From: Stephen Hemminger <stephen@networkplumber.org>
To: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Cc: <liuhangbin@gmail.com>, <kuznet@ms2.inr.ac.ru>,
<nicolas.dichtel@6wind.com>, <phil@nwl.cc>,
"wangxiaogang (F)" <wangxiaogang3@huawei.com>,
Mingfangsen <mingfangsen@huawei.com>,
"Zhoukang (A)" <zhoukang7@huawei.com>, <kouhuiying@huawei.com>,
<netdev@vger.kernel.org>
Subject: Re: [PATCH iproute2 v3] ipnetns: use-after-free problem in get_netnsid_from_name func
Date: Mon, 6 May 2019 08:42:30 -0700 [thread overview]
Message-ID: <20190506084230.196fee67@hermes.lan> (raw)
In-Reply-To: <1fca256d-fbce-4da9-471f-14573be4ea21@huawei.com>
On Sat, 4 May 2019 15:26:25 +0800
Zhiqiang Liu <liuzhiqiang26@huawei.com> wrote:
> From: Zhiqiang Liu <liuzhiqiang26@huawei.com>
>
> Follow the following steps:
> # ip netns add net1
> # export MALLOC_MMAP_THRESHOLD_=0
> # ip netns list
> then Segmentation fault (core dumped) will occur.
>
> In get_netnsid_from_name func, answer is freed before rta_getattr_u32(tb[NETNSA_NSID]),
> where tb[] refers to answer`s content. If we set MALLOC_MMAP_THRESHOLD_=0, mmap will
> be adoped to malloc memory, which will be freed immediately after calling free func.
> So reading tb[NETNSA_NSID] will access the released memory after free(answer).
>
> Here, we will call get_netnsid_from_name(tb[NETNSA_NSID]) before free(answer).
>
> Fixes: 86bf43c7c2f ("lib/libnetlink: update rtnl_talk to support malloc buff at run time")
> Reported-by: Huiying Kou <kouhuiying@huawei.com>
> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
> Acked-by: Phil Sutter <phil@nwl.cc>
Applied. You can get better and more detailed checks by running with
valgrind. Which is what I did after applying your patch.
next prev parent reply other threads:[~2019-05-06 15:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <f6c76a60-d5c4-700f-2fbf-912fc1545a31@huawei.com>
[not found] ` <815afacc-4cd2-61b4-2181-aabce6582309@huawei.com>
[not found] ` <20190429092808.GZ31599@orbyte.nwl.cc>
2019-05-04 7:08 ` [PATCH v2] ipnetns: use-after-free problem in get_netnsid_from_name func Zhiqiang Liu
2019-05-04 7:26 ` [PATCH iproute2 v3] " Zhiqiang Liu
2019-05-04 15:08 ` David Ahern
2019-05-05 1:15 ` Zhiqiang Liu
2019-05-05 1:59 ` [PATCH iproute2 v4] " Zhiqiang Liu
2019-05-06 15:42 ` Stephen Hemminger [this message]
2019-05-06 15:50 ` [PATCH iproute2 v3] " Zhiqiang Liu
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