src/main.c

   1 /*
   2  * cgi-io - LuCI non-RPC helper
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jo@mein.io>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <ctype.h>
  27 #include <sys/stat.h>
  28 #include <sys/wait.h>
  29
  30 #include <libubus.h>
  31 #include <libubox/blobmsg.h>
  32
  33 #include "multipart_parser.h"
  34
  35
  36 enum part {
  37         PART_UNKNOWN,
  38         PART_SESSIONID,
  39         PART_FILENAME,
  40         PART_FILEMODE,
  41         PART_FILEDATA
  42 };
  43
  44 const char *parts[] = {
  45         "(bug)",
  46         "sessionid",
  47         "filename",
  48         "filemode",
  49         "filedata",
  50 };
  51
  52 struct state
  53 {
  54         bool is_content_disposition;
  55         enum part parttype;
  56         char *sessionid;
  57         char *filename;
  58         bool filedata;
  59         int filemode;
  60         int filefd;
  61         int tempfd;
  62 };
  63
  64 enum {
  65         SES_ACCESS,
  66         __SES_MAX,
  67 };
  68
  69 static const struct blobmsg_policy ses_policy[__SES_MAX] = {
  70         [SES_ACCESS] = { .name = "access", .type = BLOBMSG_TYPE_BOOL },
  71 };
  72
  73
  74 static struct state st;
  75
  76 static void
  77 session_access_cb(struct ubus_request *req, int type, struct blob_attr *msg)
  78 {
  79         struct blob_attr *tb[__SES_MAX];
  80         bool *allow = (bool *)req->priv;
  81
  82         if (!msg)
  83                 return;
  84
  85         blobmsg_parse(ses_policy, __SES_MAX, tb, blob_data(msg), blob_len(msg));
  86
  87         if (tb[SES_ACCESS])
  88                 *allow = blobmsg_get_bool(tb[SES_ACCESS]);
  89 }
  90
  91 static bool
  92 session_access(const char *sid, const char *obj, const char *func)
  93 {
  94         uint32_t id;
  95         bool allow = false;
  96         struct ubus_context *ctx;
  97         static struct blob_buf req;
  98
  99         ctx = ubus_connect(NULL);
 100
 101         if (!ctx || ubus_lookup_id(ctx, "session", &id))
 102                 goto out;
 103
 104         blob_buf_init(&req, 0);
 105         blobmsg_add_string(&req, "ubus_rpc_session", sid);
 106         blobmsg_add_string(&req, "scope", "cgi-io");
 107         blobmsg_add_string(&req, "object", obj);
 108         blobmsg_add_string(&req, "function", func);
 109
 110         ubus_invoke(ctx, id, "access", req.head, session_access_cb, &allow, 500);
 111
 112 out:
 113         if (ctx)
 114                 ubus_free(ctx);
 115
 116         return allow;
 117 }
 118
 119 static char *
 120 checksum(const char *applet, size_t sumlen, const char *file)
 121 {
 122         pid_t pid;
 123         int fds[2];
 124         static char chksum[65];
 125
 126         if (pipe(fds))
 127                 return NULL;
 128
 129         switch ((pid = fork()))
 130         {
 131         case -1:
 132                 return NULL;
 133
 134         case 0:
 135                 uloop_done();
 136
 137                 dup2(fds[1], 1);
 138
 139                 close(0);
 140                 close(2);
 141                 close(fds[0]);
 142                 close(fds[1]);
 143
 144                 if (execl("/bin/busybox", "/bin/busybox", applet, file, NULL))
 145                         return NULL;
 146
 147                 break;
 148
 149         default:
 150                 memset(chksum, 0, sizeof(chksum));
 151                 read(fds[0], chksum, sumlen);
 152                 waitpid(pid, NULL, 0);
 153                 close(fds[0]);
 154                 close(fds[1]);
 155         }
 156
 157         return chksum;
 158 }
 159
 160 static char *
 161 datadup(const void *in, size_t len)
 162 {
 163         char *out = malloc(len + 1);
 164
 165         if (!out)
 166                 return NULL;
 167
 168         memcpy(out, in, len);
 169
 170         *(out + len) = 0;
 171
 172         return out;
 173 }
 174
 175 static bool
 176 urldecode(char *buf)
 177 {
 178         char *c, *p;
 179
 180         if (!buf || !*buf)
 181                 return true;
 182
 183 #define hex(x) \
 184         (((x) <= '9') ? ((x) - '0') : \
 185                 (((x) <= 'F') ? ((x) - 'A' + 10) : \
 186                         ((x) - 'a' + 10)))
 187
 188         for (c = p = buf; *p; c++)
 189         {
 190                 if (*p == '%')
 191                 {
 192                         if (!isxdigit(*(p + 1)) || !isxdigit(*(p + 2)))
 193                                 return false;
 194
 195                         *c = (char)(16 * hex(*(p + 1)) + hex(*(p + 2)));
 196
 197                         p += 3;
 198                 }
 199                 else if (*p == '+')
 200                 {
 201                         *c = ' ';
 202                         p++;
