On Fri, 2018-05-11 at 20:15 +0300, Alexey Kodanev wrote:
> 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@xxxxxxxxxx>
> ---
>
> v2: As suggested by Paul:
> * return EINVAL for SCTP socket if sa_family is AF_UNSPEC and
> address is not INADDR_ANY
> * add new 'sa_family' variable so that it equals either AF_INET
> or AF_INET6. Besides, it it will be used in the next patch that
> fixes audit record.
>
> security/selinux/hooks.c | 29 +++++++++++++++++++----------
> 1 file changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 4cafe6a..1ed7004 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -4576,6 +4576,7 @@ 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;
>
> @@ -4587,11 +4588,11 @@ 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;
>
> @@ -4601,11 +4602,20 @@ 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;
> @@ -4617,13 +4627,7 @@ 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) {
> @@ -4681,7 +4685,7 @@ 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;
> @@ -4694,6 +4698,11 @@ 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)
Tested all three patches with no unexpected problems on kernel from [1]
using:
1) lksctp-tools - Passed except test_1_to_1_events as per [2]
2) sctp-tests - As above
3) selinux-testsuite with my SCTP patch [3] - Passes all sctp and
inet_socket tests.
4) The LTP "./runltp -pq -f connect-syscall" (see [4]) - Passes
[1] https://github.com/SELinuxProject/selinux-kernel/tree/next
[2] https://github.com/sctp/lksctp-tools/issues/24
[3] https://marc.info/?l=selinux&m=152156947715709&w=2
[4] https://marc.info/?l=selinux&m=151990968221563&w=2
