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authorMariusz Kozlowski2009-07-05 19:48:35 +0000
committerDavid S. Miller2009-07-06 12:47:07 -0700
commit3c8a9c63d5fd738c261bd0ceece04d9c8357ca13 (patch)
tree7c60ab7e391f73ffcbcb98613ee454f843d7b3d1
parent1ded3f59f35a2642852b3e2a1c0fa8a97777e9af (diff)
tun/tap: Fix crashes if open() /dev/net/tun and then poll() it.
Fix NULL pointer dereference in tun_chr_pool() introduced by commit 33dccbb050bbe35b88ca8cf1228dcf3e4d4b3554 ("tun: Limit amount of queued packets per device") and triggered by this code: int fd; struct pollfd pfd; fd = open("/dev/net/tun", O_RDWR); pfd.fd = fd; pfd.events = POLLIN | POLLOUT; poll(&pfd, 1, 0); Reported-by: Eugene Kapun <abacabadabacaba@gmail.com> Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b393536012fb..027f7aba26af 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -486,12 +486,14 @@ static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
{
struct tun_file *tfile = file->private_data;
struct tun_struct *tun = __tun_get(tfile);
- struct sock *sk = tun->sk;
+ struct sock *sk;
unsigned int mask = 0;
if (!tun)
return POLLERR;
+ sk = tun->sk;
+
DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
poll_wait(file, &tun->socket.wait, wait);