kernel/linux.git/security, branch v6.6.143

landlock: Fix handling of disconnected directories

2026-06-19T11:39:24+00:00

[ Upstream commit 49c9e09d961025b22e61ef9ad56aa1c21b6ce2f1 ] Disconnected files or directories can appear when they are visible and opened from a bind mount, but have been renamed or moved from the source of the bind mount in a way that makes them inaccessible from the mount point (i.e. out of scope). Previously, access rights tied to files or directories opened through a disconnected directory were collected by walking the related hierarchy down to the root of the filesystem, without taking into account the mount point because it couldn't be found. This could lead to inconsistent access results, potential access right widening, and hard-to-debug renames, especially since such paths cannot be printed. For a sandboxed task to create a disconnected directory, it needs to have write access (i.e. FS_MAKE_REG, FS_REMOVE_FILE, and FS_REFER) to the underlying source of the bind mount, and read access to the related mount point. Because a sandboxed task cannot acquire more access rights than those defined by its Landlock domain, this could lead to inconsistent access rights due to missing permissions that should be inherited from the mount point hierarchy, while inheriting permissions from the filesystem hierarchy hidden by this mount point instead. Landlock now handles files and directories opened from disconnected directories by taking into account the filesystem hierarchy when the mount point is not found in the hierarchy walk, and also always taking into account the mount point from which these disconnected directories were opened. This ensures that a rename is not allowed if it would widen access rights [1]. The rationale is that, even if disconnected hierarchies might not be visible or accessible to a sandboxed task, relying on the collected access rights from them improves the guarantee that access rights will not be widened during a rename because of the access right comparison between the source and the destination (see LANDLOCK_ACCESS_FS_REFER). It may look like this would grant more access on disconnected files and directories, but the security policies are always enforced for all the evaluated hierarchies. This new behavior should be less surprising to users and safer from an access control perspective. Remove a wrong WARN_ON_ONCE() canary in collect_domain_accesses() and fix the related comment. Because opened files have their access rights stored in the related file security properties, there is no impact for disconnected or unlinked files. Cc: Christian Brauner Cc: Günther Noack Cc: Song Liu Reported-by: Tingmao Wang Closes: https://lore.kernel.org/r/027d5190-b37a-40a8-84e9-4ccbc352bcdf@maowtm.org Closes: https://lore.kernel.org/r/09b24128f86973a6022e6aa8338945fcfb9a33e4.1749925391.git.m@maowtm.org Fixes: b91c3e4ea756 ("landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER") Fixes: cb2c7d1a1776 ("landlock: Support filesystem access-control") Link: https://lore.kernel.org/r/b0f46246-f2c5-42ca-93ce-0d629702a987@maowtm.org [1] Reviewed-by: Tingmao Wang Link: https://lore.kernel.org/r/20251128172200.760753-2-mic@digikod.net Signed-off-by: Mickaël Salaün [ Adjust context ] Signed-off-by: Bin Lan Signed-off-by: Sasha Levin

ima: verify the previous kernel's IMA buffer lies in addressable RAM

2026-06-19T11:39:14+00:00

[ Upstream commit 10d1c75ed4382a8e79874379caa2ead8952734f9 ] Patch series "Address page fault in ima_restore_measurement_list()", v3. When the second-stage kernel is booted via kexec with a limiting command line such as "mem=" we observe a pafe fault that happens. BUG: unable to handle page fault for address: ffff97793ff47000 RIP: ima_restore_measurement_list+0xdc/0x45a #PF: error_code(0x0000) not-present page This happens on x86_64 only, as this is already fixed in aarch64 in commit: cbf9c4b9617b ("of: check previous kernel's ima-kexec-buffer against memory bounds") This patch (of 3): When the second-stage kernel is booted with a limiting command line (e.g. "mem="), the IMA measurement buffer handed over from the previous kernel may fall outside the addressable RAM of the new kernel. Accessing such a buffer can fault during early restore. Introduce a small generic helper, ima_validate_range(), which verifies that a physical [start, end] range for the previous-kernel IMA buffer lies within addressable memory: - On x86, use pfn_range_is_mapped(). - On OF based architectures, use page_is_ram(). Link: https://lkml.kernel.org/r/20251231061609.907170-1-harshit.m.mogalapalli@oracle.com Link: https://lkml.kernel.org/r/20251231061609.907170-2-harshit.m.mogalapalli@oracle.com Signed-off-by: Harshit Mogalapalli Reviewed-by: Mimi Zohar Cc: Alexander Graf Cc: Ard Biesheuvel Cc: Borislav Betkov Cc: guoweikang Cc: Henry Willard Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jiri Bohac Cc: Joel Granados Cc: Jonathan McDowell Cc: Mike Rapoport Cc: Paul Webb Cc: Sohil Mehta Cc: Sourabh Jain Cc: Thomas Gleinxer Cc: Yifei Liu Cc: Baoquan He Cc: Signed-off-by: Andrew Morton Signed-off-by: Wenshan Lan Signed-off-by: Sasha Levin

