From: YOSHIFUJI Hideaki Date: Wed, 9 May 2007 21:01:59 +0000 (-0700) Subject: [IPV6]: Do no rely on skb->dst before it is assigned. X-Git-Tag: firefly_0821_release~29184^2~16 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e76b2b2567b83448c2ee85a896433b96150c92e6;p=firefly-linux-kernel-4.4.55.git [IPV6]: Do no rely on skb->dst before it is assigned. Because skb->dst is assigned in ip6_route_input(), it is really bad to use it in hop-by-hop option handler(s). Closes: Bug #8450 (Eric Sesterhenn ) Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c index 6d8e4ac7bdad..14be0b9b77a5 100644 --- a/net/ipv6/exthdrs.c +++ b/net/ipv6/exthdrs.c @@ -660,6 +660,14 @@ EXPORT_SYMBOL_GPL(ipv6_invert_rthdr); Hop-by-hop options. **********************************/ +/* + * Note: we cannot rely on skb->dst before we assign it in ip6_route_input(). + */ +static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) +{ + return skb->dst ? ip6_dst_idev(skb->dst) : __in6_dev_get(skb->dev); +} + /* Router Alert as of RFC 2711 */ static int ipv6_hop_ra(struct sk_buff **skbp, int optoff) @@ -688,25 +696,25 @@ static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff) if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", nh[optoff+1]); - IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), + IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS); goto drop; } pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); if (pkt_len <= IPV6_MAXPLEN) { - IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); + IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS); icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); return 0; } if (ipv6_hdr(skb)->payload_len) { - IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); + IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS); icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); return 0; } if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { - IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS); + IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INTRUNCATEDPKTS); goto drop; }