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Commit 12663bfc authored by Sasha Levin's avatar Sasha Levin Committed by David S. Miller
Browse files

net: unix: allow set_peek_off to fail 



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: default avatarSasha Levin <sasha.levin@oracle.com>
Acked-by: default avatarPavel Emelyanov <xemul@parallels.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 88b07b36

include/linux/net.h

+1 −1
Original line number Diff line number Diff line
@@ -181,7 +181,7 @@ 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)	\

net/core/sock.c

+1 −1
Original line number Diff line number Diff line
@@ -882,7 +882,7 @@ 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;

net/unix/af_unix.c

+6 −2
Original line number Diff line number Diff line
@@ -530,13 +530,17 @@ static int unix_seqpacket_sendmsg(struct kiocb *, struct socket *, 
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;

}