NAME

       OCSP_resp_get0_certs, OCSP_resp_get0_signer, OCSP_resp_get0_id, OCSP_resp_get1_id,
       OCSP_resp_get0_produced_at, OCSP_resp_get0_signature, OCSP_resp_get0_tbs_sigalg,
       OCSP_resp_get0_respdata, OCSP_resp_find_status, OCSP_resp_count, OCSP_resp_get0,
       OCSP_resp_find, OCSP_single_get0_status, OCSP_check_validity, OCSP_basic_verify - OCSP
       response utility functions

SYNOPSIS

        #include <openssl/ocsp.h>

        int OCSP_resp_find_status(OCSP_BASICRESP *bs, OCSP_CERTID *id, int *status,
                                  int *reason,
                                  ASN1_GENERALIZEDTIME **revtime,
                                  ASN1_GENERALIZEDTIME **thisupd,
                                  ASN1_GENERALIZEDTIME **nextupd);

        int OCSP_resp_count(OCSP_BASICRESP *bs);
        OCSP_SINGLERESP *OCSP_resp_get0(OCSP_BASICRESP *bs, int idx);
        int OCSP_resp_find(OCSP_BASICRESP *bs, OCSP_CERTID *id, int last);
        int OCSP_single_get0_status(OCSP_SINGLERESP *single, int *reason,
                                    ASN1_GENERALIZEDTIME **revtime,
                                    ASN1_GENERALIZEDTIME **thisupd,
                                    ASN1_GENERALIZEDTIME **nextupd);

        const ASN1_GENERALIZEDTIME *OCSP_resp_get0_produced_at(
                                    const OCSP_BASICRESP* single);

        const ASN1_OCTET_STRING *OCSP_resp_get0_signature(const OCSP_BASICRESP *bs);
        const X509_ALGOR *OCSP_resp_get0_tbs_sigalg(const OCSP_BASICRESP *bs);
        const OCSP_RESPDATA *OCSP_resp_get0_respdata(const OCSP_BASICRESP *bs);
        const STACK_OF(X509) *OCSP_resp_get0_certs(const OCSP_BASICRESP *bs);

        int OCSP_resp_get0_signer(OCSP_BASICRESP *bs, X509 **signer,
                                  STACK_OF(X509) *extra_certs);

        int OCSP_resp_get0_id(const OCSP_BASICRESP *bs,
                              const ASN1_OCTET_STRING **pid,
                              const X509_NAME **pname);
        int OCSP_resp_get1_id(const OCSP_BASICRESP *bs,
                              ASN1_OCTET_STRING **pid,
                              X509_NAME **pname);

        int OCSP_check_validity(ASN1_GENERALIZEDTIME *thisupd,
                                ASN1_GENERALIZEDTIME *nextupd,
                                long sec, long maxsec);

        int OCSP_basic_verify(OCSP_BASICRESP *bs, STACK_OF(X509) *certs,
                             X509_STORE *st, unsigned long flags);

DESCRIPTION

       OCSP_resp_find_status() searches bs for an OCSP response for id. If it is successful the
       fields of the response are returned in *status, *reason, *revtime, *thisupd and *nextupd.
       The *status value will be one of V_OCSP_CERTSTATUS_GOOD, V_OCSP_CERTSTATUS_REVOKED or
       V_OCSP_CERTSTATUS_UNKNOWN. The *reason and *revtime fields are only set if the status is
       V_OCSP_CERTSTATUS_REVOKED. If set the *reason field will be set to the revocation reason
       which will be one of OCSP_REVOKED_STATUS_NOSTATUS, OCSP_REVOKED_STATUS_UNSPECIFIED,
       OCSP_REVOKED_STATUS_KEYCOMPROMISE, OCSP_REVOKED_STATUS_CACOMPROMISE,
       OCSP_REVOKED_STATUS_AFFILIATIONCHANGED, OCSP_REVOKED_STATUS_SUPERSEDED,
       OCSP_REVOKED_STATUS_CESSATIONOFOPERATION, OCSP_REVOKED_STATUS_CERTIFICATEHOLD or
       OCSP_REVOKED_STATUS_REMOVEFROMCRL.

       OCSP_resp_count() returns the number of OCSP_SINGLERESP structures in bs.

       OCSP_resp_get0() returns the OCSP_SINGLERESP structure in bs corresponding to index idx.
       Where idx runs from 0 to OCSP_resp_count(bs) - 1.

       OCSP_resp_find() searches bs for id and returns the index of the first matching entry
       after last or starting from the beginning if last is -1.

