* [PATCH] net: rtnetlink: Fix rtnl_dereference return value is NULL
@ 2021-07-08 7:37 Yajun Deng
2021-07-08 8:08 ` Eric Dumazet
0 siblings, 1 reply; 2+ messages in thread
From: Yajun Deng @ 2021-07-08 7:37 UTC (permalink / raw)
To: davem, kuba, ryazanov.s.a, johannes.berg, avagin,
vladimir.oltean, cong.wang, roopa, yajun.deng, zhudi21
Cc: netdev, linux-kernel
rtnl_dereference() may be return NULL in rtnl_unregister(),
so add this case handling.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
net/core/rtnetlink.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f6af3e74fc44..57ce22669b06 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -289,24 +289,27 @@ int rtnl_unregister(int protocol, int msgtype)
struct rtnl_link __rcu **tab;
struct rtnl_link *link;
int msgindex;
+ int ret = -ENOENT;
BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX);
msgindex = rtm_msgindex(msgtype);
rtnl_lock();
tab = rtnl_dereference(rtnl_msg_handlers[protocol]);
- if (!tab) {
- rtnl_unlock();
- return -ENOENT;
- }
+ if (!tab)
+ goto unlock;
link = rtnl_dereference(tab[msgindex]);
- rcu_assign_pointer(tab[msgindex], NULL);
- rtnl_unlock();
+ if (!link)
+ goto unlock;
+ rcu_assign_pointer(tab[msgindex], NULL);
kfree_rcu(link, rcu);
+ ret = 0;
- return 0;
+unlock:
+ rtnl_unlock();
+ return ret;
}
EXPORT_SYMBOL_GPL(rtnl_unregister);
--
2.32.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: rtnetlink: Fix rtnl_dereference return value is NULL
2021-07-08 7:37 [PATCH] net: rtnetlink: Fix rtnl_dereference return value is NULL Yajun Deng
@ 2021-07-08 8:08 ` Eric Dumazet
0 siblings, 0 replies; 2+ messages in thread
From: Eric Dumazet @ 2021-07-08 8:08 UTC (permalink / raw)
To: Yajun Deng, davem, kuba, ryazanov.s.a, johannes.berg, avagin,
vladimir.oltean, cong.wang, roopa, zhudi21
Cc: netdev, linux-kernel
On 7/8/21 9:37 AM, Yajun Deng wrote:
> rtnl_dereference() may be return NULL in rtnl_unregister(),
> so add this case handling.
>
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---
> net/core/rtnetlink.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
I do not see a use case for this.
None of rtnl_unregister() callers check the return value anyway.
Can you elaborate ?
If this was a bug fix, we would need a Fixes: tag.
If this is something you need for an upcoming work, you would need to tag
this for net-next tree.
Thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-07-08 7:37 [PATCH] net: rtnetlink: Fix rtnl_dereference return value is NULL Yajun Deng
2021-07-08 8:08 ` Eric Dumazet
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