svn commit: r353723 - stable/12/sbin/ipfw

[Andrey V. Elsukov]

Author: ae
Date: Fri Oct 18 09:09:32 2019
New Revision: 353723
URL: https://svnweb.freebsd.org/changeset/base/353723

Log:
  MFC r353545:
    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

Modified:
  stable/12/sbin/ipfw/ipv6.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/sbin/ipfw/ipv6.c
==============================================================================
--- stable/12/sbin/ipfw/ipv6.c	Fri Oct 18 08:39:10 2019	(r353722)
+++ stable/12/sbin/ipfw/ipv6.c	Fri Oct 18 09:09:32 2019	(r353723)
@@ -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++;