openssl-asn1parse.pod.in 6.1 KB

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  1. =pod
  2. {- OpenSSL::safe::output_do_not_edit_headers(); -}
  3. =head1 NAME
  4. openssl-asn1parse - ASN.1 parsing command
  5. =head1 SYNOPSIS
  6. B<openssl> B<asn1parse>
  7. [B<-help>]
  8. [B<-inform> B<DER>|B<PEM>|B<B64>]
  9. [B<-in> I<filename>]
  10. [B<-out> I<filename>]
  11. [B<-noout>]
  12. [B<-offset> I<number>]
  13. [B<-length> I<number>]
  14. [B<-i>]
  15. [B<-oid> I<filename>]
  16. [B<-dump>]
  17. [B<-dlimit> I<num>]
  18. [B<-strparse> I<offset>]
  19. [B<-genstr> I<string>]
  20. [B<-genconf> I<file>]
  21. [B<-strictpem>]
  22. [B<-item> I<name>]
  23. =head1 DESCRIPTION
  24. This command is a diagnostic utility that can parse ASN.1 structures.
  25. It can also be used to extract data from ASN.1 formatted data.
  26. =head1 OPTIONS
  27. =over 4
  28. =item B<-help>
  29. Print out a usage message.
  30. =item B<-inform> B<DER>|B<PEM>|B<B64>
  31. The input format; the default is B<PEM>.
  32. See L<openssl-format-options(1)> for details.
  33. =item B<-in> I<filename>
  34. The input file, default is standard input.
  35. =item B<-out> I<filename>
  36. Output file to place the DER encoded data into. If this
  37. option is not present then no data will be output. This is most useful when
  38. combined with the B<-strparse> option.
  39. =item B<-noout>
  40. Don't output the parsed version of the input file.
  41. =item B<-offset> I<number>
  42. Starting offset to begin parsing, default is start of file.
  43. =item B<-length> I<number>
  44. Number of bytes to parse, default is until end of file.
  45. =item B<-i>
  46. Indents the output according to the "depth" of the structures.
  47. =item B<-oid> I<filename>
  48. A file containing additional OBJECT IDENTIFIERs (OIDs). The format of this
  49. file is described in the NOTES section below.
  50. =item B<-dump>
  51. Dump unknown data in hex format.
  52. =item B<-dlimit> I<num>
  53. Like B<-dump>, but only the first B<num> bytes are output.
  54. =item B<-strparse> I<offset>
  55. Parse the contents octets of the ASN.1 object starting at B<offset>. This
  56. option can be used multiple times to "drill down" into a nested structure.
  57. =item B<-genstr> I<string>, B<-genconf> I<file>
  58. Generate encoded data based on I<string>, I<file> or both using
  59. L<ASN1_generate_nconf(3)> format. If I<file> only is
  60. present then the string is obtained from the default section using the name
  61. B<asn1>. The encoded data is passed through the ASN1 parser and printed out as
  62. though it came from a file, the contents can thus be examined and written to a
  63. file using the B<-out> option.
  64. =item B<-strictpem>
  65. If this option is used then B<-inform> will be ignored. Without this option any
  66. data in a PEM format input file will be treated as being base64 encoded and
  67. processed whether it has the normal PEM BEGIN and END markers or not. This
  68. option will ignore any data prior to the start of the BEGIN marker, or after an
  69. END marker in a PEM file.
  70. =item B<-item> I<name>
  71. Attempt to decode and print the data as an B<ASN1_ITEM> I<name>. This can be
  72. used to print out the fields of any supported ASN.1 structure if the type is
  73. known.
  74. =back
  75. =head2 Output
  76. The output will typically contain lines like this:
  77. 0:d=0 hl=4 l= 681 cons: SEQUENCE
  78. .....
  79. 229:d=3 hl=3 l= 141 prim: BIT STRING
  80. 373:d=2 hl=3 l= 162 cons: cont [ 3 ]
  81. 376:d=3 hl=3 l= 159 cons: SEQUENCE
  82. 379:d=4 hl=2 l= 29 cons: SEQUENCE
  83. 381:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Subject Key Identifier
  84. 386:d=5 hl=2 l= 22 prim: OCTET STRING
  85. 410:d=4 hl=2 l= 112 cons: SEQUENCE
  86. 412:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Authority Key Identifier
  87. 417:d=5 hl=2 l= 105 prim: OCTET STRING
  88. 524:d=4 hl=2 l= 12 cons: SEQUENCE
  89. .....
  90. This example is part of a self-signed certificate. Each line starts with the
  91. offset in decimal. C<d=XX> specifies the current depth. The depth is increased
  92. within the scope of any SET or SEQUENCE. C<hl=XX> gives the header length
  93. (tag and length octets) of the current type. C<l=XX> gives the length of
  94. the contents octets.
  95. The B<-i> option can be used to make the output more readable.
  96. Some knowledge of the ASN.1 structure is needed to interpret the output.
  97. In this example the BIT STRING at offset 229 is the certificate public key.
  98. The contents octets of this will contain the public key information. This can
  99. be examined using the option C<-strparse 229> to yield:
  100. 0:d=0 hl=3 l= 137 cons: SEQUENCE
  101. 3:d=1 hl=3 l= 129 prim: INTEGER :E5D21E1F5C8D208EA7A2166C7FAF9F6BDF2059669C60876DDB70840F1A5AAFA59699FE471F379F1DD6A487E7D5409AB6A88D4A9746E24B91D8CF55DB3521015460C8EDE44EE8A4189F7A7BE77D6CD3A9AF2696F486855CF58BF0EDF2B4068058C7A947F52548DDF7E15E96B385F86422BEA9064A3EE9E1158A56E4A6F47E5897
  102. 135:d=1 hl=2 l= 3 prim: INTEGER :010001
  103. =head1 NOTES
  104. If an OID is not part of OpenSSL's internal table it will be represented in
  105. numerical form (for example 1.2.3.4). The file passed to the B<-oid> option
  106. allows additional OIDs to be included. Each line consists of three columns,
  107. the first column is the OID in numerical format and should be followed by white
  108. space. The second column is the "short name" which is a single word followed
  109. by whitespace. The final column is the rest of the line and is the
  110. "long name". Example:
  111. C<1.2.3.4 shortName A long name>
  112. For any OID with an associated short and long name, this command will display
  113. the long name.
  114. =head1 EXAMPLES
  115. Parse a file:
  116. openssl asn1parse -in file.pem
  117. Parse a DER file:
  118. openssl asn1parse -inform DER -in file.der
  119. Generate a simple UTF8String:
  120. openssl asn1parse -genstr 'UTF8:Hello World'
  121. Generate and write out a UTF8String, don't print parsed output:
  122. openssl asn1parse -genstr 'UTF8:Hello World' -noout -out utf8.der
  123. Generate using a config file:
  124. openssl asn1parse -genconf asn1.cnf -noout -out asn1.der
  125. Example config file:
  126. asn1=SEQUENCE:seq_sect
  127. [seq_sect]
  128. field1=BOOL:TRUE
  129. field2=EXP:0, UTF8:some random string
  130. =head1 BUGS
  131. There should be options to change the format of output lines. The output of some
  132. ASN.1 types is not well handled (if at all).
  133. =head1 SEE ALSO
  134. L<openssl(1)>,
  135. L<ASN1_generate_nconf(3)>
  136. =head1 COPYRIGHT
  137. Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.
  138. Licensed under the Apache License 2.0 (the "License"). You may not use
  139. this file except in compliance with the License. You can obtain a copy
  140. in the file LICENSE in the source distribution or at
  141. L<https://www.openssl.org/source/license.html>.
  142. =cut