Commit a5527dda authored by Rainer Weikusat's avatar Rainer Weikusat Committed by David S. Miller

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: 7d267278 ("unix: avoid use-after-free in ep_remove_wait_queue")
Reported-By: default avatarPhilipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: default avatarRainer Weikusat <rweikusat@mobileactivedefense.com>
Tested-by: default avatarPhilipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1b92ee3d
...@@ -1781,7 +1781,12 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg, ...@@ -1781,7 +1781,12 @@ static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
goto out_unlock; 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) { if (timeo) {
timeo = unix_wait_for_peer(other, timeo); timeo = unix_wait_for_peer(other, timeo);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment