[PATCH net v2 4/4] ipv6: add defensive check for CHECKSUM_PARTIAL skbs in ip_fragment
From: Hannes Frederic Sowa <hidden>
Date: 2015-10-27 15:02:27
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.
Fixes: commit 32dce968dd987 ("ipv6: Allow for partial checksums on non-ufo packets")
See-also: commit 72e843bb09d45 ("ipv6: ip6_fragment() should check CHECKSUM_PARTIAL")
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/ipv6/ip6_output.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 9828a71..c6c5630 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c@@ -605,6 +605,10 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb, frag_id = ipv6_select_ident(net, &ipv6_hdr(skb)->daddr, &ipv6_hdr(skb)->saddr); + if (WARN_ON_ONCE(skb->ip_summed == CHECKSUM_PARTIAL) && + (err = skb_checksum_help(skb))) + goto fail; + hroom = LL_RESERVED_SPACE(rt->dst.dev); if (skb_has_frag_list(skb)) { int first_len = skb_pagelen(skb);
@@ -733,10 +737,6 @@ slow_path_clean: } slow_path: - if ((skb->ip_summed == CHECKSUM_PARTIAL) && - skb_checksum_help(skb)) - goto fail; - left = skb->len - hlen; /* Space per frame */ ptr = hlen; /* Where to start from */
--
2.5.0