Bug 2401525 (CVE-2023-53600) - CVE-2023-53600 kernel: tunnels: fix kasan splat when generating ipv4 pmtu error
Summary: CVE-2023-53600 kernel: tunnels: fix kasan splat when generating ipv4 pmtu error
Keywords:
Status: NEW
Alias: CVE-2023-53600
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-10-04 16:05 UTC by OSIDB Bzimport
Modified: 2025-10-06 13:56 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)

Description OSIDB Bzimport 2025-10-04 16:05:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

tunnels: fix kasan splat when generating ipv4 pmtu error

If we try to emit an icmp error in response to a nonliner skb, we get

BUG: KASAN: slab-out-of-bounds in ip_compute_csum+0x134/0x220
Read of size 4 at addr ffff88811c50db00 by task iperf3/1691
CPU: 2 PID: 1691 Comm: iperf3 Not tainted 6.5.0-rc3+ #309
[..]
 kasan_report+0x105/0x140
 ip_compute_csum+0x134/0x220
 iptunnel_pmtud_build_icmp+0x554/0x1020
 skb_tunnel_check_pmtu+0x513/0xb80
 vxlan_xmit_one+0x139e/0x2ef0
 vxlan_xmit+0x1867/0x2760
 dev_hard_start_xmit+0x1ee/0x4f0
 br_dev_queue_push_xmit+0x4d1/0x660
 [..]

ip_compute_csum() cannot deal with nonlinear skbs, so avoid it.
After this change, splat is gone and iperf3 is no longer stuck.
Comment 1 Alexander B 2025-10-06 13:53:17 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100430-CVE-2023-53600-69ba@gregkh/T
Note You need to log in before you can comment on or make changes to this bug.