[CRIU] [PATCH 1/4] signal: allow to send any siginfo to itself

[Pavel Emelyanov]

On 12/04/2012 05:17 PM, Andrew Vagin wrote:
> On Tue, Dec 04, 2012 at 03:03:19PM +0400, Pavel Emelyanov wrote:
>> On 12/04/2012 02:05 PM, Andrey Vagin wrote:
>>> A kernel prevents of sending sifinfo with positive si_code, because
>>> these codes is reserved for kernel. I think we can allow to send any
>>> siginfo to itself. This operation should not be dangerous.
>>>
>>> This functionality is required for restoring signals.
>>
>> How do I chose whether to send signal to self queue or to shared one
> 
> rt_sigqueueinfo sends to shared queue and rt_tgsigqueueinfo sends to
> private queue.
> 
> ?

OK, thanks.

>>
>>> Signed-off-by: Andrey Vagin <avagin at openvz.org>
>>> ---
>>>  kernel/signal.c | 6 ++++--
>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/kernel/signal.c b/kernel/signal.c
>>> index 0af8868..1daa015 100644
>>> --- a/kernel/signal.c
>>> +++ b/kernel/signal.c
>>> @@ -2952,7 +2952,8 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
>>>  	/* Not even root can pretend to send signals from the kernel.
>>>  	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
>>>  	 */
>>> -	if (info.si_code >= 0 || info.si_code == SI_TKILL) {
>>> +	if (((info.si_code >= 0 || info.si_code == SI_TKILL)) &&
>>> +	    (task_pid_vnr(current) != pid)) {
>>>  		/* We used to allow any < 0 si_code */
>>>  		WARN_ON_ONCE(info.si_code < 0);
>>>  		return -EPERM;
>>> @@ -2972,7 +2973,8 @@ long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>>>  	/* Not even root can pretend to send signals from the kernel.
>>>  	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
>>>  	 */
>>> -	if (info->si_code >= 0 || info->si_code == SI_TKILL) {
>>> +	if ((info->si_code >= 0 || info->si_code == SI_TKILL) &&
>>> +	    (task_pid_vnr(current) != pid)) {
>>>  		/* We used to allow any < 0 si_code */
>>>  		WARN_ON_ONCE(info->si_code < 0);
>>>  		return -EPERM;
>>>
>>
>>
> .
>