From a8348bca2944d397a528772f5c0ccb47a8b58af4 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 17 Nov 2016 22:07:58 +0800 Subject: 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: 493b2ed3f760 ("crypto: algif_hash - Handle NULL hashes correctly") Signed-off-by: Herbert Xu Tested-by: Laura Abbott --- crypto/algif_hash.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'crypto/algif_hash.c') diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c index 2d8466f9e49b..05e21b464433 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -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; -- cgit v1.2.3