On 5/8/19 2:27 PM, Marcelo Ricardo Leitner wrote:
On Wed, May 08, 2019 at 02:13:17PM -0400, Stephen Smalley wrote:
On 5/8/19 2:12 PM, Stephen Smalley wrote:
On 5/8/19 9:32 AM, Paolo Abeni wrote:
calling connect(AF_UNSPEC) on an already connected TCP socket is an
established way to disconnect() such socket. After commit 68741a8adab9
("selinux: Fix ltp test connect-syscall failure") it no longer works
and, in the above scenario connect() fails with EAFNOSUPPORT.
Fix the above falling back to the generic/old code when the address
family
is not AF_INET{4,6}, but leave the SCTP code path untouched, as it has
specific constraints.
Fixes: 68741a8adab9 ("selinux: Fix ltp test connect-syscall failure")
Reported-by: Tom Deseyn <tdeseyn@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
---
security/selinux/hooks.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index c61787b15f27..d82b87c16b0a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4649,7 +4649,7 @@ static int
selinux_socket_connect_helper(struct socket *sock,
struct lsm_network_audit net = {0,};
struct sockaddr_in *addr4 = NULL;
struct sockaddr_in6 *addr6 = NULL;
- unsigned short snum;
+ unsigned short snum = 0;
u32 sid, perm;
/* sctp_connectx(3) calls via selinux_sctp_bind_connect()
@@ -4674,12 +4674,12 @@ static int
selinux_socket_connect_helper(struct socket *sock,
break;
default:
/* Note that SCTP services expect -EINVAL, whereas
- * others expect -EAFNOSUPPORT.
+ * others must handle this at the protocol level:
+ * connect(AF_UNSPEC) on a connected socket is
+ * a documented way disconnect the socket.
*/
if (sksec->sclass == SECCLASS_SCTP_SOCKET)
return -EINVAL;
- else
- return -EAFNOSUPPORT;
I think we need to return 0 here. Otherwise, we'll fall through with an
uninitialized snum, triggering a random/bogus permission check.
Sorry, I see that you initialize snum above. Nonetheless, I think the
correct behavior here is to skip the check since this is a disconnect, not a
connect.
Skipping the check would make it less controllable. So should it
somehow re-use shutdown() stuff? It gets very confusing, and after
all, it still is, in essence, a connect() syscall.
The function checks CONNECT permission on entry, before reaching this
point. This logic is only in preparation for a further check
(NAME_CONNECT) on the port. In this case, there is no further check to
perform and we can just return.
}
err = sel_netport_sid(sk->sk_protocol, snum, &sid);
