From 4355142245f7e55336dcc005ec03592df4d546f8 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 5 Feb 2026 20:59:21 -0800 Subject: dm-verity-fec: correctly reject too-small hash devices Fix verity_fec_ctr() to reject too-small hash devices by correctly taking hash_start into account. Note that this is necessary because dm-verity doesn't call dm_bufio_set_sector_offset() on the hash device's bufio client (v->bufio). Thus, dm_bufio_get_device_size(v->bufio) returns a size relative to 0 rather than hash_start. An alternative fix would be to call dm_bufio_set_sector_offset() on v->bufio, but then all the code that reads from the hash device would have to be adjusted accordingly. 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 --- drivers/md/dm-verity-fec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-verity-fec.c b/drivers/md/dm-verity-fec.c index 9d5dace7d420..721b7c377386 100644 --- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -688,7 +688,8 @@ int verity_fec_ctr(struct dm_verity *v) * it to be large enough. */ f->hash_blocks = f->blocks - v->data_blocks; - if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) { + if (dm_bufio_get_device_size(v->bufio) < + v->hash_start + f->hash_blocks) { ti->error = "Hash device is too small for " DM_VERITY_OPT_FEC_BLOCKS; return -E2BIG; -- cgit v1.2.3