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Date: Wed, 4 Aug 2010 22:48:12 +0800
From: Changli Gao <xiaosuo@...il.com>
To: Patrick McHardy <kaber@...sh.net>
Cc: Jamal Hadi Salim <hadi@...erus.ca>,
"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Changli Gao <xiaosuo@...il.com>
Subject: [PATCH v2 2/4] 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 <xiaosuo@...il.com>
---
v2: use pskb_network_may_pull(), and handle the error path gracefully.
remove the return value change.
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 f73542d..e17096e 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:
--
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