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authorHerbert Xu <herbert@gondor.apana.org.au>2008-01-28 20:45:20 -0800
committerDavid S. Miller <davem@davemloft.net>2008-01-31 19:27:07 -0800
commit29ffe1a5c52dae13b6efead97aab9b058f38fce4 (patch)
treebcca1391f02a01cf1b2d5942a06d392ac0f5be11
parent1987e7b4855fcb6a866d3279ee9f2890491bc34d (diff)
[INET]: Prevent out-of-sync truesize on ip_fragment slow path
When ip_fragment has to hit the slow path the value of skb->truesize may go out of sync because we would have updated it without changing the packet length. This violates the constraints on truesize. This patch postpones the update of skb->truesize to prevent this. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/ip_output.c4
-rw-r--r--net/ipv6/ip6_output.c4
2 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 18070ca65771..6e4d5f493bf9 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -476,6 +476,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
if (skb_shinfo(skb)->frag_list) {
struct sk_buff *frag;
int first_len = skb_pagelen(skb);
+ int truesizes = 0;
if (first_len - hlen > mtu ||
((first_len - hlen) & 7) ||
@@ -499,7 +500,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
sock_hold(skb->sk);
frag->sk = skb->sk;
frag->destructor = sock_wfree;
- skb->truesize -= frag->truesize;
+ truesizes += frag->truesize;
}
}
@@ -510,6 +511,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
frag = skb_shinfo(skb)->frag_list;
skb_shinfo(skb)->frag_list = NULL;
skb->data_len = first_len - skb_headlen(skb);
+ skb->truesize -= truesizes;
skb->len = first_len;
iph->tot_len = htons(first_len);
iph->frag_off = htons(IP_MF);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 15c4f6cee3e6..cfe9e707883c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -636,6 +636,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
if (skb_shinfo(skb)->frag_list) {
int first_len = skb_pagelen(skb);
+ int truesizes = 0;
if (first_len - hlen > mtu ||
((first_len - hlen) & 7) ||
@@ -658,7 +659,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
sock_hold(skb->sk);
frag->sk = skb->sk;
frag->destructor = sock_wfree;
- skb->truesize -= frag->truesize;
+ truesizes += frag->truesize;
}
}
@@ -689,6 +690,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
first_len = skb_pagelen(skb);
skb->data_len = first_len - skb_headlen(skb);
+ skb->truesize -= truesizes;
skb->len = first_len;
ipv6_hdr(skb)->payload_len = htons(first_len -
sizeof(struct ipv6hdr));