| =pod |
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| =for comment |
| Original text by James Westby, contributed under the OpenSSL license. |
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| =head1 NAME |
| |
| openssl-c_rehash, openssl-rehash, |
| c_rehash, rehash - Create symbolic links to files named by the hash values |
| |
| =head1 SYNOPSIS |
| |
| B<openssl> |
| B<rehash> |
| B<[-h]> |
| B<[-help]> |
| B<[-old]> |
| B<[-n]> |
| B<[-v]> |
| [ I<directory>...] |
| |
| B<c_rehash> |
| I<flags...> |
| |
| =head1 DESCRIPTION |
| |
| On some platforms, the OpenSSL B<rehash> command is available as |
| an external script called B<c_rehash>. They are functionally equivalent, |
| except for minor differences noted below. |
| |
| B<rehash> scans directories and calculates a hash value of each |
| C<.pem>, C<.crt>, C<.cer>, or C<.crl> |
| file in the specified directory list and creates symbolic links |
| for each file, where the name of the link is the hash value. |
| (If the platform does not support symbolic links, a copy is made.) |
| This utility is useful as many programs that use OpenSSL require |
| directories to be set up like this in order to find certificates. |
| |
| If any directories are named on the command line, then those are |
| processed in turn. If not, then the B<SSL_CERT_DIR> environment variable |
| is consulted; this should be a colon-separated list of directories, |
| like the Unix B<PATH> variable. |
| If that is not set then the default directory (installation-specific |
| but often B</usr/local/ssl/certs>) is processed. |
| |
| In order for a directory to be processed, the user must have write |
| permissions on that directory, otherwise an error will be generated. |
| |
| The links created are of the form C<HHHHHHHH.D>, where each B<H> |
| is a hexadecimal character and B<D> is a single decimal digit. |
| When processing a directory, B<rehash> will first remove all links |
| that have a name in that syntax, even if they are being used for some |
| other purpose. |
| To skip the removal step, use the B<-n> flag. |
| Hashes for CRL's look similar except the letter B<r> appears after |
| the period, like this: C<HHHHHHHH.rD>. |
| |
| Multiple objects may have the same hash; they will be indicated by |
| incrementing the B<D> value. Duplicates are found by comparing the |
| full SHA-1 fingerprint. A warning will be displayed if a duplicate |
| is found. |
| |
| A warning will also be displayed if there are files that |
| cannot be parsed as either a certificate or a CRL or if |
| more than one such object appears in the file. |
| |
| =head2 Script Configuration |
| |
| The B<c_rehash> script |
| uses the B<openssl> program to compute the hashes and |
| fingerprints. If not found in the user's B<PATH>, then set the |
| B<OPENSSL> environment variable to the full pathname. |
| Any program can be used, it will be invoked as follows for either |
| a certificate or CRL: |
| |
| $OPENSSL x509 -hash -fingerprint -noout -in FILENAME |
| $OPENSSL crl -hash -fingerprint -noout -in FILENAME |
| |
| where B<FILENAME> is the filename. It must output the hash of the |
| file on the first line, and the fingerprint on the second, |
| optionally prefixed with some text and an equals sign. |
| |
| =head1 OPTIONS |
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| =over 4 |
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| =item B<-help> B<-h> |
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| Display a brief usage message. |
| |
| =item B<-old> |
| |
| Use old-style hashing (MD5, as opposed to SHA-1) for generating |
| links to be used for releases before 1.0.0. |
| Note that current versions will not use the old style. |
| |
| =item B<-n> |
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| Do not remove existing links. |
| This is needed when keeping new and old-style links in the same directory. |
| |
| =item B<-compat> |
| |
| Generate links for both old-style (MD5) and new-style (SHA1) hashing. |
| This allows releases before 1.0.0 to use these links along-side newer |
| releases. |
| |
| =item B<-v> |
| |
| Print messages about old links removed and new links created. |
| By default, B<rehash> only lists each directory as it is processed. |
| |
| =back |
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| =head1 ENVIRONMENT |
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| =over 4 |
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| =item B<OPENSSL> |
| |
| The path to an executable to use to generate hashes and |
| fingerprints (see above). |
| |
| =item B<SSL_CERT_DIR> |
| |
| Colon separated list of directories to operate on. |
| Ignored if directories are listed on the command line. |
| |
| =back |
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| =head1 SEE ALSO |
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| L<openssl(1)>, |
| L<crl(1)>. |
| L<x509(1)>. |
| |
| =head1 COPYRIGHT |
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| Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. |
| |
| Licensed under the OpenSSL license (the "License"). You may not use |
| this file except in compliance with the License. You can obtain a copy |
| in the file LICENSE in the source distribution or at |
| L<https://www.openssl.org/source/license.html>. |
| |
| =cut |