ucert.c

   1 /*
   2  * Copyright (C) 2018 Daniel Golle <daniel@makrotopia.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #define _GNU_SOURCE
  15
  16 #include <fcntl.h>
  17 #include <dlfcn.h>
  18 #include <stdio.h>
  19 #include <stdbool.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <getopt.h>
  23 #include <stdint.h>
  24 #include <unistd.h>
  25 #include <inttypes.h>
  26 #include <sys/stat.h>
  27 #include <sys/wait.h>
  28
  29 #include <json-c/json.h>
  30 #include <libubox/blob.h>
  31 #include <libubox/utils.h>
  32 #include <libubox/list.h>
  33 #include <libubox/vlist.h>
  34 #include <libubox/blobmsg_json.h>
  35
  36 #include "usign.h"
  37
  38 #define CERT_BUF_LEN 4096
  39
  40 static enum {
  41         CMD_APPEND,
  42         CMD_DUMP,
  43         CMD_ISSUE,
  44         CMD_REVOKE,
  45         CMD_VERIFY,
  46         CMD_NONE,
  47 } cmd = CMD_NONE;
  48
  49 static bool quiet;
  50
  51 enum cert_attr {
  52         CERT_ATTR_SIGNATURE,
  53         CERT_ATTR_PAYLOAD,
  54         CERT_ATTR_MAX
  55 };
  56
  57 static const struct blob_attr_info cert_policy[CERT_ATTR_MAX] = {
  58         [CERT_ATTR_SIGNATURE] = { .type = BLOB_ATTR_BINARY },
  59         [CERT_ATTR_PAYLOAD] = { .type = BLOB_ATTR_NESTED },
  60 };
  61
  62 enum cert_payload_attr {
  63         CERT_PL_ATTR_CERTTYPE,
  64         CERT_PL_ATTR_CERTID,
  65         CERT_PL_ATTR_VALIDFROMTIME,
  66         CERT_PL_ATTR_EXPIRETIME,
  67         CERT_PL_ATTR_PUBKEY,
  68         CERT_PL_ATTR_KEY_FINGERPRINT,
  69         CERT_PL_ATTR_MAX
  70 };
  71
  72 enum certtype_id {
  73         CERTTYPE_UNSPEC,
  74         CERTTYPE_AUTH,
  75         CERTTYPE_REVOKE
  76 };
  77
  78 static const struct blobmsg_policy cert_payload_policy[CERT_PL_ATTR_MAX] = {
  79         [CERT_PL_ATTR_CERTTYPE] = { .name = "certtype", .type = BLOBMSG_TYPE_INT32 },
  80         [CERT_PL_ATTR_CERTID] = { .name = "certid", .type = BLOBMSG_TYPE_INT32 },
  81         [CERT_PL_ATTR_VALIDFROMTIME] = { .name = "validfrom", .type = BLOBMSG_TYPE_INT64 },
  82         [CERT_PL_ATTR_EXPIRETIME] = { .name = "expiresat", .type = BLOBMSG_TYPE_INT64 },
  83         [CERT_PL_ATTR_PUBKEY] = { .name = "pubkey", .type = BLOBMSG_TYPE_STRING },
  84         [CERT_PL_ATTR_KEY_FINGERPRINT] = { .name = "fingerprint", .type = BLOBMSG_TYPE_STRING },
  85 };
  86
  87 struct cert_object {
  88         struct list_head list;
  89         struct blob_attr **cert;
  90 };
  91
  92 static int write_file(const char *filename, void *buf, size_t len, bool append) {
  93         FILE *f;
  94         size_t outlen;
  95
  96         f = fopen(filename, append?"a":"w");
  97         if (!f)
  98                 return 1;
  99
 100         outlen = fwrite(buf, 1, len, f);
 101         fclose(f);
 102         return (outlen == len);
 103 }
 104
 105 static int cert_load(const char *certfile, struct list_head *chain) {
 106         FILE *f;
 107         struct blob_attr *certtb[CERT_ATTR_MAX];
 108         struct cert_object *cobj;
 109         char filebuf[CERT_BUF_LEN];
 110         int ret = 0;
 111         int len;
 112
 113         f = fopen(certfile, "r");
 114         if (!f)
 115                 return 1;
 116
 117         len = fread(&filebuf, 1, CERT_BUF_LEN - 1, f);
 118         ret = ferror(f) || !feof(f);
 119         fclose(f);
 120         if (ret)
 121                 return 1;
 122         ret = blob_parse(filebuf, certtb, cert_policy, CERT_ATTR_MAX);
 123         cobj = calloc(1, sizeof(*cobj));
 124         cobj->cert = &certtb;
 125         list_add_tail(&cobj->list, chain);
 126
 127         fprintf(stderr, "blob_parse return %d\n", ret);
 128         return (ret <= 0);
 129 }
 130
 131 static int cert_append(const char *certfile, const char *pubkeyfile, const char *sigfile) {
 132         fprintf(stderr, "not implemented\n");
 133         return 1;
 134 }
 135
 136 static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX]) {
 137         int i;
 138
 139         for (i = 0; i < CERT_ATTR_MAX; i++) {
 140                 struct blob_attr *v = cert[i];
 141
 142                 if (!v)
 143                         continue;
 144
 145                 switch(cert_policy[i].type) {
 146                 case BLOB_ATTR_BINARY:
 147                         fprintf(stdout, "signature: %s\n", blob_data(v));
 148                         break;
 149                 case BLOB_ATTR_NESTED:
