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[NET]: Add skb->truesize assertion checking.

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Add some sanity checking.  truesize should be at least sizeof(struct
sk_buff) plus the current packet length.  If not, then truesize is
seriously mangled and deserves a kernel log message.

Currently we'll do the check for release of stream socket buffers.

But we can add checks to more spots over time.

Incorporating ideas from Herbert Xu.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2006-04-20 00:10:50 -07:00
parent b60b49ea6a
commit dc6de33674
4 changed files with 17 additions and 0 deletions
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7
include/linux/skbuff.h
View File

@ -344,6 +344,13 @@ extern void skb_over_panic(struct sk_buff *skb, int len,
void *here);
extern void skb_under_panic(struct sk_buff *skb, int len,
void *here);
extern void skb_truesize_bug(struct sk_buff *skb);
static inline void skb_truesize_check(struct sk_buff *skb)
{
if (unlikely((int)skb->truesize < sizeof(struct sk_buff) + skb->len))
skb_truesize_bug(skb);
}
extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
int getfrag(void *from, char *to, int offset,

1
include/net/sock.h
View File

@ -454,6 +454,7 @@ static inline void sk_stream_set_owner_r(struct sk_buff *skb, struct sock *sk)
static inline void sk_stream_free_skb(struct sock *sk, struct sk_buff *skb)
{
skb_truesize_check(skb);
sock_set_flag(sk, SOCK_QUEUE_SHRUNK);
sk->sk_wmem_queued -= skb->truesize;
sk->sk_forward_alloc += skb->truesize;

8
net/core/skbuff.c
View File

@ -112,6 +112,14 @@ void skb_under_panic(struct sk_buff *skb, int sz, void *here)
BUG();
}
void skb_truesize_bug(struct sk_buff *skb)
{
printk(KERN_ERR "SKB BUG: Invalid truesize (%u) "
"len=%u, sizeof(sk_buff)=%Zd\n",
skb->truesize, skb->len, sizeof(struct sk_buff));
}
EXPORT_SYMBOL(skb_truesize_bug);
/* Allocate a new skbuff. We do this ourselves so we can fill in a few
* 'private' fields and also do memory statistics to find all the
* [BEEP] leaks.

1
net/core/stream.c
View File

@ -176,6 +176,7 @@ void sk_stream_rfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
skb_truesize_check(skb);
atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
sk->sk_forward_alloc += skb->truesize;
}