From: Taehee Yoo <ap420073@gmail.com>
To: davem@davemloft.net, kuba@kernel.org, dsahern@kernel.org,
netdev@vger.kernel.org, tgraf@suug.ch, roopa@cumulusnetworks.com,
jbenc@redhat.com
Cc: ap420073@gmail.com
Subject: [PATCH net] net: validate lwtstate->data before returning from skb_tunnel_info()
Date: Fri, 9 Jul 2021 17:35:18 +0000 [thread overview]
Message-ID: <20210709173518.24696-1-ap420073@gmail.com> (raw)
skb_tunnel_info() returns pointer of lwtstate->data as ip_tunnel_info
type without validation. lwtstate->data can have various types such as
mpls_iptunnel_encap, etc and these are not compatible.
So skb_tunnel_info() should validate before returning that pointer.
Splat looks like:
BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan]
Read of size 2 at addr ffff888106ec2698 by task ping/811
CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195
Call Trace:
dump_stack_lvl+0x56/0x7b
print_address_description.constprop.8.cold.13+0x13/0x2ee
? vxlan_get_route+0x418/0x4b0 [vxlan]
? vxlan_get_route+0x418/0x4b0 [vxlan]
kasan_report.cold.14+0x83/0xdf
? vxlan_get_route+0x418/0x4b0 [vxlan]
vxlan_get_route+0x418/0x4b0 [vxlan]
[ ... ]
vxlan_xmit_one+0x148b/0x32b0 [vxlan]
[ ... ]
vxlan_xmit+0x25c5/0x4780 [vxlan]
[ ... ]
dev_hard_start_xmit+0x1ae/0x6e0
__dev_queue_xmit+0x1f39/0x31a0
[ ... ]
neigh_xmit+0x2f9/0x940
mpls_xmit+0x911/0x1600 [mpls_iptunnel]
lwtunnel_xmit+0x18f/0x450
ip_finish_output2+0x867/0x2040
[ ... ]
Fixes: 61adedf3e3f1 ("route: move lwtunnel state to dst_entry")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
---
include/net/dst_metadata.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index 56cb3c38569a..14efa0ded75d 100644
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h
@@ -45,7 +45,9 @@ skb_tunnel_info(const struct sk_buff *skb)
return &md_dst->u.tun_info;
dst = skb_dst(skb);
- if (dst && dst->lwtstate)
+ if (dst && dst->lwtstate &&
+ (dst->lwtstate->type == LWTUNNEL_ENCAP_IP ||
+ dst->lwtstate->type == LWTUNNEL_ENCAP_IP6))
return lwt_tun_info(dst->lwtstate);
return NULL;
--
2.17.1
next reply other threads:[~2021-07-09 17:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-09 17:35 Taehee Yoo [this message]
2021-07-09 21:00 ` [PATCH net] net: validate lwtstate->data before returning from skb_tunnel_info() patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210709173518.24696-1-ap420073@gmail.com \
--to=ap420073@gmail.com \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=jbenc@redhat.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=roopa@cumulusnetworks.com \
--cc=tgraf@suug.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.