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Mandriva Advisories

Package name modutils
Date November 24th, 2000
Advisory ID MDKSA-2000:071-2
Affected versions 7.1, 7.2
Synopsis Updated modutils packages fix problem with improper safe guard measures

Problem Description

All 2.3.x versions of modutils (since March 12 1999) contain a
vulnerability that can lead to a local root compromise. The modprobe
program uses popen() to execute the "echo" program argumented with
user input. Because popen() relies on /bin/sh to parse the command
string and execute "echo", un-escaped shell meta-characters can be
included in user input to execute commands. Although modprobe is not
installed setuid root, this vulnerability can be exploited to gain root
access provided the target system is using kmod. Kmod is a kernel
facility that automatically executes the program modprobe when a module
is requested via request_module(). One program that can take advantage
of this vulnerability is ping. When a device is specified at the
command line that doesn't exist, request_module is called with the
user-supplied arguments passed to the kernel. The kernel then takes
the arguments and executes modprobe with them. Arbitrary commands
included in the argument for module name (device name to ping) are then
executed when popen() is called as root.

A new version of modutils (2.3.20) has been released that fixes this
particular vulnerability. modutils still supports meta expansion,
including back quoted commands, but only for data read from the
configuration file. This assumes that when modutils is run as root
out of the kernel, normal users cannot specify their own configuration


The previous version of modutils (2.3.20) contained an error in the
new safe guards that caused them to not properly be enabled when run
as root from the kmod process. These new safe guards check the
arguments passed to modules. The 2.3.21 modutils package fixes this
error and correctly checks the arguments when running from kmod,
limiting kernel module arguments to those specified in
/etc/conf.modules (Linux-Mandrake 7.1) or /etc/modules.conf
(Linux-Mandrake 7.2).

Updated Packages

Mandrakelinux 7.1

 f037682a4339be923b9a6299198b83af  7.1/RPMS/modutils-2.3.21-1.4mdk.i586.rpm
93e6342933861a8be5f84c8823f3ff9c  7.1/SRPMS/modutils-2.3.21-1.4mdk.src.rpm

Mandrakelinux 7.2

 7b647e5f9fc2110407fc6e89a3d64548  7.2/RPMS/modutils-2.3.21-1.3mdk.i586.rpm
264421bfa296e484ba2bee270584661b  7.2/SRPMS/modutils-2.3.21-1.3mdk.src.rpm


To upgrade automatically, use MandrivaUpdate.


Please verify the update prior to upgrading to ensure the integrity of the downloaded package. You can do this with the command :

                rpm --checksig package.rpm

You can get the GPG public key of the Mandriva Security Team to verify the GPG signature of each RPM.

If you use MandrivaUpdate, the verification of md5 checksum and GPG signature is performed automatically for you.