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@vger.kernel.org
Reported-by: Harsh Jain <harshjain.prof@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Stephan Mueller <smueller@chronox.de>

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 1396ad0787fc6b84ebdd9a9d552ce7eaccf1e698..b4c24fe3dcfb5ed575350406c9dd7ece3c006aef 100644 (file)
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -181,9 +181,14 @@ 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;
 
@@ -194,7 +199,10 @@ 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) {