It is possible to set up dm-integrity in such a way that the "tag_size" parameter is less than the actual digest size. In this situation, a part of the digest beyond tag_size is ignored.
In this case, dm-integrity would write beyond the end of the ic->recalc_tags array and corrupt memory. The corruption happened in integrity_recalc->integrity_sector_checksum->crypto_shash_final. This patch fixes the corruption. Signed-off-by: Mikulas Patocka <[email protected]> Cc: [email protected] # v4.19+ --- drivers/md/dm-integrity.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) Index: linux-2.6/drivers/md/dm-integrity.c =================================================================== --- linux-2.6.orig/drivers/md/dm-integrity.c 2022-04-02 14:17:13.000000000 +0200 +++ linux-2.6/drivers/md/dm-integrity.c 2022-04-02 14:43:06.000000000 +0200 @@ -4399,6 +4399,7 @@ try_smaller_buffer: } if (ic->internal_hash) { + size_t recalc_tags_size; ic->recalc_wq = alloc_workqueue("dm-integrity-recalc", WQ_MEM_RECLAIM, 1); if (!ic->recalc_wq ) { ti->error = "Cannot allocate workqueue"; @@ -4412,8 +4413,10 @@ try_smaller_buffer: r = -ENOMEM; goto bad; } - ic->recalc_tags = kvmalloc_array(RECALC_SECTORS >> ic->sb->log2_sectors_per_block, - ic->tag_size, GFP_KERNEL); + recalc_tags_size = (RECALC_SECTORS >> ic->sb->log2_sectors_per_block) * ic->tag_size; + if (crypto_shash_digestsize(ic->internal_hash) > ic->tag_size) + recalc_tags_size += crypto_shash_digestsize(ic->internal_hash) - ic->tag_size; + ic->recalc_tags = kvmalloc(recalc_tags_size, GFP_KERNEL); if (!ic->recalc_tags) { ti->error = "Cannot allocate tags for recalculating"; r = -ENOMEM; -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
