This is a note to let you know that I've just added the patch titled
tun: fix a crash bug and a memory leak
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:
tun-fix-a-crash-bug-and-a-memory-leak.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 <[email protected]> know about it.
>From b09e786bd1dd66418b69348cb110f3a64764626a Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <[email protected]>
Date: Thu, 19 Jul 2012 06:13:36 +0000
Subject: tun: fix a crash bug and a memory leak
From: Mikulas Patocka <[email protected]>
commit b09e786bd1dd66418b69348cb110f3a64764626a upstream.
This patch fixes a crash
tun_chr_close -> netdev_run_todo -> tun_free_netdev -> sk_release_kernel ->
sock_release -> iput(SOCK_INODE(sock))
introduced by commit 1ab5ecb90cb6a3df1476e052f76a6e8f6511cb3d
The problem is that this socket is embedded in struct tun_struct, it has
no inode, iput is called on invalid inode, which modifies invalid memory
and optionally causes a crash.
sock_release also decrements sockets_in_use, this causes a bug that
"sockets: used" field in /proc/*/net/sockstat keeps on decreasing when
creating and closing tun devices.
This patch introduces a flag SOCK_EXTERNALLY_ALLOCATED that instructs
sock_release to not free the inode and not decrement sockets_in_use,
fixing both memory corruption and sockets_in_use underflow.
It should be backported to 3.3 an 3.4 stabke.
Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/net/tun.c | 3 +++
include/linux/net.h | 1 +
net/socket.c | 3 +++
3 files changed, 7 insertions(+)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -358,6 +358,8 @@ static void tun_free_netdev(struct net_d
{
struct tun_struct *tun = netdev_priv(dev);
+ BUG_ON(!test_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags));
+
sk_release_kernel(tun->socket.sk);
}
@@ -1115,6 +1117,7 @@ static int tun_set_iff(struct net *net,
tun->flags = flags;
tun->txflt.count = 0;
tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
+ set_bit(SOCK_EXTERNALLY_ALLOCATED, &tun->socket.flags);
err = -ENOMEM;
sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -72,6 +72,7 @@ struct net;
#define SOCK_NOSPACE 2
#define SOCK_PASSCRED 3
#define SOCK_PASSSEC 4
+#define SOCK_EXTERNALLY_ALLOCATED 5
#ifndef ARCH_HAS_SOCKET_TYPES
/**
--- a/net/socket.c
+++ b/net/socket.c
@@ -522,6 +522,9 @@ void sock_release(struct socket *sock)
if (rcu_dereference_protected(sock->wq, 1)->fasync_list)
printk(KERN_ERR "sock_release: fasync list not empty!\n");
+ if (test_bit(SOCK_EXTERNALLY_ALLOCATED, &sock->flags))
+ return;
+
percpu_sub(sockets_in_use, 1);
if (!sock->file) {
iput(SOCK_INODE(sock));
Patches currently in stable-queue which might be from
[email protected] are
queue-3.4/tun-fix-a-crash-bug-and-a-memory-leak.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
