85 lines
3.0 KiB
Plaintext
85 lines
3.0 KiB
Plaintext
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=pod
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=head1 NAME
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OCSP_request_add1_nonce, OCSP_basic_add1_nonce, OCSP_check_nonce, OCSP_copy_nonce - OCSP nonce functions
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=head1 SYNOPSIS
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#include <openssl/ocsp.h>
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int OCSP_request_add1_nonce(OCSP_REQUEST *req, unsigned char *val, int len);
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int OCSP_basic_add1_nonce(OCSP_BASICRESP *resp, unsigned char *val, int len);
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int OCSP_copy_nonce(OCSP_BASICRESP *resp, OCSP_REQUEST *req);
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int OCSP_check_nonce(OCSP_REQUEST *req, OCSP_BASICRESP *resp);
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=head1 DESCRIPTION
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OCSP_request_add1_nonce() adds a nonce of value B<val> and length B<len> to
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OCSP request B<req>. If B<val> is B<NULL> a random nonce is used. If B<len>
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is zero or negative a default length will be used (currently 16 bytes).
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OCSP_basic_add1_nonce() is identical to OCSP_request_add1_nonce() except
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it adds a nonce to OCSP basic response B<resp>.
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OCSP_check_nonce() compares the nonce value in B<req> and B<resp>.
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OCSP_copy_nonce() copies any nonce value present in B<req> to B<resp>.
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=head1 RETURN VALUES
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OCSP_request_add1_nonce() and OCSP_basic_add1_nonce() return 1 for success
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and 0 for failure.
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OCSP_copy_nonce() returns 1 if a nonce was successfully copied, 2 if no nonce
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was present in B<req> and 0 if an error occurred.
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OCSP_check_nonce() returns the result of the nonce comparison between B<req>
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and B<resp>. The return value indicates the result of the comparison. If
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nonces are present and equal 1 is returned. If the nonces are absent 2 is
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returned. If a nonce is present in the response only 3 is returned. If nonces
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are present and unequal 0 is returned. If the nonce is present in the request
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only then -1 is returned.
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=head1 NOTES
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For most purposes the nonce value in a request is set to a random value so
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the B<val> parameter in OCSP_request_add1_nonce() is usually NULL.
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An OCSP nonce is typically added to an OCSP request to thwart replay attacks
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by checking the same nonce value appears in the response.
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Some responders may include a nonce in all responses even if one is not
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supplied.
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Some responders cache OCSP responses and do not sign each response for
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performance reasons. As a result they do not support nonces.
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The return values of OCSP_check_nonce() can be checked to cover each case. A
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positive return value effectively indicates success: nonces are both present
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and match, both absent or present in the response only. A nonzero return
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additionally covers the case where the nonce is present in the request only:
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this will happen if the responder doesn't support nonces. A zero return value
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indicates present and mismatched nonces: this should be treated as an error
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condition.
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=head1 SEE ALSO
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L<crypto(7)>,
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L<OCSP_cert_to_id(3)>,
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L<OCSP_REQUEST_new(3)>,
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L<OCSP_resp_find_status(3)>,
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L<OCSP_response_status(3)>,
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L<OCSP_sendreq_new(3)>
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=head1 COPYRIGHT
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Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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