NAME

       OCSP_resp_find_status, OCSP_resp_count, OCSP_resp_get0, OCSP_resp_find,
       OCSP_single_get0_status, OCSP_resp_get0_produced_at, OCSP_resp_get0_signature,
       OCSP_resp_get0_tbs_sigalg, OCSP_resp_get0_respdata, OCSP_resp_get0_certs,
       OCSP_resp_get0_signer, OCSP_resp_get0_id, OCSP_resp_get1_id, 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 via the 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() is the same as OCSP_resp_get0_id() but leaves ownership of *pid and
       *pname with the caller, who is responsible for freeing them unless the function returns 0.

       OCSP_check_validity() checks the validity of its thisupd and nextupd arguments, which will
       be typically obtained from OCSP_resp_find_status() or OCSP_single_get0_status(). If sec is
       nonzero 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 then searches the certificates the responder may
       have included in bs unless flags contains OCSP_NOINTERN.  It fails if the signer
       certificate cannot be found.  Next, unless flags contains OCSP_NOSIGS, the function checks
       the signature of bs and fails on error. Then the function already returns success if flags
       contains OCSP_NOVERIFY or if the signer certificate was found in certs and flags contains
       OCSP_TRUSTOTHER.  Otherwise the function continues by validating the signer certificate.
       If flags contains OCSP_PARTIAL_CHAIN it takes intermediate CA certificates in st as trust
       anchors.  For more details, see the description of X509_V_FLAG_PARTIAL_CHAIN in
       "VERIFICATION FLAGS" in X509_VERIFY_PARAM_set_flags(3).  If flags contains OCSP_NOCHAIN it
       ignores all certificates in certs and in bs, else it takes them as untrusted intermediate
       CA certificates and uses them for constructing the validation path for the signer
       certificate.  Certicate revocation status checks using CRLs is disabled during path
       validation if the signer certificate contains the id-pkix-ocsp-no-check extension.  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 OCSP_NOEXPLICIT flag is not set 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 or -1 on error.

       OCSP_resp_get0() returns a pointer to an OCSP_SINGLERESP structure or NULL on error, such
       as idx being out of range.

       OCSP_resp_find() returns the index of id in bs (which may be 0) or -1 on error, such as
       when id was not found.

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

       OCSP_resp_get0_produced_at() returns the producedAt field from bs.

       OCSP_resp_get0_signature() returns the signature from bs.

       OCSP_resp_get0_tbs_sigalg() returns the signatureAlgorithm field from bs.

       OCSP_resp_get0_respdata() returns the tbsResponseData field from bs.

       OCSP_resp_get0_certs() returns any certificates included in bs.

       OCSP_resp_get0_signer() returns 1 if the signing certificate was located, or 0 if not
       found or on error.

       OCSP_resp_get0_id() and OCSP_resp_get1_id() return 1 on success, 0 on failure.

       OCSP_check_validity() returns 1 if thisupd and nextupd are valid time values and the
       current time + sec is not before thisupd and, if maxsec >= 0, the current time - maxsec is
       not past nextupd.  Otherwise it returns 0 to indicate an error.

       OCSP_basic_verify() returns 1 on success, 0 on verification not successful, or -1 on a
       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 nonzero 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), X509_VERIFY_PARAM_set_flags(3)

COPYRIGHT

       Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (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>.