linux-stable.git/security/selinux, branch linux-rolling-lts

selinux: fix incorrect execmem checks on overlayfs

2026-07-24T14:16:57+00:00

commit 9fe595fad54d4ac6a402edb3f60bec859d52cea6 upstream.

The commit fixing the overlayfs mmap() and mprotect() access checks
failed to skip the execmem check in __file_map_prot_check() for the case
where the "mounter check" is being performed. This check should be
performed only against the credentials of the task that is calling
mmap()/mprotect(), since it doesn't pertain to the file itself, but
rather just gates the ability of the calling task to get an executable
memory mapping in general.

The purpose of the "mounter check" is to guard against using an
overlayfs mount to gain file access that would otherwise be denied to
the mounter. For execmem this is not relevant, as there is no further
file access granted based on it (notice that the file's context is not
used as the target in the check), so checking it also against the
mounter credentials would be incorrect.

Fix this by passing a boolean to [__]file_map_prot_check() and
selinux_mmap_file_common() that indicates if we are doing the "mounter
check" and skiping the execmem check in that case. Since this boolean
also indicates if we use current_cred() or the mounter cred as the
subject, also remove the "cred" argument from these functions and
determine it based on the boolean and the file struct.

Cc: stable@vger.kernel.org
Fixes: 82544d36b172 ("selinux: fix overlayfs mmap() and mprotect() access checks")
Signed-off-by: Ondrej Mosnacek 
Reviewed-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: avoid sk_socket dereference in selinux_sctp_bind_connect()

2026-07-24T14:16:56+00:00

commit 56acfeb10019e200ab6787d01f8d7cbe0f01526f upstream.

selinux_sctp_bind_connect() dereferences sk->sk_socket to pass a
struct socket * to selinux_socket_bind() and
selinux_socket_connect_helper().  However, when the hook is invoked
from the ASCONF softirq path (sctp_process_asconf), there is no file
reference guaranteeing that sk->sk_socket is non-NULL.  The setsockopt
callers (bindx, connectx, set_primary, sendmsg connect) hold a file
reference and are not affected.

Both selinux_socket_bind() and selinux_socket_connect_helper()
immediately resolve sock->sk, never using the struct socket * for
anything else.  Refactor the inner logic into helpers that take a
struct sock * directly so that selinux_sctp_bind_connect() never needs
to touch sk->sk_socket at all.

Cc: stable@vger.kernel.org
Fixes: d452930fd3b9 ("selinux: Add SCTP support")
Suggested-by: Stephen Smalley 
Signed-off-by: Tristan Madani 
Reviewed-by: Stephen Smalley 
Tested-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: check connect-related permissions on TCP Fast Open

2026-07-24T14:16:56+00:00

commit 44c74d27d1b9aaa99fa8a83640c1223575262b80 upstream.

Similar to Landlock, SELinux was not updated when TCP Fast Open
support was introduced to ensure connect-related permissions are
checked when using TCP Fast Open. Update its socket_sendmsg() hook to
call selinux_socket_connect() when MSG_FASTOPEN is passed.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-security-module/20260616201615.275032-1-hexlabsecurity@proton.me/
Link: https://lore.kernel.org/linux-security-module/20260617180526.15627-2-matthieu@buffet.re/
Reported-by: Bryam Vargas 
Reported-by: Matthieu Buffet 
Reported-by: Mikhail Ivanov 
Signed-off-by: Stephen Smalley 
Tested-by: Bryam Vargas 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: fix overlayfs mmap() and mprotect() access checks

2026-07-04T11:44:14+00:00

[ Upstream commit 82544d36b1729153c8aeb179e84750f0c085d3b1 ]

The existing SELinux security model for overlayfs is to allow access if
the current task is able to access the top level file (the "user" file)
and the mounter's credentials are sufficient to access the lower
level file (the "backing" file).  Unfortunately, the current code does
not properly enforce these access controls for both mmap() and mprotect()
operations on overlayfs filesystems.

This patch makes use of the newly created security_mmap_backing_file()
LSM hook to provide the missing backing file enforcement for mmap()
operations, and leverages the backing file API and new LSM blob to
provide the necessary information to properly enforce the mprotect()
access controls.

