2021-07-24 15:03:50 +00:00
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#!/usr/bin/env perl
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##
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## Author......: See docs/credits.txt
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## License.....: MIT
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##
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use strict;
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use warnings;
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2022-01-30 09:35:51 +00:00
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use Digest::MD5 qw (md5 md5_hex);
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use Digest::SHA qw (sha1 sha1_hex);
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use Digest::HMAC qw (hmac_hex);
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2021-07-24 15:03:50 +00:00
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2022-11-27 22:51:28 +00:00
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sub module_constraints { [[0, 256], [24, 3000], [-1, -1], [-1, -1], [-1, -1]] }
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2021-07-24 15:03:50 +00:00
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sub module_generate_hash
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{
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my $word = shift;
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my $salt = shift;
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2022-01-30 09:35:51 +00:00
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my $pkt_num = shift // int (rand (100000000));
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my $engineID = shift // random_hex_string (26, 34);
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my $mode = shift // int (rand (1)) + 1;
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2021-07-24 15:03:50 +00:00
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# make even if needed
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2022-01-30 09:35:51 +00:00
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if (length ($salt) % 2 == 1)
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2021-07-24 15:03:50 +00:00
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{
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$salt = $salt . "8";
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}
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my $string1 = $word x 1048576;
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$string1 = substr ($string1, 0, 1048576);
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my $digest1 = '';
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if ($mode eq 2)
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{
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$digest1 = sha1_hex ($string1);
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}
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elsif ($mode eq 1)
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{
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$digest1 = md5_hex ($string1);
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}
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my $buf = join '', $digest1, $engineID, $digest1;
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my $digest = '';
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if ($mode eq 2)
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{
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2022-01-30 09:35:51 +00:00
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my $digest2 = sha1 (pack ("H*", $buf));
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2021-07-24 15:03:50 +00:00
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2022-01-30 09:35:51 +00:00
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$digest = hmac_hex (pack ("H*", $salt), $digest2, \&sha1);
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2021-07-24 15:03:50 +00:00
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}
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elsif ($mode eq 1)
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{
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2022-01-30 09:35:51 +00:00
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my $digest2 = md5 (pack ("H*", $buf));
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2021-07-24 15:03:50 +00:00
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2022-01-30 09:35:51 +00:00
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$digest = hmac_hex (pack ("H*", $salt), $digest2, \&md5);
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2021-07-24 15:03:50 +00:00
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}
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$digest = substr ($digest, 0, 24);
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my $hash = sprintf ("\$SNMPv3\$0\$%s\$%s\$%s\$%s", $pkt_num, $salt, $engineID, $digest);
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return $hash;
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}
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sub module_verify_hash
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{
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my $line = shift;
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my $idx = index ($line, ':');
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return unless $idx >= 0;
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my $hash = substr ($line, 0, $idx);
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my $word = substr ($line, $idx + 1);
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return unless length ($word) gt 0;
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return unless substr ($hash, 0, 10) eq '$SNMPv3$0$';
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my (undef, $signature, $version, $pkt_num, $salt, $engineID, $digest) = split '\$', $hash;
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return unless defined $signature;
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return unless defined $version;
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return unless defined $pkt_num;
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return unless defined $salt;
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return unless defined $engineID;
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return unless defined $digest;
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my $word_packed = pack_if_HEX_notation ($word);
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# gen md5 & sha1 hashes
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my $new_hash_md5 = module_generate_hash ($word_packed, $salt, $pkt_num, $engineID, 1);
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my $new_hash_sha1 = module_generate_hash ($word_packed, $salt, $pkt_num, $engineID, 2);
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# parse digests
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my (undef, undef, undef, undef, undef, undef, $digest_md5) = split '\$', $new_hash_md5;
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my (undef, undef, undef, undef, undef, undef, $digest_sha1) = split '\$', $new_hash_sha1;
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if ($digest eq $digest_md5)
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{
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return ($new_hash_md5, $word);
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}
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else
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{
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return ($new_hash_sha1, $word);
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}
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}
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1;
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