[PATCH net v2 2/4] ipv4: add defensive check for CHECKSUM_PARTIAL skbs in ip_fragment
From: Hannes Frederic Sowa <hidden>
Date: 2015-10-27 15:02:25
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
CHECKSUM_PARTIAL skbs should never arrive in ip_fragment. If we get one of those warn about them once and handle them gracefully by recalculating the checksum. Cc: Eric Dumazet <edumazet@google.com> Cc: Vlad Yasevich <redacted> Cc: Benjamin Coddington <redacted> Cc: Tom Herbert <redacted> Signed-off-by: Hannes Frederic Sowa <redacted> --- net/ipv4/ip_output.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 0b02417..3f94a3b 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c@@ -533,6 +533,11 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, dev = rt->dst.dev; + /* for offloaded checksums cleanup checksum before fragmentation */ + if (WARN_ON_ONCE(skb->ip_summed == CHECKSUM_PARTIAL) && + (err = skb_checksum_help(skb))) + goto fail; + /* * Point into the IP datagram header. */
@@ -657,9 +662,6 @@ slow_path_clean: } slow_path: - /* for offloaded checksums cleanup checksum before fragmentation */ - if ((skb->ip_summed == CHECKSUM_PARTIAL) && skb_checksum_help(skb)) - goto fail; iph = ip_hdr(skb); left = skb->len - hlen; /* Space per frame */
--
2.5.0