Cc: stable@vger.kernel.org
Acked-by: Amir Goldstein 
Signed-off-by: Paul Moore 
Signed-off-by: Cai Xinchen 
Signed-off-by: Sasha Levin

selinux: prune /sys/fs/selinux/user

2026-05-14T13:30:14+00:00

commit ad1ac3d740cc6b858a99ab9c45c8c0574be7d1d3 upstream.

Remove the previously deprecated /sys/fs/selinux/user interface aside
from a residual stub for userspace compatibility.

Commit d7b6918e22c7 ("selinux: Deprecate /sys/fs/selinux/user") started
the deprecation process for /sys/fs/selinux/user:

    The selinuxfs "user" node allows userspace to request a list
    of security contexts that can be reached for a given SELinux
    user from a given starting context. This was used by libselinux
    when various login-style programs requested contexts for
    users, but libselinux stopped using it in 2020.
    Kernel support will be removed no sooner than Dec 2025.

A pr_warn() message has been in place since Linux v6.13, and a 5
second sleep was introduced since Linux v6.17 to help make it more
noticeable.

We are now past the stated deadline of Dec 2025, so remove the
underlying functionality and replace it with a stub that returns a
'0\0' buffer to avoid breaking userspace. This also avoids a local DoS
from logspam and an uninterruptible sleep delay.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: prune /sys/fs/selinux/disable

2026-05-14T13:30:14+00:00

commit 19cfa0099024bb9cd40f6d950caa7f47ff8e77f6 upstream.

Commit f22f9aaf6c3d ("selinux: remove the runtime disable
functionality") removed the underlying SELinux runtime disable
functionality but left everything else intact and started logging an
error message to warn any residual users.

Prune it to just log an error message once and to return count
(i.e. all bytes written successfully) to avoid breaking
userspace. This also fixes a local DoS from logspam.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: prune /sys/fs/selinux/checkreqprot

2026-05-14T13:30:14+00:00

commit 644132a48f4e28a1d949d162160869286f3e75de upstream.

commit a7e4676e8e2cb ("selinux: remove the 'checkreqprot'
functionality") removed the ability to modify the checkreqprot setting
but left everything except the updating of the checkreqprot value
intact. Aside from unnecessary processing, this could produce a local
DoS from log spam and incorrectly calls selinux_ima_measure_state() on
each write even though no state has changed. Prune it to just log an
error message once and return count (i.e. all bytes written
successfully) so that userspace never breaks.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: shrink critical section in sel_write_load()

2026-05-14T13:30:14+00:00

commit 868f31e4061eca8c3cd607d79d954d5e54f204aa upstream.

Currently sel_write_load() takes the policy mutex earlier than
necessary. Move the taking of the mutex later. This avoids
holding it unnecessarily across the vmalloc() and copy_from_user()
of the policy data.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: don't reserve xattr slot when we won't fill it

2026-05-14T13:30:14+00:00

commit 1e5a8eed7821e7a43a31b4c1b3675a91be6bc6f6 upstream.

Move lsm_get_xattr_slot() below the SBLABEL_MNT check so we don't leave
a NULL-named slot in the array when returning -EOPNOTSUPP; filesystem
initxattrs() callbacks stop iterating at the first NULL ->name, silently
dropping xattrs installed by later LSMs.

Cc: stable@vger.kernel.org
Signed-off-by: David Windsor 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

selinux: use sk blob accessor in socket permission helpers

2026-05-14T13:30:14+00:00

commit 032e70aff025d7c519af9ab791cd084380619263 upstream.

SELinux socket state lives in the composite LSM socket blob.

sock_has_perm() and nlmsg_sock_has_extended_perms() currently
dereference sk->sk_security directly, which assumes the SELinux socket
blob is at offset zero.

In stacked configurations that assumption does not hold. If another LSM
allocates socket blob storage before SELinux, these helpers may read the
wrong blob and feed invalid SID and class values into AVC checks.

Use selinux_sock() instead of accessing sk->sk_security directly.

Fixes: d1d991efaf34 ("selinux: Add netlink xperm support")
Cc: stable@vger.kernel.org # v6.13+
Signed-off-by: Zongyao Chen 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman