From cba9f33d13a8ca3125b2a30abe2425ce562d8a83 Mon Sep 17 00:00:00 2001
From: Bart Samwel <bart@samwel.tk>
Date: Fri, 24 Mar 2006 03:15:50 -0800
Subject: [PATCH] Range checking in do_proc_dointvec_(userhz_)jiffies_conv

When (integer) sysctl values are in either seconds or centiseconds, but
represented internally as jiffies, the allowable value range is decreased.
This patch adds range checks to the conversion routines.

For values in seconds: maximum LONG_MAX / HZ.

For values in centiseconds: maximum (LONG_MAX / HZ) * USER_HZ.

(BTW, does anyone else feel that an interface in seconds should not be
accepting negative values?)

Signed-off-by: Bart Samwel <bart@samwel.tk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index d134266..e82726f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2053,6 +2053,8 @@ static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
 					 int write, void *data)
 {
 	if (write) {
+		if (*lvalp > LONG_MAX / HZ)
+			return 1;
 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
 	} else {
 		int val = *valp;
@@ -2074,6 +2076,8 @@ static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
 						int write, void *data)
 {
 	if (write) {
+		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
+			return 1;
 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
 	} else {
 		int val = *valp;
-- 
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