From: Christoph Hellwig <hch@lst.de>
Date: Wed, 23 Jun 2021 14:59:06 +0000 (+0200)
Subject: loop: don't allow deleting an unspecified loop device
X-Git-Tag: microblaze-v5.15~28^2~18
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=e5d66a10324f2a0c31153fd6210d99a9d00ef047;p=linux-2.6-microblaze.git

loop: don't allow deleting an unspecified loop device

Passing a negative index to loop_lookup while return any unbound device.
Doing that for a delete does not make much sense, so add check to
explicitly reject that case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210623145908.92973-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c18e2930ca11..b217065a6d67 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2404,6 +2404,11 @@ static int loop_control_remove(int idx)
 {
 	struct loop_device *lo;
 	int ret;
+
+	if (idx < 0) {
+		pr_warn("deleting an unspecified loop device is not supported.\n");
+		return -EINVAL;
+	}
 		
 	ret = mutex_lock_killable(&loop_ctl_mutex);
 	if (ret)