svn commit: r353545 - head/sbin/ipfw

[Andrey V. Elsukov]

Author: ae
Date: Tue Oct 15 09:50:02 2019
New Revision: 353545
URL: https://svnweb.freebsd.org/changeset/base/353545

Log:
  Explicitly initialize the memory buffer to store O_ICMP6TYPE opcode.
  
  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

Modified:
  head/sbin/ipfw/ipv6.c

Modified: head/sbin/ipfw/ipv6.c
==============================================================================
--- head/sbin/ipfw/ipv6.c	Tue Oct 15 08:33:05 2019	(r353544)
+++ head/sbin/ipfw/ipv6.c	Tue Oct 15 09:50:02 2019	(r353545)
@@ -143,6 +143,7 @@ fill_icmp6types(ipfw_insn_icmp6 *cmd, char *av, int cb
        uint8_t type;
 
        CHECK_LENGTH(cblen, F_INSN_SIZE(ipfw_insn_icmp6));
+       memset(cmd, 0, sizeof(*cmd));
        while (*av) {
 	       if (*av == ',')
 		       av++;