CVE-2011-1019: Low severity linux kernel vulnerability
Last updated 24 July 2024
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Since a8f80e8ff94ecba629542d9b4b5f5a8ee3eb565c any process with CAPNETADMIN may load any module from /lib/modules/. This doesn't mean that CAPNETADMIN is a superset of CAPSYSMODULE as modules are limited to /lib/modules/. However, CAPNETADMIN capability shouldn't allow anybody load any module not related to networking.
This patch restricts an ability of autoloading modules to netdev modules with explicit aliases. This fixes CVE-2011-1019.
Arnd Bergmann suggested to leave untouched the old pre-v2.6.32 behavior of loading netdev modules by name (without any prefix) for processes with CAPSYSMODULE to maintain the compatibility with network scripts that use autoloading netdev modules by aliases like "eth0", "wlan0".
Currently there are only three users of the feature in the upstream kernel: ipip, ipgre and sit.
root@albatros:~# capsh --drop=$(seq -s, 0 11),$(seq -s, 13 34) -- root@albatros:~# grep Cap /proc/$$/status CapInh: 0000000000000000 CapPrm: fffffff800001000 CapEff: fffffff800001000 CapBnd: fffffff800001000 root@albatros:~# modprobe xfs FATAL: Error inserting xfs (/lib/modules/2.6.38-rc6-00001-g2bf4ca3/kernel/fs/xfs/xfs.ko): Operation not permitted root@albatros:~# lsmod | grep xfs root@albatros:~# ifconfig xfs xfs: error fetching interface information: Device not found root@albatros:~# lsmod | grep xfs root@albatros:~# lsmod | grep sit root@albatros:~# ifconfig sit sit: error fetching interface information: Device not found root@albatros:~# lsmod | grep sit root@albatros:~# ifconfig sit0 sit0 Link encap:IPv6-in-IPv4 NOARP MTU:1480 Metric:1
root@albatros:~# lsmod | grep sit sit 10457 0 tunnel4 2957 1 sit
For CAPSYSMODULE module loading is still relaxed:
root@albatros:~# grep Cap /proc/$$/status CapInh: 0000000000000000 CapPrm: ffffffffffffffff CapEff: ffffffffffffffff CapBnd: ffffffffffffffff root@albatros:~# ifconfig xfs xfs: error fetching interface information: Device not found root@albatros:~# lsmod | grep xfs xfs 745319 0
References: https://lkml.org/lkml/2011/2/24/203 http://www.spinics.net/lists/netdev/msg156587.html
Acknowledgements:
Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting this issue.
— Red Hat
The devload function in net/core/dev.c in the Linux kernel before 2.6.38 allows local users to bypass an intended CAPSYSMODULE capability requirement and load arbitrary modules by leveraging the CAPNETADMIN capability.
Affected Software
Remediation
Patch Available
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2011-1019?
CVE-2011-1019 has a high severity level due to its potential to allow unauthorized module loading by any process with CAP_NET_ADMIN privilege.
How do I fix CVE-2011-1019?
To fix CVE-2011-1019, you should update your kernel to kernel-rt version 0:2.6.33.9-rt31.64.el5 or kernel version 0:2.6.32-71.29.1.el6 for Red Hat systems.
What are the affected software versions for CVE-2011-1019?
CVE-2011-1019 affects Linux kernel versions up to 2.6.38, along with specific Red Hat and Debian kernel packages.
What does CVE-2011-1019 allow an attacker to do?
CVE-2011-1019 allows an attacker with CAP_NET_ADMIN capability to load arbitrary kernel modules from the /lib/modules directory.
Is CVE-2011-1019 specific to any operating system?
CVE-2011-1019 primarily affects Linux-based operating systems including those using affected Red Hat and Debian kernel packages.