 203                 }
 204                 else
 205                 {
 206                         *c = *p++;
 207                 }
 208         }
 209
 210         *c = 0;
 211
 212         return true;
 213 }
 214
 215 static bool
 216 postdecode(char **fields, int n_fields)
 217 {
 218         char *p;
 219         const char *var;
 220         static char buf[1024];
 221         int i, len, field, found = 0;
 222
 223         var = getenv("CONTENT_TYPE");
 224
 225         if (!var || strncmp(var, "application/x-www-form-urlencoded", 33))
 226                 return false;
 227
 228         memset(buf, 0, sizeof(buf));
 229
 230         if ((len = read(0, buf, sizeof(buf) - 1)) > 0)
 231         {
 232                 for (p = buf, i = 0; i <= len; i++)
 233                 {
 234                         if (buf[i] == '=')
 235                         {
 236                                 buf[i] = 0;
 237
 238                                 for (field = 0; field < (n_fields * 2); field += 2)
 239                                 {
 240                                         if (!strcmp(p, fields[field]))
 241                                         {
 242                                                 fields[field + 1] = buf + i + 1;
 243                                                 found++;
 244                                         }
 245                                 }
 246                         }
 247                         else if (buf[i] == '&' || buf[i] == '\0')
 248                         {
 249                                 buf[i] = 0;
 250
 251                                 if (found >= n_fields)
 252                                         break;
 253
 254                                 p = buf + i + 1;
 255                         }
 256                 }
 257         }
 258
 259         for (field = 0; field < (n_fields * 2); field += 2)
 260                 if (!urldecode(fields[field + 1]))
 261                         return false;
 262
 263         return (found >= n_fields);
 264 }
 265
 266 static int
 267 response(bool success, const char *message)
 268 {
 269         char *chksum;
 270         struct stat s;
 271
 272         printf("Status: 200 OK\r\n");
 273         printf("Content-Type: text/plain\r\n\r\n{\n");
 274
 275         if (success)
 276         {
 277                 if (!stat(st.filename, &s))
 278                         printf("\t\"size\": %u,\n", (unsigned int)s.st_size);
 279                 else
 280                         printf("\t\"size\": null,\n");
 281
 282                 chksum = checksum("md5sum", 32, st.filename);
 283                 printf("\t\"checksum\": %s%s%s,\n",
 284                         chksum ? "\"" : "",
 285                         chksum ? chksum : "null",
 286                         chksum ? "\"" : "");
 287
 288                 chksum = checksum("sha256sum", 64, st.filename);
 289                 printf("\t\"sha256sum\": %s%s%s\n",
 290                         chksum ? "\"" : "",
 291                         chksum ? chksum : "null",
 292                         chksum ? "\"" : "");
 293         }
 294         else
 295         {
 296                 if (message)
 297                         printf("\t\"message\": \"%s\",\n", message);
 298
 299                 printf("\t\"failure\": [ %u, \"%s\" ]\n", errno, strerror(errno));
 300
 301                 if (st.filefd > -1)
 302                         unlink(st.filename);
 303         }
 304
 305         printf("}\n");
 306
 307         return -1;
 308 }
 309
 310 static int
 311 failure(int e, const char *message)
 312 {
 313         printf("Status: 500 Internal Server failure\r\n");
 314         printf("Content-Type: text/plain\r\n\r\n");
 315         printf("%s", message);
 316
 317         if (e)
 318                 printf(": %s", strerror(e));
 319
 320         return -1;
 321 }
 322
 323 static int
 324 filecopy(void)
 325 {
 326         int len;
 327         char buf[4096];
 328
 329         if (!st.filedata)
 330         {
 331                 close(st.tempfd);
 332                 errno = EINVAL;
 333                 return response(false, "No file data received");
 334         }
 335
 336         if (lseek(st.tempfd, 0, SEEK_SET) < 0)
 337         {
 338                 close(st.tempfd);
 339                 return response(false, "Failed to rewind temp file");
 340         }
 341
 342         st.filefd = open(st.filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 343
 344         if (st.filefd < 0)
 345         {
 346                 close(st.tempfd);
 347                 return response(false, "Failed to open target file");
 348         }
 349
 350         while ((len = read(st.tempfd, buf, sizeof(buf))) > 0)
 351         {
 352                 if (write(st.filefd, buf, len) != len)
 353                 {
 354                         close(st.tempfd);
 355                         close(st.filefd);
 356                         return response(false, "I/O failure while writing target file");
 357                 }
 358         }
 359
 360         close(st.tempfd);
 361         close(st.filefd);
 362
 363         if (chmod(st.filename, st.filemode))
 364                 return response(false, "Failed to chmod target file");
 365
 366         return 0;
 367 }
 368
 369 static int
 370 header_field(multipart_parser *p, const char *data, size_t len)
 371 {
 372         st.is_content_disposition = !strncasecmp(data, "Content-Disposition", len);
 373         return 0;
 374 }
 375
 376 static int
 377 header_value(multipart_parser *p, const char *data, size_t len)
 378 {
 379         int i, j;
 380
 381         if (!st.is_content_disposition)
 382                 return 0;
 383
 384         if (len < 10 || strncasecmp(data, "form-data", 9))
 385                 return 0;
 386
 387         for (data += 9, len -= 9; *data == ' ' || *data == ';'; data++, len--);
 388
 389         if (len < 8 || strncasecmp(data, "name=\"", 6))
 390                 return 0;
 391
 392         for (data += 6, len -= 6, i = 0; i <= len; i++)
 393         {
 394                 if (*(data + i) != '"')
 395                         continue;
 396
 397                 for (j = 1; j < sizeof(parts) / sizeof(parts[0]); j++)
 398                         if (!strncmp(data, parts[j], i))
 399                                 st.parttype = j;
 400
 401                 break;
 402         }
 403
 404         return 0;
 405 }
 406
 407 static int
 408 data_begin_cb(multipart_parser *p)
 409 {
 410         char tmpname[24] = "/tmp/luci-upload.XXXXXX";
 411
 412         if (st.parttype == PART_FILEDATA)
 413         {
 414                 if (!st.sessionid)
 415                         return response(false, "File data without session");
 416
 417                 if (!st.filename)
 418                         return response(false, "File data without name");
 419
 420                 st.tempfd = mkstemp(tmpname);
 421
 422                 if (st.tempfd < 0)
 423                         return response(false, "Failed to create temporary file");
 424
 425                 unlink(tmpname);
 426         }
 427
 428         return 0;
 429 }
 430
 431 static int
 432 data_cb(multipart_parser *p, const char *data, size_t len)
 433 {
 434         switch (st.parttype)
 435         {
 436         case PART_SESSIONID:
 437                 st.sessionid = datadup(data, len);
 438                 break;
 439
 440         case PART_FILENAME:
 441                 st.filename = datadup(data, len);
 442                 break;
 443
 444         case PART_FILEMODE:
 445                 st.filemode = strtoul(data, NULL, 8);
 446                 break;
 447
 448         case PART_FILEDATA:
 449                 if (write(st.tempfd, data, len) != len)
 450                 {
 451                         close(st.tempfd);
 452                         return response(false, "I/O failure while writing temporary file");
 453                 }
 454
 455                 if (!st.filedata)
 456                         st.filedata = !!len;
 457
 458                 break;
 459
 460         default:
 461                 break;
 462         }
 463
 464         return 0;
 465 }
 466
 467 static int
 468 data_end_cb(multipart_parser *p)
 469 {
 470         if (st.parttype == PART_SESSIONID)
 471         {
 472                 if (!session_access(st.sessionid, "upload", "write"))
 473                 {
 474                         errno = EPERM;
 475                         return response(false, "Upload permission denied");
 476                 }
 477         }
 478         else if (st.parttype == PART_FILEDATA)
 479         {
 480                 if (st.tempfd < 0)
 481                         return response(false, "Internal program failure");
 482
 483 #if 0
 484                 /* prepare directory */
 485                 for (ptr = st.filename; *ptr; ptr++)
 486                 {
 487                         if (*ptr == '/')
 488                         {
 489                                 *ptr = 0;
 490
 491                                 if (mkdir(st.filename, 0755))
 492                                 {
 493                                         unlink(st.tmpname);
 494                                         return response(false, "Failed to create destination directory");
 495                                 }
 496
 497                                 *ptr = '/';
 498                         }
 499                 }
 500 #endif
 501
 502                 if (filecopy())
 503                         return -1;
