Commit ffc41cf8 authored Apr 02, 2008 by Mike Snitzer Committed by Linus Torvalds Apr 02, 2008

nbd: prevent sock_xmit from attempting to use a NULL socket



NBD does not protect the nbd_device's socket from becoming NULL during
receives.

This closes a race with the NBD_CLEAR_SOCK ioctl (nbd-client -d) setting
the nbd_device's socket to NULL right before NBD calls sock_xmit.

Signed-off-by: Mike Snitzer <snitzer@gmail.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f2b2ea69

drivers/block/nbd.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -153,6 +153,12 @@ static int sock_xmit(struct nbd_device lo, int send, void buf, int size,
		struct kvec iov;
		sigset_t blocked, oldset;

		if (unlikely(!sock)) {
		printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n",
		lo->disk->disk_name, (send ? "send" : "recv"));
		return -EINVAL;
		}

		/* Allow interception of SIGKILL only
		* Don't allow other signals to interrupt the transmission */
		siginitsetinv(&blocked, sigmask(SIGKILL));

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