upstream proposed fix: http://marc.info/?l=netfilter- devel&m=145757134822741&w=2
** Information type changed from Private Security to Public Security -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1555338 Title: Linux netfilter IPT_SO_SET_REPLACE memory corruption Status in linux package in Ubuntu: Confirmed Bug description: [From https://code.google.com/p/google-security- research/issues/detail?id=758 ] A memory corruption vulnerability exists in the IPT_SO_SET_REPLACE ioctl in the netfilter code for iptables support. This ioctl is can be triggered by an unprivileged user on PF_INET sockets when unprivileged user namespaces are available (CONFIG_USER_NS=y). Android does not enable this option, but desktop/server distributions and Chrome OS will commonly enable this to allow for containers support or sandboxing. 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: newpos = pos + e->next_offset; ... e = (struct ipt_entry *) (entry0 + newpos); e->counters.pcnt = pos; This means that an out of bounds 32-bit write can occur in a 64kb range from the allocated heap entry, with a controlled offset and a partially controlled write value ("pos") or zero. The attached proof- of-concept (netfilter_setsockopt_v3.c) triggers the corruption multiple times to set adjacent heap structures to zero. This issue affects (at least) kernel versions 3.10, 3.18 and 4.4. It appears that a similar codepath is accessible via arp_tables.c/ARPT_SO_SET_REPLACE as well. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1555338/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
