laptop-kernel/drivers/md, branch master

dm-integrity: validate the superblock on resume

2026-10-01T11:18:00Z

dm_integrity_resume() re-reads the superblock from the device so that it picks up the flags and the recalculate position. It performs no validation on the result, while the constructor validates the superblock it reads and sizes all the in-memory structures according to it. The user may modify the superblock on the underlying device while the dm-integrity device is suspended, so that the two no longer agree. In particular, access_journal_data() shifts the journal entry index by ic->sb->log2_sectors_per_block, while ic->journal_section_sectors and the journal page list were computed with the value that was present at constructor time. Increasing log2_sectors_per_block makes the index run past the end of the journal, and dm-integrity then writes 512 bytes through lowmem_page_address(NULL). Snapshot the validated superblock in the constructor and refuse to resume if any of the fields that describe the on-disk geometry changed. Reported-by: syzbot+675c91651049ad042c5f@syzkaller.appspotmail.com Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Fixes: 118ba36e446c ("dm-integrity: fix recalculation in bitmap mode") Assisted-by: Claude:claude-opus-5

dm-snap: reject the transient exception store for snapshot-merge

2026-09-30T12:16:56Z

snapshot_merge_next_chunks() calls s->store->type->prepare_merge() without checking it. The transient store ("N") implements neither prepare_merge nor commit_merge, and snapshot_ctr() validates those callbacks only on the handover path (__validate_exception_handover()), so a directly constructed snapshot-merge calls a NULL prepare_merge on resume: snapshot_merge_resume -> snapshot_merge_next_chunks -> prepare_merge(...) commit_merge() is NULL for the same reason. Userspace only issues documented device-mapper ioctls (CAP_SYS_ADMIN); this is a misconfiguration the kernel must reject rather than oops on. Reject the combination in snapshot_ctr() at table-load time (-EINVAL), the same check the handover path already performs; this also covers the commit_merge() call site, which a guard local to the prepare_merge call would miss. Tested on Linux v6.6.157 KASAN: unpatched, the dmsetup reproducer oopses in snapshot_merge_next_chunks(); with this patch, the table load fails with -EINVAL and no oops. Also present on v6.6.145; still present on the linux-dm tree (555f3d7be91a) and on torvalds/linux master (62f4c998b297) as of 2026-09-22. Note that this is not a security bug because only root can trigger it. Signed-off-by: Ma Xinmeng <1564938642@qq.com> Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org

dm: fix reading free memory in do_resume

2026-09-30T12:14:38Z

When do_resume calls dm_table_get_mode(new_map), the call is done without holding any locks (it only holds a reference to the md). It may be possible that another concurrent ioctl on the same device will swap table after dm_swap_table and before dm_table_get_mode. In this case, dm_table_get_mode(new_map) reads freed memory. This race condition was triggered by syzbot. This commit fixes the race by reading mode of the new table before dm_swap_table. Note that new_map is also passed to dm_ima_need_measure, but this function doesn't attempt to dereference it, so this call should be safe. Note that this is not a security bug because only root can trigger it and the commonly used tools such as lvm or cryptsetup do not call the ioctls concurrently, so that they can't trigger it acceidentally. Signed-off-by: Mikulas Patocka Reported-by: syzbot+bdff1ecf726d2af66afd@syzkaller.appspotmail.com Cc: stable@vger.kernel.org

dm ioctl: don't let data_start run past the buffer

2026-09-21T13:55:47Z

struct dm_ioctl has seven bytes of trailing padding, so the smallest buffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data), is seven bytes shorter than sizeof(struct dm_ioctl). get_result_buffer() sets data_start to sizeof(struct dm_ioctl) without looking at how big the buffer actually is. Ask for the minimum and data_start ends up seven bytes past the end. Callers add it to data_size, and ctl_ioctl() copies that much back to userspace: BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0 Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140 ctl_ioctl+0x5e3/0xcb0 dm_ctl_ioctl+0x25/0x40 allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31) A DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the seven bytes that leak are whatever sat next to the allocation. Clamp data_start to the buffer size. Note that this is not a security bug because the out-of-bounds read can only be triggered by root. Reported-by: syzbot+48d935cf48a4a76be346@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=48d935cf48a4a76be346 Fixes: 76c072b48e39 ("dm ioctl: move compat code") Cc: stable@vger.kernel.org Signed-off-by: Palla Raghunath Signed-off-by: Mikulas Patocka

