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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | EXIT STATUS | SEE ALSO | AUTHORS | COPYRIGHT | BUGS | COLOPHON |
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ocsptool(1) User Commands ocsptool(1)
ocsptool - GnuTLS OCSP tool
ocsptool [-flags] [-flag [value]] [--option-name[[=| ]value]]
All arguments must be options.
On verification
Responses are typically signed/issued by designated certificates
or certificate authorities and thus this tool requires on
verification the certificate of the issuer or the full
certificate chain in order to determine the appropriate signing
authority. The specified certificate of the issuer is assumed
trusted.
-d num, --debug=num
Enable debugging. This option takes an integer number as
its argument. The value of num is constrained to being:
in the range 0 through 9999
Specifies the debug level.
-V, --verbose
More verbose output.
--infile=file
Input file.
--outfile=str
Output file.
--ask=server name|url
Ask an OCSP/HTTP server on a certificate validity.
Connects to the specified HTTP OCSP server and queries on
the validity of the loaded certificate. Its argument can
be a URL or a plain server name. It can be combined with
--load-chain, where it checks all certificates in the
provided chain, or with --load-cert and --load-issuer
options. The latter checks the provided certificate
against its specified issuer certificate.
-e, --verify-response
Verify response.
Verifies the provided OCSP response against the system
trust anchors (unless --load-trust is provided). It
requires the --load-signer or --load-chain options to
obtain the signer of the OCSP response.
-i, --request-info
Print information on a OCSP request.
Display detailed information on the provided OCSP request.
-j, --response-info
Print information on a OCSP response.
Display detailed information on the provided OCSP
response.
-q, --generate-request
Generates an OCSP request.
--nonce, --no-nonce
Use (or not) a nonce to OCSP request. The no-nonce form
will disable the option.
--load-chain=file
Reads a set of certificates forming a chain from file.
--load-issuer=file
Reads issuer's certificate from file.
--load-cert=file
Reads the certificate to check from file.
--load-trust=file
Read OCSP trust anchors from file. This option must not
appear in combination with any of the following options:
load-signer.
When verifying an OCSP response read the trust anchors
from the provided file. When this is not provided, the
system's trust anchors will be used.
--load-signer=file
Reads the OCSP response signer from file. This option
must not appear in combination with any of the following
options: load-trust.
--inder, --no-inder
Use DER format for input certificates and private keys.
The no-inder form will disable the option.
--outder
Use DER format for output of responses (this is the
default).
The output will be in DER encoded format. Unlike other
GnuTLS tools, this is the default for this tool
--outpem
Use PEM format for output of responses.
The output will be in PEM format.
-Q file, --load-request=file
Reads the DER encoded OCSP request from file.
-S file, --load-response=file
Reads the DER encoded OCSP response from file.
--ignore-errors
Ignore any verification errors.
--verify-allow-broken
Allow broken algorithms, such as MD5 for verification.
This can be combined with --verify-response.
-v arg, --version=arg
Output version of program and exit. The default mode is
`v', a simple version. The `c' mode will print copyright
information and `n' will print the full copyright notice.
-h, --help
Display usage information and exit.
-!, --more-help
Pass the extended usage information through a pager.
Print information about an OCSP request
To parse an OCSP request and print information about the content,
the -i or --request-info parameter may be used as follows. The
-Q parameter specify the name of the file containing the OCSP
request, and it should contain the OCSP request in binary DER
format.
$ ocsptool -i -Q ocsp-request.der
The input file may also be sent to standard input like this:
$ cat ocsp-request.der | ocsptool --request-info
Print information about an OCSP response
Similar to parsing OCSP requests, OCSP responses can be parsed
using the -j or --response-info as follows.
$ ocsptool -j -Q ocsp-response.der
$ cat ocsp-response.der | ocsptool --response-info
Generate an OCSP request
The -q or --generate-request parameters are used to generate an
OCSP request. By default the OCSP request is written to standard
output in binary DER format, but can be stored in a file using
--outfile. To generate an OCSP request the issuer of the
certificate to check needs to be specified with --load-issuer and
the certificate to check with --load-cert. By default PEM format
is used for these files, although --inder can be used to specify
that the input files are in DER format.
$ ocsptool -q --load-issuer issuer.pem --load-cert client.pem --outfile ocsp-request.der
When generating OCSP requests, the tool will add an OCSP
extension containing a nonce. This behaviour can be disabled by
specifying --no-nonce.
Verify signature in OCSP response
To verify the signature in an OCSP response the -e or
--verify-response parameter is used. The tool will read an OCSP
response in DER format from standard input, or from the file
specified by --load-response. The OCSP response is verified
against a set of trust anchors, which are specified using
--load-trust. The trust anchors are concatenated certificates in
PEM format. The certificate that signed the OCSP response needs
to be in the set of trust anchors, or the issuer of the signer
certificate needs to be in the set of trust anchors and the OCSP
Extended Key Usage bit has to be asserted in the signer
certificate.
$ ocsptool -e --load-trust issuer.pem --load-response ocsp-response.der
The tool will print status of verification.
Verify signature in OCSP response against given certificate
It is possible to override the normal trust logic if you know
that a certain certificate is supposed to have signed the OCSP
response, and you want to use it to check the signature. This is
achieved using --load-signer instead of --load-trust. This will
load one certificate and it will be used to verify the signature
in the OCSP response. It will not check the Extended Key Usage
bit.
$ ocsptool -e --load-signer ocsp-signer.pem --load-response ocsp-response.der
This approach is normally only relevant in two situations. The
first is when the OCSP response does not contain a copy of the
signer certificate, so the --load-trust code would fail. The
second is if you want to avoid the indirect mode where the OCSP
response signer certificate is signed by a trust anchor.
Real-world example
Here is an example of how to generate an OCSP request for a
certificate and to verify the response. For illustration we'll
use the blog.josefsson.org host, which (as of writing) uses a
certificate from CACert. First we'll use gnutls-cli to get a
copy of the server certificate chain. The server is not required
to send this information, but this particular one is configured
to do so.
$ echo | gnutls-cli -p 443 blog.josefsson.org --save-cert chain.pem
The saved certificates normally contain a pointer to where the
OCSP responder is located, in the Authority Information Access
Information extension. For example, from certtool -i < chain.pem
there is this information:
Authority Information Access Information (not critical):
Access Method: 1.3.6.1.5.5.7.48.1 (id-ad-ocsp)
Access Location URI: https://ocsp.CAcert.org/
This means that ocsptool can discover the servers to contact over
HTTP. We can now request information on the chain certificates.
$ ocsptool --ask --load-chain chain.pem
The request is sent via HTTP to the OCSP server address found in
the certificates. It is possible to override the address of the
OCSP server as well as ask information on a particular
certificate using --load-cert and --load-issuer.
$ ocsptool --ask https://ocsp.CAcert.org/ --load-chain chain.pem
One of the following exit values will be returned:
0 (EXIT_SUCCESS)
Successful program execution.
1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.
certtool(1)
Copyright (C) 2020-2021 Free Software Foundation, and others all
rights reserved. This program is released under the terms of the
GNU General Public License, version 3 or later
Please send bug reports to: bugs@gnutls.org
This page is part of the GnuTLS (GnuTLS Transport Layer Security
Library) project. Information about the project can be found at
⟨http://www.gnutls.org/⟩. If you have a bug report for this
manual page, send it to bugs@gnutls.org. This page was obtained
from the tarball gnutls-3.7.8.tar.xz fetched from
⟨http://www.gnutls.org/download.html⟩ on 2022-12-17. If you
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or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
3.7.8 27 Sep 2022 ocsptool(1)
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