security/keys: fix missed RCU read section on lookup

2026-06-01T15:43:16+00:00

commit 43a1e3744548e6fd85873e6fb43e293eb4010694 upstream. Nicholas Carlini reports that the keyring code calls assoc_array_find() in find_key_to_update() without holding the RCU read lock, while the assoc_array_gc() code really is designed around removing the node from the tree and then freeing it after an RCU grace-period. The regular key handling doesn't see this because holding the keyring semaphore hides any lifetime issues, but the persistent key handling uses a different model. Instead of extending the keyring locking, just do the simple RCU locking that the assoc_array was designed for. Reported-by: Nicholas Carlini Cc: David Howells Cc: Jarkko Sakkinen Cc: Paul Moore Cc: James Morris James Morris Cc: Serge E. Hallyn Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ima: check return value of crypto_shash_final() in boot aggregate

2026-05-23T11:03:18+00:00

[ Upstream commit 870819434c8dfcc3158033b66e7851b81bb17e21 ] The return value of crypto_shash_final() is not checked in ima_calc_boot_aggregate_tfm(). If the hash finalization fails, the function returns success and a corrupted boot aggregate digest could be used for IMA measurements. Capture the return value and propagate any error to the caller. Fixes: 76bb28f6126f ("ima: use new crypto_shash API instead of old crypto_hash") Signed-off-by: Daniel Hodges Reviewed-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin

selinux: prune /sys/fs/selinux/disable

2026-05-17T15:13:38+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: shrink critical section in sel_write_load()

2026-05-17T15:13:38+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

2026-05-17T15:13:38+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

xen/privcmd: add boot control for restricted usage in domU

2026-03-25T10:06:10+00:00

commit 1613462be621ad5103ec338a7b0ca0746ec4e5f1 upstream. When running in an unprivileged domU under Xen, the privcmd driver is restricted to allow only hypercalls against a target domain, for which the current domU is acting as a device model. Add a boot parameter "unrestricted" to allow all hypercalls (the hypervisor will still refuse destructive hypercalls affecting other guests). Make this new parameter effective only in case the domU wasn't started using secure boot, as otherwise hypercalls targeting the domU itself might result in violating the secure boot functionality. This is achieved by adding another lockdown reason, which can be tested to not being set when applying the "unrestricted" option. This is part of XSA-482 Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

apparmor: fix race between freeing data and fs accessing it

2026-03-25T10:05:43+00:00

commit 8e135b8aee5a06c52a4347a5a6d51223c6f36ba3 upstream. 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 and 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 Reviewed-by: Georgia Garcia Reviewed-by: Maxime Bélair Reviewed-by: Cengiz Can Signed-off-by: John Johansen Signed-off-by: Greg Kroah-Hartman

apparmor: fix race on rawdata dereference

2026-03-25T10:05:43+00:00

commit a0b7091c4de45a7325c8780e6934a894f92ac86b upstream. 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 Reviewed-by: Georgia Garcia Reviewed-by: Maxime Bélair Reviewed-by: Cengiz Can Tested-by: Salvatore Bonaccorso Signed-off-by: John Johansen Signed-off-by: Greg Kroah-Hartman