[sudo-announce] sudo 1.9.5 released

Todd C. Miller Todd.Miller at sudo.ws
Mon Jan 11 08:48:41 MST 2021


Sudo version 1.9.5 is now available which fixes several bugs, including
CVE-2021-23239 and CVE-2021-23240 which have security implications.
See below for details.

Source:
    https://www.sudo.ws/dist/sudo-1.9.5.tar.gz
    ftp://ftp.sudo.ws/pub/sudo/sudo-1.9.5.tar.gz

SHA256 checksum:
    3718b16de71fd6076858d5a1efe93a0d11d2f713fc51f24a314dfee78e4e83a5
MD5 checksum:
    faf1dfc975929c5f99a1fdc64e9b7098

Binary packages:
    https://www.sudo.ws/download.html#binary

For a list of download mirror sites, see:
    https://www.sudo.ws/download_mirrors.html

Sudo web site:
    https://www.sudo.ws/

Sudo web site mirrors:
    https://www.sudo.ws/mirrors.html

Major changes between sudo 1.9.5 and 1.9.4p2

 * Fixed a crash introduced in 1.9.4 when running "sudo -i" as an
   unknown user.  This is related to but distinct from Bug #948.

 * If the "lecture_file" setting is enabled in sudoers, it must now
   refer to a regular file or a symbolic link to a regular file.

 * Fixed a potential use-after-free bug in sudo_logsrvd when the
   server shuts down if there are existing connections from clients
   that are only logging events and not session I/O data.

 * Fixed a buffer size mismatch when serializing the list of IP
   addresses for configured network interfaces.  This bug is not
   actually exploitable since the allocated buffer is large enough
   to hold the list of addresses.

 * If sudo is executed with a name other than "sudo" or "sudoedit",
   it will now fall back to "sudo" as the program name.  This affects
   warning, help and usage messages as well as the matching of Debug
   lines in the /etc/sudo.conf file.  Previously, it was possible
   for the invoking user to manipulate the program name by setting
   argv[0] to an arbitrary value when executing sudo.

 * Sudo now checks for failure when setting the close-on-exec flag
   on open file descriptors.  This should never fail but, if it
   were to, there is the possibility of a file descriptor leak to
   a child process (such as the command sudo runs).

 * Fixed CVE-2021-23239, a potential information leak in sudoedit
   that could be used to test for the existence of directories not
   normally accessible to the user in certain circumstances.  When
   creating a new file, sudoedit checks to make sure the parent
   directory of the new file exists before running the editor.
   However, a race condition exists if the invoking user can replace
   (or create) the parent directory.  If a symbolic link is created
   in place of the parent directory, sudoedit will run the editor
   as long as the target of the link exists.  If the target of the
   link does not exist, an error message will be displayed.  The
   race condition can be used to test for the existence of an
   arbitrary directory.  However, it _cannot_ be used to write to
   an arbitrary location.

 * Fixed CVE-2021-23240, a flaw in the temporary file handling of
   sudoedit's SELinux RBAC support.  On systems where SELinux is
   enabled, a user with sudoedit permissions may be able to set the
   owner of an arbitrary file to the user-ID of the target user.
   On Linux kernels that support "protected symlinks", setting
   /proc/sys/fs/protected_symlinks to 1 will prevent the bug from
   being exploited.  For more information see
   https://www.sudo.ws/alerts/sudoedit_selinux.html.

 * Added writability checks for sudoedit when SELinux RBAC is in use.
   This makes sudoedit behavior consistent regardless of whether
   or not SELinux RBAC is in use.  Previously, the "sudoedit_checkdir"
   setting had no effect for RBAC entries.

 * A new sudoers option "selinux" can be used to disable sudo's
   SELinux RBAC support.

 * Quieted warnings from PVS Studio, clang analyzer, and cppcheck.
   Added suppression annotations for PVS Studio false positives.
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