Commit 3a774521 authored Apr 14, 2014 by Milan Broz Committed by Mike Snitzer Apr 15, 2014

dm verity: fix biovecs hash calculation regression



Commit 003b5c57 ("block: Convert drivers
to immutable biovecs") incorrectly converted biovec iteration in
dm-verity to always calculate the hash from a full biovec, but the
function only needs to calculate the hash from part of the biovec (up to
the calculated "todo" value).

Fix this issue by limiting hash input to only the requested data size.

This problem was identified using the cryptsetup regression test for
veritysetup (verity-compat-test).

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.14+

parent b10ebd34

drivers/md/dm-verity.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -330,15 +330,17 @@ test_block_hash:
		return r;
		}
		}

		todo = 1 << v->data_dev_block_bits;
		while (io->iter.bi_size) {
		do {
		u8 *page;
		unsigned len;
		struct bio_vec bv = bio_iter_iovec(bio, io->iter);

		page = kmap_atomic(bv.bv_page);
		r = crypto_shash_update(desc, page + bv.bv_offset,
		bv.bv_len);
		len = bv.bv_len;
		if (likely(len >= todo))
		len = todo;
		r = crypto_shash_update(desc, page + bv.bv_offset, len);
		kunmap_atomic(page);

		if (r < 0) {
		@@ -346,8 +348,9 @@ test_block_hash:
		return r;
		}

		bio_advance_iter(bio, &io->iter, bv.bv_len);
		}
		bio_advance_iter(bio, &io->iter, len);
		todo -= len;
		} while (todo);

		if (!v->version) {
		r = crypto_shash_update(desc, v->salt, v->salt_size);

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