 150                         fprintf(stdout, "payload:\n%s\n", blobmsg_format_json(blob_data(v), false));
 151                         break;
 152                 }
 153         }
 154 }
 155
 156 static int cert_dump(const char *certfile) {
 157         struct cert_object *cobj;
 158         static LIST_HEAD(certchain);
 159
 160         if (cert_load(certfile, &certchain)) {
 161                 fprintf(stderr, "cannot parse cert\n");
 162                 return 1;
 163         }
 164
 165         list_for_each_entry(cobj, &certchain, list)
 166                 cert_dump_blob(cobj->cert);
 167
 168         return 0;
 169 }
 170
 171 static int cert_issue(const char *certfile, const char *pubkeyfile, const char *seckeyfile) {
 172         struct blob_buf certbuf;
 173         struct blob_buf payloadbuf;
 174         struct timeval tv;
 175         struct stat st;
 176         int pklen, siglen;
 177         int revoker = 1;
 178         void *c;
 179
 180         FILE *pkf, *sigf;
 181         char pkb[512];
 182         char sigb[512];
 183         char fname[256], sfname[256];
 184         char pkfp[17];
 185         char tmpdir[] = "/tmp/ucert-XXXXXX";
 186
 187         if (stat(certfile, &st) == 0) {
 188                 fprintf(stderr, "certfile %s exists, won't overwrite.\n", certfile);
 189                 return -1;
 190         }
 191
 192         pkf = fopen(pubkeyfile, "r");
 193         if (!pkf)
 194                 return -1;
 195
 196         pklen = fread(pkb, 1, 512, pkf);
 197         pkb[pklen - 1] = '\0';
 198
 199         if (pklen < 32)
 200                 return -1;
 201
 202         fclose(pkf);
 203
 204         if (usign_f_pubkey(pkfp, pubkeyfile))
 205                 return -1;
 206
 207         gettimeofday(&tv, NULL);
 208
 209         if (mkdtemp(tmpdir) == NULL)
 210                 return errno;
 211
 212         while (revoker >= 0) {
 213                 blob_buf_init(&payloadbuf, 0);
 214                 c = blobmsg_open_table(&payloadbuf, "ucert");
 215                 blobmsg_add_u32(&payloadbuf, "certtype", revoker?CERTTYPE_REVOKE:CERTTYPE_AUTH);
 216                 blobmsg_add_u64(&payloadbuf, "validfrom", tv.tv_sec);
 217                 if (!revoker) {
 218                         blobmsg_add_u64(&payloadbuf, "expiresat", tv.tv_sec + 60 * 60 * 24 * 365);
 219                         blobmsg_add_string(&payloadbuf, "pubkey", pkb);
 220                 } else {
 221                         blobmsg_add_string(&payloadbuf, "fingerprint", pkfp);
 222                 }
 223
 224                 blobmsg_close_table(&payloadbuf, c);
 225
 226                 snprintf(fname, sizeof(fname) - 1, "%s/%s", tmpdir, revoker?"revoker":"payload");
 227                 write_file(fname, blob_data(payloadbuf.head), blob_len(payloadbuf.head), false);
 228
 229                 snprintf(sfname, sizeof(sfname) - 1, "%s/%s", tmpdir, revoker?"revoker.sig":"payload.sig");
 230                 if (usign_s(fname, seckeyfile, sfname, quiet))
 231                         return 1;
 232
 233                 sigf = fopen(sfname, "r");
 234                 if (!sigf)
 235                         return 1;
 236
 237                 siglen = fread(sigb, 1, 1024, sigf);
 238                 if (siglen < 1)
 239                         return 1;
 240
 241                 sigb[siglen-1] = '\0';
 242                 fclose(sigf);
 243
 244                 unlink(fname);
 245                 unlink(sfname);
 246
 247                 blob_buf_init(&certbuf, 0);
 248                 blob_put(&certbuf, CERT_ATTR_SIGNATURE, sigb, siglen);
 249                 blob_put(&certbuf, CERT_ATTR_PAYLOAD, blob_data(payloadbuf.head), blob_len(payloadbuf.head));
 250                 snprintf(fname, sizeof(fname) - 1, "%s%s", certfile, revoker?".revoke":"");
 251                 write_file(fname, certbuf.head, blob_raw_len(certbuf.head), false);
 252                 revoker--;
 253         }
 254
 255         rmdir(tmpdir);
 256
 257         return 0;
 258 }
 259
 260 static int cert_process_revoker(const char *certfile) {
 261         fprintf(stderr, "not implemented\n");
 262         return 1;
 263 }
 264
 265 static int cert_verify(const char *certfile, const char *pubkeyfile, const char *pubkeydir, const char *msgfile) {
 266         fprintf(stderr, "not implemented\n");
 267         return 1;
 268 }
 269
 270 static int usage(const char *cmd)
 271 {
 272         fprintf(stderr,
