Re: [PATCH 1/2] fs: add link restrictions

[Kees Cook]

On Sun, Jul 1, 2012 at 5:43 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Sat, Jun 30, 2012 at 2:14 AM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>> On Mon, Jun 25, 2012 at 02:05:26PM -0700, Kees Cook wrote:
>>> +                     err = may_follow_link(&link);
>>> +                     if (unlikely(err))
>>> +                             break;
>>
>> No.  This is definitely wrong - you are leaking dentries and vfsmount here.
>
> What should I do to avoid the leak? I thought it was avoiding the need
> to call put_link because it aborts before calling follow_link.

Does this need "path_put(&nd->path);" added to the abort case?

If so, is this also missing from follow_link()'s final "return error",
or is it the responsibility of dentry->d_inode->i_op->follow_link() to
have already called path_put()?

-Kees

-- 
Kees Cook
Chrome OS Security
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