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From: Clara Engler <cve@cve.cx>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: davem@davemloft.net, dsahern@kernel.org, edumazet@google.com,
	kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, cve@cve.cx
Subject: [PATCH] ipv4: Fix log message for martian source
Date: Wed, 26 Nov 2025 22:59:58 +0100	[thread overview]
Message-ID: <aSd4Xj8rHrh-krjy@4944566b5c925f79> (raw)

From: Clara Engler <cve@cve.cx>

At the current moment, the log message for packets with a martian source
IP address is wrong.  In fact, the current syntax looks as follows:

```
martian source <DESTINATION> from <SOURCE>, on dev <DEV>
```

This is wrong because `<SOURCE>` and `<DESTINATION>` need to be swapped.

Another verification for this claim can be seen when looking at the
(correct) implementation for logging packets with a martian destination
IP address, which happens to be identical, as it can be seen in line
2477 on the same file.

Signed-off-by: Clara Engler <cve@cve.cx>
---
 net/ipv4/route.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b549d6a57307..913de56d2c2d 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1796,7 +1796,7 @@ static void ip_handle_martian_source(struct net_device *dev,
 		 *	the only hint is MAC header.
 		 */
 		pr_warn("martian source %pI4 from %pI4, on dev %s\n",
-			&daddr, &saddr, dev->name);
+			&saddr, &daddr, dev->name);
 		if (dev->hard_header_len && skb_mac_header_was_set(skb)) {
 			print_hex_dump(KERN_WARNING, "ll header: ",
 				       DUMP_PREFIX_OFFSET, 16, 1,
-- 
2.50.1 (Apple Git-155)


             reply	other threads:[~2025-11-26 22:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-26 21:59 Clara Engler [this message]
2025-11-28  2:17 ` [PATCH] ipv4: Fix log message for martian source Jakub Kicinski
2025-11-28 16:47   ` Clara Engler
2025-11-28 18:47     ` Jakub Kicinski
2025-12-01 18:54       ` Clara Engler
2025-12-01 19:40         ` Jakub Kicinski
2025-12-01 21:35           ` Clara Engler

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