 273                 "Usage: %s <command> <options>\n"
 274                 "Commands:\n"
 275                 "  -A:                  append (needs -c and -p and/or -x)\n"
 276                 "  -D:                  dump\n"
 277                 "  -I:                  issue cert and revoker (needs -c and -p and -s)\n"
 278                 "  -R:                  process revoker certificate (needs -c)\n"
 279                 "  -V:                  verify (needs -c and -p|-P)\n"
 280                 "Options:\n"
 281                 "  -c <file>:           certificate file\n"
 282                 "  -m <file>:           message file (verify only)\n"
 283                 "  -p <file>:           public key file\n"
 284                 "  -P <path>:           public key directory (verify only)\n"
 285                 "  -q:                  quiet (do not print verification result, use return code only)\n"
 286                 "  -s <file>:           secret key file (issue only)\n"
 287                 "  -x <file>:           signature file\n"
 288                 "\n",
 289                 cmd);
 290         return 1;
 291 }
 292
 293 int main(int argc, char *argv[]) {
 294         int ch;
 295         const char *msgfile = NULL;
 296         const char *sigfile = NULL;
 297         const char *pubkeyfile = NULL;
 298         const char *pubkeydir = NULL;
 299         const char *certfile = NULL;
 300         const char *seckeyfile = NULL;
 301
 302         quiet = false;
 303         while ((ch = getopt(argc, argv, "ADIRVc:m:p:P:qs:x:")) != -1) {
 304                 switch (ch) {
 305                 case 'A':
 306                         cmd = CMD_APPEND;
 307                         break;
 308                 case 'D':
 309                         cmd = CMD_DUMP;
 310                         break;
 311                 case 'I':
 312                         cmd = CMD_ISSUE;
 313                         break;
 314                 case 'R':
 315                         cmd = CMD_REVOKE;
 316                         break;
 317                 case 'V':
 318                         cmd = CMD_VERIFY;
 319                         break;
 320                 case 'c':
 321                         certfile = optarg;
 322                         break;
 323                 case 'm':
 324                         msgfile = optarg;
 325                         break;
 326                 case 'p':
 327                         pubkeyfile = optarg;
 328                         break;
 329                 case 'P':
 330                         pubkeydir = optarg;
 331                         break;
 332                 case 's':
 333                         seckeyfile = optarg;
 334                         break;
 335                 case 'q':
 336                         quiet = true;
 337                         break;
 338                 case 'x':
 339                         sigfile = optarg;
 340                         break;
 341                 default:
 342                         return usage(argv[0]);
 343                 }
 344         }
 345
 346         switch (cmd) {
 347         case CMD_APPEND:
 348                 if (certfile && (pubkeyfile || sigfile))
 349                         return cert_append(certfile, pubkeyfile, sigfile);
 350                 else
 351                         return usage(argv[0]);
 352         case CMD_DUMP:
 353                 if (certfile)
 354                         return cert_dump(certfile);
 355                 else
 356                         return usage(argv[0]);
 357         case CMD_ISSUE:
 358                 if (certfile && pubkeyfile && seckeyfile)
 359                         return cert_issue(certfile, pubkeyfile, seckeyfile);
 360                 else
 361                         return usage(argv[0]);
 362         case CMD_REVOKE:
 363                 if (certfile)
 364                         return cert_process_revoker(certfile);
 365                 else
 366                         return usage(argv[0]);
 367         case CMD_VERIFY:
 368                 if (certfile && (pubkeyfile || pubkeydir))
 369                         return cert_verify(certfile, pubkeyfile, pubkeydir, msgfile);
 370                 else
 371                         return usage(argv[0]);
 372         case CMD_NONE:
 373                 return usage(argv[0]);
 374         }
 375
 376         /* unreachable */
 377         return usage(argv[0]);
 378 }