kernel/linux.git/drivers/md, branch v6.18.43

dm: avoid leaking the caller's thread keyring via the table device file

2026-08-03T09:22:11+00:00

[ Upstream commit 981ccd97f7153d310dfa92a534525bbaf46752c2 ] The refactoring in commit a28d893eb327 ("md: port block device access to file") accidentally causes the caller's thread keyring to be kept alive long beyond the caller's lifetime. As a result, "cryptsetup luksSuspend" silently fails to wipe the LUKS volume key from memory. In detail: "cryptsetup luksOpen" uses its supposedly ephemeral thread keyring to pass the volume key to the kernel. dm-crypt's crypt_set_keyring_key() copies the key material into its own crypt_config structure and then drops its own reference to the key in the keyring with key_put(). With this fix, restoring pre-v6.9 behavior, the copy in the thread keyring is then promptly garbage collected, such that exactly one copy of the volume key remains. This single copy is correctly wiped from memory on "cryptsetup luksSuspend". Without this fix, the thread keyring and the volume key in it remains. This second copy is only freed on "luksClose". "luksSuspend" neither knows about this copy nor has any way to remove it, so the key remains recoverable from RAM after a suspend that is documented to have wiped it. This fix should not introduce new security problems, as the code is anyway gated by CAP_SYS_ADMIN. The device-mapper core, not the calling task, is the legitimate owner of this long-lived file. Fixes: a28d893eb327 ("md: port block device access to file") Closes: https://gitlab.com/cryptsetup/cryptsetup/-/work_items/993 Link: https://www.speicherleck.de/iblech/cryptsetup-luksSuspend-issue-reproduction/ Signed-off-by: Ingo Blechschmidt Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Tested-by: Ondrej Kozina Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

dm-verity: fix buffer overflow in FEC calculation

2026-08-03T09:22:07+00:00

commit 31d6e6c0ba8d5a7bd59660035a089307100c5e8e upstream. There's a buffer overflow in dm-verity-fec: if (neras && *neras <= v->fec->roots) fio->erasures[(*neras)++] = i; This allows *neras to reach roots + 1 (the post-increment pushes it past roots). This value is then passed as no_eras to decode_rs8(). Inside the RS decoder (lib/reed_solomon/decode_rs.c:113-121), the erasure locator polynomial loop writes lambda[j] where j can reach nroots + 1 — one element past the end of lambda[] (which is sized nroots + 1, valid indices 0..nroots). The out-of-bounds write lands on syn[0], corrupting the syndrome buffer. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4-6 Cc: stable@vger.kernel.org Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Reviewed-by: Sami Tolvanen Signed-off-by: Mikulas Patocka Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

dm-verity-fec: replace {MAX,MIN}_RSN with {MIN,MAX}_ROOTS

2026-08-03T09:22:07+00:00

commit 82fbd6a3e29a329d439690cd7ccc4162c9cd8db6 upstream. Every time DM_VERITY_FEC_{MAX,MIN}_RSN are used, they are subtracted from DM_VERITY_FEC_RSM to get the bounds on the number of roots. Therefore, replace these with {MIN,MAX}_ROOTS constants which are more directly useful. (Note the inversion, where MAX_RSN maps to MIN_ROOTS and MIN_RSN maps to MAX_ROOTS.) No functional change. Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka Signed-off-by: Sasha Levin

dm-verity-fec: fix reading parity bytes split across blocks (take 3)