 504
 505                 return response(true, NULL);
 506         }
 507
 508         st.parttype = PART_UNKNOWN;
 509         return 0;
 510 }
 511
 512 static multipart_parser *
 513 init_parser(void)
 514 {
 515         char *boundary;
 516         const char *var;
 517
 518         multipart_parser *p;
 519         static multipart_parser_settings s = {
 520                 .on_part_data        = data_cb,
 521                 .on_headers_complete = data_begin_cb,
 522                 .on_part_data_end    = data_end_cb,
 523                 .on_header_field     = header_field,
 524                 .on_header_value     = header_value
 525         };
 526
 527         var = getenv("CONTENT_TYPE");
 528
 529         if (!var || strncmp(var, "multipart/form-data;", 20))
 530                 return NULL;
 531
 532         for (var += 20; *var && *var != '='; var++);
 533
 534         if (*var++ != '=')
 535                 return NULL;
 536
 537         boundary = malloc(strlen(var) + 3);
 538
 539         if (!boundary)
 540                 return NULL;
 541
 542         strcpy(boundary, "--");
 543         strcpy(boundary + 2, var);
 544
 545         st.tempfd = -1;
 546         st.filefd = -1;
 547         st.filemode = 0600;
 548
 549         p = multipart_parser_init(boundary, &s);
 550
 551         free(boundary);
 552
 553         return p;
 554 }
 555
 556 static int
 557 main_upload(int argc, char *argv[])
 558 {
 559         int rem, len;
 560         char buf[4096];
 561         multipart_parser *p;
 562
 563         p = init_parser();
 564
 565         if (!p)
 566         {
 567                 errno = EINVAL;
 568                 return response(false, "Invalid request");
 569         }
 570
 571         while ((len = read(0, buf, sizeof(buf))) > 0)
 572         {
 573                 rem = multipart_parser_execute(p, buf, len);
 574
 575                 if (rem < len)
 576                         break;
 577         }
 578
 579         multipart_parser_free(p);
 580
 581         /* read remaining post data */
 582         while ((len = read(0, buf, sizeof(buf))) > 0);
 583
 584         return 0;
 585 }
 586
 587 static int
 588 main_backup(int argc, char **argv)
 589 {
 590         pid_t pid;
 591         time_t now;
 592         int len;
 593         int status;
 594         int fds[2];
 595         char buf[4096];
 596         char datestr[16] = { 0 };
 597         char hostname[64] = { 0 };
 598         char *fields[] = { "sessionid", NULL };
 599
 600         if (!postdecode(fields, 1) || !session_access(fields[1], "backup", "read"))
 601                 return failure(0, "Backup permission denied");
 602
 603         if (pipe(fds))
 604                 return failure(errno, "Failed to spawn pipe");
 605
 606         switch ((pid = fork()))
 607         {
 608         case -1:
 609                 return failure(errno, "Failed to fork process");
 610
 611         case 0:
 612                 dup2(fds[1], 1);
 613
 614                 close(0);
 615                 close(2);
 616                 close(fds[0]);
 617                 close(fds[1]);
 618
 619                 chdir("/");
 620
 621                 execl("/sbin/sysupgrade", "/sbin/sysupgrade",
 622                       "--create-backup", "-", NULL);
 623
 624                 return -1;
 625
 626         default:
 627                 fcntl(fds[0], F_SETFL, fcntl(fds[0], F_GETFL) | O_NONBLOCK);
 628                 now = time(NULL);
 629                 strftime(datestr, sizeof(datestr) - 1, "%Y-%m-%d", localtime(&now));
 630
 631                 if (gethostname(hostname, sizeof(hostname) - 1))
 632                         sprintf(hostname, "OpenWrt");
 633
 634                 printf("Status: 200 OK\r\n");
 635                 printf("Content-Type: application/x-targz\r\n");
 636                 printf("Content-Disposition: attachment; "
 637                        "filename=\"backup-%s-%s.tar.gz\"\r\n\r\n", hostname, datestr);
 638
 639                 do {
 640                         waitpid(pid, &status, 0);
 641
 642                         while ((len = read(fds[0], buf, sizeof(buf))) > 0) {
 643                                 fwrite(buf, len, 1, stdout);
 644                                 fflush(stdout);
 645                         }
 646
 647                 } while (!WIFEXITED(status));
 648
 649                 close(fds[0]);
 650                 close(fds[1]);
 651
 652                 return 0;
 653         }
 654 }
 655
 656 int main(int argc, char **argv)
 657 {
 658         if (strstr(argv[0], "cgi-upload"))
 659                 return main_upload(argc, argv);
 660         else if (strstr(argv[0], "cgi-backup"))
 661                 return main_backup(argc, argv);
 662
 663         return -1;
 664 }