Hi,
What is YAMA?
Where is the tree?
Thanks,
Dmitry
On 22/06/10 04:14, ext Kees Cook wrote:
> Hi Tetsuo,
>
> On Tue, Jun 22, 2010 at 09:28:37AM +0900, Tetsuo Handa wrote:
>
>> Kees Cook wrote:
>>
>>> + /* require ptrace target be a child of ptracer on attach */
>>> + if (mode == PTRACE_MODE_ATTACH && ptrace_scope &&
>>> + !capable(CAP_SYS_PTRACE)) {
>>> + struct task_struct *walker = child;
>>> +
>>> + read_lock(&tasklist_lock);
>>>
>> Holding tasklist_lock does not imply rcu protection.
>> Don't you need rcu_read_lock() like setpriority() and getppid()?
>>
> You're totally right, thanks for the catch! Looks like setpriority() does
> a similar kind of thing, so I've wrapped the whole thing in rcu_ now:
>
> ...
> + rcu_read_lock();
> read_lock(&tasklist_lock);
> while (walker->pid > 0) {
> ...
> rc = -EPERM;
> read_unlock(&tasklist_lock);
> + rcu_read_unlock();
> ...
>
>
> -Kees
>
>
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