From 1b92ee3d03af6643df395300ba7748f19ecdb0c5 Mon Sep 17 00:00:00 2001
From: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Date: Mon, 8 Feb 2016 18:47:19 +0000
Subject: af_unix: Don't set err in unix_stream_read_generic unless there was
an error
The present unix_stream_read_generic contains various code sequences of
the form
err = -EDISASTER;
if (<test>)
goto out;
This has the unfortunate side effect of possibly causing the error code
to bleed through to the final
out:
return copied ? : err;
and then to be wrongly returned if no data was copied because the caller
didn't supply a data buffer, as demonstrated by the program available at
http://pad.lv/1540731
Change it such that err is only set if an error condition was detected.
Fixes: 3822b5c2fc62 ("af_unix: Revert 'lock_interruptible' in stream receive code")
Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/unix/af_unix.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
(limited to 'net/unix/af_unix.c')
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 29be035f9c65..df923caa8389 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2277,13 +2277,15 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
size_t size = state->size;
unsigned int last_len;
- err = -EINVAL;
- if (sk->sk_state != TCP_ESTABLISHED)
+ if (unlikely(sk->sk_state != TCP_ESTABLISHED)) {
+ err = -EINVAL;
goto out;
+ }
- err = -EOPNOTSUPP;
- if (flags & MSG_OOB)
+ if (unlikely(flags & MSG_OOB)) {
+ err = -EOPNOTSUPP;
goto out;
+ }
target = sock_rcvlowat(sk, flags & MSG_WAITALL, size);
timeo = sock_rcvtimeo(sk, noblock);
@@ -2329,9 +2331,11 @@ again:
goto unlock;
unix_state_unlock(sk);
- err = -EAGAIN;
- if (!timeo)
+ if (!timeo) {
+ err = -EAGAIN;
break;
+ }
+
mutex_unlock(&u->readlock);
timeo = unix_stream_data_wait(sk, timeo, last,
--
cgit
From a5527dda344fff0514b7989ef7a755729769daa1 Mon Sep 17 00:00:00 2001
From: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Date: Thu, 11 Feb 2016 19:37:27 +0000
Subject: 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>
---
net/unix/af_unix.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
(limited to 'net/unix/af_unix.c')
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);
--
cgit
From 18eceb818dc37bbc783ec7ef7703f270cc6cd281 Mon Sep 17 00:00:00 2001
From: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Date: Thu, 18 Feb 2016 12:39:46 +0000
Subject: af_unix: Don't use continue to re-execute unix_stream_read_generic
loop
The unix_stream_read_generic function tries to use a continue statement
to restart the receive loop after waiting for a message. This may not
work as intended as the caller might use a recvmsg call to peek at
control messages without specifying a message buffer. If this was the
case, the continue will cause the function to return without an error
and without the credential information if the function had to wait for a
message while it had returned with the credentials otherwise. Change to
using goto to restart the loop without checking the condition first in
this case so that credentials are returned either way.
Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/unix/af_unix.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
(limited to 'net/unix/af_unix.c')
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index c51e2831f498..f75f847e688d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2312,6 +2312,7 @@ static int unix_stream_read_generic(struct unix_stream_read_state *state)
bool drop_skb;
struct sk_buff *skb, *last;
+redo:
unix_state_lock(sk);
if (sock_flag(sk, SOCK_DEAD)) {
err = -ECONNRESET;
@@ -2353,7 +2354,7 @@ again:
}
mutex_lock(&u->readlock);
- continue;
+ goto redo;
unlock:
unix_state_unlock(sk);
break;
--
cgit