From dc6de33674608f978ec29f5c2f7e3af458c06f78 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@sunset.davemloft.net>
Date: Thu, 20 Apr 2006 00:10:50 -0700
Subject: [PATCH] [NET]: Add skb->truesize assertion checking.
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>
---
include/linux/skbuff.h | 7 +++++++
include/net/sock.h | 1 +
net/core/skbuff.c | 8 ++++++++
net/core/stream.c | 1 +
4 files changed, 17 insertions(+)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index c4619a428d9b..f8f234708b98 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -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,
diff --git a/include/net/sock.h b/include/net/sock.h
index af2b0544586e..ff8b0dad7b0f 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -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;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 09464fa8d72f..fb3770f9c094 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -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.
diff --git a/net/core/stream.c b/net/core/stream.c
index 35e25259fd95..e9489696f694 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -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;
}
--
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