apps/lib/http_server.c

   1 /*
   2  * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /* Very basic HTTP server */
  11
  12 #if !defined(_POSIX_C_SOURCE) && defined(OPENSSL_SYS_VMS)
  13 /*
  14  * On VMS, you need to define this to get the declaration of fileno().  The
  15  * value 2 is to make sure no function defined in POSIX-2 is left undefined.
  16  */
  17 # define _POSIX_C_SOURCE 2
  18 #endif
  19
  20 #include <ctype.h>
  21 #include "http_server.h"
  22 #include "internal/sockets.h"
  23 #include <openssl/err.h>
  24 #include <openssl/trace.h>
  25 #include <openssl/rand.h>
  26 #include "s_apps.h"
  27 #include "log.h"
  28
  29 #if defined(__TANDEM)
  30 # if defined(OPENSSL_TANDEM_FLOSS)
  31 #  include <floss.h(floss_fork)>
  32 # endif
  33 #endif
  34
  35 #define HTTP_PREFIX "HTTP/"
  36 #define HTTP_VERSION_PATT "1." /* allow 1.x */
  37 #define HTTP_PREFIX_VERSION HTTP_PREFIX""HTTP_VERSION_PATT
  38 #define HTTP_1_0 HTTP_PREFIX_VERSION"0" /* "HTTP/1.0" */
  39 #define HTTP_VERSION_STR " "HTTP_PREFIX_VERSION
  40
  41 #define log_HTTP(prog, level, text) \
  42     trace_log_message(OSSL_TRACE_CATEGORY_HTTP, prog, level, "%s", text)
  43 #define log_HTTP1(prog, level, fmt, arg) \
  44     trace_log_message(OSSL_TRACE_CATEGORY_HTTP, prog, level, fmt, arg)
  45 #define log_HTTP2(prog, level, fmt, arg1, arg2) \
  46     trace_log_message(OSSL_TRACE_CATEGORY_HTTP, prog, level, fmt, arg1, arg2)
  47 #define log_HTTP3(prog, level, fmt, a1, a2, a3)                        \
  48     trace_log_message(OSSL_TRACE_CATEGORY_HTTP, prog, level, fmt, a1, a2, a3)
  49
  50 #ifdef HTTP_DAEMON
  51 int n_responders = 0; /* run multiple responder processes, set by ocsp.c */
  52 int acfd = (int)INVALID_SOCKET;
  53
  54 void socket_timeout(int signum)
  55 {
  56     if (acfd != (int)INVALID_SOCKET)
  57         (void)shutdown(acfd, SHUT_RD);
  58 }
  59
  60 static void killall(int ret, pid_t *kidpids)
  61 {
  62     int i;
  63
  64     for (i = 0; i < n_responders; ++i)
  65         if (kidpids[i] != 0)
  66             (void)kill(kidpids[i], SIGTERM);
  67     OPENSSL_free(kidpids);
  68     OSSL_sleep(1000);
  69     exit(ret);
  70 }
  71
  72 static int termsig = 0;
  73
  74 static void noteterm(int sig)
  75 {
  76     termsig = sig;
  77 }
  78
  79 /*
  80  * Loop spawning up to `multi` child processes, only child processes return
  81  * from this function.  The parent process loops until receiving a termination
  82  * signal, kills extant children and exits without returning.
  83  */
  84 void spawn_loop(const char *prog)
  85 {
  86     pid_t *kidpids = NULL;
  87     int status;
  88     int procs = 0;
  89     int i;
  90
  91     openlog(prog, LOG_PID, LOG_DAEMON);
  92
  93     if (setpgid(0, 0)) {
  94         log_HTTP1(prog, LOG_CRIT,
  95                   "error detaching from parent process group: %s",
  96                   strerror(errno));
  97         exit(1);
  98     }
  99     kidpids = app_malloc(n_responders * sizeof(*kidpids), "child PID array");
 100     for (i = 0; i < n_responders; ++i)
 101         kidpids[i] = 0;
 102
 103     signal(SIGINT, noteterm);
 104     signal(SIGTERM, noteterm);
 105
 106     while (termsig == 0) {
 107         pid_t fpid;
 108
 109         /*
 110          * Wait for a child to replace when we're at the limit.
