sctp: Do not leak memory on multiple listen() calls

SCTP permits multiple listen call and on subsequent calls
we leak he memory allocated for the crypto transforms.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index a0e879bb202..fd7ed9d46a4 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5773,7 +5773,7 @@ int sctp_inet_listen(struct socket *sock, int backlog)
                 goto out;
 
         /* Allocate HMAC for generating cookie. */
-        if (sctp_hmac_alg) {
+        if (!sctp_sk(sk)->hmac && sctp_hmac_alg) {
                 tfm = crypto_alloc_hash(sctp_hmac_alg, 0, CRYPTO_ALG_ASYNC);
                 if (IS_ERR(tfm)) {
                         if (net_ratelimit()) {
@@ -5801,7 +5801,8 @@ int sctp_inet_listen(struct socket *sock, int backlog)
                 goto cleanup;
 
         /* Store away the transform reference. */
-        sctp_sk(sk)->hmac = tfm;
+        if (!sctp_sk(sk)->hmac)
+                sctp_sk(sk)->hmac = tfm;
 out:
         sctp_release_sock(sk);
         return err;