Pull vfs i_ino updates from Christian Brauner:
"For historical reasons, the inode->i_ino field is an unsigned long,
which means that it's 32 bits on 32 bit architectures. This has caused
a number of filesystems to implement hacks to hash a 64-bit identifier
into a 32-bit field, and deprives us of a universal identifier field
for an inode.
This changes the inode->i_ino field from an unsigned long to a u64.
This shouldn't make any material difference on 64-bit hosts, but
32-bit hosts will see struct inode grow by at least 4 bytes. This
could have effects on slabcache sizes and field alignment.
The bulk of the changes are to format strings and tracepoints, since
the kernel itself doesn't care that much about the i_ino field. The
first patch changes some vfs function arguments, so check that one out
carefully.
With this change, we may be able to shrink some inode structures. For
instance, struct nfs_inode has a fileid field that holds the 64-bit
inode number. With this set of changes, that field could be
eliminated. I'd rather leave that sort of cleanups for later just to
keep this simple"
* tag 'vfs-7.1-rc1.kino' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
nilfs2: fix 64-bit division operations in nilfs_bmap_find_target_in_group()
EVM: add comment describing why ino field is still unsigned long
vfs: remove externs from fs.h on functions modified by i_ino widening
treewide: fix missed i_ino format specifier conversions
ext4: fix signed format specifier in ext4_load_inode trace event
treewide: change inode->i_ino from unsigned long to u64
nilfs2: widen trace event i_ino fields to u64
f2fs: widen trace event i_ino fields to u64
ext4: widen trace event i_ino fields to u64
zonefs: widen trace event i_ino fields to u64
hugetlbfs: widen trace event i_ino fields to u64
ext2: widen trace event i_ino fields to u64
cachefiles: widen trace event i_ino fields to u64
vfs: widen trace event i_ino fields to u64
net: change sock.sk_ino and sock_i_ino() to u64
audit: widen ino fields to u64
vfs: widen inode hash/lookup functions to u64
Pull vfs directory updates from Christian Brauner:
"Recently 'start_creating', 'start_removing', 'start_renaming' and
related interfaces were added which combine the locking and the
lookup.
At that time many callers were changed to use the new interfaces.
However there are still an assortment of places out side of the core
vfs where the directory is locked explictly, whether with inode_lock()
or lock_rename() or similar. These were missed in the first pass for
an assortment of uninteresting reasons.
This addresses the remaining places where explicit locking is used,
and changes them to use the new interfaces, or otherwise removes the
explicit locking.
The biggest changes are in overlayfs. The other changes are quite
simple, though maybe the cachefiles changes is the least simple of
those"
* tag 'vfs-7.1-rc1.directory' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
VFS: unexport lock_rename(), lock_rename_child(), unlock_rename()
ovl: remove ovl_lock_rename_workdir()
ovl: use is_subdir() for testing if one thing is a subdir of another
ovl: change ovl_create_real() to get a new lock when re-opening created file.
ovl: pass name buffer to ovl_start_creating_temp()
cachefiles: change cachefiles_bury_object to use start_renaming_dentry()
ovl: Simplify ovl_lookup_real_one()
VFS: make lookup_one_qstr_excl() static.
nfsd: switch purge_old() to use start_removing_noperm()
selinux: Use simple_start_creating() / simple_done_creating()
Apparmor: Use simple_start_creating() / simple_done_creating()
libfs: change simple_done_creating() to use end_creating()
VFS: move the start_dirop() kerndoc comment to before start_dirop()
fs/proc: Don't lock root inode when creating "self" and "thread-self"
VFS: note error returns in documentation for various lookup functions
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: c961ee5f21 ("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>
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: 5d5182cae4 ("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>
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: b7fd2c0340 ("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>
On 32-bit architectures, unsigned long is only 32 bits wide, which
causes 64-bit inode numbers to be silently truncated. Several
filesystems (NFS, XFS, BTRFS, etc.) can generate inode numbers that
exceed 32 bits, and this truncation can lead to inode number collisions
and other subtle bugs on 32-bit systems.
Change the type of inode->i_ino from unsigned long to u64 to ensure that
inode numbers are always represented as 64-bit values regardless of
architecture. Update all format specifiers treewide from %lu/%lx to
%llu/%llx to match the new type, along with corresponding local variable
types.
