From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 1 May 2017 18:43:43 +0000 (+0300)
Subject: cifs: small underflow in cnvrtDosUnixTm()
X-Git-Tag: v4.12-rc1~75^2~12
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=564277eceeca01e02b1ef3e141cfb939184601b4;hp=204f144c9fcac355843412b6ba1150086488a208;p=karo-tx-linux.git

cifs: small underflow in cnvrtDosUnixTm()

January is month 1.  There is no zero-th month.  If someone passes a
zero month then it means we read from one space before the start of the
total_days_of_prev_months[] array.

We may as well also be strict about days as well.

Fixes: 1bd5bbcb6531 ("[CIFS] Legacy time handling for Win9x and OS/2 part 1")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <smfrench@gmail.com>
---

diff --git a/fs/cifs/netmisc.c b/fs/cifs/netmisc.c
index abae6dd2c6b9..cc88f4f0325e 100644
--- a/fs/cifs/netmisc.c
+++ b/fs/cifs/netmisc.c
@@ -980,10 +980,10 @@ struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time, int offset)
 		cifs_dbg(VFS, "illegal hours %d\n", st->Hours);
 	days = sd->Day;
 	month = sd->Month;
-	if ((days > 31) || (month > 12)) {
+	if (days < 1 || days > 31 || month < 1 || month > 12) {
 		cifs_dbg(VFS, "illegal date, month %d day: %d\n", month, days);
-		if (month > 12)
-			month = 12;
+		days = clamp(days, 1, 31);
+		month = clamp(month, 1, 12);
 	}
 	month -= 1;
 	days += total_days_of_prev_months[month];