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Date: Fri, 7 Jan 2011 02:47:57 +0300
From: Dan Carpenter <error27@gmail.com>
To: Jesper Juhl <jj@chaosbits.net>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH][rfc] xattr acl: Suspicious use of potentially null
 pointer.
Message-ID: <20110106234750.GB1761@bicker>
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	Jesper Juhl <jj@chaosbits.net>, linux-fsdevel@vger.kernel.org,
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	Alexander Viro <viro@zeniv.linux.org.uk>
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On Thu, Jan 06, 2011 at 10:52:22PM +0100, Jesper Juhl wrote:
> 
> In posix_acl_from_xattr() we have this at the head of the function:
> 
>   		posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
>    		posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
> 
> Since 'value' is passed in by the caller and may be NULL, the second line 
> looks suspicious to me - taking a potentially NULL pointer (at least 
> btrfs will pass something allocated with kmalloc() which may be NULL), 
> adding one to it and casting it does not seem like it would always be such 
> a hot idea.

The original code is fine.

regards,
dan carpenter