[Acked] [Lucid][CVE-2013-2141] kernel/signal.c: stop info leak via the tkill and the tgkill syscalls

[Luis Henriques]

Andy Whitcroft <apw at canonical.com> writes:

> On Thu, Jun 20, 2013 at 12:31:29PM +0100, Luis Henriques wrote:
>> From: Emese Revfy <re.emese at gmail.com>
>> 
>> BugLink: https://bugs.launchpad.net/bugs/1187732
>> 
>> CVE-2013-2141
>> 
>> This fixes a kernel memory contents leak via the tkill and tgkill syscalls
>> for compat processes.
>> 
>> This is visible in the siginfo_t->_sifields._rt.si_sigval.sival_ptr field
>> when handling signals delivered from tkill.
>> 
>> The place of the infoleak:
>> 
>> int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
>> {
>>         ...
>>         put_user_ex(ptr_to_compat(from->si_ptr), &to->si_ptr);
>>         ...
>> }
>> 
>> Signed-off-by: Emese Revfy <re.emese at gmail.com>
>> Reviewed-by: PaX Team <pageexec at freemail.hu>
>> Signed-off-by: Kees Cook <keescook at chromium.org>
>> Cc: Al Viro <viro at zeniv.linux.org.uk>
>> Cc: Oleg Nesterov <oleg at redhat.com>
>> Cc: "Eric W. Biederman" <ebiederm at xmission.com>
>> Cc: Serge Hallyn <serge.hallyn at canonical.com>
>> Cc: <stable at vger.kernel.org>
>> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
>> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
>> (cherry picked from commit b9e146d8eb3b9ecae5086d373b50fa0c1f3e7f0f)
>> 
>> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
>> ---
>>  kernel/signal.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 1c6675b..fb7e242 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -2301,7 +2301,7 @@ do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
>>  
>>  static int do_tkill(pid_t tgid, pid_t pid, int sig)
>>  {
>> -	struct siginfo info;
>> +	struct siginfo info = {};
>>  
>>  	info.si_signo = sig;
>>  	info.si_errno = 0;
>> -- 
>> 1.8.1.2
>> 
>> -- 
>> kernel-team mailing list
>> kernel-team at lists.ubuntu.com
>> https://lists.ubuntu.com/mailman/listinfo/kernel-team
>
> Matches upstream and looks to do what is claimed.
>
> Acked-by: Andy Whitcroft <apw at canonical.com>
>
> That this is only for lucid, does that imply we are getting the rest via
> stable?

Yes, the fixes for both CVEs are already queued (or released) in the
stable trees.  Since these patches are already too late for this SRU
cycle, I guess we can just wait for the stable updates to bring the
fixes into the other series.

Cheers,
-- 
Luis