[PATCH 5.11 386/601] ataflop: potential out of bounds in do_format()

Greg Kroah-Hartman
2021-05-12T17:41:43Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 1ffec389a6431782a8a28805830b6fae9bf00af1 ]

The function uses "type" as an array index:

q = unit[drive].disk[type]->queue;

Unfortunately the bounds check on "type" isn't done until later in the
function. Fix this by moving the bounds check to the start.

Fixes: bf9c0538e485 ("ataflop: use a separate gendisk for each media format")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/ataflop.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 104b713f4055..aed2c2a4f4ea 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -729,8 +729,12 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
unsigned long flags;
int ret;

- if (type)
+ if (type) {
type--;
+ if (type >= NUM_DISK_MINORS ||
+ minor2disktype[type].drive_types > DriveType)
+ return -EINVAL;
+ }

q = unit[drive].disk[type]->queue;
blk_mq_freeze_queue(q);
@@ -742,11 +746,6 @@ static int do_format(int drive, int type, struct atari_format_descr *desc)
local_irq_restore(flags);

if (type) {
- if (type >= NUM_DISK_MINORS ||
- minor2disktype[type].drive_types > DriveType) {
- ret = -EINVAL;
- goto out;
- }
type = minor2disktype[type].index;
UDT = &atari_disk_type[type];
}
--
2.30.2