net/cgi-io/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 md5sum(const char *file)
 121 {
 122         pid_t pid;
 123         int fds[2];
 124         static char md5[33];
 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", "md5sum", file, NULL))
 145                         return NULL;
 146
 147                 break;
 148
 149         default:
 150                 memset(md5, 0, sizeof(md5));
 151                 read(fds[0], md5, 32);
 152                 waitpid(pid, NULL, 0);
 153                 close(fds[0]);
 154                 close(fds[1]);
 155         }
 156
 157         return md5;
 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 *md5;
 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) && (md5 = md5sum(st.filename)) != NULL)
 278                         printf("\t\"size\": %u,\n\t\"checksum\": \"%s\"\n",
 279                                    (unsigned int)s.st_size, md5);
 280         }
 281         else
 282         {
 283                 if (message)
 284                         printf("\t\"message\": \"%s\",\n", message);
 285
 286                 printf("\t\"failure\": [ %u, \"%s\" ]\n", errno, strerror(errno));
 287
 288                 if (st.filefd > -1)
 289                         unlink(st.filename);
 290         }
 291
 292         printf("}\n");
 293
 294         return -1;
 295 }
 296
 297 static int
 298 failure(int e, const char *message)
 299 {
 300         printf("Status: 500 Internal Server failure\r\n");
 301         printf("Content-Type: text/plain\r\n\r\n");
 302         printf("%s", message);
 303
 304         if (e)
 305                 printf(": %s", strerror(e));
 306
 307         return -1;
 308 }
 309
 310 static int
 311 filecopy(void)
 312 {
 313         int len;
 314         char buf[4096];
 315
 316         if (!st.filedata)
 317         {
 318                 close(st.tempfd);
 319                 errno = EINVAL;
 320                 return response(false, "No file data received");
 321         }
 322
 323         if (lseek(st.tempfd, 0, SEEK_SET) < 0)
 324         {
 325                 close(st.tempfd);
 326                 return response(false, "Failed to rewind temp file");
 327         }
 328
 329         st.filefd = open(st.filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 330
 331         if (st.filefd < 0)
 332         {
 333                 close(st.tempfd);
 334                 return response(false, "Failed to open target file");
 335         }
 336
 337         while ((len = read(st.tempfd, buf, sizeof(buf))) > 0)
 338         {
 339                 if (write(st.filefd, buf, len) != len)
 340                 {
 341                         close(st.tempfd);
 342                         close(st.filefd);
 343                         return response(false, "I/O failure while writing target file");
 344                 }
 345         }
 346
 347         close(st.tempfd);
 348         close(st.filefd);
 349
 350         if (chmod(st.filename, st.filemode))
 351                 return response(false, "Failed to chmod target file");
 352
 353         return 0;
 354 }
 355
 356 static int
 357 header_field(multipart_parser *p, const char *data, size_t len)
 358 {
 359         st.is_content_disposition = !strncasecmp(data, "Content-Disposition", len);
 360         return 0;
 361 }
 362
 363 static int
 364 header_value(multipart_parser *p, const char *data, size_t len)
 365 {
 366         int i, j;
 367
 368         if (!st.is_content_disposition)
 369                 return 0;
 370
 371         if (len < 10 || strncasecmp(data, "form-data", 9))
 372                 return 0;
 373
 374         for (data += 9, len -= 9; *data == ' ' || *data == ';'; data++, len--);
 375
 376         if (len < 8 || strncasecmp(data, "name=\"", 6))
 377                 return 0;
 378
 379         for (data += 6, len -= 6, i = 0; i <= len; i++)
 380         {
 381                 if (*(data + i) != '"')
 382                         continue;
 383
 384                 for (j = 1; j < sizeof(parts) / sizeof(parts[0]); j++)
 385                         if (!strncmp(data, parts[j], i))
 386                                 st.parttype = j;
 387
 388                 break;
 389         }
 390
 391         return 0;
 392 }
 393
 394 static int
 395 data_begin_cb(multipart_parser *p)
 396 {
 397         char tmpname[24] = "/tmp/luci-upload.XXXXXX";
 398
 399         if (st.parttype == PART_FILEDATA)
 400         {
 401                 if (!st.sessionid)
 402                         return response(false, "File data without session");
 403
 404                 if (!st.filename)
 405                         return response(false, "File data without name");
 406
 407                 st.tempfd = mkstemp(tmpname);
 408
 409                 if (st.tempfd < 0)
 410                         return response(false, "Failed to create temporary file");
 411
 412                 unlink(tmpname);
 413         }
 414
 415         return 0;
 416 }
 417
 418 static int
 419 data_cb(multipart_parser *p, const char *data, size_t len)
 420 {
 421         switch (st.parttype)
 422         {
 423         case PART_SESSIONID:
 424                 st.sessionid = datadup(data, len);
 425                 break;
 426
 427         case PART_FILENAME:
 428                 st.filename = datadup(data, len);
 429                 break;
 430
 431         case PART_FILEMODE:
 432                 st.filemode = strtoul(data, NULL, 8);
 433                 break;
 434
 435         case PART_FILEDATA:
 436                 if (write(st.tempfd, data, len) != len)
 437                 {
 438                         close(st.tempfd);
 439                         return response(false, "I/O failure while writing temporary file");
 440                 }
 441
 442                 if (!st.filedata)
 443                         st.filedata = !!len;
 444
 445                 break;
 446
 447         default:
 448                 break;
 449         }
 450
 451         return 0;
 452 }
 453
 454 static int
 455 data_end_cb(multipart_parser *p)
 456 {