 111          * Slow down if a child exited abnormally or waitpid() < 0
 112          */
 113         while (termsig == 0 && procs >= n_responders) {
 114             if ((fpid = waitpid(-1, &status, 0)) > 0) {
 115                 for (i = 0; i < procs; ++i) {
 116                     if (kidpids[i] == fpid) {
 117                         kidpids[i] = 0;
 118                         --procs;
 119                         break;
 120                     }
 121                 }
 122                 if (i >= n_responders) {
 123                     log_HTTP1(prog, LOG_CRIT,
 124                               "internal error: no matching child slot for pid: %ld",
 125                               (long)fpid);
 126                     killall(1, kidpids);
 127                 }
 128                 if (status != 0) {
 129                     if (WIFEXITED(status)) {
 130                         log_HTTP2(prog, LOG_WARNING,
 131                                   "child process: %ld, exit status: %d",
 132                                   (long)fpid, WEXITSTATUS(status));
 133                     } else if (WIFSIGNALED(status)) {
 134                         char *dumped = "";
 135
 136 # ifdef WCOREDUMP
 137                         if (WCOREDUMP(status))
 138                             dumped = " (core dumped)";
 139 # endif
 140                         log_HTTP3(prog, LOG_WARNING,
 141                                   "child process: %ld, term signal %d%s",
 142                                   (long)fpid, WTERMSIG(status), dumped);
 143                     }
 144                     OSSL_sleep(1000);
 145                 }
 146                 break;
 147             } else if (errno != EINTR) {
 148                 log_HTTP1(prog, LOG_CRIT,
 149                           "waitpid() failed: %s", strerror(errno));
 150                 killall(1, kidpids);
 151             }
 152         }
 153         if (termsig)
 154             break;
 155
 156         switch (fpid = fork()) {
 157         case -1: /* error */
 158             /* System critically low on memory, pause and try again later */
 159             OSSL_sleep(30000);
 160             break;
 161         case 0: /* child */
 162             OPENSSL_free(kidpids);
 163             signal(SIGINT, SIG_DFL);
 164             signal(SIGTERM, SIG_DFL);
 165             if (termsig)
 166                 _exit(0);
 167             if (RAND_poll() <= 0) {
 168                 log_HTTP(prog, LOG_CRIT, "RAND_poll() failed");
 169                 _exit(1);
 170             }
 171             return;
 172         default:            /* parent */
 173             for (i = 0; i < n_responders; ++i) {
 174                 if (kidpids[i] == 0) {
 175                     kidpids[i] = fpid;
 176                     procs++;
 177                     break;
 178                 }
 179             }
 180             if (i >= n_responders) {
 181                 log_HTTP(prog, LOG_CRIT,
 182                          "internal error: no free child slots");
 183                 killall(1, kidpids);
 184             }
 185             break;
 186         }
 187     }
 188
 189     /* The loop above can only break on termsig */
 190     log_HTTP1(prog, LOG_INFO, "terminating on signal: %d", termsig);
 191     killall(0, kidpids);
 192 }
 193 #endif
 194
 195 #ifndef OPENSSL_NO_SOCK
 196 BIO *http_server_init(const char *prog, const char *port, int verb)
 197 {
 198     BIO *acbio = NULL, *bufbio;
 199     int asock;
 200     int port_num;
 201     char name[40];
 202
 203     snprintf(name, sizeof(name), "[::]:%s", port); /* port may be "0" */
 204     if (verb >= 0 && !log_set_verbosity(prog, verb))
 205         return NULL;
 206     bufbio = BIO_new(BIO_f_buffer());
 207     if (bufbio == NULL)
 208         goto err;
 209     acbio = BIO_new(BIO_s_accept());
 210     if (acbio == NULL
 211         || BIO_set_bind_mode(acbio, BIO_BIND_REUSEADDR) < 0
 212         || BIO_set_accept_name(acbio, name) < 0) {
 213         log_HTTP(prog, LOG_ERR, "error setting up accept BIO");
 214         goto err;
 215     }
 216
 217     BIO_set_accept_bios(acbio, bufbio);
 218     bufbio = NULL;
 219     if (BIO_do_accept(acbio) <= 0) {
 220         log_HTTP1(prog, LOG_ERR, "error setting accept on port %s", port);
 221         goto err;
 222     }
 223
 224     /* Report back what address and port are used */
 225     BIO_get_fd(acbio, &asock);
 226     port_num = report_server_accept(bio_out, asock, 1, 1);
 227     if (port_num == 0) {
 228         log_HTTP(prog, LOG_ERR, "error printing ACCEPT string");
 229         goto err;
 230     }
 231
 232     return acbio;
 233
 234  err:
 235     ERR_print_errors(bio_err);
 236     BIO_free_all(acbio);
 237     BIO_free(bufbio);
 238     return NULL;
 239 }
 240
 241 /*
 242  * Decode %xx URL-decoding in-place. Ignores malformed sequences.
