An issue was discovered in the Linux kernel through 4.17.10. There is a use-after-free in try_merge_free_space() when mounting a crafted btrfs image, because of a lack of chunk type flag checks in btrfs_check_chunk_valid in fs/btrfs/volumes.c.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| http://www.securityfocus.com/bid/104917 | vdb entry third party advisory |
| https://bugzilla.kernel.org/show_bug.cgi?id=199839 | issue tracking exploit third party advisory |
| https://patchwork.kernel.org/patch/10503099/ | third party advisory patch |
| https://lists.debian.org/debian-lts-announce/2019/03/msg00017.html | third party advisory mailing list |
| https://usn.ubuntu.com/3932-1/ | vendor advisory |
| https://usn.ubuntu.com/3932-2/ | vendor advisory |
| https://usn.ubuntu.com/4094-1/ | vendor advisory |
| https://usn.ubuntu.com/4118-1/ | vendor advisory |
| https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html | mailing list |
| https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html | mailing list |