dm-crypt: reject the lmk IV mode with AEAD ciphers

2026-09-21T11:54:29Z

A "capi:" table line that pairs an AEAD cipher with the lmk IV mode, for example "capi:gcm(aes)-lmk" with the integrity:28:aead option, causes an oops when it is loaded. lmk sets tfms_count to 64, but crypt_alloc_tfms_aead only allocates one transform, so crypt_setkey reads past the end of the tfms_aead array and calls crypto_aead_setkey on the values it finds there. lmk exists for compatibility with Loop-AES, which uses CBC, so refuse it with an AEAD cipher rather than allocate 64 AEAD transforms. The check cannot go in crypt_iv_lmk_ctr with the other lmk checks, because the IV constructor runs after crypt_set_key. Note that this is not a security bug because the memory corruption can only be triggered by root. Fixes: 33d2f09fcb35 ("dm crypt: introduce new format of cipher with "capi:" prefix") Cc: stable@vger.kernel.org Signed-off-by: Ben Cressey Assisted-by: LLM Signed-off-by: Mikulas Patocka

dm-integrity: fix buffer overflow in inline mode with large tag size

2026-09-21T11:44:41Z

In inline mode, dm_integrity_check and dm_integrity_inline_recheck compute the checksum of each block into an on-stack buffer of HASH_MAX_DIGESTSIZE bytes. integrity_sector_checksum pads its result with zeroes up to the tag size, so if the tag size is larger than HASH_MAX_DIGESTSIZE, the padding runs past the end of the buffer. With CONFIG_STACKPROTECTOR the kernel panics in dm_integrity_check on the first read. Enlarge both buffers to hold MAX_TAG_SIZE bytes, as commit b93b6643e9b5 ("dm integrity: fix a crash with unusually large tag size") did for integrity_metadata. Note that this is not a security bug because the buffer overflow can only be triggered by root. Fixes: fb0987682c62 ("dm-integrity: introduce the Inline mode") Cc: stable@vger.kernel.org Signed-off-by: Ben Cressey Assisted-by: LLM Signed-off-by: Mikulas Patocka

treewide: refresh kmalloc_obj() conversions

2026-09-05T04:37:00Z

This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook

dm-ebs: fix incorrect device offset check in ebs_ctr()

2026-09-02T15:01:13Z

is a backing-device sector offset; ti->len is the virtual target length. Comparing them rejects valid tables, e.g.: dmsetup create ebs0 --table "0 1048576 ebs /dev/sda 2097152 1 8" -> ebs: Invalid device offset sector (-EINVAL) Drop the check. Bounds against the backing device are already enforced later by device_area_is_invalid() via ebs_iterate_devices(). Cc: stable@vger.kernel.org Fixes: d3c7b35c20d6 ("dm: add emulated block size target") Signed-off-by: Genjian Zhang Signed-off-by: Mikulas Patocka

dm-integrity: fix NULL pointer dereference when the 'R' flag is used

2026-09-02T14:36:26Z

If the dm-integrity device has the SB_FLAG_DIRTY_BITMAP flag set and the user activates the device in the 'R' mode, a crash in dm_integrity_resume happens because the function attempts to read the journal containing the bitmap. This patch makes dm-integrity skip any writes to the device in dm_integrity_resume if the device is activated in the 'R' mode. Signed-off-by: Mikulas Patocka Fixes: 468dfca38b1a ("dm integrity: add a bitmap mode") Cc: stable@vger.kernel.org

dm cache: fix demotion stats in passthrough mode

2026-09-01T13:22:36Z

The demotion counter is incremented per incoming write bio before the invalidation begins, causing the demotion count to exceed the actual number of cached blocks when multiple bios target the same cached block. Additionally, the counter is incremented unconditionally regardless of invalidation failure. Reproduce steps: 1. Create a cache device consisting of 512 cache entries modprobe brd rd_size=262144 dmsetup create cmeta --table "0 8192 linear /dev/ram0 0" dmsetup create cdata --table "0 65536 linear /dev/ram0 8192" dmsetup create corig --table "0 65536 linear /dev/ram0 262144" dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table "0 65536 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" 2. Populate the cache, and record the number of cached blocks fio --name=populate --filename=/dev/mapper/cache --rw=randwrite --bs=4k \ --direct=1 --ioengine=libaio --iodepth=32 --io_size=2048m nr_cached=$(dmsetup status cache | awk '{split($7, a, "/"); print a[1]}') 3. Reload the cache into passthrough mode dmsetup suspend cache dmsetup reload cache --table "0 65536 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0" dmsetup resume cache 4. Write to the passthrough cache with multiple jobs to trigger multiple bios hitting the same cached block. fio --filename=/dev/mapper/cache --name=test --rw=write --bs=4k \ --direct=1 --ioengine=libaio --iodepth=32 --numjobs=4 5. Check if demoted matches cached block count. These numbers should match but may differ due to overcounting per bio. nr_demoted=$(dmsetup status cache | awk '{print $12}') echo "$nr_cached, $nr_demoted" Fix by moving the demotion counter increment into invalidate_complete(), gated on the success flag. Reported-by: Ben Marzinski Fixes: b29d4986d0da ("dm cache: significant rework to leverage dm-bio-prison-v2") Cc: stable@vger.kernel.org Signed-off-by: Ming-Hung Tsai Reviewed-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka