selinux: Check address length before reading address family

KMSAN will complain if valid address length passed to bind()/connect() is
shorter than sizeof("struct sockaddr"->sa_family) bytes.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d5fdcb0d26fe7e3116541af083bc9f7ff4c85374..c61787b15f27b2b0bd0ed7d448fd6ba2d73ca07a 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4512,7 +4512,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                struct lsm_network_audit net = {0,};
                struct sockaddr_in *addr4 = NULL;
                struct sockaddr_in6 *addr6 = NULL;
-               u16 family_sa = address->sa_family;
+               u16 family_sa;
                unsigned short snum;
                u32 sid, node_perm;
 
@@ -4522,6 +4522,9 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                 * need to check address->sa_family as it is possible to have
                 * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
                 */
+               if (addrlen < offsetofend(struct sockaddr, sa_family))
+                       return -EINVAL;
+               family_sa = address->sa_family;
                switch (family_sa) {
                case AF_UNSPEC:
                case AF_INET:
@@ -4654,6 +4657,8 @@ static int selinux_socket_connect_helper(struct socket *sock,
                 * need to check address->sa_family as it is possible to have
                 * sk->sk_family = PF_INET6 with addr->sa_family = AF_INET.
                 */
+               if (addrlen < offsetofend(struct sockaddr, sa_family))
+                       return -EINVAL;
                switch (address->sa_family) {
                case AF_INET:
                        addr4 = (struct sockaddr_in *)address;