[PATCH] I2C: Fix oops in eeprom driver

This fixes an oops in the eeprom driver. It was first reported here:
  http://bugzilla.kernel.org/show_bug.cgi?id=4347

It was additionally discussed here (while tracking a completely
different bug):
  http://archives.andrew.net.au/lm-sensors/msg30021.html

The patch is already in 2.6.12-rc1:
  http://linux.bkbits.net:8080/linux-2.5/cset@1.2227

The oops happens when one reads data from the sysfs interface file such
that (off < 16) and (count < 16 - off). For example "sensors" from
lm_sensors 2.9.0 does this, and causes the oops.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/i2c/chips/eeprom.c b/drivers/i2c/chips/eeprom.c
index 31ea1300ec9c785c300438406d05e18ceed2a8c7..53dddf09df32ebc1a51d0fa399856c3dc1e56857 100644 (file)
--- a/drivers/i2c/chips/eeprom.c
+++ b/drivers/i2c/chips/eeprom.c
@@ -130,7 +130,8 @@ static ssize_t eeprom_read(struct kobject *kobj, char *buf, loff_t off, size_t c
 
        /* Hide Vaio security settings to regular users (16 first bytes) */
        if (data->nature == VAIO && off < 16 && !capable(CAP_SYS_ADMIN)) {
-               int in_row1 = 16 - off;
+               size_t in_row1 = 16 - off;
+               in_row1 = min(in_row1, count);
                memset(buf, 0, in_row1);
                if (count - in_row1 > 0)
                        memcpy(buf + in_row1, &data->data[16], count - in_row1);