       OCSP_single_get0_status() extracts the fields of single in *reason, *revtime, *thisupd and
       *nextupd.

       OCSP_resp_get0_produced_at() extracts the producedAt field from the single response bs.

       OCSP_resp_get0_signature() returns the signature from bs.

       OCSP_resp_get0_tbs_sigalg() returns the signatureAlgorithm from bs.

       OCSP_resp_get0_respdata() returns the tbsResponseData from bs.

       OCSP_resp_get0_certs() returns any certificates included in bs.

       OCSP_resp_get0_signer() attempts to retrieve the certificate that directly signed bs.  The
       OCSP protocol does not require that this certificate is included in the certs field of the
       response, so additional certificates can be supplied in extra_certs if the certificates
       that may have signed the response are known via some out-of-band mechanism.

       OCSP_resp_get0_id() gets the responder id of bs. If the responder ID is a name then
       <*pname> is set to the name and *pid is set to NULL. If the responder ID is by key ID then
       *pid is set to the key ID and *pname is set to NULL. OCSP_resp_get1_id() leaves ownership
       of *pid and *pname with the caller, who is responsible for freeing them. Both functions
       return 1 in case of success and 0 in case of failure. If OCSP_resp_get1_id() returns 0, no
       freeing of the results is necessary.

       OCSP_check_validity() checks the validity of thisupd and nextupd values which will be
       typically obtained from OCSP_resp_find_status() or OCSP_single_get0_status(). If sec is
       non-zero it indicates how many seconds leeway should be allowed in the check. If maxsec is
       positive it indicates the maximum age of thisupd in seconds.

       OCSP_basic_verify() checks that the basic response message bs is correctly signed and that
       the signer certificate can be validated. It takes st as the trusted store and certs as a
       set of untrusted intermediate certificates.  The function first tries to find the signer
       certificate of the response in <certs>. It also searches the certificates the responder
       may have included in bs unless the flags contain OCSP_NOINTERN.  It fails if the signer
       certificate cannot be found.  Next, the function checks the signature of bs and fails on
       error unless the flags contain OCSP_NOSIGS. Then the function already returns success if
       the flags contain OCSP_NOVERIFY or if the signer certificate was found in certs and the
       flags contain OCSP_TRUSTOTHER.  Otherwise the function continues by validating the signer
       certificate.  To this end, all certificates in cert and in bs are considered as untrusted
       certificates for the construction of the validation path for the signer certificate unless
       the OCSP_NOCHAIN flag is set. After successful path validation the function returns
       success if the OCSP_NOCHECKS flag is set.  Otherwise it verifies that the signer
       certificate meets the OCSP issuer criteria including potential delegation. If this does
       not succeed and the flags do not contain OCSP_NOEXPLICIT the function checks for explicit
       trust for OCSP signing in the root CA certificate.

RETURN VALUES

       OCSP_resp_find_status() returns 1 if id is found in bs and 0 otherwise.

       OCSP_resp_count() returns the total number of OCSP_SINGLERESP fields in bs.

       OCSP_resp_get0() returns a pointer to an OCSP_SINGLERESP structure or NULL if idx is out
       of range.

       OCSP_resp_find() returns the index of id in bs (which may be 0) or -1 if id was not found.

       OCSP_single_get0_status() returns the status of single or -1 if an error occurred.

       OCSP_resp_get0_signer() returns 1 if the signing certificate was located, or 0 on error.

       OCSP_basic_verify() returns 1 on success, 0 on error, or -1 on fatal error such as malloc
       failure.

NOTES

       Applications will typically call OCSP_resp_find_status() using the certificate ID of
       interest and then check its validity using OCSP_check_validity(). They can then take
       appropriate action based on the status of the certificate.

       An OCSP response for a certificate contains thisUpdate and nextUpdate fields. Normally the
       current time should be between these two values. To account for clock skew the maxsec
       field can be set to non-zero in OCSP_check_validity(). Some responders do not set the
       nextUpdate field, this would otherwise mean an ancient response would be considered valid:
       the maxsec parameter to OCSP_check_validity() can be used to limit the permitted age of
       responses.

       The values written to *revtime, *thisupd and *nextupd by OCSP_resp_find_status() and
       OCSP_single_get0_status() are internal pointers which MUST NOT be freed up by the calling
       application. Any or all of these parameters can be set to NULL if their value is not
       required.

SEE ALSO

       crypto(7), OCSP_cert_to_id(3), OCSP_request_add1_nonce(3), OCSP_REQUEST_new(3),
       OCSP_response_status(3), OCSP_sendreq_new(3)

COPYRIGHT

       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 <https://www.openssl.org/source/license.html>.