CVE-2019-15792

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu
5.0 and 5.3 kernel series, shiftfs_btrfs_ioctl_fd_replace() calls
fdget(oldfd), then without further checks passes the resulting file* into
shiftfs_real_fdget(), which casts file->private_data, a void* that points
to a filesystem-dependent type, to a “struct shiftfs_file_info *”. As the
private_data is not required to be a pointer, an attacker can use this to
cause a denial of service or possibly execute arbitrary code.

Bugs

• <https://bugs.launchpad.net/bugs/1850867&gt;