This is a note to let you know that I've just added the patch titled
net: unix: allow set_peek_off to fail
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-unix-allow-set_peek_off-to-fail.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Jan 13 09:28:30 PST 2014
From: Sasha Levin <sasha.levin@xxxxxxxxxx>
Date: Sat, 7 Dec 2013 17:26:27 -0500
Subject: net: unix: allow set_peek_off to fail
From: Sasha Levin <sasha.levin@xxxxxxxxxx>
[ Upstream commit 12663bfc97c8b3fdb292428105dd92d563164050 ]
unix_dgram_recvmsg() will hold the readlock of the socket until recv
is complete.
In the same time, we may try to setsockopt(SO_PEEK_OFF) which will hang until
unix_dgram_recvmsg() will complete (which can take a while) without allowing
us to break out of it, triggering a hung task spew.
Instead, allow set_peek_off to fail, this way userspace will not hang.
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/net.h | 2 +-
net/core/sock.c | 2 +-
net/unix/af_unix.c | 8 ++++++--
3 files changed, 8 insertions(+), 4 deletions(-)
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -215,7 +215,7 @@ struct proto_ops {
int offset, size_t size, int flags);
ssize_t (*splice_read)(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len, unsigned int flags);
- void (*set_peek_off)(struct sock *sk, int val);
+ int (*set_peek_off)(struct sock *sk, int val);
};
#define DECLARE_SOCKADDR(type, dst, src) \
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -795,7 +795,7 @@ set_rcvbuf:
case SO_PEEK_OFF:
if (sock->ops->set_peek_off)
- sock->ops->set_peek_off(sk, val);
+ ret = sock->ops->set_peek_off(sk, val);
else
ret = -EOPNOTSUPP;
break;
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -524,13 +524,17 @@ static int unix_seqpacket_sendmsg(struct
static int unix_seqpacket_recvmsg(struct kiocb *, struct socket *,
struct msghdr *, size_t, int);
-static void unix_set_peek_off(struct sock *sk, int val)
+static int unix_set_peek_off(struct sock *sk, int val)
{
struct unix_sock *u = unix_sk(sk);
- mutex_lock(&u->readlock);
+ if (mutex_lock_interruptible(&u->readlock))
+ return -EINTR;
+
sk->sk_peek_off = val;
mutex_unlock(&u->readlock);
+
+ return 0;
}
Patches currently in stable-queue which might be from sasha.levin@xxxxxxxxxx are
queue-3.4/net-unix-allow-set_peek_off-to-fail.patch
queue-3.4/net-unix-allow-bind-to-fail-on-mutex-lock.patch
queue-3.4/rds-prevent-dereference-of-a-null-device.patch
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