This is the bulk treewide conversion. Earlier patches in this series
handled trace events separately to allow trace field reordering for
better struct packing on 32-bit.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260304-iino-u64-v3-12-2257ad83d372@kernel.org
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Instead of explicitly locking the parent and performing a look up in
apparmor, use simple_start_creating(), and then simple_done_creating()
to unlock and drop the dentry.
This removes the need to check for an existing entry (as
simple_start_creating() acts like an exclusive create and can return
-EEXIST), simplifies error paths, and keeps dir locking code
centralised.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20260224222542.3458677-6-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
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>
strcpy() is deprecated; use memcpy() instead. Unlike strcpy(), memcpy()
does not copy the NUL terminator from the source string, which would be
overwritten anyway on every iteration when using strcpy(). snprintf()
then ensures that 'char *s' is NUL-terminated.
Replace the hard-coded path length to remove the magic number 6, and add
a comment explaining the extra 11 bytes.
Closes: https://github.com/KSPP/linux/issues/88
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
Pull LSM updates from Paul Moore:
- Rework the LSM initialization code
What started as a "quick" patch to enable a notification event once
all of the individual LSMs were initialized, snowballed a bit into a
30+ patch patchset when everything was done. Most of the patches, and
diffstat, is due to splitting out the initialization code into
security/lsm_init.c and cleaning up some of the mess that was there.
While not strictly necessary, it does cleanup the code signficantly,
and hopefully makes the upkeep a bit easier in the future.
Aside from the new LSM_STARTED_ALL notification, these changes also
ensure that individual LSM initcalls are only called when the LSM is
enabled at boot time. There should be a minor reduction in boot times
for those who build multiple LSMs into their kernels, but only enable
a subset at boot.
It is worth mentioning that nothing at present makes use of the
LSM_STARTED_ALL notification, but there is work in progress which is
dependent upon LSM_STARTED_ALL.
- Make better use of the seq_put*() helpers in device_cgroup
* tag 'lsm-pr-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (36 commits)
lsm: use unrcu_pointer() for current->cred in security_init()
device_cgroup: Refactor devcgroup_seq_show to use seq_put* helpers
lsm: add a LSM_STARTED_ALL notification event
lsm: consolidate all of the LSM framework initcalls
selinux: move initcalls to the LSM framework
ima,evm: move initcalls to the LSM framework
lockdown: move initcalls to the LSM framework
apparmor: move initcalls to the LSM framework
safesetid: move initcalls to the LSM framework
tomoyo: move initcalls to the LSM framework
smack: move initcalls to the LSM framework
ipe: move initcalls to the LSM framework
loadpin: move initcalls to the LSM framework
lsm: introduce an initcall mechanism into the LSM framework
lsm: group lsm_order_parse() with the other lsm_order_*() functions
lsm: output available LSMs when debugging
lsm: cleanup the debug and console output in lsm_init.c
lsm: add/tweak function header comment blocks in lsm_init.c
lsm: fold lsm_init_ordered() into security_init()
lsm: cleanup initialize_lsm() and rename to lsm_init_single()
...
At this point there are very few call chains that might lead to
d_make_discardable() on a dentry that hadn't been made persistent:
calls of simple_unlink() and simple_rmdir() in configfs and
apparmorfs.
Both filesystems do pin (part of) their contents in dcache, but
they are currently playing very unusual games with that. Converting
them to more usual patterns might be possible, but it's definitely
going to be a long series of changes in both cases.
For now the easiest solution is to have both stop using simple_unlink()
and simple_rmdir() - that allows to make d_make_discardable() warn
when given a non-persistent dentry.
Rather than giving them full-blown private copies (with calls of
d_make_discardable() replaced with dput()), let's pull the parts of
simple_unlink() and simple_rmdir() that deal with timestamps and link
counts into separate helpers (__simple_unlink() and __simple_rmdir()
resp.) and have those used by configfs and apparmorfs.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
start_removing_dentry() is similar to start_removing() but instead of
providing a name for lookup, the target dentry is given.
start_removing_dentry() checks that the dentry is still hashed and in
the parent, and if so it locks and increases the refcount so that
end_removing() can be used to finish the operation.
This is used in cachefiles, overlayfs, smb/server, and apparmor.
There will be other users including ecryptfs.
