[PATCH 3.16 107/134] cifs: small underflow in cnvrtDosUnixTm()

From: Ben Hutchings
Date: Fri Aug 18 2017 - 09:28:44 EST


3.16.47-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 564277eceeca01e02b1ef3e141cfb939184601b4 upstream.

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@xxxxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/cifs/netmisc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/cifs/netmisc.c
+++ b/fs/cifs/netmisc.c
@@ -966,10 +966,10 @@ struct timespec cnvrtDosUnixTm(__le16 le
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];