[PATCH AUTOSEL 4.14 141/186] cmd64x: potential buffer overflow in cmd64x_program_timings()

[Sasha Levin]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit 117fcc3053606d8db5cef8821dca15022ae578bb ]

The "drive->dn" value is a u8 and it is controlled by root only, but
it could be out of bounds here so let's check.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/ide/cmd64x.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/ide/cmd64x.c b/drivers/ide/cmd64x.c
index b127ed60c7336..9dde8390da09b 100644
--- a/drivers/ide/cmd64x.c
+++ b/drivers/ide/cmd64x.c
@@ -65,6 +65,9 @@ static void cmd64x_program_timings(ide_drive_t *drive, u8 mode)
 	struct ide_timing t;
 	u8 arttim = 0;
 
+	if (drive->dn >= ARRAY_SIZE(drwtim_regs))
+		return;
+
 	ide_timing_compute(drive, mode, &t, T, 0);
 
 	/*
-- 
2.20.1