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crypto: algif_hash - Fix NULL hash crash with shash 

Recently algif_hash has been changed to allow null hashes.  This
triggers a bug when used with an shash algorithm whereby it will
cause a crash during the digest operation.

This patch fixes it by avoiding the digest operation and instead
doing an init followed by a final which avoids the buggy code in
shash.

This patch also ensures that the result buffer is freed after an
error so that it is not returned as a genuine hash result on the
next recv call.

The shash/ahash wrapper code will be fixed later to handle this
case correctly.

Fixes: 493b2ed3f7 ("crypto: algif_hash - Handle NULL hashes correctly")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Laura Abbott <labbott@redhat.com>
This commit is contained in:
Herbert Xu 2016-11-17 22:07:58 +08:00
parent a5a40d4624
commit a8348bca29
1 changed files with 10 additions and 7 deletions
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17
crypto/algif_hash.c
View File

@ -214,23 +214,26 @@ static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
if (ctx->more) {
if (!result) {
err = af_alg_wait_for_completion(
crypto_ahash_init(&ctx->req),
&ctx->completion);
if (err)
goto unlock;
}
if (!result || ctx->more) {
ctx->more = 0;
err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
&ctx->completion);
if (err)
goto unlock;
} else if (!result) {
err = af_alg_wait_for_completion(
crypto_ahash_digest(&ctx->req),
&ctx->completion);
}
err = memcpy_to_msg(msg, ctx->result, len);
hash_free_result(sk, ctx);
unlock:
hash_free_result(sk, ctx);
release_sock(sk);
return err ?: len;