[SCTP]: Fix NULL dereference of asoc.

Commit 7cbca67c073263c179f605bdbbdc565ab29d801d ("[IPV6]: Support
Source Address Selection API (RFC5014)") introduced NULL dereference
of asoc to sctp_v6_get_saddr in net/sctp/ipv6.c.
Pointed out by Johann Felix Soden <johfel@users.sourceforge.net>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index e45e44c60635..e4aac3266fcd 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -299,7 +299,8 @@ static inline int sctp_v6_addr_match_len(union sctp_addr *s1,
 /* Fills in the source address(saddr) based on the destination address(daddr)
  * and asoc's bind address list.
  */
-static void sctp_v6_get_saddr(struct sctp_association *asoc,
+static void sctp_v6_get_saddr(struct sctp_sock *sk,
+                              struct sctp_association *asoc,
                               struct dst_entry *dst,
                               union sctp_addr *daddr,
                               union sctp_addr *saddr)
@@ -318,7 +319,7 @@ static void sctp_v6_get_saddr(struct sctp_association *asoc,
         if (!asoc) {
                 ipv6_dev_get_saddr(dst ? ip6_dst_idev(dst)->dev : NULL,
                                    &daddr->v6.sin6_addr,
-                                   inet6_sk(asoc->base.sk)->srcprefs,
+                                   inet6_sk(&sk->inet.sk)->srcprefs,
                                    &saddr->v6.sin6_addr);
                 SCTP_DEBUG_PRINTK("saddr from ipv6_get_saddr: " NIP6_FMT "\n",
                                   NIP6(saddr->v6.sin6_addr));