 243  */
 244 static int urldecode(char *p)
 245 {
 246     unsigned char *out = (unsigned char *)p;
 247     unsigned char *save = out;
 248
 249     for (; *p; p++) {
 250         if (*p != '%') {
 251             *out++ = *p;
 252         } else if (isxdigit(_UC(p[1])) && isxdigit(_UC(p[2]))) {
 253             /* Don't check, can't fail because of ixdigit() call. */
 254             *out++ = (OPENSSL_hexchar2int(p[1]) << 4)
 255                 | OPENSSL_hexchar2int(p[2]);
 256             p += 2;
 257         } else {
 258             return -1;
 259         }
 260     }
 261     *out = '\0';
 262     return (int)(out - save);
 263 }
 264
 265 /* if *pcbio != NULL, continue given connected session, else accept new */
 266 /* if found_keep_alive != NULL, return this way connection persistence state */
 267 int http_server_get_asn1_req(const ASN1_ITEM *it, ASN1_VALUE **preq,
 268                              char **ppath, BIO **pcbio, BIO *acbio,
 269                              int *found_keep_alive,
 270                              const char *prog, int accept_get, int timeout)
 271 {
 272     BIO *cbio = *pcbio, *getbio = NULL, *b64 = NULL;
 273     int len;
 274     char reqbuf[2048], inbuf[2048];
 275     char *meth, *url, *end;
 276     ASN1_VALUE *req;
 277     int ret = 0;
 278
 279     *preq = NULL;
 280     if (ppath != NULL)
 281         *ppath = NULL;
 282
 283     if (cbio == NULL) {
 284         char *port;
 285
 286         get_sock_info_address(BIO_get_fd(acbio, NULL), NULL, &port);
 287         if (port == NULL) {
 288             log_HTTP(prog, LOG_ERR, "cannot get port listening on");
 289             goto fatal;
 290         }
 291         log_HTTP1(prog, LOG_DEBUG,
 292                   "awaiting new connection on port %s ...", port);
 293         OPENSSL_free(port);
 294
 295         if (BIO_do_accept(acbio) <= 0)
 296             /* Connection loss before accept() is routine, ignore silently */
 297             return ret;
 298
 299         *pcbio = cbio = BIO_pop(acbio);
 300     } else {
 301         log_HTTP(prog, LOG_DEBUG, "awaiting next request ...");
 302     }
 303     if (cbio == NULL) {
 304         /* Cannot call http_server_send_status(..., cbio, ...) */
 305         ret = -1;
 306         goto out;
 307     }
 308
 309 # ifdef HTTP_DAEMON
 310     if (timeout > 0) {
 311         (void)BIO_get_fd(cbio, &acfd);
 312         alarm(timeout);
 313     }
 314 # endif
 315
 316     /* Read the request line. */
 317     len = BIO_gets(cbio, reqbuf, sizeof(reqbuf));
 318     if (len == 0)
 319         return ret;
 320     ret = 1;
 321     if (len < 0) {
 322         log_HTTP(prog, LOG_WARNING, "request line read error");
 323         (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 324         goto out;
 325     }
 326
 327     if (((end = strchr(reqbuf, '\r')) != NULL && end[1] == '\n')
 328             || (end = strchr(reqbuf, '\n')) != NULL)
 329         *end = '\0';
 330     if (log_get_verbosity() < LOG_TRACE)
 331         trace_log_message(-1, prog, LOG_INFO,
 332                           "received request, 1st line: %s", reqbuf);
 333     log_HTTP(prog, LOG_TRACE, "received request header:");
 334     log_HTTP1(prog, LOG_TRACE, "%s", reqbuf);
 335     if (end == NULL) {
 336         log_HTTP(prog, LOG_WARNING,
 337                  "cannot parse HTTP header: missing end of line");
 338         (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 339         goto out;
 340     }
 341
 342     url = meth = reqbuf;
 343     if ((accept_get && CHECK_AND_SKIP_PREFIX(url, "GET "))
 344             || CHECK_AND_SKIP_PREFIX(url, "POST ")) {
