Bug 2348571 (CVE-2025-21755)

Summary:	CVE-2025-21755 kernel: vsock: Orphan socket after transport release
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
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:	[REJECTED CVE] A vulnerability was identified in the Linux kernel’s vsock module where the socket was orphaned before releasing the transport, leading to a NULL pointer dereference if SO_LINGER was enabled. This was caused by sock_orphan() nullifying sk->sk_wq, which was later accessed in virtio_transport_wait_close(). An attacker exploiting this flaw could trigger a kernel crash by closing a vsock socket with SO_LINGER set, leading to a denial of service on the host system.	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 2025-02-27 03:03:39 UTC

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

vsock: Orphan socket after transport release

During socket release, sock_orphan() is called without considering that it
sets sk->sk_wq to NULL. Later, if SO_LINGER is enabled, this leads to a
null pointer dereferenced in virtio_transport_wait_close().

Orphan the socket only after transport release.

Partially reverts the 'Fixes:' commit.

KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
 lock_acquire+0x19e/0x500
 _raw_spin_lock_irqsave+0x47/0x70
 add_wait_queue+0x46/0x230
 virtio_transport_release+0x4e7/0x7f0
 __vsock_release+0xfd/0x490
 vsock_release+0x90/0x120
 __sock_release+0xa3/0x250
 sock_close+0x14/0x20
 __fput+0x35e/0xa90
 __x64_sys_close+0x78/0xd0
 do_syscall_64+0x93/0x1b0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Comment 1 Michal Findra 2025-02-27 18:52:03 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022603-CVE-2025-21755-5887@gregkh/T

Comment 2 TEJ RATHI 2025-05-15 07:45:12 UTC

This CVE has been rejected upstream: https://lore.kernel.org/linux-cve-announce/2025032718-REJECTED-05aa@gregkh/