[PATCH 1/6] hwmon: (dell-smm) Fail in ioctl I8K_BIOS_VERSION when bios version is not a number

[Pali Rohár]

ABI of I8K_BIOS_VERSION ioctl can return only number. But new BIOS versions
contain also other characters, which does not fit into that ABI. So in case
of non digit values return -EINVAL.

Reported-by: Mario Limonciello <mario_limoncie...@dell.com>
Signed-off-by: Pali Rohár <pali.ro...@gmail.com>
---
 drivers/hwmon/dell-smm-hwmon.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index c43318d..480b2fa 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -35,6 +35,7 @@
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/sched.h>
+#include <linux/ctype.h>
 
 #include <linux/i8k.h>
 
@@ -387,6 +388,10 @@ i8k_ioctl_unlocked(struct file *fp, unsigned int cmd, 
unsigned long arg)
 
        switch (cmd) {
        case I8K_BIOS_VERSION:
+               if (!isdigit(bios_version[0]) || !isdigit(bios_version[1]) ||
+                   !isdigit(bios_version[2]))
+                       return -EINVAL;
+
                val = (bios_version[0] << 16) |
                                (bios_version[1] << 8) | bios_version[2];
                break;
-- 
1.7.9.5