cve/published/2024/CVE-2024-50304.mbox

From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: <linux-cve-announce@vger.kernel.org>
Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org>
Subject: CVE-2024-50304: ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_find()

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_find()

The per-netns IP tunnel hash table is protected by the RTNL mutex and
ip_tunnel_find() is only called from the control path where the mutex is
taken.

Add a lockdep expression to hlist_for_each_entry_rcu() in
ip_tunnel_find() in order to validate that the mutex is held and to
silence the suspicious RCU usage warning [1].

[1]
WARNING: suspicious RCU usage
6.12.0-rc3-custom-gd95d9a31aceb #139 Not tainted
-----------------------------
net/ipv4/ip_tunnel.c:221 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by ip/362:
 #0: ffffffff86fc7cb0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x377/0xf60

stack backtrace:
CPU: 12 UID: 0 PID: 362 Comm: ip Not tainted 6.12.0-rc3-custom-gd95d9a31aceb #139
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Call Trace:
 <TASK>
 dump_stack_lvl+0xba/0x110
 lockdep_rcu_suspicious.cold+0x4f/0xd6
 ip_tunnel_find+0x435/0x4d0
 ip_tunnel_newlink+0x517/0x7a0
 ipgre_newlink+0x14c/0x170
 __rtnl_newlink+0x1173/0x19c0
 rtnl_newlink+0x6c/0xa0
 rtnetlink_rcv_msg+0x3cc/0xf60
 netlink_rcv_skb+0x171/0x450
 netlink_unicast+0x539/0x7f0
 netlink_sendmsg+0x8c1/0xd80
 ____sys_sendmsg+0x8f9/0xc20
 ___sys_sendmsg+0x197/0x1e0
 __sys_sendmsg+0x122/0x1f0
 do_syscall_64+0xbb/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The Linux kernel CVE team has assigned CVE-2024-50304 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 5.10.234 with commit 31bd7378c6fe100a8af0e996ea0b5dafd3579df6
	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 5.15.178 with commit 6ac5dfa575136da8dd8a9e7c1437c41f3a593993
	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 6.1.128 with commit ce11424026cbf87d5861b09e5e33565ff7f2ec8d
	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 6.6.75 with commit e0500e4373cd3d5eace1f1712444ab830b82c114
	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 6.11.7 with commit f20fe2cfe06ca1b008b09da4f2b4e0c5547ccef6
	Issue introduced in 3.10 with commit c54419321455631079c7d6e60bc732dd0c5914c5 and fixed in 6.12 with commit 90e0569dd3d32f4f4d2ca691d3fa5a8a14a13c12

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-50304
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/ipv4/ip_tunnel.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/31bd7378c6fe100a8af0e996ea0b5dafd3579df6
	https://git.kernel.org/stable/c/6ac5dfa575136da8dd8a9e7c1437c41f3a593993
	https://git.kernel.org/stable/c/ce11424026cbf87d5861b09e5e33565ff7f2ec8d
	https://git.kernel.org/stable/c/e0500e4373cd3d5eace1f1712444ab830b82c114
	https://git.kernel.org/stable/c/f20fe2cfe06ca1b008b09da4f2b4e0c5547ccef6
	https://git.kernel.org/stable/c/90e0569dd3d32f4f4d2ca691d3fa5a8a14a13c12