From 24c890dd712f6345e382256cae8c97abb0406b70 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 1 Feb 2024 13:49:09 +0800
Subject: [PATCH] crypto: algif_hash - Remove bogus SGL free on zero-length
 error path

When a zero-length message is hashed by algif_hash, and an error
is triggered, it tries to free an SG list that was never allocated
in the first place.  Fix this by not freeing the SG list on the
zero-length error path.

Reported-by: Shigeru Yoshida <syoshida@redhat.com>
Reported-by: xingwei lee <xrivendell7@gmail.com>
Fixes: b6d972f68983 ("crypto: af_alg/hash: Fix recvmsg() after sendmsg(MSG_MORE)")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reported-by: syzbot+3266db0c26d1fbbe3abb@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 crypto/algif_hash.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 82c44d4899b96..e24c829d7a015 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -91,13 +91,13 @@ static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
 		if (!(msg->msg_flags & MSG_MORE)) {
 			err = hash_alloc_result(sk, ctx);
 			if (err)
-				goto unlock_free;
+				goto unlock_free_result;
 			ahash_request_set_crypt(&ctx->req, NULL,
 						ctx->result, 0);
 			err = crypto_wait_req(crypto_ahash_final(&ctx->req),
 					      &ctx->wait);
 			if (err)
-				goto unlock_free;
+				goto unlock_free_result;
 		}
 		goto done_more;
 	}
@@ -170,6 +170,7 @@ unlock:
 
 unlock_free:
 	af_alg_free_sg(&ctx->sgl);
+unlock_free_result:
 	hash_free_result(sk, ctx);
 	ctx->more = false;
 	goto unlock;
-- 
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