/*-
 * Copyright (c) 2018, Juniper Networks, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#define NEED_BRSSL_H
#include <libsecureboot.h>
#include <brssl.h>

#include "decode.h"

/**
 * @brief decode ascii armor
 *
 * once we get rid of the trailing checksum
 * we can treat as PEM.
 *
 * @sa rfc4880:6.2
 */
unsigned char *
dearmor(char *pem, size_t nbytes, size_t *len)
{
#ifdef USE_BEARSSL
        pem_object *po;
        size_t npo;
#else
        BIO *bp;
        char *name = NULL;
        char *header = NULL;
#endif
        unsigned char *data = NULL;
        char *cp;
        char *ep;

        /* we need to remove the Armor tail */
        if ((cp = strstr((char *)pem, "\n=")) &&
            (ep = strstr(cp, "\n---"))) {
                memmove(cp, ep, nbytes - (size_t)(ep - pem));
                nbytes -= (size_t)(ep - cp);
                pem[nbytes] = '\0';
        }
#ifdef USE_BEARSSL
        /* we also need to remove any headers */
        if ((cp = strstr((char *)pem, "---\n")) &&
            (ep = strstr(cp, "\n\n"))) {
                cp += 4;
                ep += 2;
                memmove(cp, ep, nbytes - (size_t)(ep - pem));
                nbytes -= (size_t)(ep - cp);
                pem[nbytes] = '\0';
        }
        if ((po = decode_pem(pem, nbytes, &npo))) {
                data = po->data;
                *len = po->data_len;
        }
#else
        if ((bp = BIO_new_mem_buf(pem, (int)nbytes))) {
                long llen = (long)nbytes;

                if (!PEM_read_bio(bp, &name, &header, &data, &llen))
                        data = NULL;
                BIO_free(bp);
                *len = (size_t)llen;
        }
#endif
        return (data);
}

#ifdef MAIN_DEARMOR
#include <unistd.h>
#include <fcntl.h>
#include <err.h>

/*
 * Mostly a unit test.
 */
int
main(int argc, char *argv[])
{
        const char *infile, *outfile;
        unsigned char *data;
        size_t n, x;
        int fd;
        int o;

        infile = outfile = NULL;
        while ((o = getopt(argc, argv, "i:o:")) != -1) {
                switch (o) {
                case 'i':
                        infile = optarg;
                        break;
                case 'o':
                        outfile = optarg;
                        break;
                default:
                        errx(1, "unknown option: -%c", o);
                }
        }
        if (!infile)
                errx(1, "need -i infile");
        if (outfile) {
                if ((fd = open(outfile, O_WRONLY|O_CREAT|O_TRUNC)) < 0)
                        err(1, "cannot open %s", outfile);
        } else {
                fd = 1;                 /* stdout */
        }
        data = read_file(infile, &n);
        if (!(data[0] & OPENPGP_TAG_ISTAG))
                data = dearmor(data, n, &n);
        for (x = 0; x < n; ) {
                o = write(fd, &data[x], (n - x));
                if (o < 0)
                        err(1, "cannot write");
                x += o;
        }
        if (fd != 1)
                close(fd);
        free(data);
        return (0);
}
#endif