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authorMariusz Kozlowski <m.kozlowski@tuxland.pl>2009-07-05 19:48:35 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-19 20:38:47 -0700
commit3f8fd3f9f677ce452556aca82473b7fcac370830 (patch)
tree7afa1b6b3b273530c5d62cfc6bc8444afe5db686 /drivers
parent2401fe3fbc5bd7db741867102fe355babce76506 (diff)
tun/tap: Fix crashes if open() /dev/net/tun and then poll() it. (CVE-2009-1897)
commit 3c8a9c63d5fd738c261bd0ceece04d9c8357ca13 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-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 1be6a6b2385b..828929212c18 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);