crypto: rsa-pkcs1pad - fix buffer overread in pkcs1pad_verify_complete()
Before checking whether the expected digest_info is present, we need to
check that there are enough bytes remaining.
Fixes: a49de377e051 ("crypto: Add hash param to pkcs1pad")
Cc: <stable@vger.kernel.org> # v4.6+
Cc: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 6b556dd..9d80483 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -476,6 +476,8 @@ static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
pos++;
if (digest_info) {
+ if (digest_info->size > dst_len - pos)
+ goto done;
if (crypto_memneq(out_buf + pos, digest_info->data,
digest_info->size))
goto done;