4.9-stable review patch. If anyone has any objections, please let me know.
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From: Steffen Klassert steffen.klassert@secunet.com
[ Upstream commit e3dc847a5f85b43ee2bfc8eae407a7e383483228 ]
In vti6_xmit(), the check for IPV6_MIN_MTU before we send a ICMPV6_PKT_TOOBIG message is missing. So we might report a PMTU below 1280. Fix this by adding the required check.
Fixes: ccd740cbc6e ("vti6: Add pmtu handling to vti6_xmit.") Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_vti.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -485,11 +485,15 @@ vti6_xmit(struct sk_buff *skb, struct ne if (!skb->ignore_df && skb->len > mtu) { skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);
- if (skb->protocol == htons(ETH_P_IPV6)) + if (skb->protocol == htons(ETH_P_IPV6)) { + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); - else + } else { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); + }
return -EMSGSIZE; }