[Devel] [PATCH RHEL7 COMMIT] ms/crypto: algif_hash - Only export and import on sockets with data

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-327.36.1.vz7.19.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.36.1.vz7.19.3
------>
commit 073d41957b1a3aea22cf2e54f6d7014ca291941a
Author: Vasily Averin <vvs at virtuozzo.com>
Date:   Mon Oct 24 14:18:29 2016 +0400

    ms/crypto: algif_hash - Only export and import on sockets with data
    
    This patch fixes oops in shash_async_export().
    ms commit 4afa5f9617927453ac04b24b584f6c718dfb4f45
    
    Author: Herbert Xu <herbert at gondor.apana.org.au>
    Date:   Sun Nov 1 17:11:19 2015 +0800
    
        crypto: algif_hash - Only export and import on sockets with data
    
        The hash_accept call fails to work on sockets that have not received
        any data.  For some algorithm implementations it may cause crashes.
    
        This patch fixes this by ensuring that we only export and import on
        sockets that have received data.
    
        Cc: stable at vger.kernel.org
        Reported-by: Harsh Jain <harshjain.prof at gmail.com>
        Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
        Tested-by: Stephan Mueller <smueller at chronox.de>
    
    https://jira.sw.ru/browse/PSBM-54117
    
    Signed-off-by:	Vasily Averin <vvs at virtuozzo.com>
---
 crypto/algif_hash.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 8502462..a68b56a 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -192,9 +192,14 @@ static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
 	struct sock *sk2;
 	struct alg_sock *ask2;
 	struct hash_ctx *ctx2;
+	bool more;
 	int err;
 
-	err = crypto_ahash_export(req, state);
+	lock_sock(sk);
+	more = ctx->more;
+	err = more ? crypto_ahash_export(req, state) : 0;
+	release_sock(sk);
+
 	if (err)
 		return err;
 
@@ -205,7 +210,10 @@ static int hash_accept(struct socket *sock, struct socket *newsock, int flags)
 	sk2 = newsock->sk;
 	ask2 = alg_sk(sk2);
 	ctx2 = ask2->private;
-	ctx2->more = 1;
+	ctx2->more = more;
+
+	if (!more)
+		return err;
 
 	err = crypto_ahash_import(&ctx2->req, state);
 	if (err) {