CURLOPT_ISSUERCERT_BLOB(3)                            curl_easy_setopt options

NAME
       CURLOPT_ISSUERCERT_BLOB - issuer SSL certificate from memory blob

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ISSUERCERT_BLOB, struct
       curl_blob *stblob);

DESCRIPTION
       Pass a pointer to a curl_blob structure, which contains information
       (pointer and size) about a memory block with binary data of a CA
       certificate in PEM format. If the option is set, an additional check
       against the peer certificate is performed to verify the issuer is
       indeed the one associated with the certificate provided by the option.
       This additional check is useful in multi-level PKI where one needs to
       enforce that the peer certificate is from a specific branch of the
       tree.

       This option should be used in combination with the
       _SSL_VERIFYPEER&section=3">CURLOPT_SSL_VERIFYPEER(3) option. Otherwise, the result of the check is
       not considered as failure.

       A specific error code (CURLE_SSL_ISSUER_ERROR) is defined with the
       option, which is returned if the setup of the SSL/TLS session has
       failed due to a mismatch with the issuer of peer certificate
       (CURLOPT_SSL_VERIFYPEER(3) has to be set too for the check to fail).

       If the blob is initialized with the flags member of struct curl_blob
       set to CURL_BLOB_COPY, the application does not have to keep the buffer
       around after setting this.

       This option is an alternative to _ISSUERCERT&section=3">CURLOPT_ISSUERCERT(3) which instead
       expects a file name as input.

DEFAULT
       NULL

PROTOCOLS
       All TLS-based protocols

EXAMPLE
       CURL *curl = curl_easy_init();
       if(curl) {
         struct curl_blob blob;
         curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
         blob.data = certificateData;
         blob.len = filesize;
         blob.flags = CURL_BLOB_COPY;
         curl_easy_setopt(curl, CURLOPT_ISSUERCERT_BLOB, &blob);
         ret = curl_easy_perform(curl);
         curl_easy_cleanup(curl);
       }

AVAILABILITY
       Added in libcurl 7.71.0. This option is supported by the OpenSSL
       backends.

RETURN VALUE
       Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if
       not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.

SEE ALSO
       CURLOPT_ISSUERCERT(3), CURLOPT_CRLFILE(3), CURLOPT_SSL_VERIFYPEER(3),

libcurl 7.77.0                 November 4, 2020     CURLOPT_ISSUERCERT_BLOB(3)