Bug 2347906 (CVE-2022-49198)

Summary:	CVE-2022-49198 kernel: mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	dfreiber, drow, jburrell, vkumar
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A vulnerability in the Linux kernel's Multipath TCP (MPTCP) implementation can lead to a system crash under specific conditions. The issue arises from improper memory handling during the allocation and release of socket buffers (skb) in the __mptcp_alloc_tx_skb function.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-02-26 03:10:53 UTC

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

mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb

Got crash when doing pressure test of mptcp:

===========================================================================
dst_release: dst:ffffa06ce6e5c058 refcnt:-1
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffffa06ce6e5c058
PGD 190a01067 P4D 190a01067 PUD 43fffb067 PMD 22e403063 PTE 8000000226e5c063
Oops: 0011 [#1] SMP PTI
CPU: 7 PID: 7823 Comm: kworker/7:0 Kdump: loaded Tainted: G            E
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.2.1 04/01/2014
Call Trace:
 ? skb_release_head_state+0x68/0x100
 ? skb_release_all+0xe/0x30
 ? kfree_skb+0x32/0xa0
 ? mptcp_sendmsg_frag+0x57e/0x750
 ? __mptcp_retrans+0x21b/0x3c0
 ? __switch_to_asm+0x35/0x70
 ? mptcp_worker+0x25e/0x320
 ? process_one_work+0x1a7/0x360
 ? worker_thread+0x30/0x390
 ? create_worker+0x1a0/0x1a0
 ? kthread+0x112/0x130
 ? kthread_flush_work_fn+0x10/0x10
 ? ret_from_fork+0x35/0x40
===========================================================================

In __mptcp_alloc_tx_skb skb was allocated and skb->tcp_tsorted_anchor will
be initialized, in under memory pressure situation sk_wmem_schedule will
return false and then kfree_skb. In this case skb->_skb_refdst is not null
because_skb_refdst and tcp_tsorted_anchor are stored in the same mem, and
kfree_skb will try to release dst and cause crash.

Comment 1 Avinash Hanwate 2025-02-26 13:53:51 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022617-CVE-2022-49198-98a2@gregkh/T

Comment 4 Avinash Hanwate 2025-02-26 18:01:02 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022617-CVE-2022-49198-98a2@gregkh/T