4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Xin Long <[email protected]> [ Upstream commit 912964eacb111551db73429719eb5fadcab0ff8a ] Commit 6f29a1306131 ("sctp: sctp_addr_id2transport should verify the addr before looking up assoc") invoked sctp_verify_addr to verify the addr. But it didn't check af variable beforehand, once users pass an address with family = 0 through sockopt, sctp_get_af_specific will return NULL and NULL pointer dereference will be caused by af->sockaddr_len. This patch is to fix it by returning NULL if af variable is NULL. Fixes: 6f29a1306131 ("sctp: sctp_addr_id2transport should verify the addr before looking up assoc") Signed-off-by: Xin Long <[email protected]> Acked-by: Marcelo Ricardo Leitner <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/sctp/socket.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -239,7 +239,7 @@ static struct sctp_transport *sctp_addr_ union sctp_addr *laddr = (union sctp_addr *)addr; struct sctp_transport *transport; - if (sctp_verify_addr(sk, laddr, af->sockaddr_len)) + if (!af || sctp_verify_addr(sk, laddr, af->sockaddr_len)) return NULL; addr_asoc = sctp_endpoint_lookup_assoc(sctp_sk(sk)->ep,
