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From: Genjian <zhanggenjian@126.com>
To: stable@vger.kernel.org
Cc: axboe@kernel.dk, stable@kernel.org, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, zhanggenjian123@gmail.com,
	Zhong Jinghua <zhongjinghua@huawei.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Genjian Zhang <zhanggenjian@kylinos.cn>
Subject: [PATCH 4.19.y 9/9] loop: loop_set_status_from_info() check before assignment
Date: Fri,  1 Mar 2024 09:30:28 +0800	[thread overview]
Message-ID: <20240301013028.2293831-10-zhanggenjian@126.com> (raw)
In-Reply-To: <20240301013028.2293831-1-zhanggenjian@126.com>

From: Zhong Jinghua <zhongjinghua@huawei.com>

[ Upstream commit 9f6ad5d533d1c71e51bdd06a5712c4fbc8768dfa ]

In loop_set_status_from_info(), lo->lo_offset and lo->lo_sizelimit should
be checked before reassignment, because if an overflow error occurs, the
original correct value will be changed to the wrong value, and it will not
be changed back.

More, the original patch did not solve the problem, the value was set and
ioctl returned an error, but the subsequent io used the value in the loop
driver, which still caused an alarm:

loop_handle_cmd
 do_req_filebacked
  loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
  lo_rw_aio
   cmd->iocb.ki_pos = pos

Fixes: c490a0b5a4f3 ("loop: Check for overflow while configuring loop")
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230221095027.3656193-1-zhongjinghua@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Genjian Zhang <zhanggenjian@kylinos.cn>
---
 drivers/block/loop.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c1caa3e2355f..6050b039e4d2 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1269,13 +1269,13 @@ loop_set_status_from_info(struct loop_device *lo,
 	if (err)
 		return err;
 
+	/* Avoid assigning overflow values */
+	if (info->lo_offset > LLONG_MAX || info->lo_sizelimit > LLONG_MAX)
+		return -EOVERFLOW;
+
 	lo->lo_offset = info->lo_offset;
 	lo->lo_sizelimit = info->lo_sizelimit;
 
-	/* loff_t vars have been assigned __u64 */
-	if (lo->lo_offset < 0 || lo->lo_sizelimit < 0)
-		return -EOVERFLOW;
-
 	memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
 	memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
 	lo->lo_file_name[LO_NAME_SIZE-1] = 0;
-- 
2.25.1


  parent reply	other threads:[~2024-03-01  1:33 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-01  1:30 [PATCH 4.19.y 0/9] Fix the UAF issue caused by the loop driver Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 1/9] Revert "loop: Check for overflow while configuring loop" Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 2/9] loop: Call loop_config_discard() only after new config is applied Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 3/9] loop: Remove sector_t truncation checks Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 4/9] loop: Factor out setting loop device size Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 5/9] loop: Refactor loop_set_status() size calculation Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 6/9] loop: properly observe rotational flag of underlying device Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 7/9] loop: Factor out configuring loop from status Genjian
2024-03-01  1:30 ` [PATCH 4.19.y 8/9] loop: Check for overflow while configuring loop Genjian
2024-03-01  1:30 ` Genjian [this message]
2024-03-04 13:31 ` [PATCH 4.19.y 0/9] Fix the UAF issue caused by the loop driver Greg KH
2024-03-07  2:34   ` genjian zhang
2024-03-29 12:38     ` Greg KH

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