2026-08-03T09:22:07+00:00

commit 430a05cb926f6bdf53e81460a2c3a553257f3f61 upstream. fec_decode_bufs() assumes that the parity bytes of the first RS codeword it decodes are never split across parity blocks. This assumption is false. Consider v->fec->block_size == 4096 && v->fec->roots == 17 && fio->nbufs == 1, for example. In that case, each call to fec_decode_bufs() consumes v->fec->roots * (fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS) = 272 parity bytes. Considering that the parity data for each message block starts on a block boundary, the byte alignment in the parity data will iterate through 272*i mod 4096 until the 3 parity blocks have been consumed. On the 16th call (i=15), the alignment will be 4080 bytes into the first block. Only 16 bytes remain in that block, but 17 parity bytes will be needed. The code reads out-of-bounds from the parity block buffer. Fortunately this doesn't normally happen, since it can occur only for certain non-default values of fec_roots *and* when the maximum number of buffers couldn't be allocated due to low memory. For example with block_size=4096 only the following cases are affected: fec_roots=17: nbufs in [1, 3, 5, 15] fec_roots=19: nbufs in [1, 229] fec_roots=21: nbufs in [1, 3, 5, 13, 15, 39, 65, 195] fec_roots=23: nbufs in [1, 89] Regardless, fix it by refactoring how the parity blocks are read. Fixes: 6df90c02bae4 ("dm-verity FEC: Fix RS FEC repair for roots unaligned to block size (take 2)") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka Signed-off-by: Sasha Levin

dm-verity-fec: fix the size of dm_verity_fec_io::erasures

2026-08-03T09:22:07+00:00

commit a7fca324d7d90f7b139d4d32747c83a629fdb446 upstream. At most 25 entries in dm_verity_fec_io::erasures are used: the maximum number of FEC roots plus one. Therefore, set the array size accordingly. This reduces the size of dm_verity_fec_io by 912 bytes. Note: a later commit introduces a constant DM_VERITY_FEC_MAX_ROOTS, which allows the size to be more clearly expressed as DM_VERITY_FEC_MAX_ROOTS + 1. This commit just fixes the size first. Fixes: a739ff3f543a ("dm verity: add support for forward error correction") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka Signed-off-by: Sasha Levin

dm-verity: make error counter atomic

2026-07-24T14:17:09+00:00

commit 8ec4d9c5a5cf4b61fc087f871465b1f79b393325 upstream. The error counter "v->corrupted_errs" was not atomic, thus it could be subject to race conditions. The call to dm_audit_log_target("max-corrupted-errors") may be skipped due to the races. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4.6 Fixes: 65ff5b7ddf05 ("dm verity: add error handling modes for corrupted blocks") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

dm-verity: increase sprintf buffer size

2026-07-24T14:17:09+00:00

commit 88dd117c92a142253fb7a17e791773902b3babc6 upstream. The prefix "DM_VERITY_ERR_BLOCK_NR" is 22 chars. Add '=', one digit for type, ',', up to 20 digits for a u64 block number, and a NUL terminator: that's 46 bytes. The buffer is 42 bytes. For block numbers >= 16 decimal digits (devices larger than ~16 EB with 4K blocks), snprintf silently truncates the uevent environment variable. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4.6 Fixes: 65ff5b7ddf05 ("dm verity: add error handling modes for corrupted blocks") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

dm-verity: fix a possible NULL pointer dereference

2026-07-24T14:17:09+00:00

commit e72b793ae440f6900fb17a4b8518c707b5cd3e17 upstream. Fix a possible NULL pointer dereference dm_verity_loadpin_is_bdev_trusted if the device has no table. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4-6 Fixes: b6c1c5745ccc ("dm: Add verity helpers for LoadPin") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

dm-verity: avoid double increment of &use_bh_wq_enabled

2026-07-24T14:17:09+00:00

commit 72e9ec2fe32b00994f41719cf77423fca67d48b2 upstream. verity_parse_opt_args is called twice, first with the only_modifier_opts, first with only_modifier_opts == true and then with only_modifier_opts == false. Thus, the static branch &use_bh_wq_enabled was incremented twice and the destructor verity_dtr would only decrement it once. Fix tihs bug by only incrementing it on the first call, on the second call, when v->use_bh_wq is true, do nothing. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4-6 Cc: stable@vger.kernel.org Fixes: df326e7a0699 ("dm verity: allow optional args to alter primary args handling") Signed-off-by: Greg Kroah-Hartman

dm-integrity: don't increment hash_offset twice

2026-07-24T14:17:09+00:00

commit edf025f083854f80032b73a1aad69a3c90db236f upstream. hash_offset is already incremented in the loop "for (i = 0; i < to_copy; i++, ts--)". Do not increment it again. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4.6 Fixes: 84597a44a9d8 ("dm-integrity: dm integrity: add optional discard support") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman