mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-11 13:27:06 +09:00
324318f024
When looking up an iptables rule, the iptables binary compares the aligned match and target data (XT_ALIGN). In some cases this can exceed the actual data size to include padding bytes. Before commitf77bc5b23f("iptables: use match, target and data copy_to_user helpers") the malloc()ed bytes were overwritten by the kernel with kzalloced contents, zeroing the padding and making the comparison succeed. After this patch, the kernel copies and clears only data, leaving the padding bytes undefined. Extend the clear operation from data size to aligned data size to include the padding bytes, if any. Padding bytes can be observed in both match and target, and the bug triggered, by issuing a rule with match icmp and target ACCEPT: iptables -t mangle -A INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT iptables -t mangle -D INPUT -i lo -p icmp --icmp-type 1 -j ACCEPT Fixes:f77bc5b23f("iptables: use match, target and data copy_to_user helpers") Reported-by: Paul Moore <pmoore@redhat.com> Reported-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.