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Commit bc01637a authored by Dmitry Kasatkin's avatar Dmitry Kasatkin Committed by Linus Torvalds
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digsig: add hash size comparision on signature verification 



When pkcs_1_v1_5_decode_emsa() returns without error and hash sizes do
not match, hash comparision is not done and digsig_verify_rsa() returns
no error.  This is a bug and this patch fixes it.

The bug was introduced in v3.3 by commit b35e286a ("lib/digsig:
pkcs_1_v1_5_decode_emsa cleanup").

Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8507876a

lib/digsig.c

+4 −2
Original line number Diff line number Diff line
@@ -163,9 +163,11 @@ static int digsig_verify_rsa(struct key *key, 
	memcpy(out1 + head, p, l);



	err = pkcs_1_v1_5_decode_emsa(out1, len, mblen, out2, &len);

	if (err)

		goto err;



	if (!err && len == hlen)

		err = memcmp(out2, h, hlen);

	if (len != hlen || memcmp(out2, h, hlen))

		err = -EINVAL;



err:

	mpi_free(in);