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[NET]: Warn in __skb_trim if skb is paged

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It's better to warn and fail rather than rarely triggering BUG on paths
that incorrectly call skb_trim/__skb_trim on a non-linear skb.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2006-06-09 16:13:38 -07:00 committed by David S. Miller
parent b38dfee3d6
commit 3cc0e87398
2 changed files with 14 additions and 17 deletions
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24
include/linux/skbuff.h
View File

@ -975,15 +975,16 @@ static inline void skb_reserve(struct sk_buff *skb, int len)
#define NET_SKB_PAD 16
#endif
extern int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc);
extern int ___pskb_trim(struct sk_buff *skb, unsigned int len);
static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
{
if (!skb->data_len) {
skb->len = len;
skb->tail = skb->data + len;
} else
___pskb_trim(skb, len, 0);
if (unlikely(skb->data_len)) {
WARN_ON(1);
return;
}
skb->len = len;
skb->tail = skb->data + len;
}
/**
@ -993,6 +994,7 @@ static inline void __skb_trim(struct sk_buff *skb, unsigned int len)
*
* Cut the length of a buffer down by removing data from the tail. If
* the buffer is already under the length specified it is not modified.
* The skb must be linear.
*/
static inline void skb_trim(struct sk_buff *skb, unsigned int len)
{
@ -1003,12 +1005,10 @@ static inline void skb_trim(struct sk_buff *skb, unsigned int len)
static inline int __pskb_trim(struct sk_buff *skb, unsigned int len)
{
if (!skb->data_len) {
skb->len = len;
skb->tail = skb->data+len;
return 0;
}
return ___pskb_trim(skb, len, 1);
if (skb->data_len)
return ___pskb_trim(skb, len);
__skb_trim(skb, len);
return 0;
}
static inline int pskb_trim(struct sk_buff *skb, unsigned int len)

7
net/core/skbuff.c
View File

@ -801,12 +801,10 @@ struct sk_buff *skb_pad(struct sk_buff *skb, int pad)
return nskb;
}
/* Trims skb to length len. It can change skb pointers, if "realloc" is 1.
* If realloc==0 and trimming is impossible without change of data,
* it is BUG().
/* Trims skb to length len. It can change skb pointers.
*/
int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
int ___pskb_trim(struct sk_buff *skb, unsigned int len)
{
int offset = skb_headlen(skb);
int nfrags = skb_shinfo(skb)->nr_frags;
@ -816,7 +814,6 @@ int ___pskb_trim(struct sk_buff *skb, unsigned int len, int realloc)
int end = offset + skb_shinfo(skb)->frags[i].size;
if (end > len) {
if (skb_cloned(skb)) {
BUG_ON(!realloc);
if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
return -ENOMEM;
}