From: Simon Wunderlich <sw@simonwunderlich.de>
To: davem@davemloft.net, kuba@kernel.org
Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org,
Sven Eckelmann <sven@narfation.org>,
Felix Kaechele <felix@kaechele.ca>,
Simon Wunderlich <sw@simonwunderlich.de>
Subject: [PATCH 1/1] batman-adv: Don't skb_split skbuffs with frag_list
Date: Sun, 8 May 2022 15:21:10 +0200 [thread overview]
Message-ID: <20220508132110.20451-2-sw@simonwunderlich.de> (raw)
In-Reply-To: <20220508132110.20451-1-sw@simonwunderlich.de>
From: Sven Eckelmann <sven@narfation.org>
The receiving interface might have used GRO to receive more fragments than
MAX_SKB_FRAGS fragments. In this case, these will not be stored in
skb_shinfo(skb)->frags but merged into the frag list.
batman-adv relies on the function skb_split to split packets up into
multiple smaller packets which are not larger than the MTU on the outgoing
interface. But this function cannot handle frag_list entries and is only
operating on skb_shinfo(skb)->frags. If it is still trying to split such an
skb and xmit'ing it on an interface without support for NETIF_F_FRAGLIST,
then validate_xmit_skb() will try to linearize it. But this fails due to
inconsistent information. And __pskb_pull_tail will trigger a BUG_ON after
skb_copy_bits() returns an error.
In case of entries in frag_list, just linearize the skb before operating on
it with skb_split().
Reported-by: Felix Kaechele <felix@kaechele.ca>
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Tested-by: Felix Kaechele <felix@kaechele.ca>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
net/batman-adv/fragmentation.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 0899a729a23f..c120c7c6d25f 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -475,6 +475,17 @@ int batadv_frag_send_packet(struct sk_buff *skb,
goto free_skb;
}
+ /* GRO might have added fragments to the fragment list instead of
+ * frags[]. But this is not handled by skb_split and must be
+ * linearized to avoid incorrect length information after all
+ * batman-adv fragments were created and submitted to the
+ * hard-interface
+ */
+ if (skb_has_frag_list(skb) && __skb_linearize(skb)) {
+ ret = -ENOMEM;
+ goto free_skb;
+ }
+
/* Create one header to be copied to all fragments */
frag_header.packet_type = BATADV_UNICAST_FRAG;
frag_header.version = BATADV_COMPAT_VERSION;
--
2.30.2
next prev parent reply other threads:[~2022-05-08 13:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-08 13:21 [PATCH 0/1] pull request for net: batman-adv 2022-05-08 Simon Wunderlich
2022-05-08 13:21 ` Simon Wunderlich [this message]
2022-05-10 1:20 ` [PATCH 1/1] batman-adv: Don't skb_split skbuffs with frag_list 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=20220508132110.20451-2-sw@simonwunderlich.de \
--to=sw@simonwunderlich.de \
--cc=b.a.t.m.a.n@lists.open-mesh.org \
--cc=davem@davemloft.net \
--cc=felix@kaechele.ca \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=sven@narfation.org \
/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;
as well as URLs for NNTP newsgroup(s).