By default next_cmd() initializes only first u32 of opcode. O_ICMP6TYPE
opcode has array of bit masks to store corresponding ICMPv6 types.
An opcode that precedes O_ICMP6TYPE, e.g. O_IP6_DST, can have variable
length and during opcode filling it can modify memory that will be used
by O_ICMP6TYPE opcode. Without explicit initialization this leads to
creation of wrong opcode.
Reported by: Boris N. Lytochkin
Obtained from: Yandex LLC
MFC after: 3 days
It produces incompatibility when rules listing is used again to
restore saved ruleset, because "ip6" keyword produces separate opcode.
The kernel already has the check and only IPv6 packets will be checked
for matching.
PR: 232939
MFC after: 3 days
The buffer is already zeroed in compile_rule() function, and also it
may contain configured F_NOT flag in o.len field. This fixes the filling
for "not icmp6types" opcode.
PR: 232939
MFC after: 3 days
After r331668 handling of F_NOT flag done in one place by
print_instruction() function. Also remove unused argument from
print_ip[6]() functions.
MFC after: 1 week
After consultation with SPDX experts and their matching guidelines[1],
the licensing doesn't exactly match the BSD-2-Clause. It yet remains to be
determined if they are equivalent or if there is a recognized license that
matches but it is safer to just revert the tags.
Let this also be a reminder that on FreeBSD, SPDX tags are only advisory
and have no legal value (but IANAL).
Pointyhat to: pfg
Thanks to: Rodney Grimes, Gary O'Neall
[1] https://spdx.org/spdx-license-list/matching-guidelines
Usual moving of code with no changes from ipfw2.c to the
newly created files, and addition of prototypes to ipfw2.h
I have added forward declarations for ipfw_insn_* in ipfw2.h
to avoid a global dependency on ip_fw.h
