From: Samuel Moelius <sam.moelius@trailofbits.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Samuel Moelius <sam.moelius@trailofbits.com>,
Jiri Pirko <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>,
netdev@vger.kernel.org (open list:TC subsystem),
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] net/sched: act_pedit: require matching IPv4 L4 protocol
Date: Fri, 5 Jun 2026 19:46:39 +0000 [thread overview]
Message-ID: <20260605194640.2645386-1-sam.moelius@trailofbits.com> (raw)
The extended IPv4 L4 header mode in act_pedit can select TCP or UDP
header fields without confirming that the IPv4 protocol field matches
the selected transport header.
That lets a rule written for TCP or UDP modify unrelated payload bytes
in a packet carrying a different protocol.
Verify the IPv4 protocol before applying TCP or UDP extended header
edits.
Assisted-by: Codex:gpt-5.5-cyber-preview
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
---
net/sched/act_pedit.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index bc20f08a2789..9a4590451f7e 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -341,6 +341,8 @@ static int pedit_l4_skb_offset(struct sk_buff *skb, int *hoffset, const int head
if (!iph)
goto out;
+ if (iph->ihl < 5 || iph->protocol != header_type)
+ goto out;
*hoffset = noff + iph->ihl * 4;
ret = 0;
break;
--
2.43.0
reply other threads:[~2026-06-05 19:46 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=20260605194640.2645386-1-sam.moelius@trailofbits.com \
--to=sam.moelius@trailofbits.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=horms@kernel.org \
--cc=jhs@mojatatu.com \
--cc=jiri@resnulli.us \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox