A buffer overflow was found in the Linux kernel in isdn_net_newslave() function in /drivers/isdn/i4l/isdn_net.c file. An overflow happens when user-controlled buffer is copied into a local buffer of constant size using strcpy() without a length check. References: http://seclists.org/oss-sec/2017/q3/274 https://patchwork.kernel.org/patch/9880041/ Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9f5af546e6acc30f075828cb58c7f09665033967
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1481179]
This issue was fixed in kernel 4.12.5, currently available to all supported Fedora releases.
Statement: This issue affects the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2. This has been rated as having Low security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
The ISDN kernel module is automatically loaded when the system boots and the ISDN service is present and enabled. The kernel modules can be prevented from being loaded by using system-wide modprobe rules. Run the following commands to blacklist the ISDN module, thus preventing them from loading: # echo "install isdn /bin/true">> /etc/modprobe.d/disable-isdn.conf On RHEL 6 execute the following commands as root to check if any isdn-related services are present: # chkconfig --list | grep isdn and disable them is yes: # chkconfig isdn off (or use a name of another isdn-related service)
Mitigation: The ISDN kernel module is automatically loaded when the system boots and the ISDN service is present and enabled. The kernel modules can be prevented from being loaded by using system-wide modprobe rules. Run the following commands to blacklist the ISDN module, thus preventing them from loading: ```# echo "install isdn /bin/true">> /etc/modprobe.d/disable-isdn.conf``` On RHEL 6 execute the following commands as root to check if any isdn-related services are present: ```# chkconfig --list | grep isdn``` and disable them if they are: ```# chkconfig isdn off``` (or use a name of another isdn-related service)