 457         if (st.parttype == PART_SESSIONID)
 458         {
 459                 if (!session_access(st.sessionid, "upload", "write"))
 460                 {
 461                         errno = EPERM;
 462                         return response(false, "Upload permission denied");
 463                 }
 464         }
 465         else if (st.parttype == PART_FILEDATA)
 466         {
 467                 if (st.tempfd < 0)
 468                         return response(false, "Internal program failure");
 469
 470 #if 0
 471                 /* prepare directory */
 472                 for (ptr = st.filename; *ptr; ptr++)
 473                 {
 474                         if (*ptr == '/')
 475                         {
 476                                 *ptr = 0;
 477
 478                                 if (mkdir(st.filename, 0755))
 479                                 {
 480                                         unlink(st.tmpname);
 481                                         return response(false, "Failed to create destination directory");
 482                                 }
 483
 484                                 *ptr = '/';
 485                         }
 486                 }
 487 #endif
 488
 489                 if (filecopy())
 490                         return -1;
 491
 492                 return response(true, NULL);
 493         }
 494
 495         st.parttype = PART_UNKNOWN;
 496         return 0;
 497 }
 498
 499 static multipart_parser *
 500 init_parser(void)
 501 {
 502         char *boundary;
 503         const char *var;
 504
 505         multipart_parser *p;
 506         static multipart_parser_settings s = {
 507                 .on_part_data        = data_cb,
 508                 .on_headers_complete = data_begin_cb,
 509                 .on_part_data_end    = data_end_cb,
 510                 .on_header_field     = header_field,
 511                 .on_header_value     = header_value
 512         };
 513
 514         var = getenv("CONTENT_TYPE");
 515
 516         if (!var || strncmp(var, "multipart/form-data;", 20))
 517                 return NULL;
 518
 519         for (var += 20; *var && *var != '='; var++);
 520
 521         if (*var++ != '=')
 522                 return NULL;
 523
 524         boundary = malloc(strlen(var) + 3);
 525
 526         if (!boundary)
 527                 return NULL;
 528
 529         strcpy(boundary, "--");
 530         strcpy(boundary + 2, var);
 531
 532         st.tempfd = -1;
 533         st.filefd = -1;
 534         st.filemode = 0600;
 535
 536         p = multipart_parser_init(boundary, &s);
 537
 538         free(boundary);
 539
 540         return p;
 541 }
 542
 543 static int
 544 main_upload(int argc, char *argv[])
 545 {
 546         int rem, len;
 547         char buf[4096];
 548         multipart_parser *p;
 549
 550         p = init_parser();
 551
 552         if (!p)
 553         {
 554                 errno = EINVAL;
 555                 return response(false, "Invalid request");
 556         }
 557
 558         while ((len = read(0, buf, sizeof(buf))) > 0)
 559         {
 560                 rem = multipart_parser_execute(p, buf, len);
 561
 562                 if (rem < len)
 563                         break;
 564         }
 565
 566         multipart_parser_free(p);
 567
 568         /* read remaining post data */
 569         while ((len = read(0, buf, sizeof(buf))) > 0);
 570
 571         return 0;
 572 }
 573
 574 static int
 575 main_backup(int argc, char **argv)
 576 {
 577         pid_t pid;
 578         time_t now;
 579         int len;
 580         int status;
 581         int fds[2];
 582         char buf[4096];
 583         char datestr[16] = { 0 };
 584         char hostname[64] = { 0 };
 585         char *fields[] = { "sessionid", NULL };
 586
 587         if (!postdecode(fields, 1) || !session_access(fields[1], "backup", "read"))
 588                 return failure(0, "Backup permission denied");
 589
 590         if (pipe(fds))
 591                 return failure(errno, "Failed to spawn pipe");
 592
 593         switch ((pid = fork()))
 594         {
 595         case -1:
 596                 return failure(errno, "Failed to fork process");
 597
 598         case 0:
 599                 dup2(fds[1], 1);
 600
 601                 close(0);
 602                 close(2);
 603                 close(fds[0]);
 604                 close(fds[1]);
 605
 606                 chdir("/");
 607
 608                 execl("/sbin/sysupgrade", "/sbin/sysupgrade",
 609                       "--create-backup", "-", NULL);
 610
 611                 return -1;
 612
 613         default:
 614                 fcntl(fds[0], F_SETFL, fcntl(fds[0], F_GETFL) | O_NONBLOCK);
 615                 now = time(NULL);
 616                 strftime(datestr, sizeof(datestr) - 1, "%Y-%m-%d", localtime(&now));
 617
 618                 if (gethostname(hostname, sizeof(hostname) - 1))
 619                         sprintf(hostname, "OpenWrt");
 620
 621                 printf("Status: 200 OK\r\n");
 622                 printf("Content-Type: application/x-targz\r\n");
 623                 printf("Content-Disposition: attachment; "
 624                        "filename=\"backup-%s-%s.tar.gz\"\r\n\r\n", hostname, datestr);
 625
 626                 do {
 627                         waitpid(pid, &status, 0);
 628
 629                         while ((len = read(fds[0], buf, sizeof(buf))) > 0) {
 630                                 fwrite(buf, len, 1, stdout);
 631                                 fflush(stdout);
 632                         }
 633
 634                 } while (!WIFEXITED(status));
 635
 636                 close(fds[0]);
 637                 close(fds[1]);
 638
 639                 return 0;
 640         }
 641 }
 642
 643 int main(int argc, char **argv)
 644 {
 645         if (strstr(argv[0], "cgi-upload"))
 646                 return main_upload(argc, argv);
 647         else if (strstr(argv[0], "cgi-backup"))
 648                 return main_backup(argc, argv);
 649
 650         return -1;
 651 }