From d53865ac5f5814e6f344b349f175fcab56dea3dd Mon Sep 17 00:00:00 2001
From: Tomoki Shirasawa <sira@popeye.cc.u-tokyo.ac.jp>
Date: Wed, 18 Mar 2015 12:59:05 +0900
Subject: [PATCH] change to check sequence of kill syscall,  check sig num zero
 after uid checking

---
 arch/x86/kernel/syscall.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/syscall.c b/arch/x86/kernel/syscall.c
index f897f69d..c4e0fe8a 100644
--- a/arch/x86/kernel/syscall.c
+++ b/arch/x86/kernel/syscall.c
@@ -926,11 +926,6 @@ do_kill(int pid, int tid, int sig, siginfo_t *info, int ptracecont)
 		cpu_restore_interrupt(irqstate);
 		return -ESRCH;
 	}
-	if(sig == 0){
-		ihk_mc_spinlock_unlock_noirq(savelock);
-		cpu_restore_interrupt(irqstate);
-		return 0;
-	}
 
 	if(sig != SIGCONT &&
 	   proc->ftn->euid != 0 &&
@@ -943,6 +938,12 @@ do_kill(int pid, int tid, int sig, siginfo_t *info, int ptracecont)
 		return -EPERM;
 	}
 
+	if(sig == 0){
+		ihk_mc_spinlock_unlock_noirq(savelock);
+		cpu_restore_interrupt(irqstate);
+		return 0;
+	}
+
 	doint = 0;
 	if(tid == -1){
 		ihk_mc_spinlock_lock_noirq(&tproc->sigshared->lock);