 345
 346         /* Expecting (GET|POST) {sp} /URL {sp} HTTP/1.x */
 347         url[-1] = '\0';
 348         while (*url == ' ')
 349             url++;
 350         if (*url != '/') {
 351             log_HTTP2(prog, LOG_WARNING,
 352                       "invalid %s -- URL does not begin with '/': %s",
 353                       meth, url);
 354             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 355             goto out;
 356         }
 357         url++;
 358
 359         /* Splice off the HTTP version identifier. */
 360         for (end = url; *end != '\0'; end++)
 361             if (*end == ' ')
 362                 break;
 363         if (!HAS_PREFIX(end, HTTP_VERSION_STR)) {
 364             log_HTTP2(prog, LOG_WARNING,
 365                       "invalid %s -- bad HTTP/version string: %s",
 366                       meth, end + 1);
 367             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 368             goto out;
 369         }
 370         *end = '\0';
 371         /* above HTTP 1.0, connection persistence is the default */
 372         if (found_keep_alive != NULL)
 373             *found_keep_alive = end[sizeof(HTTP_VERSION_STR) - 1] > '0';
 374
 375         /*-
 376          * Skip "GET / HTTP..." requests often used by load-balancers.
 377          * 'url' was incremented above to point to the first byte *after*
 378          * the leading slash, so in case 'GET / ' it is now an empty string.
 379          */
 380         if (strlen(meth) == 3 && url[0] == '\0') {
 381             (void)http_server_send_status(prog, cbio, 200, "OK");
 382             goto out;
 383         }
 384
 385         len = urldecode(url);
 386         if (len < 0) {
 387             log_HTTP2(prog, LOG_WARNING,
 388                       "invalid %s request -- bad URL encoding: %s", meth, url);
 389             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 390             goto out;
 391         }
 392         if (strlen(meth) == 3) { /* GET */
 393             if ((getbio = BIO_new_mem_buf(url, len)) == NULL
 394                 || (b64 = BIO_new(BIO_f_base64())) == NULL) {
 395                 log_HTTP1(prog, LOG_ERR,
 396                           "could not allocate base64 bio with size = %d", len);
 397                 goto fatal;
 398             }
 399             BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
 400             getbio = BIO_push(b64, getbio);
 401         }
 402     } else {
 403         log_HTTP2(prog, LOG_WARNING,
 404                   "HTTP request does not begin with %sPOST: %s",
 405                   accept_get ? "GET or " : "", reqbuf);
 406         (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 407         goto out;
 408     }
 409
 410     /* chop any further/duplicate leading or trailing '/' */
 411     while (*url == '/')
 412         url++;
 413     while (end >= url + 2 && end[-2] == '/' && end[-1] == '/')
 414         end--;
 415     *end = '\0';
 416
 417     /* Read and skip past the headers. */
 418     for (;;) {
 419         char *key, *value;
 420
 421         len = BIO_gets(cbio, inbuf, sizeof(inbuf));
 422         if (len <= 0) {
 423             log_HTTP(prog, LOG_WARNING, "error reading HTTP header");
 424             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 425             goto out;
 426         }
 427
 428         if (((end = strchr(inbuf, '\r')) != NULL && end[1] == '\n')
 429             || (end = strchr(inbuf, '\n')) != NULL)
 430             *end = '\0';
 431         log_HTTP1(prog, LOG_TRACE, "%s", *inbuf == '\0' ?
