Joined: 12 May 2004
|Posted: Wed Mar 09, 2016 6:26 pm Post subject: [ glsa 201603-04 ] fuse
|Gentoo Linux Security Advisory
Title: FUSE: incorrect filtering of environment variables leading to
Date: March 09, 2016
The fusermount binary in FUSE does not properly clear the
environment before invoking mount or umount as root that allows a local
user to overwrite arbitrary files.
FUSE provides an interface for filesystems implemented in userspace.
Vulnerable: < 2.9.4
Unaffected: >= 2.9.4
Architectures: All supported architectures
The fusermount binary calls setuid(geteuid()) to reset the RUID when it
invokes /bin/mount so that it can use privileged mount options that are
normally restricted if RUID != EUID. FUSE does not properly clear
environment variables before invoking mount or umount as root allowing
this to be passed to operations using elevated privileges such as
LIBMOUNT_MTAB that is used by the mount commands debugging feature.
The FUSE vulnerability allows a local, unprivileged user to overwrite
arbitrary files on the system.
There is no known work around at this time.
All FUSE users should upgrade to the latest version:
|# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-fs/fuse-2.9.4"