* [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush
@ 2019-07-01 8:29 Li RongQing
2019-07-01 9:03 ` Florian Westphal
0 siblings, 1 reply; 3+ messages in thread
From: Li RongQing @ 2019-07-01 8:29 UTC (permalink / raw)
To: netdev
The iterated pol maybe be freed since it is not protected
by RCU or spinlock when put it, lead to UAF, so use _safe
function to iterate over it against removal
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
net/xfrm/xfrm_policy.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 3235562f6588..87d770dab1f5 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1772,7 +1772,7 @@ xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)
int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
{
int dir, err = 0, cnt = 0;
- struct xfrm_policy *pol;
+ struct xfrm_policy *pol, *tmp;
spin_lock_bh(&net->xfrm.xfrm_policy_lock);
@@ -1781,7 +1781,7 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
goto out;
again:
- list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) {
+ list_for_each_entry_safe(pol, tmp, &net->xfrm.policy_all, walk.all) {
dir = xfrm_policy_id2dir(pol->index);
if (pol->walk.dead ||
dir >= XFRM_POLICY_MAX ||
--
2.16.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush
2019-07-01 8:29 [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush Li RongQing
@ 2019-07-01 9:03 ` Florian Westphal
2019-07-01 9:27 ` 答复: " Li,Rongqing
0 siblings, 1 reply; 3+ messages in thread
From: Florian Westphal @ 2019-07-01 9:03 UTC (permalink / raw)
To: Li RongQing; +Cc: netdev
Li RongQing <lirongqing@baidu.com> wrote:
> The iterated pol maybe be freed since it is not protected
> by RCU or spinlock when put it, lead to UAF, so use _safe
> function to iterate over it against removal
>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>
> ---
> net/xfrm/xfrm_policy.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
> index 3235562f6588..87d770dab1f5 100644
> --- a/net/xfrm/xfrm_policy.c
> +++ b/net/xfrm/xfrm_policy.c
> @@ -1772,7 +1772,7 @@ xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)
> int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
> {
> int dir, err = 0, cnt = 0;
> - struct xfrm_policy *pol;
> + struct xfrm_policy *pol, *tmp;
>
> spin_lock_bh(&net->xfrm.xfrm_policy_lock);
>
> @@ -1781,7 +1781,7 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
> goto out;
>
> again:
> - list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) {
> + list_for_each_entry_safe(pol, tmp, &net->xfrm.policy_all, walk.all) {
> dir = xfrm_policy_id2dir(pol->index);
> if (pol->walk.dead ||
> dir >= XFRM_POLICY_MAX ||
This function drops the lock, but after re-acquire jumps to the 'again'
label, so I do not see the UAF as the entire loop gets restarted.
^ permalink raw reply [flat|nested] 3+ messages in thread* 答复: [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush
2019-07-01 9:03 ` Florian Westphal
@ 2019-07-01 9:27 ` Li,Rongqing
0 siblings, 0 replies; 3+ messages in thread
From: Li,Rongqing @ 2019-07-01 9:27 UTC (permalink / raw)
To: Florian Westphal; +Cc: netdev
> -----邮件原件-----
> 发件人: Florian Westphal [mailto:fw@strlen.de]
> 发送时间: 2019年7月1日 17:04
> 收件人: Li,Rongqing <lirongqing@baidu.com>
> 抄送: netdev@vger.kernel.org
> 主题: Re: [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush
>
> Li RongQing <lirongqing@baidu.com> wrote:
> > The iterated pol maybe be freed since it is not protected by RCU or
> > spinlock when put it, lead to UAF, so use _safe function to iterate
> > over it against removal
> >
> > Signed-off-by: Li RongQing <lirongqing@baidu.com>
> > ---
> > net/xfrm/xfrm_policy.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index
> > 3235562f6588..87d770dab1f5 100644
> > --- a/net/xfrm/xfrm_policy.c
> > +++ b/net/xfrm/xfrm_policy.c
> > @@ -1772,7 +1772,7 @@ xfrm_policy_flush_secctx_check(struct net *net,
> > u8 type, bool task_valid) int xfrm_policy_flush(struct net *net, u8
> > type, bool task_valid) {
> > int dir, err = 0, cnt = 0;
> > - struct xfrm_policy *pol;
> > + struct xfrm_policy *pol, *tmp;
> >
> > spin_lock_bh(&net->xfrm.xfrm_policy_lock);
> >
> > @@ -1781,7 +1781,7 @@ int xfrm_policy_flush(struct net *net, u8 type, bool
> task_valid)
> > goto out;
> >
> > again:
> > - list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) {
> > + list_for_each_entry_safe(pol, tmp, &net->xfrm.policy_all, walk.all)
> > +{
> > dir = xfrm_policy_id2dir(pol->index);
> > if (pol->walk.dead ||
> > dir >= XFRM_POLICY_MAX ||
>
> This function drops the lock, but after re-acquire jumps to the 'again'
> label, so I do not see the UAF as the entire loop gets restarted.
You are right, sorry for the noise
-Li
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-07-01 8:29 [PATCH] xfrm: use list_for_each_entry_safe in xfrm_policy_flush Li RongQing
2019-07-01 9:03 ` Florian Westphal
2019-07-01 9:27 ` 答复: " Li,Rongqing
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