act_csum: fix possible use after free
tcf_csum_skb_nextlayer() / pskb_may_pull() can change skb->head, so we must be careful not keeping pointers to previous headers. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Grégoire Baron <baronchon@n7mm.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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3619eb8541
Коммит
d14a489a41
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@ -166,15 +166,17 @@ static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
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return 1;
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}
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static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
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unsigned int ihl, unsigned int ipl)
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{
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struct icmp6hdr *icmp6h;
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const struct ipv6hdr *ip6h;
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icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
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if (icmp6h == NULL)
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return 0;
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ip6h = ipv6_hdr(skb);
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icmp6h->icmp6_cksum = 0;
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skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
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icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
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@ -186,15 +188,17 @@ static int tcf_csum_ipv6_icmp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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return 1;
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}
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static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
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static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
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unsigned int ihl, unsigned int ipl)
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{
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struct tcphdr *tcph;
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const struct iphdr *iph;
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tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
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if (tcph == NULL)
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return 0;
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iph = ip_hdr(skb);
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tcph->check = 0;
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skb->csum = csum_partial(tcph, ipl - ihl, 0);
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tcph->check = tcp_v4_check(ipl - ihl,
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@ -205,15 +209,17 @@ static int tcf_csum_ipv4_tcp(struct sk_buff *skb, struct iphdr *iph,
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return 1;
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}
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static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
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unsigned int ihl, unsigned int ipl)
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{
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struct tcphdr *tcph;
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const struct ipv6hdr *ip6h;
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tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
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if (tcph == NULL)
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return 0;
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ip6h = ipv6_hdr(skb);
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tcph->check = 0;
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skb->csum = csum_partial(tcph, ipl - ihl, 0);
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tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
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@ -225,10 +231,11 @@ static int tcf_csum_ipv6_tcp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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return 1;
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}
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static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
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static int tcf_csum_ipv4_udp(struct sk_buff *skb,
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unsigned int ihl, unsigned int ipl, int udplite)
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{
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struct udphdr *udph;
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const struct iphdr *iph;
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u16 ul;
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/*
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@ -242,6 +249,7 @@ static int tcf_csum_ipv4_udp(struct sk_buff *skb, struct iphdr *iph,
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if (udph == NULL)
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return 0;
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iph = ip_hdr(skb);
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ul = ntohs(udph->len);
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if (udplite || udph->check) {
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@ -276,10 +284,11 @@ ignore_obscure_skb:
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return 1;
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}
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static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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static int tcf_csum_ipv6_udp(struct sk_buff *skb,
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unsigned int ihl, unsigned int ipl, int udplite)
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{
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struct udphdr *udph;
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const struct ipv6hdr *ip6h;
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u16 ul;
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/*
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@ -293,6 +302,7 @@ static int tcf_csum_ipv6_udp(struct sk_buff *skb, struct ipv6hdr *ip6h,
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if (udph == NULL)
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return 0;
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ip6h = ipv6_hdr(skb);
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ul = ntohs(udph->len);
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udph->check = 0;
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@ -328,7 +338,7 @@ ignore_obscure_skb:
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static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
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{
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struct iphdr *iph;
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const struct iphdr *iph;
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int ntkoff;
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ntkoff = skb_network_offset(skb);
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@ -353,19 +363,19 @@ static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
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break;
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case IPPROTO_TCP:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
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if (!tcf_csum_ipv4_tcp(skb, iph, iph->ihl * 4,
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if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
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ntohs(iph->tot_len)))
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goto fail;
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break;
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case IPPROTO_UDP:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
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if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
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if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
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ntohs(iph->tot_len), 0))
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goto fail;
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break;
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case IPPROTO_UDPLITE:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
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if (!tcf_csum_ipv4_udp(skb, iph, iph->ihl * 4,
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if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
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ntohs(iph->tot_len), 1))
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goto fail;
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break;
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@ -377,7 +387,7 @@ static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
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pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
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goto fail;
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ip_send_check(iph);
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ip_send_check(ip_hdr(skb));
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}
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return 1;
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@ -456,6 +466,7 @@ static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
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ixhl = ipv6_optlen(ip6xh);
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if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
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goto fail;
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ip6xh = (void *)(skb_network_header(skb) + hl);
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if ((nexthdr == NEXTHDR_HOP) &&
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!(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
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goto fail;
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@ -464,25 +475,25 @@ static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
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break;
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case IPPROTO_ICMPV6:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
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if (!tcf_csum_ipv6_icmp(skb, ip6h,
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if (!tcf_csum_ipv6_icmp(skb,
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hl, pl + sizeof(*ip6h)))
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goto fail;
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goto done;
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case IPPROTO_TCP:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
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if (!tcf_csum_ipv6_tcp(skb, ip6h,
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if (!tcf_csum_ipv6_tcp(skb,
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hl, pl + sizeof(*ip6h)))
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goto fail;
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goto done;
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case IPPROTO_UDP:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
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if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
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if (!tcf_csum_ipv6_udp(skb, hl,
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pl + sizeof(*ip6h), 0))
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goto fail;
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goto done;
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case IPPROTO_UDPLITE:
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if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
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if (!tcf_csum_ipv6_udp(skb, ip6h, hl,
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if (!tcf_csum_ipv6_udp(skb, hl,
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pl + sizeof(*ip6h), 1))
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goto fail;
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goto done;
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