From: Jean PIHET <jpihet@mvista.com>
Date: Mon, 23 Nov 2009 16:03:32 +0000 (+0100)
Subject: ARM: 5793/1: ARM: Check put_user fail in do_signal when enable OABI_COMPAT
X-Git-Tag: firefly_0821_release~11827^2~1
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3336f4f08e0dad7a2b6493c80b49b685141d53ad;p=firefly-linux-kernel-4.4.55.git

ARM: 5793/1: ARM: Check put_user fail in do_signal when enable OABI_COMPAT

Using OABI, the call to put_user in do_signal can fail causing the
calling app to hang.

The solution is to check if put_user fails and force the app to
seg fault in that case.

Tested with multiple sleeping apps/threads (using the nanosleep syscall)
and suspend/resume.

Signed-off-by: janboe <janboe.ye at gmail.com>
Signed-off-by: Jean Pihet <jpihet@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 2a573d4fea24..e7714f367eb8 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -662,8 +662,12 @@ static void do_signal(struct pt_regs *regs, int syscall)
 				regs->ARM_sp -= 4;
 				usp = (u32 __user *)regs->ARM_sp;
 
-				put_user(regs->ARM_pc, usp);
-				regs->ARM_pc = KERN_RESTART_CODE;
+				if (put_user(regs->ARM_pc, usp) == 0) {
+					regs->ARM_pc = KERN_RESTART_CODE;
+				} else {
+					regs->ARM_sp += 4;
+					force_sigsegv(0, current);
+				}
 #endif
 			}
 		}