selinux: add AF_UNSPEC and INADDR_ANY checks to selinux_socket_bind()

Commit d452930fd3b9 ("selinux: Add SCTP support") breaks compatibility
with the old programs that can pass sockaddr_in structure with AF_UNSPEC
and INADDR_ANY to bind(). As a result, bind() returns EAFNOSUPPORT error.
This was found with LTP/asapi_01 test.

Similar to commit 29c486df6a20 ("net: ipv4: relax AF_INET check in
bind()"), which relaxed AF_INET check for compatibility, add AF_UNSPEC
case to AF_INET and make sure that the address is INADDR_ANY.

Fixes: d452930fd3b9 ("selinux: Add SCTP support")
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 21b377a..16df6cc 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4568,6 +4568,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, int addrlen)
 {
        struct sock *sk = sock->sk;
+       struct sk_security_struct *sksec = sk->sk_security;
        u16 family;
        int err;
 
@@ -4579,11 +4580,11 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
        family = sk->sk_family;
        if (family == PF_INET || family == PF_INET6) {
                char *addrp;
-               struct sk_security_struct *sksec = sk->sk_security;
                struct common_audit_data ad;
                struct lsm_network_audit net = {0,};
                struct sockaddr_in *addr4 = NULL;
                struct sockaddr_in6 *addr6 = NULL;
+               u16 family_sa = address->sa_family;
                unsigned short snum;
                u32 sid, node_perm;
 
@@ -4593,11 +4594,20 @@ 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.
                 */
-               switch (address->sa_family) {
+               switch (family_sa) {
+               case AF_UNSPEC:
                case AF_INET:
                        if (addrlen < sizeof(struct sockaddr_in))
                                return -EINVAL;
                        addr4 = (struct sockaddr_in *)address;
+                       if (family_sa == AF_UNSPEC) {
+                               /* see __inet_bind(), we only want to allow
+                                * AF_UNSPEC if the address is INADDR_ANY
+                                */
+                               if (addr4->sin_addr.s_addr != htonl(INADDR_ANY))
+                                       goto err_af;
+                               family_sa = AF_INET;
+                       }
                        snum = ntohs(addr4->sin_port);
                        addrp = (char *)&addr4->sin_addr.s_addr;
                        break;
@@ -4609,13 +4619,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                        addrp = (char *)&addr6->sin6_addr.s6_addr;
                        break;
                default:
-                       /* Note that SCTP services expect -EINVAL, whereas
-                        * others expect -EAFNOSUPPORT.
-                        */
-                       if (sksec->sclass == SECCLASS_SCTP_SOCKET)
-                               return -EINVAL;
-                       else
-                               return -EAFNOSUPPORT;
+                       goto err_af;
                }
 
                if (snum) {
@@ -4673,7 +4677,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                ad.u.net->sport = htons(snum);
                ad.u.net->family = family;
 
-               if (address->sa_family == AF_INET)
+               if (family_sa == AF_INET)
                        ad.u.net->v4info.saddr = addr4->sin_addr.s_addr;
                else
                        ad.u.net->v6info.saddr = addr6->sin6_addr;
@@ -4686,6 +4690,11 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
        }
 out:
        return err;
+err_af:
+       /* Note that SCTP services expect -EINVAL, others -EAFNOSUPPORT. */
+       if (sksec->sclass == SECCLASS_SCTP_SOCKET)
+               return -EINVAL;
+       return -EAFNOSUPPORT;
 }
 
 /* This supports connect(2) and SCTP connect services such as sctp_connectx(3)