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4c59406ed0
After xfrm_add_policy add a policy, its ref is 2, then
xfrm_policy_timer
read_lock
xp->walk.dead is 0
....
mod_timer()
xfrm_policy_kill
policy->walk.dead = 1
....
del_timer(&policy->timer)
xfrm_pol_put //ref is 1
xfrm_pol_put //ref is 0
xfrm_policy_destroy
call_rcu
xfrm_pol_hold //ref is 1
read_unlock
xfrm_pol_put //ref is 0
xfrm_policy_destroy
call_rcu
xfrm_policy_destroy is called twice, which may leads to
double free.
Call Trace:
RIP: 0010:refcount_warn_saturate+0x161/0x210
...
xfrm_policy_timer+0x522/0x600
call_timer_fn+0x1b3/0x5e0
? __xfrm_decode_session+0x2990/0x2990
? msleep+0xb0/0xb0
? _raw_spin_unlock_irq+0x24/0x40
? __xfrm_decode_session+0x2990/0x2990
? __xfrm_decode_session+0x2990/0x2990
run_timer_softirq+0x5c5/0x10e0
Fix this by use write_lock_bh in xfrm_policy_kill.
Fixes:
|
||
---|---|---|
.. | ||
espintcp.c | ||
Kconfig | ||
Makefile | ||
xfrm_algo.c | ||
xfrm_device.c | ||
xfrm_hash.c | ||
xfrm_hash.h | ||
xfrm_inout.h | ||
xfrm_input.c | ||
xfrm_interface.c | ||
xfrm_ipcomp.c | ||
xfrm_output.c | ||
xfrm_policy.c | ||
xfrm_proc.c | ||
xfrm_replay.c | ||
xfrm_state.c | ||
xfrm_sysctl.c | ||
xfrm_user.c |