local user can do privileged policy management
An unprivileged local user can load, replace, and remove profiles by
opening the apparmorfs interfaces, via a confused deputy attack, by
passing the opened fd to a privileged process, and getting the
privileged process to write to the interface.
This does require a privileged target that can be manipulated to do
the write for the unprivileged process, but once such access is
achieved full policy management is possible and all the possible
implications that implies: removing confinement, DoS of system or
target applications by denying all execution, by-passing the
unprivileged user namespace restriction, to exploiting kernel bugs for
a local privilege escalation.
The policy management interface can not have its permissions simply
changed from 0666 to 0600 because non-root processes need to be able
to load policy to different policy namespaces.
Instead ensure the task writing the interface has privileges that
are a subset of the task that opened the interface. This is already
done via policy for confined processes, but unconfined can delegate
access to the opened fd, by-passing the usual policy check.
Fixes: b7fd2c0340eac ("apparmor: add per policy ns .load, .replace, .remove interface files")
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Reviewed-by: Cengiz Can <cengiz.can@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 796c146f | 25-Dec-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: split xxx_in_ns into its two separate semantic use cases
This patch doesn't change current functionality, it switches the two
uses of the in_ns fns and macros into the two semantically dif
apparmor: split xxx_in_ns into its two separate semantic use cases
This patch doesn't change current functionality, it switches the two
uses of the in_ns fns and macros into the two semantically different
cases they are used for.
xxx_in_scope for checking mediation interaction between profiles
xxx_in_view to determine which profiles are visible.The scope will
always be a subset of the view as profiles that can not see each
other can not interact.
The split can not be completely done for label_match because it has to
distinct uses matching permission against label in scope, and checking
if a transition to a profile is allowed. The transition to a profile
can include profiles that are in view but not in scope, so retain this
distinction as a parameter.
While at the moment the two uses are very similar, in the future there
will be additional differences. So make sure the semantics differences
are present in the code.
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| acf2a94a | 08-Nov-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: refactor/cleanup cred helper fns.
aa_cred_raw_label() and cred_label() now do the same things so
consolidate to cred_label()
Document the crit section use and constraints better and refac
apparmor: refactor/cleanup cred helper fns.
aa_cred_raw_label() and cred_label() now do the same things so
consolidate to cred_label()
Document the crit section use and constraints better and refactor
__begin_current_label_crit_section() into a base fn
__begin_cred_crit_section() and a wrapper that calls the base with
current cred.
Reviewed-by: Georgia Garcia <georgia.garcia@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 3d28e239 | 02-Apr-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: add support loading per permission tagging
Add support for the per permission tag index for a given permission
set. This will be used by both meta-data tagging, to allow annotating
accept
apparmor: add support loading per permission tagging
Add support for the per permission tag index for a given permission
set. This will be used by both meta-data tagging, to allow annotating
accept states with context and debug information. As well as by rule
tainting and triggers to specify the taint or trigger to be applied.
Since these are low frequency ancillary data items they are stored
in a tighter packed format to that allows for sharing and reuse of the
strings between permissions and accept states. Reducing the amount of
kernel memory use at the cost of having to go through a couple if
index based indirections.
The tags are just strings that has no meaning with out context. When
used as meta-data for auditing and debugging its entirely information
for userspace, but triggers, and tainting can be used to affect the
domain. However they all exist in the same packed data set and can
be shared between different uses.
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 6456ccbd | 04-Jun-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix regression in fs based unix sockets when using old abi
Policy loaded using abi 7 socket mediation was not being applied
correctly in all cases. In some cases with fs based unix sockets
apparmor: fix regression in fs based unix sockets when using old abi
Policy loaded using abi 7 socket mediation was not being applied
correctly in all cases. In some cases with fs based unix sockets a
subset of permissions where allowed when they should have been denied.
This was happening because the check for if the socket was an fs based
unix socket came before the abi check. But the abi check is where the
correct path is selected, so having the fs unix socket check occur
early would cause the wrong code path to be used.
Fix this by pushing the fs unix to be done after the abi check.
Fixes: dcd7a559411e ("apparmor: gate make fine grained unix mediation behind v9 abi")
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| 50d56a1a | 14-Jun-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix AA_DEBUG_LABEL()
AA_DEBUG_LABEL() was not specifying it vargs, which is needed so it can
output debug parameters.
Fixes: 71e6cff3e0dd ("apparmor: Improve debug print infrastructure")
apparmor: fix AA_DEBUG_LABEL()
AA_DEBUG_LABEL() was not specifying it vargs, which is needed so it can
output debug parameters.
Fixes: 71e6cff3e0dd ("apparmor: Improve debug print infrastructure")
Signed-off-by: John Johansen <john.johansen@canonical.com>
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| a30a9fdb | 14-Jun-2025 |
John Johansen <john.johansen@canonical.com> |
apparmor: fix af_unix auditing to include all address information
The auditing of addresses currently doesn't include the source address
and mixes source and foreign/peer under the same audit name.
apparmor: fix af_unix auditing to include all address information
The auditing of addresses currently doesn't include the source address
and mixes source and foreign/peer under the same audit name. Fix this
so source is always addr, and the foreign/peer is peer_addr.
Fixes: c05e705812d1 ("apparmor: add fine grained af_unix mediation")
Signed-off-by: John Johansen <john.johansen@canonical.com>
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