dmi: fix date handling in dmi_get_year()

Year parsing in dmi_get_year() had the following two bugs.

* "00" is treated as invalid instead of 2000 because zero return from
  simple_strtoul() is treated as error.

* "0N" where N >= 8 is treated as invalid of 200N because the leading
  0 is considered to specify octal.

Fix the above two bugs by using endptr to detect invalid number and
forcing decimal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 24c84ae8152..531e621677c 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -577,6 +577,7 @@ int dmi_get_year(int field)
 {
         int year;
         const char *s = dmi_get_system_info(field);
+        char *e;
 
         if (!s)
                 return -1;
@@ -587,8 +588,8 @@ int dmi_get_year(int field)
                 return 0;
 
         s += 1;
-        year = simple_strtoul(s, NULL, 0);
-        if (year && year < 100) {       /* 2-digit year */
+        year = simple_strtoul(s, &e, 10);
+        if (s != e && year < 100) {     /* 2-digit year */
                 year += 1900;
                 if (year < 1996)        /* no dates < spec 1.0 */
                         year += 100;