In the mark_source_chains function (net/ipv4/netfilter/ip_tables.c) it is possible for a user-supplied ipt_entry structure to have a large next_offset field. This field is not bounds checked prior to writing a counter value at the supplied offset. Proposed fix: patch v1 message: http://marc.info/?l=netfilter-devel&m=145757134822741&w=2 patch v2 thread: http://marc.info/?t=145757149500006&r=1&w=2 patch v2 message: http://marc.info/?l=netfilter-devel&m=145762719008418&w=2 patch v2 thread: (none yet) http://marc.info/?l=netfilter-devel&r=4&b=201603&w=2 CVE request and assignment: http://seclists.org/oss-sec/2016/q1/581 http://seclists.org/oss-sec/2016/q1/619 Audit done by netfilter team found several related bugs, patches to better validate rulesets are currently queued in pablos nf-next tree upstream (use "parent" link to cycle to next one - there are 17 additional patches): https://git.kernel.org/cgit/linux/kernel/git/pablo/nf-next.git/commit/?id=d7591f0c41ce3e67600a982bab6989ef0f07b3ce
Created kernel tracking bugs for this issue: Affects: fedora-all [bug 1317384]
Statement: This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6. This issue is not currently planned to be addressed in future updates, as user namespaces which the flaw affects are not supported in these products. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/. This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and MRG-2. Future Linux kernel updates for the respective releases might address this issue.
*** Bug 1320138 has been marked as a duplicate of this bug. ***
kernel-4.4.6-300.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.
kernel-4.4.6-200.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.
kernel-4.5.0-302.fc24 has been pushed to the Fedora 24 stable repository. If problems still persist, please make note of it in this bug report.
I'd prefer if the maintainers of those trees can take care of picking these patches up since I don't know how to do this. All changes are now in rhel7.git . I only see a problem with older rhel7 kernels (where netfilter rule blob is percpu), if 7.1 and 7.2 releases need a zstream please let me know. If there are any other questions feel free to ping me.
This issue has been addressed in the following products: MRG for RHEL-6 v.2 Via RHSA-2016:1883 https://rhn.redhat.com/errata/RHSA-2016-1883.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2016:1847 https://rhn.redhat.com/errata/RHSA-2016-1847.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2016:1875 https://rhn.redhat.com/errata/RHSA-2016-1875.html