CVE-2021-3995

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

The util-linux package contains a random collection of files that implements some low-level basic linux utilities.

Security Fix(es):

A logical error was found in util-linux's libmount library in a function that allows unprivileged users to unmount FUSE filesystems. Incorrect uid checking allows unprivileged users to unmount FUSE filesystems with similar uid users, an attacker could exploit this vulnerability to cause a denial of service to applications using the affected filesystem.(CVE-2021-3995)

that allows unprivileged users to unmount FUSE filesystems. Issues related to parsing the /proc/self/mountinfo file allow unprivileged users to unmount other users' filesystems that are themselves world-writable (such as /tmp) or mounted in a world-writable directory. An attacker could exploit this vulnerability to cause a denial of service to applications that use the affected file system.(CVE-2021-3996)

A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows an unprivileged local attacker to unmount FUSE filesystems that belong to certain other users who have a UID that is a prefix of the UID of the attacker in its string form. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.

An integer overflow in util-linux through 2.37.1 can potentially cause a buffer overflow if an attacker were able to use system resources in a way that leads to a large number in the /proc/sysvipc/sem file. NOTE: this is unexploitable in GNU C Library environments, and possibly in all realistic environments. (CVE-2021-37600)

Unauthorized unmount of FUSE filesystems belonging to users with similar uid. (CVE-2021-3995)

Unauthorized unmount of filesystems in libmount (CVE-2021-3996)

A flaw was found in the util-linux chfn and chsh utilities when compiled with Readline support. The Readline library uses an "INPUTRC" environment variable to get a path to the library config file. When the library cannot parse the specified file, it prints an error message containing data from the file. This flaw allows an unprivileged user to read root-owned files, potentially leading to privilege escalation. This flaw affects util-linux versions prior to 2.37.4. (CVE-2022-0563)

Additional bug fixes included by updating to version 2.36.2. See release notes for details.

This security update for libeconf, shadow and util-linux fix the following issues:

libeconf:

• Add libeconf to SLE-Module-Basesystem_15-SP3 because needed by 'util-linux' and 'shadow' to fix autoyast handling of security related parameters (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

Issues fixed in libeconf:

• Reading numbers with different bases (e.g. oktal) (bsc#1193632) (#157)
• Fixed different issues while writing string values to file.
• Writing comments to file too.
• Fixed crash while merging values.
• Added econftool cat option (#146)
• new API call: econf_readDirsHistory (showing ALL locations)
• new API call: econf_getPath (absolute path of the configuration file)
• Man pages libeconf.3 and econftool.8.
• Handling multiline strings.
• Added libeconf_ext which returns more information like line_nr, comments, path of the configuration file,...
• Econftool, an command line interface for handling configuration files.
• Generating HTML API documentation with doxygen.
• Improving error handling and semantic file check.
• Joining entries with the same key to one single entry if env variable ECONF_JOIN_SAME_ENTRIES has been set.

shadow:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

util-linux:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)
• Allow use of larger values for start sector to prevent blockdev --report aborting (bsc#1188507)
• Fixed blockdev --report using non-space characters as a field separator (bsc#1188507)
• CVE-2021-3995: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)
• CVE-2021-3996: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)

These are all security issues fixed in the libblkid-devel-2.37.3-1.1 package on the GA media of openSUSE Tumbleweed.

This security update for libeconf, shadow and util-linux fix the following issues:

libeconf:

• Add libeconf to SLE-Module-Basesystem_15-SP3 because needed by 'util-linux' and 'shadow' to fix autoyast handling of security related parameters (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

Issues fixed in libeconf:

• Reading numbers with different bases (e.g. oktal) (bsc#1193632) (#157)
• Fixed different issues while writing string values to file.
• Writing comments to file too.
• Fixed crash while merging values.
• Added econftool cat option (#146)
• new API call: econf_readDirsHistory (showing ALL locations)
• new API call: econf_getPath (absolute path of the configuration file)
• Man pages libeconf.3 and econftool.8.
• Handling multiline strings.
• Added libeconf_ext which returns more information like line_nr, comments, path of the configuration file,...
• Econftool, an command line interface for handling configuration files.
• Generating HTML API documentation with doxygen.
• Improving error handling and semantic file check.
• Joining entries with the same key to one single entry if env variable ECONF_JOIN_SAME_ENTRIES has been set.

shadow:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

util-linux:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)
• Allow use of larger values for start sector to prevent blockdev --report aborting (bsc#1188507)
• Fixed blockdev --report using non-space characters as a field separator (bsc#1188507)
• CVE-2021-3995: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)
• CVE-2021-3996: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)

This security update for libeconf, shadow and util-linux fix the following issues:

libeconf:

• Add libeconf to SLE-Module-Basesystem_15-SP3 because needed by 'util-linux' and 'shadow' to fix autoyast handling of security related parameters (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

Issues fixed in libeconf:

• Reading numbers with different bases (e.g. oktal) (bsc#1193632) (#157)
• Fixed different issues while writing string values to file.
• Writing comments to file too.
• Fixed crash while merging values.
• Added econftool cat option (#146)
• new API call: econf_readDirsHistory (showing ALL locations)
• new API call: econf_getPath (absolute path of the configuration file)
• Man pages libeconf.3 and econftool.8.
• Handling multiline strings.
• Added libeconf_ext which returns more information like line_nr, comments, path of the configuration file,...
• Econftool, an command line interface for handling configuration files.
• Generating HTML API documentation with doxygen.
• Improving error handling and semantic file check.
• Joining entries with the same key to one single entry if env variable ECONF_JOIN_SAME_ENTRIES has been set.

shadow:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)

util-linux:

• The legacy code does not support /etc/login.defs.d used by YaST. Enable libeconf to read it (bsc#1192954, jsc#SLE-23384, jsc#SLE-23402)
• Allow use of larger values for start sector to prevent blockdev --report aborting (bsc#1188507)
• Fixed blockdev --report using non-space characters as a field separator (bsc#1188507)
• CVE-2021-3995: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)
• CVE-2021-3996: Fixed unauthorized unmount in util-linux's libmount. (bsc#1194976)

It was discovered that util-linux incorrectly handled unmounting FUSE filesystems. A local attacker could possibly use this issue to unmount FUSE filesystems belonging to other users.