It was found that the Linux kernel's ping socket implementation didn't properly handle socket unhashing during spurious disconnects which could lead to use-after-free flaw. On x86-64 architecture systems, a local user able to create ping sockets could use this flaw to crash the system. On non-x86-64 architecture systems, a local user able to create ping sockets could use this flaw to increase their privileges on the system. Note: By default ping sockets are disabled on the system (net.ipv4.ping_group_range = 1 0) and have to be explicitly enabled by the system administrator for specific user groups in order to exploit this issue. Upstream fix: https://github.com/torvalds/linux/commit/a134f083e79fb4c3d0a925691e732c56911b4326 References: http://www.openwall.com/lists/oss-security/2015/05/02/5
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1218110]
Statement: This issue does not affect the Linux kernel as shipped with Red Hat Enterprise Linux 5. This issue does affect the Linux kernel as shipped with Red Hat Enterprise Linux 6, 7 and Red Hat Enterprise MRG 2. Future kernel updates for the respective releases will address this issue. Please note that on x86-64 architecture systems the impact is limited to local Denial of Service and that the ping sockets functionality is disabled by default (net.ipv4.ping_group_range sysctl is "1 0").
Mitigation: You can check whether ping socket functionality is enabled by examining the net.ipv4.ping_group_range sysctl value: ~]# sysctl net.ipv4.ping_group_range net.ipv4.ping_group_range = 1 0 "1 0" is the default value and disables the ping socket functionality even for root user. Any other value means that the ping socket functionality might be enabled for certain users on the system. To mitigate this vulnerability make sure that you either allow the functionality to trusted local users (groups) only or set the net.ipv4.ping_group_range sysctl to the default and disabled state: ~]# sysctl net.ipv4.ping_group_range="1 0" Please note that this might prevent some programs relying on this functionality from functioning properly.
kernel-4.0.2-300.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
kernel-3.19.7-200.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.
kernel-3.19.8-100.fc20 has been pushed to the Fedora 20 stable repository. If problems still persist, please make note of it in this bug report.
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2015:1221 https://rhn.redhat.com/errata/RHSA-2015-1221.html
This issue has been addressed in the following products: MRG for RHEL-6 v.2 Via RHSA-2015:1564 https://rhn.redhat.com/errata/RHSA-2015-1564.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:1565 https://access.redhat.com/errata/RHSA-2015:1565
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:1534 https://rhn.redhat.com/errata/RHSA-2015-1534.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 6.5 EUS - Server and Compute Node Only Via RHSA-2015:1583 https://rhn.redhat.com/errata/RHSA-2015-1583.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 6.4 AUS - Server Only Via RHSA-2015:1643 https://rhn.redhat.com/errata/RHSA-2015-1643.html