CVE-2022-49849 Information

Description

In the Linux kernel the following vulnerability has been resolved:

btrfs: fix match incorrectly in dev_args_match_device

syzkaller found a failed assertion:

assertion failed: (args->devid != (u64)-1) || args->missing in fs/btrfs/volumes.c:6921

This can be triggered when we set devid to (u64)-1 by ioctl. In this case the match of devid will be skipped and the match of device may succeed incorrectly.

Patch 562d7b1512f7 introduced this function which is used to match device. This function contains two matching scenarios we can distinguish them by checking the value of args->missing rather than check whether args->devid and args->uuid is default value.

Reference

https://git.kernel.org/stable/c/0fca385d6ebc3cabb20f67bcf8a71f1448bdc001 https://git.kernel.org/stable/c/bc6c127c377010f136360552ebf91c2723081c1b https://git.kernel.org/stable/c/c9fe4719c662e0af17eea723cf345e37719fd3c9