As start_removing_dentry() takes an extra reference to the dentry (to be
put by end_removing()), there is no need to explicitly take an extra
reference to stop d_delete() from using dentry_unlink_inode() to negate
the dentry - as in cachefiles_delete_object(), and ksmbd_vfs_unlink().
cachefiles_bury_object() now gets an extra ref to the victim, which is
drops. As it includes the needed end_removing() calls, the caller
doesn't need them.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-9-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull apparmor updates from John Johansen:
"This has one major feature, it pulls in a cleaned up version of
af_unix mediation that Ubuntu has been carrying for years. It is
placed behind a new abi to ensure that it does cause policy
regressions. With pulling in the af_unix mediation there have been
cleanups and some refactoring of network socket mediation. This
accounts for the majority of the changes in the diff.
In addition there are a few improvements providing minor code
optimizations. several code cleanups, and bug fixes.
Features:
- improve debug printing
- carry mediation check on label (optimization)
- improve ability for compiler to optimize
__begin_current_label_crit_section
- transition for a linked list of rulesets to a vector of rulesets
- don't hardcode profile signal, allow it to be set by policy
- ability to mediate caps via the state machine instead of lut
- Add Ubuntu af_unix mediation, put it behind new v9 abi
Cleanups:
- fix typos and spelling errors
- cleanup kernel doc and code inconsistencies
- remove redundant checks/code
- remove unused variables
- Use str_yes_no() helper function
- mark tables static where appropriate
- make all generated string array headers const char *const
- refactor to doc semantics of file_perm checks
- replace macro calls to network/socket fns with explicit calls
- refactor/cleanup socket mediation code preparing for finer grained
mediation of different network families
- several updates to kernel doc comments
Bug fixes:
- fix incorrect profile->signal range check
- idmap mount fixes
- policy unpack unaligned access fixes
- kfree_sensitive() where appropriate
- fix oops when freeing policy
- fix conflicting attachment resolution
- fix exec table look-ups when stacking isn't first
- fix exec auditing
- mitigate userspace generating overly large xtables"
* tag 'apparmor-pr-2025-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: (60 commits)
apparmor: fix: oops when trying to free null ruleset
apparmor: fix Regression on linux-next (next-20250721)
apparmor: fix test error: WARNING in apparmor_unix_stream_connect
apparmor: Remove the unused variable rules
apparmor: fix: accept2 being specifie even when permission table is presnt
apparmor: transition from a list of rules to a vector of rules
apparmor: fix documentation mismatches in val_mask_to_str and socket functions
apparmor: remove redundant perms.allow MAY_EXEC bitflag set
apparmor: fix kernel doc warnings for kernel test robot
apparmor: Fix unaligned memory accesses in KUnit test
apparmor: Fix 8-byte alignment for initial dfa blob streams
apparmor: shift uid when mediating af_unix in userns
apparmor: shift ouid when mediating hard links in userns
apparmor: make sure unix socket labeling is correctly updated.
apparmor: fix regression in fs based unix sockets when using old abi
apparmor: fix AA_DEBUG_LABEL()
apparmor: fix af_unix auditing to include all address information
apparmor: Remove use of the double lock
apparmor: update kernel doc comments for xxx_label_crit_section
apparmor: make __begin_current_label_crit_section() indicate whether put is needed
...
The set of rules on a profile is not dynamically extended, instead
if a new ruleset is needed a new version of the profile is created.
This allows us to use a vector of rules instead of a list, slightly
reducing memory usage and simplifying the code.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The lookup_one_len family of functions is (now) only used internally by
a filesystem on itself either
- in a context where permission checking is irrelevant such as by a
virtual filesystem populating itself, or xfs accessing its ORPHANAGE
or dquota accessing the quota file; or
- in a context where a permission check (MAY_EXEC on the parent) has just
been performed such as a network filesystem finding in "silly-rename"
file in the same directory. This is also the context after the
_parentat() functions where currently lookup_one_qstr_excl() is used.
So the permission check is pointless.
The name "one_len" is unhelpful in understanding the purpose of these
functions and should be changed. Most of the callers pass the len as
"strlen()" so using a qstr and QSTR() can simplify the code.
This patch renames these functions (include lookup_positive_unlocked()
which is part of the family despite the name) to have a name based on
"lookup_noperm". They are changed to receive a 'struct qstr' instead
of separate name and len. In a few cases the use of QSTR() results in a
new call to strlen().
try_lookup_noperm() takes a pointer to a qstr instead of the whole
qstr. This is consistent with d_hash_and_lookup() (which is nearly
identical) and useful for lookup_noperm_unlocked().
