Commit 9f6ad5d5 authored by Zhong Jinghua's avatar Zhong Jinghua Committed by Jens Axboe

loop: loop_set_status_from_info() check before assignment

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: c490a0b5 ("loop: Check for overflow while configuring loop")
Signed-off-by: default avatarZhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230221095027.3656193-1-zhongjinghua@huaweicloud.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9c7c4bc9
......@@ -977,13 +977,13 @@ loop_set_status_from_info(struct loop_device *lo,
return -EINVAL;
}
/* 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);
lo->lo_file_name[LO_NAME_SIZE-1] = 0;
lo->lo_flags = info->lo_flags;
......
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