netdev - Re: [PATCH] netfilter: ebtables: compat: fix a memory leak bug

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Date:   Sun, 21 Jul 2019 02:26:23 +0200
From:   Florian Westphal <fw@...len.de>
To:     Wenwen Wang <wang6495@....edu>
Cc:     Wenwen Wang <wenwen@...uga.edu>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Florian Westphal <fw@...len.de>,
        Roopa Prabhu <roopa@...ulusnetworks.com>,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        "David S. Miller" <davem@...emloft.net>,
        "open list:NETFILTER" <netfilter-devel@...r.kernel.org>,
        "open list:NETFILTER" <coreteam@...filter.org>,
        "moderated list:ETHERNET BRIDGE" <bridge@...ts.linux-foundation.org>,
        "open list:ETHERNET BRIDGE" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] netfilter: ebtables: compat: fix a memory leak bug

Wenwen Wang <wang6495@....edu> wrote:
> From: Wenwen Wang <wenwen@...uga.edu>
> 
> In compat_do_replace(), a temporary buffer is allocated through vmalloc()
> to hold entries copied from the user space. The buffer address is firstly
> saved to 'newinfo->entries', and later on assigned to 'entries_tmp'. Then
> the entries in this temporary buffer is copied to the internal kernel
> structure through compat_copy_entries(). If this copy process fails,
> compat_do_replace() should be terminated. However, the allocated temporary
> buffer is not freed on this path, leading to a memory leak.
> 
> To fix the bug, free the buffer before returning from compat_do_replace().
> 
> Signed-off-by: Wenwen Wang <wenwen@...uga.edu>

Reviewed-by: Florian Westphal <fw@...len.de>