diff options
| author | Pavel Emelyanov <xemul@openvz.org> | 2008-01-10 03:48:38 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2008-01-10 03:48:38 -0800 |
| commit | 9cd40029423701c376391da59d2c6469672b4bed (patch) | |
| tree | a49624a361ab9c28879efc68862aee819538e9bc /net/core | |
| parent | b0de8e402dc5d3ee04f4d0f669ae492a3e569933 (diff) | |
[NEIGH]: Fix race between neigh_parms_release and neightbl_fill_parms
The neightbl_fill_parms() is called under the write-locked tbl->lock
and accesses the parms->dev. The negh_parm_release() calls the
dev_put(parms->dev) without this lock. This creates a tiny race window
on which the parms contains potentially stale dev pointer.
To fix this race it's enough to move the dev_put() upper under the
tbl->lock, but note, that the parms are held by neighbors and thus can
live after the neigh_parms_release() is called, so we still can have a
parm with bad dev pointer.
I didn't find where the neigh->parms->dev is accessed, but still think
that putting the dev is to be done in a place, where the parms are
really freed. Am I right with that?
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/neighbour.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 29b8ee4e35d6..cc8a2f190acf 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1316,8 +1316,6 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms) *p = parms->next; parms->dead = 1; write_unlock_bh(&tbl->lock); - if (parms->dev) - dev_put(parms->dev); call_rcu(&parms->rcu_head, neigh_rcu_free_parms); return; } @@ -1328,6 +1326,8 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms) void neigh_parms_destroy(struct neigh_parms *parms) { + if (parms->dev) + dev_put(parms->dev); kfree(parms); } |