Re: [PATCH] Fix mountpoint reference leakage in linkat

From: Oleg Drokin
Date: Fri Jan 31 2014 - 16:13:36 EST



On Jan 31, 2014, at 4:03 PM, Al Viro wrote:
>> diff --git a/fs/namei.c b/fs/namei.c
>> index bcb838e..e620937 100644
>> --- a/fs/namei.c
>> +++ b/fs/namei.c
>> @@ -3931,6 +3931,7 @@ out_dput:
>> goto retry;
>> }
>> if (retry_estale(error, how)) {
>> + path_put(&old_path);
>> how |= LOOKUP_REVAL;
>> goto retry;
>> }
> Umm... That obviously can't be right - we have another goto retry
> in the same situation (see in your diff context). I agree that
> we have a leak there, but you've fixed only a half of it.

Hm, you are right, I did not notice this other one somehow.

So, not to take any guesses, should I convert the other goto retry into
retry_deleg similar in style to what happens in rename and unlink, only
make retry)deleg label before call to the security_path_link?
After the call to the security_path_link?
Or would you prefer to just free old_path in both cases?

Bye,
Oleg
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