Bug 2327361 (CVE-2024-50304)

Summary: CVE-2024-50304 kernel: ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_find()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2327464    
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Description OSIDB Bzimport 2024-11-19 18:03:03 UTC
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

Comment 2 errata-xmlrpc 2025-05-13 08:35:57 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:6966 https://access.redhat.com/errata/RHSA-2025:6966