netdev - Re: [PATCH iproute2 v3] ipnetns: use-after-free problem in get_netnsid_from

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <afffe3c9-5f08-3cc5-f356-dbb41e94ab75@gmail.com>
Date:   Sat, 4 May 2019 09:08:13 -0600
From:   David Ahern <dsahern@...il.com>
To:     Zhiqiang Liu <liuzhiqiang26@...wei.com>,
        stephen@...workplumber.org, liuhangbin@...il.com,
        kuznet@....inr.ac.ru
Cc:     nicolas.dichtel@...nd.com, phil@....cc,
        "wangxiaogang (F)" <wangxiaogang3@...wei.com>,
        Mingfangsen <mingfangsen@...wei.com>,
        "Zhoukang (A)" <zhoukang7@...wei.com>, kouhuiying@...wei.com,
        netdev@...r.kernel.org
Subject: Re: [PATCH iproute2 v3] ipnetns: use-after-free problem in
 get_netnsid_from_name func

On 5/4/19 1:26 AM, Zhiqiang Liu wrote:
>
> diff --git a/ip/ipnetns.c b/ip/ipnetns.c
> index 430d884..d72be95 100644
> --- a/ip/ipnetns.c
> +++ b/ip/ipnetns.c
> @@ -107,7 +107,7 @@ int get_netnsid_from_name(const char *name)
>  	struct nlmsghdr *answer;
>  	struct rtattr *tb[NETNSA_MAX + 1];
>  	struct rtgenmsg *rthdr;
> -	int len, fd;
> +	int len, fd, ret = -1;
> 
>  	netns_nsid_socket_init();
> 
> @@ -134,8 +134,9 @@ int get_netnsid_from_name(const char *name)
>  	parse_rtattr(tb, NETNSA_MAX, NETNS_RTA(rthdr), len);
> 
>  	if (tb[NETNSA_NSID]) {
> +		ret = rta_getattr_u32(tb[NETNSA_NSID]);
>  		free(answer);
> -		return rta_getattr_u32(tb[NETNSA_NSID]);
> +		return ret;

set ret here, drop the free, let it proceed down to the existing free
and return but now using ret. That way there is 1 exit path and handles
the cleanup.

>  	}
> 
>  err_out:
>