]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
tunnels: fix kasan splat when generating ipv4 pmtu error
authorFlorian Westphal <fw@strlen.de>
Thu, 3 Aug 2023 15:26:49 +0000 (17:26 +0200)
committerJakub Kicinski <kuba@kernel.org>
Sat, 5 Aug 2023 01:24:52 +0000 (18:24 -0700)
commit6a7ac3d20593865209dceb554d8b3f094c6bd940
tree64098f03b3c7f4a917f4bd3b99b3ec2aab3919e0
parent8a9896177784063d01068293caea3f74f6830ff6
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.

Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets")
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20230803152653.29535-2-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/ipv4/ip_tunnel_core.c