 432                   " " /* workaround for "" getting ignored */ : inbuf);
 433         if (end == NULL) {
 434             log_HTTP(prog, LOG_WARNING,
 435                      "error parsing HTTP header: missing end of line");
 436             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 437             goto out;
 438         }
 439
 440         if (inbuf[0] == '\0')
 441             break;
 442
 443         key = inbuf;
 444         value = strchr(key, ':');
 445         if (value == NULL) {
 446             log_HTTP(prog, LOG_WARNING,
 447                      "error parsing HTTP header: missing ':'");
 448             (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 449             goto out;
 450         }
 451         *(value++) = '\0';
 452         while (*value == ' ')
 453             value++;
 454         /* https://tools.ietf.org/html/rfc7230#section-6.3 Persistence */
 455         if (found_keep_alive != NULL
 456             && OPENSSL_strcasecmp(key, "Connection") == 0) {
 457             if (OPENSSL_strcasecmp(value, "keep-alive") == 0)
 458                 *found_keep_alive = 1;
 459             else if (OPENSSL_strcasecmp(value, "close") == 0)
 460                 *found_keep_alive = 0;
 461         }
 462     }
 463
 464 # ifdef HTTP_DAEMON
 465     /* Clear alarm before we close the client socket */
 466     alarm(0);
 467     timeout = 0;
 468 # endif
 469
 470     /* Try to read and parse request */
 471     req = ASN1_item_d2i_bio(it, getbio != NULL ? getbio : cbio, NULL);
 472     if (req == NULL) {
 473         log_HTTP(prog, LOG_WARNING,
 474                  "error parsing DER-encoded request content");
 475         (void)http_server_send_status(prog, cbio, 400, "Bad Request");
 476     } else if (ppath != NULL && (*ppath = OPENSSL_strdup(url)) == NULL) {
 477         log_HTTP1(prog, LOG_ERR,
 478                   "out of memory allocating %zu bytes", strlen(url) + 1);
 479         ASN1_item_free(req, it);
 480         goto fatal;
 481     }
 482
 483     *preq = req;
 484
 485  out:
 486     BIO_free_all(getbio);
 487 # ifdef HTTP_DAEMON
 488     if (timeout > 0)
 489         alarm(0);
 490     acfd = (int)INVALID_SOCKET;
 491 # endif
 492     return ret;
 493
 494  fatal:
 495     (void)http_server_send_status(prog, cbio, 500, "Internal Server Error");
 496     if (ppath != NULL) {
 497         OPENSSL_free(*ppath);
 498         *ppath = NULL;
 499     }
 500     BIO_free_all(cbio);
 501     *pcbio = NULL;
 502     ret = -1;
 503     goto out;
 504 }
 505
 506 /* assumes that cbio does not do an encoding that changes the output length */
 507 int http_server_send_asn1_resp(const char *prog, BIO *cbio, int keep_alive,
 508                                const char *content_type,
 509                                const ASN1_ITEM *it, const ASN1_VALUE *resp)
 510 {
 511     char buf[200], *p;
 512     int ret = BIO_snprintf(buf, sizeof(buf), HTTP_1_0" 200 OK\r\n%s"
 513                            "Content-type: %s\r\n"
 514                            "Content-Length: %d\r\n",
 515                            keep_alive ? "Connection: keep-alive\r\n" : "",
 516                            content_type,
 517                            ASN1_item_i2d(resp, NULL, it));
 518
 519     if (ret < 0 || (size_t)ret >= sizeof(buf))
 520         return 0;
 521     if (log_get_verbosity() < LOG_TRACE && (p = strchr(buf, '\r')) != NULL)
 522         trace_log_message(-1, prog, LOG_INFO,
 523                           "sending response, 1st line: %.*s", (int)(p - buf),
 524                           buf);
 525     log_HTTP1(prog, LOG_TRACE, "sending response header:\n%s", buf);
 526
 527     ret = BIO_printf(cbio, "%s\r\n", buf) > 0
 528         && ASN1_item_i2d_bio(it, cbio, resp) > 0;
 529
 530     (void)BIO_flush(cbio);
 531     return ret;
 532 }
 533
 534 int http_server_send_status(const char *prog, BIO *cbio,
 535                             int status, const char *reason)
 536 {
 537     char buf[200];
 538     int ret = BIO_snprintf(buf, sizeof(buf), HTTP_1_0" %d %s\r\n\r\n",
 539                            /* This implicitly cancels keep-alive */
 540                            status, reason);
 541
 542     if (ret < 0 || (size_t)ret >= sizeof(buf))
 543         return 0;
 544     log_HTTP1(prog, LOG_TRACE, "sending response header:\n%s", buf);
 545
 546     ret = BIO_printf(cbio, "%s\r\n", buf) > 0;
 547     (void)BIO_flush(cbio);
 548     return ret;
 549 }
 550 #endif