[PATCH] Range checking in do_proc_dointvec_(userhz_)jiffies_conv

cba9f33d · Bart Samwel <[email protected]> · 2006-03-24 03:15:50 -08:00

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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: cba9f33d13a8ca3125b2a30abe2425ce562d8a83
Parents: ed5b43f1

Changes

1 files changed · +4 −0

File	Status	Add	Del	Content
kernel/sysctl.c	modified	+4	−0	View file

kernel/sysctl.c

View file

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;