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Date: Tue, 5 Nov 2013 12:02:13 +0100
From: Jiri Pirko <jiri@...nulli.us>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, pablo@...filter.org,
netfilter-devel@...r.kernel.org, yoshfuji@...ux-ipv6.org,
kadlec@...ckhole.kfki.hu, kaber@...sh.net, mleitner@...hat.com,
kuznet@....inr.ac.ru, jmorris@...ei.org, wensong@...ux-vs.org,
horms@...ge.net.au, ja@....bg, edumazet@...gle.com,
pshelar@...ira.com, jasowang@...hat.com,
alexander.h.duyck@...el.com, coreteam@...filter.org, fw@...len.de
Subject: [patch net-next 3/3] fix skb_morph to preserve skb->sk and skb->destructor pointers
Currently __skb_clone sets skb->sk and skb->destructor to NULL. This is
not right for skb_morph use case because skb->sk may be previously
set (e. g. by xt_TPROXY).
Also, during skb_morph the destructor should not be called. It might be
previously set, e. g. by xt_TPROXY to sock_edemux, and that would cause
put sk while skb is still in flight.
This patch fixes these.
Signed-off-by: Jiri Pirko <jiri@...nulli.us>
---
net/core/skbuff.c | 44 +++++++++++++++++++++++++++-----------------
1 file changed, 27 insertions(+), 17 deletions(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3735fad..21b320e 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -515,7 +515,7 @@ static void skb_free_head(struct sk_buff *skb)
kfree(skb->head);
}
-static void skb_release_data(struct sk_buff *skb)
+static void __skb_release_data(struct sk_buff *skb)
{
if (!skb->cloned ||
!atomic_sub_return(skb->nohdr ? (1 << SKB_DATAREF_SHIFT) + 1 : 1,
@@ -579,16 +579,12 @@ static void kfree_skbmem(struct sk_buff *skb)
}
}
-static void skb_release_head_state(struct sk_buff *skb)
+static void __skb_release_head_state(struct sk_buff *skb)
{
skb_dst_drop(skb);
#ifdef CONFIG_XFRM
secpath_put(skb->sp);
#endif
- if (skb->destructor) {
- WARN_ON(in_irq());
- skb->destructor(skb);
- }
#if IS_ENABLED(CONFIG_NF_CONNTRACK)
nf_conntrack_put(skb->nfct);
#endif
@@ -607,12 +603,19 @@ static void skb_release_head_state(struct sk_buff *skb)
#endif
}
-/* Free everything but the sk_buff shell. */
-static void skb_release_all(struct sk_buff *skb)
+static void skb_release_head_state(struct sk_buff *skb)
+{
+ if (skb->destructor) {
+ WARN_ON(in_irq());
+ skb->destructor(skb);
+ }
+ __skb_release_head_state(skb);
+}
+
+static void skb_release_data(struct sk_buff *skb)
{
- skb_release_head_state(skb);
if (likely(skb->head))
- skb_release_data(skb);
+ __skb_release_data(skb);
}
/**
@@ -626,7 +629,8 @@ static void skb_release_all(struct sk_buff *skb)
void __kfree_skb(struct sk_buff *skb)
{
- skb_release_all(skb);
+ skb_release_head_state(skb);
+ skb_release_data(skb);
kfree_skbmem(skb);
}
EXPORT_SYMBOL(__kfree_skb);
@@ -761,12 +765,11 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
* You should not add any new code to this function. Add it to
* __copy_skb_header above instead.
*/
-static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
+static struct sk_buff *___skb_clone(struct sk_buff *n, struct sk_buff *skb)
{
#define C(x) n->x = skb->x
n->next = n->prev = NULL;
- n->sk = NULL;
__copy_skb_header(n, skb);
C(len);
@@ -775,7 +778,6 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
n->hdr_len = skb->nohdr ? skb_headroom(skb) : skb->hdr_len;
n->cloned = 1;
n->nohdr = 0;
- n->destructor = NULL;
C(tail);
C(end);
C(head);
@@ -791,6 +793,13 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
#undef C
}
+static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
+{
+ n->sk = NULL;
+ n->destructor = NULL;
+ return ___skb_clone(n, skb);
+}
+
/**
* skb_morph - morph one skb into another
* @dst: the skb to receive the contents
@@ -803,8 +812,9 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
*/
struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
{
- skb_release_all(dst);
- return __skb_clone(dst, src);
+ __skb_release_head_state(dst);
+ skb_release_data(dst);
+ return ___skb_clone(dst, src);
}
EXPORT_SYMBOL_GPL(skb_morph);
@@ -1107,7 +1117,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
if (skb_has_frag_list(skb))
skb_clone_fraglist(skb);
- skb_release_data(skb);
+ __skb_release_data(skb);
} else {
skb_free_head(skb);
}
--
1.8.3.1
--
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