/*      $Id: chngproc.c,v 1.17 2022/05/05 19:51:35 florian Exp $ */
/*
 * Copyright (c) 2016 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

int
chngproc(int netsock, const char *root)
{
        char             *tok = NULL, *th = NULL, *fmt = NULL, **fs = NULL;
        size_t            i, fsz = 0;
        int               rc = 0, fd = -1, cc;
        long              lval;
        enum chngop       op;
        void             *pp;


        if (unveil(root, "wc") == -1) {
                warn("unveil %s", root);
                goto out;
        }

        if (pledge("stdio cpath wpath", NULL) == -1) {
                warn("pledge");
                goto out;
        }

        /*
         * Loop while we wait to get a thumbprint and token.
         * We'll get this for each SAN request.
         */

        for (;;) {
                op = CHNG__MAX;
                if ((lval = readop(netsock, COMM_CHNG_OP)) == 0)
                        op = CHNG_STOP;
                else if (lval == CHNG_SYN)
                        op = lval;

                if (op == CHNG__MAX) {
                        warnx("unknown operation from netproc");
                        goto out;
                } else if (op == CHNG_STOP)
                        break;

                assert(op == CHNG_SYN);

                /*
                 * Read the thumbprint and token.
                 * The token is the filename, so store that in a vector
                 * of tokens that we'll later clean up.
                 */

                if ((th = readstr(netsock, COMM_THUMB)) == NULL)
                        goto out;
                else if ((tok = readstr(netsock, COMM_TOK)) == NULL)
                        goto out;
                else if (strlen(tok) < 1) {
                        warnx("token is too short");
                        goto out;
                }

                for (i = 0; tok[i]; ++i) {
                        int ch = (unsigned char)tok[i];
                        if (!isalnum(ch) && ch != '-' && ch != '_') {
                                warnx("token is not a valid base64url");
                                goto out;
                        }
                }

                if (asprintf(&fmt, "%s.%s", tok, th) == -1) {
                        warn("asprintf");
                        goto out;
                }

                /* Vector appending... */

                pp = reallocarray(fs, (fsz + 1), sizeof(char *));
                if (pp == NULL) {
                        warn("realloc");
                        goto out;
                }
                fs = pp;
                if (asprintf(&fs[fsz], "%s/%s", root, tok) == -1) {
                        warn("asprintf");
                        goto out;
                }
                fsz++;
                free(tok);
                tok = NULL;

                /*
                 * Create and write to our challenge file.
                 * Note: we use file descriptors instead of FILE
                 * because we want to minimise our pledges.
                 */
                fd = open(fs[fsz - 1], O_WRONLY|O_CREAT|O_TRUNC, 0444);
                if (fd == -1) {
                        warn("%s", fs[fsz - 1]);
                        goto out;
                }
                if (write(fd, fmt, strlen(fmt)) == -1) {
                        warn("%s", fs[fsz - 1]);
                        goto out;
                }
                if (close(fd) == -1) {
                        warn("%s", fs[fsz - 1]);
                        goto out;
                }
                fd = -1;

                free(th);
                free(fmt);
                th = fmt = NULL;

                dodbg("%s: created", fs[fsz - 1]);

                /*
                 * Write our acknowledgement.
                 * Ignore reader failure.
                 */

                cc = writeop(netsock, COMM_CHNG_ACK, CHNG_ACK);
                if (cc == 0)
                        break;
                if (cc < 0)
                        goto out;
        }

        rc = 1;
out:
        close(netsock);
        if (fd != -1)
                close(fd);
        for (i = 0; i < fsz; i++) {
                if (unlink(fs[i]) == -1 && errno != ENOENT)
                        warn("%s", fs[i]);
                free(fs[i]);
        }
        free(fs);
        free(fmt);
        free(th);
        free(tok);
        return rc;
}