cmd64x: potential buffer overflow in cmd64x_program_timings()

[ 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@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/ide/cmd64x.c b/drivers/ide/cmd64x.c
index b127ed6..9dde839 100644 (file)
--- 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);
 
        /*