From: Bart Samwel <bart@samwel.tk>
Date: Fri, 24 Mar 2006 11:15:50 +0000 (-0800)
Subject: [PATCH] Range checking in do_proc_dointvec_(userhz_)jiffies_conv
X-Git-Tag: v2.6.17-rc1~942
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cba9f33d13a8ca3125b2a30abe2425ce562d8a83;p=linux-2.6

[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 d13426680d..e82726faee 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;