Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-43835

Disclosure Date: August 17, 2024 •
CVE-2024-43835 CVSS v3 Base Score: 5.5
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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

virtio_net: Fix napi_skb_cache_put warning

After the commit bdacf3e34945 (“net: Use nested-BH locking for
napi_alloc_cache.”) was merged, the following warning began to appear:

 WARNING: CPU: 5 PID: 1 at net/core/skbuff.c:1451 napi_skb_cache_put+0x82/0x4b0

  __warn+0x12f/0x340
  napi_skb_cache_put+0x82/0x4b0
  napi_skb_cache_put+0x82/0x4b0
  report_bug+0x165/0x370
  handle_bug+0x3d/0x80
  exc_invalid_op+0x1a/0x50
  asm_exc_invalid_op+0x1a/0x20
  __free_old_xmit+0x1c8/0x510
  napi_skb_cache_put+0x82/0x4b0
  __free_old_xmit+0x1c8/0x510
  __free_old_xmit+0x1c8/0x510
  __pfx___free_old_xmit+0x10/0x10

The issue arises because virtio is assuming it’s running in NAPI context
even when it’s not, such as in the netpoll case.

To resolve this, modify virtnet_poll_tx() to only set NAPI when budget
is available. Same for virtnet_poll_cleantx(), which always assumed that
it was in a NAPI context.

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
Linux 19ac6f29bf64
Linux not down converted
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • linux

Products

  • linux kernel
Technical Analysis