From 4b95c3d40d7d9927438ed7b7b49c84c60e27b65b Mon Sep 17 00:00:00 2001 From: Changli Gao Date: Wed, 4 Aug 2010 04:48:12 +0000 Subject: [PATCH] cls_flow: add sanity check for the packet length The packet length should be checked before the packet data is dereferenced. Signed-off-by: Changli Gao Acked-by: Patrick McHardy Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 96 ++++++++++++++++++++++++++------------------ 1 file changed, 56 insertions(+), 40 deletions(-) diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index f73542d2cdd0..e17096e3913c 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -65,37 +65,47 @@ static inline u32 addr_fold(void *addr) return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0); } -static u32 flow_get_src(const struct sk_buff *skb) +static u32 flow_get_src(struct sk_buff *skb) { switch (skb->protocol) { case htons(ETH_P_IP): - return ntohl(ip_hdr(skb)->saddr); + if (pskb_network_may_pull(skb, sizeof(struct iphdr))) + return ntohl(ip_hdr(skb)->saddr); + break; case htons(ETH_P_IPV6): - return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]); - default: - return addr_fold(skb->sk); + if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) + return ntohl(ipv6_hdr(skb)->saddr.s6_addr32[3]); + break; } + + return addr_fold(skb->sk); } -static u32 flow_get_dst(const struct sk_buff *skb) +static u32 flow_get_dst(struct sk_buff *skb) { switch (skb->protocol) { case htons(ETH_P_IP): - return ntohl(ip_hdr(skb)->daddr); + if (pskb_network_may_pull(skb, sizeof(struct iphdr))) + return ntohl(ip_hdr(skb)->daddr); + break; case htons(ETH_P_IPV6): - return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]); - default: - return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; + if (pskb_network_may_pull(skb, sizeof(struct ipv6hdr))) + return ntohl(ipv6_hdr(skb)->daddr.s6_addr32[3]); + break; } + + return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; } -static u32 flow_get_proto(const struct sk_buff *skb) +static u32 flow_get_proto(struct sk_buff *skb) { switch (skb->protocol) { case htons(ETH_P_IP): - return ip_hdr(skb)->protocol; + return pskb_network_may_pull(skb, sizeof(struct iphdr)) ? + ip_hdr(skb)->protocol : 0; case htons(ETH_P_IPV6): - return ipv6_hdr(skb)->nexthdr; + return pskb_network_may_pull(skb, sizeof(struct ipv6hdr)) ? + ipv6_hdr(skb)->nexthdr : 0; default: return 0; } @@ -116,58 +126,64 @@ static int has_ports(u8 protocol) } } -static u32 flow_get_proto_src(const struct sk_buff *skb) +static u32 flow_get_proto_src(struct sk_buff *skb) { - u32 res = 0; - switch (skb->protocol) { case htons(ETH_P_IP): { - struct iphdr *iph = ip_hdr(skb); + struct iphdr *iph; + if (!pskb_network_may_pull(skb, sizeof(*iph))) + break; + iph = ip_hdr(skb); if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) && - has_ports(iph->protocol)) - res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4)); + has_ports(iph->protocol) && + pskb_network_may_pull(skb, iph->ihl * 4 + 2)) + return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4)); break; } case htons(ETH_P_IPV6): { - struct ipv6hdr *iph = ipv6_hdr(skb); + struct ipv6hdr *iph; + if (!pskb_network_may_pull(skb, sizeof(*iph) + 2)) + break; + iph = ipv6_hdr(skb); if (has_ports(iph->nexthdr)) - res = ntohs(*(__be16 *)&iph[1]); + return ntohs(*(__be16 *)&iph[1]); break; } - default: - res = addr_fold(skb->sk); } - return res; + return addr_fold(skb->sk); } -static u32 flow_get_proto_dst(const struct sk_buff *skb) +static u32 flow_get_proto_dst(struct sk_buff *skb) { - u32 res = 0; - switch (skb->protocol) { case htons(ETH_P_IP): { - struct iphdr *iph = ip_hdr(skb); + struct iphdr *iph; + if (!pskb_network_may_pull(skb, sizeof(*iph))) + break; + iph = ip_hdr(skb); if (!(iph->frag_off&htons(IP_MF|IP_OFFSET)) && - has_ports(iph->protocol)) - res = ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + 2)); + has_ports(iph->protocol) && + pskb_network_may_pull(skb, iph->ihl * 4 + 4)) + return ntohs(*(__be16 *)((void *)iph + iph->ihl * 4 + 2)); break; } case htons(ETH_P_IPV6): { - struct ipv6hdr *iph = ipv6_hdr(skb); + struct ipv6hdr *iph; + if (!pskb_network_may_pull(skb, sizeof(*iph) + 4)) + break; + iph = ipv6_hdr(skb); if (has_ports(iph->nexthdr)) - res = ntohs(*(__be16 *)((void *)&iph[1] + 2)); + return ntohs(*(__be16 *)((void *)&iph[1] + 2)); break; } - default: - res = addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; } - return res; + return addr_fold(skb_dst(skb)) ^ (__force u16)skb->protocol; } static u32 flow_get_iif(const struct sk_buff *skb) @@ -211,7 +227,7 @@ static u32 flow_get_nfct(const struct sk_buff *skb) }) #endif -static u32 flow_get_nfct_src(const struct sk_buff *skb) +static u32 flow_get_nfct_src(struct sk_buff *skb) { switch (skb->protocol) { case htons(ETH_P_IP): @@ -223,7 +239,7 @@ fallback: return flow_get_src(skb); } -static u32 flow_get_nfct_dst(const struct sk_buff *skb) +static u32 flow_get_nfct_dst(struct sk_buff *skb) { switch (skb->protocol) { case htons(ETH_P_IP): @@ -235,14 +251,14 @@ fallback: return flow_get_dst(skb); } -static u32 flow_get_nfct_proto_src(const struct sk_buff *skb) +static u32 flow_get_nfct_proto_src(struct sk_buff *skb) { return ntohs(CTTUPLE(skb, src.u.all)); fallback: return flow_get_proto_src(skb); } -static u32 flow_get_nfct_proto_dst(const struct sk_buff *skb) +static u32 flow_get_nfct_proto_dst(struct sk_buff *skb) { return ntohs(CTTUPLE(skb, dst.u.all)); fallback: @@ -281,7 +297,7 @@ static u32 flow_get_vlan_tag(const struct sk_buff *skb) return tag & VLAN_VID_MASK; } -static u32 flow_key_get(const struct sk_buff *skb, int key) +static u32 flow_key_get(struct sk_buff *skb, int key) { switch (key) { case FLOW_KEY_SRC: -- 2.20.1