130 lines
3.8 KiB
Plaintext
130 lines
3.8 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
asn1parse - ASN.1 parsing tool
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
B<openssl> B<asn1parse>
|
|
[B<-inform PEM|DER>]
|
|
[B<-in filename>]
|
|
[B<-out filename>]
|
|
[B<-noout>]
|
|
[B<-offset number>]
|
|
[B<-length number>]
|
|
[B<-i>]
|
|
[B<-oid filename>]
|
|
[B<-strparse offset>]
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
The B<asn1parse> command is a diagnostic utility that can parse ASN.1
|
|
structures. It can also be used to extract data from ASN.1 formatted data.
|
|
|
|
=head1 OPTIONS
|
|
|
|
=over 4
|
|
|
|
=item B<-inform> B<DER|PEM>
|
|
|
|
the input format. B<DER> is binary format and B<PEM> (the default) is base64
|
|
encoded.
|
|
|
|
=item B<-in filename>
|
|
|
|
the input file, default is standard input
|
|
|
|
=item B<-out filename>
|
|
|
|
output file to place the DER encoded data into. If this
|
|
option is not present then no data will be output. This is most useful when
|
|
combined with the B<-strparse> option.
|
|
|
|
=item B<-noout>
|
|
|
|
don't output the parsed version of the input file.
|
|
|
|
=item B<-offset number>
|
|
|
|
starting offset to begin parsing, default is start of file.
|
|
|
|
=item B<-length number>
|
|
|
|
number of bytes to parse, default is until end of file.
|
|
|
|
=item B<-i>
|
|
|
|
indents the output according to the "depth" of the structures.
|
|
|
|
=item B<-oid filename>
|
|
|
|
a file containing additional OBJECT IDENTIFIERs (OIDs). The format of this
|
|
file is described in the NOTES section below.
|
|
|
|
=item B<-strparse offset>
|
|
|
|
parse the contents octets of the ASN.1 object starting at B<offset>. This
|
|
option can be used multiple times to "drill down" into a nested structure.
|
|
|
|
|
|
=back
|
|
|
|
=head2 OUTPUT
|
|
|
|
The output will typically contain lines like this:
|
|
|
|
0:d=0 hl=4 l= 681 cons: SEQUENCE
|
|
|
|
.....
|
|
|
|
229:d=3 hl=3 l= 141 prim: BIT STRING
|
|
373:d=2 hl=3 l= 162 cons: cont [ 3 ]
|
|
376:d=3 hl=3 l= 159 cons: SEQUENCE
|
|
379:d=4 hl=2 l= 29 cons: SEQUENCE
|
|
381:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Subject Key Identifier
|
|
386:d=5 hl=2 l= 22 prim: OCTET STRING
|
|
410:d=4 hl=2 l= 112 cons: SEQUENCE
|
|
412:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Authority Key Identifier
|
|
417:d=5 hl=2 l= 105 prim: OCTET STRING
|
|
524:d=4 hl=2 l= 12 cons: SEQUENCE
|
|
|
|
.....
|
|
|
|
This example is part of a self signed certificate. Each line starts with the
|
|
offset in decimal. B<d=XX> specifies the current depth. The depth is increased
|
|
within the scope of any SET or SEQUENCE. B<hl=XX> gives the header length
|
|
(tag and length octets) of the current type. B<l=XX> gives the length of
|
|
the contents octets.
|
|
|
|
The B<-i> option can be used to make the output more readable.
|
|
|
|
Some knowledge of the ASN.1 structure is needed to interpret the output.
|
|
|
|
In this example the BIT STRING at offset 229 is the certificate public key.
|
|
The contents octets of this will contain the public key information. This can
|
|
be examined using the option B<-strparse 229> to yield:
|
|
|
|
0:d=0 hl=3 l= 137 cons: SEQUENCE
|
|
3:d=1 hl=3 l= 129 prim: INTEGER :E5D21E1F5C8D208EA7A2166C7FAF9F6BDF2059669C60876DDB70840F1A5AAFA59699FE471F379F1DD6A487E7D5409AB6A88D4A9746E24B91D8CF55DB3521015460C8EDE44EE8A4189F7A7BE77D6CD3A9AF2696F486855CF58BF0EDF2B4068058C7A947F52548DDF7E15E96B385F86422BEA9064A3EE9E1158A56E4A6F47E5897
|
|
135:d=1 hl=2 l= 3 prim: INTEGER :010001
|
|
|
|
=head1 NOTES
|
|
|
|
If an OID is not part of OpenSSL's internal table it will be represented in
|
|
numerical form (for example 1.2.3.4). The file passed to the B<-oid> option
|
|
allows additional OIDs to be included. Each line consists of three columns,
|
|
the first column is the OID in numerical format and should be followed by white
|
|
space. The second column is the "short name" which is a single word followed
|
|
by white space. The final column is the rest of the line and is the
|
|
"long name". B<asn1parse> displays the long name. Example:
|
|
|
|
C<1.2.3.4 shortName A long name>
|
|
|
|
=head1 BUGS
|
|
|
|
There should be options to change the format of input lines. The output of some
|
|
ASN.1 types is not well handled (if at all).
|
|
|
|
=cut
|