1 files changed, 58 insertions, 18 deletions

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 531e621677ce..938100f14b16 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -568,36 +568,76 @@ const struct dmi_device * dmi_find_device(int type, const char *name,
 EXPORT_SYMBOL(dmi_find_device);
 
 /**
- *	dmi_get_year - Return year of a DMI date
- *	@field:	data index (like dmi_get_system_info)
+ *	dmi_get_date - parse a DMI date
+ *	@field:	data index (see enum dmi_field)
+ *	@yearp: optional out parameter for the year
+ *	@monthp: optional out parameter for the month
+ *	@dayp: optional out parameter for the day
  *
- *	Returns -1 when the field doesn't exist. 0 when it is broken.
+ *	The date field is assumed to be in the form resembling
+ *	[mm[/dd]]/yy[yy] and the result is stored in the out
+ *	parameters any or all of which can be omitted.
+ *
+ *	If the field doesn't exist, all out parameters are set to zero
+ *	and false is returned.  Otherwise, true is returned with any
+ *	invalid part of date set to zero.
+ *
+ *	On return, year, month and day are guaranteed to be in the
+ *	range of [0,9999], [0,12] and [0,31] respectively.
  */
-int dmi_get_year(int field)
+bool dmi_get_date(int field, int *yearp, int *monthp, int *dayp)
 {
-	int year;
-	const char *s = dmi_get_system_info(field);
+	int year = 0, month = 0, day = 0;
+	bool exists;
+	const char *s, *y;
 	char *e;
 
-	if (!s)
-		return -1;
-	if (*s == '\0')
-		return 0;
-	s = strrchr(s, '/');
-	if (!s)
-		return 0;
+	s = dmi_get_system_info(field);
+	exists = s;
+	if (!exists)
+		goto out;
 
-	s += 1;
-	year = simple_strtoul(s, &e, 10);
-	if (s != e && year < 100) {	/* 2-digit year */
+	/*
+	 * Determine year first.  We assume the date string resembles
+	 * mm/dd/yy[yy] but the original code extracted only the year
+	 * from the end.  Keep the behavior in the spirit of no
+	 * surprises.
+	 */
+	y = strrchr(s, '/');
+	if (!y)
+		goto out;
+
+	y++;
+	year = simple_strtoul(y, &e, 10);
+	if (y != e && year < 100) {	/* 2-digit year */
 		year += 1900;
 		if (year < 1996)	/* no dates < spec 1.0 */
 			year += 100;
 	}
+	if (year > 9999)		/* year should fit in %04d */
+		year = 0;
+
+	/* parse the mm and dd */
+	month = simple_strtoul(s, &e, 10);
+	if (s == e || *e != '/' || !month || month > 12) {
+		month = 0;
+		goto out;
+	}
 
-	return year;
+	s = e + 1;
+	day = simple_strtoul(s, &e, 10);
+	if (s == y || s == e || *e != '/' || day > 31)
+		day = 0;
+out:
+	if (yearp)
+		*yearp = year;
+	if (monthp)
+		*monthp = month;
+	if (dayp)
+		*dayp = day;
+	return exists;
 }
-EXPORT_SYMBOL(dmi_get_year);
+EXPORT_SYMBOL(dmi_get_date);
 
 /**
  *	dmi_walk - Walk the DMI table and get called back for every record