The new lookup_noperm_common() doesn't take a qstr yet. That will be
tidied up in a subsequent patch.
Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g. on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns. For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.
This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes. Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.
This lookup-after-mkdir requires that the directory remains locked to
avoid races. Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.
To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
NULL - the directory was created and no other dentry was used
ERR_PTR() - an error occurred
non-NULL - this other dentry was spliced in
This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations. Subsequent patches will make
further changes to some file-systems to return a correct dentry.
Not all filesystems reliably result in a positive hashed dentry:
- NFS, cifs, hostfs will sometimes need to perform a lookup of
the name to get inode information. Races could result in this
returning something different. Note that this lookup is
non-atomic which is what we are trying to avoid. Placing the
lookup in filesystem code means it only happens when the filesystem
has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
operation ensures that lookup will be called to correctly populate
the dentry. This could be fixed but I don't think it is important
to any of the users of vfs_mkdir() which look at the dentry.
The recommendation to use
d_drop();d_splice_alias()
is ugly but fits with current practice. A planned future patch will
change this.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
dbus permission queries need to be synced with fine grained unix
mediation to avoid potential policy regressions. To ensure that
dbus queries don't result in a case where fine grained unix mediation
is not being applied but dbus mediation is check the loaded policy
support ABI and abort the query if policy doesn't support the
v9 ABI.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Fine grained unix mediation in Ubuntu used ABI v7, and policy using
this has propogated onto systems where fine grained unix mediation was
not supported. The userspace policy compiler supports downgrading
policy so the policy could be shared without changes.
Unfortunately this had the side effect that policy was not updated for
the none Ubuntu systems and enabling fine grained unix mediation on
those systems means that a new kernel can break a system with existing
policy that worked with the previous kernel. With fine grained af_unix
mediation this regression can easily break the system causing boot to
fail, as it affect unix socket files, non-file based unix sockets, and
dbus communication.
To aoid this regression move fine grained af_unix mediation behind
a new abi. This means that the system's userspace and policy must
be updated to support the new policy before it takes affect and
dropping a new kernel on existing system will not result in a
regression.
The abi bump is done in such a way as existing policy can be activated
on the system by changing the policy abi declaration and existing unix
policy rules will apply. Policy then only needs to be incrementally
updated, can even be backported to existing Ubuntu policy.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Extend af_unix mediation to support fine grained controls based on
the type (abstract, anonymous, fs), the address, and the labeling
on the socket.
This allows for using socket addresses to label and the socket and
control which subjects can communicate.
The unix rule format follows standard apparmor rules except that fs
based unix sockets can be mediated by existing file rules. None fs
unix sockets can be mediated by a unix socket rule. Where The address
of an abstract unix domain socket begins with the @ character, similar
to how they are reported (as paths) by netstat -x. The address then
follows and may contain pattern matching and any characters including
the null character. In apparmor null characters must be specified by
using an escape sequence \000 or \x00. The pattern matching is the
same as is used by file path matching so * will not match / even
though it has no special meaning with in an abstract socket name. Eg.
allow unix addr=@*,
Autobound unix domain sockets have a unix sun_path assigned to them by
the kernel, as such specifying a policy based address is not possible.
The autobinding of sockets can be controlled by specifying the special
auto keyword. Eg.
allow unix addr=auto,
To indicate that the rule only applies to auto binding of unix domain
sockets. It is important to note this only applies to the bind
permission as once the socket is bound to an address it is
indistinguishable from a socket that have an addr bound with a
specified name. When the auto keyword is used with other permissions
or as part of a peer addr it will be replaced with a pattern that can
match an autobound socket. Eg. For some kernels
allow unix rw addr=auto,
It is important to note, this pattern may match abstract sockets that
were not autobound but have an addr that fits what is generated by the
kernel when autobinding a socket.
Anonymous unix domain sockets have no sun_path associated with the
socket address, however it can be specified with the special none
keyword to indicate the rule only applies to anonymous unix domain
sockets. Eg.
allow unix addr=none,
If the address component of a rule is not specified then the rule
applies to autobind, abstract and anonymous sockets.
The label on the socket can be compared using the standard label=
rule conditional. Eg.
allow unix addr=@foo peer=(label=bar),
see man apparmor.d for full syntax description.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Linus Torvalds
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