A kernel prevents of sending siginfo 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.
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
CC: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
---
kernel/signal.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index 7aaa51d..ac5f5e7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2944,7 +2944,8 @@ 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;
@@ -2964,7 +2965,8 @@ 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;
--
1.7.11.7
--
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