diff options
| author | Ziyang Xuan <william.xuanziyang@huawei.com> | 2023-07-08 14:59:10 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-07-23 13:53:43 +0200 |
| commit | 1f656e483eb4733d62f18dfb206a49b78f60f495 (patch) | |
| tree | 4e76d9261690e8750997d64da36d98b18c010e5a | |
| parent | c9a6bd1cc028e095e08f1447a8b30c8897311f9e (diff) | |
ipv6/addrconf: fix a potential refcount underflow for idev
[ Upstream commit 06a0716949c22e2aefb648526580671197151acc ]
Now in addrconf_mod_rs_timer(), reference idev depends on whether
rs_timer is not pending. Then modify rs_timer timeout.
There is a time gap in [1], during which if the pending rs_timer
becomes not pending. It will miss to hold idev, but the rs_timer
is activated. Thus rs_timer callback function addrconf_rs_timer()
will be executed and put idev later without holding idev. A refcount
underflow issue for idev can be caused by this.
if (!timer_pending(&idev->rs_timer))
in6_dev_hold(idev);
<--------------[1]
mod_timer(&idev->rs_timer, jiffies + when);
To fix the issue, hold idev if mod_timer() return 0.
Fixes: b7b1bfce0bb6 ("ipv6: split duplicate address detection and router solicitation timer")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/ipv6/addrconf.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 3797917237d0..5affca8e2f53 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -318,9 +318,8 @@ static void addrconf_del_dad_work(struct inet6_ifaddr *ifp) static void addrconf_mod_rs_timer(struct inet6_dev *idev, unsigned long when) { - if (!timer_pending(&idev->rs_timer)) + if (!mod_timer(&idev->rs_timer, jiffies + when)) in6_dev_hold(idev); - mod_timer(&idev->rs_timer, jiffies + when); } static void addrconf_mod_dad_work(struct inet6_ifaddr *ifp, |