selinux: Fix error priority for bind with AF_UNSPEC on PF_INET6 socket

The IPv6 network stack first checks the sockaddr length (-EINVAL error)
before checking the family (-EAFNOSUPPORT error).

This was discovered thanks to commit a549d055a22e ("selftests/landlock:
Add network tests").

Cc: Eric Paris <eparis@parisplace.org>
Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Closes: https://lore.kernel.org/r/0584f91c-537c-4188-9e4f-04f192565667@collabora.com
Fixes: 0f8db8cc73df ("selinux: add AF_UNSPEC and INADDR_ANY checks to selinux_socket_bind()")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 863ff67e784974dd9ddce84a1f34ce709350b44a..7c69ce62c1069e7ecadba48232a8e2fe6c89d385 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4695,6 +4695,13 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in
                                return -EINVAL;
                        addr4 = (struct sockaddr_in *)address;
                        if (family_sa == AF_UNSPEC) {
+                               if (family == PF_INET6) {
+                                       /* Length check from inet6_bind_sk() */
+                                       if (addrlen < SIN6_LEN_RFC2133)
+                                               return -EINVAL;
+                                       /* Family check from __inet6_bind() */
+                                       goto err_af;
+                               }
                                /* see __inet_bind(), we only want to allow
                                 * AF_UNSPEC if the address is INADDR_ANY
                                 */