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authorRainer Weikusat <rweikusat@mobileactivedefense.com>2016-02-11 19:37:27 +0000
committerDavid S. Miller <davem@davemloft.net>2016-02-16 12:53:35 -0500
commita5527dda344fff0514b7989ef7a755729769daa1 (patch)
treed41947f8a33b2f7a5b77e2a848a4f0d789a89e30
parent1b92ee3d03af6643df395300ba7748f19ecdb0c5 (diff)
af_unix: Guard against other == sk in unix_dgram_sendmsg
The unix_dgram_sendmsg routine use the following test if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) { to determine if sk and other are in an n:1 association (either established via connect or by using sendto to send messages to an unrelated socket identified by address). This isn't correct as the specified address could have been bound to the sending socket itself or because this socket could have been connected to itself by the time of the unix_peer_get but disconnected before the unix_state_lock(other). In both cases, the if-block would be entered despite other == sk which might either block the sender unintentionally or lead to trying to unlock the same spin lock twice for a non-blocking send. Add a other != sk check to guard against this. Fixes: 7d267278a9ec ("unix: avoid use-after-free in ep_remove_wait_queue") Reported-By: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Tested-by: Philipp Hahn <pmhahn@pmhahn.de> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/unix/af_unix.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index df923caa8389..c51e2831f498 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1781,7 +1781,12 @@ restart_locked:
goto out_unlock;
}
- if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
+ /* other == sk && unix_peer(other) != sk if
+ * - unix_peer(sk) == NULL, destination address bound to sk
+ * - unix_peer(sk) == sk by time of get but disconnected before lock
+ */
+ if (other != sk &&
+ unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {
if (timeo) {
timeo = unix_wait_for_peer(other, timeo);