NAME¶
c_rehash - Create symbolic links to files named by the hash values
SYNOPSIS¶
c_rehash [-old] [-h] [-n] [-v] [
directory...]
DESCRIPTION¶
c_rehash scans directories and calculates a hash value of each
".pem", ".crt", ".cer", or ".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
SSL_CERT_DIR environment variable is consulted;
this shold be a colon-separated list of directories, like the Unix
PATH
variable. If that is not set then the default directory (installation-specific
but often
/usr/local/ssl/certs) is processed.
In order for a directory to be processed, the user must have write permissions
on that directory, otherwise it will be skipped. The links created are of the
form "HHHHHHHH.D", where each
H is a hexadecimal character
and
D is a single decimal digit. When processing a directory,
c_rehash will first remove all links that have a name in that syntax.
If you have links in that format used for other purposes, they will be
removed. To skip the removal step, use the
-n flag. Hashes for CRL's
look similar except the letter
r appears after the period, like this:
"HHHHHHHH.rD".
Multiple objects may have the same hash; they will be indicated by incrementing
the
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.
The program uses the
openssl program to compute the hashes and
fingerprints. If not found in the user's
PATH, then set the
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
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.
OPTIONS¶
- -old
- Use old-style hashing (MD5, as opposed to SHA-1) for generating links for
releases before 1.0.0. Note that current versions will not use the old
style.
- -h
- Display a brief usage message.
- -n
- Do not remove existing links. This is needed when keeping new and
old-style links in the same directory.
- -v
- Print messages about old links removed and new links created. By default,
c_rehash only lists each directory as it is processed.
ENVIRONMENT¶
- OPENSSL
- The path to an executable to use to generate hashes and fingerprints (see
above).
- SSL_CERT_DIR
- Colon separated list of directories to operate on. Ignored if directories
are listed on the command line.
SEE ALSO¶
openssl(1),
crl(1).
x509(1).