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ipsec: Fix xfrm_state_walk race

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As discovered by Timo Teräs, the currently xfrm_state_walk scheme
is racy because if a second dump finishes before the first, we
may free xfrm states that the first dump would walk over later.

This patch fixes this by storing the dumps in a list in order
to calculate the correct completion counter which cures this
problem.

I've expanded netlink_cb in order to accomodate the extra state
related to this.  It shouldn't be a big deal since netlink_cb
is kmalloced for each dump and we're just increasing it by 4 or
8 bytes.

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
2008-09-22 19:48:19 -07:00
committed by David S. Miller
parent fcaa40669c
commit 5c1824587f
3 changed files with 34 additions and 17 deletions
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10
include/net/xfrm.h
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@@ -1246,6 +1246,8 @@ struct xfrm6_tunnel {
};
struct xfrm_state_walk {
struct list_head list;
unsigned long genid;
struct xfrm_state *state;
int count;
u8 proto;
@@ -1281,13 +1283,7 @@ static inline void xfrm6_fini(void)
extern int xfrm_proc_init(void);
#endif
static inline void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto)
{
walk->proto = proto;
walk->state = NULL;
walk->count = 0;
}
extern void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto);
extern int xfrm_state_walk(struct xfrm_state_walk *walk,
int (*func)(struct xfrm_state *, int, void*), void *);
extern void xfrm_state_walk_done(struct xfrm_state_walk *walk);