gotwebd/fcgi.c

   1 /*
   2  * Copyright (c) 2020-2022 Tracey Emery <tracey@traceyemery.net>
   3  * Copyright (c) 2013 David Gwynne <dlg@openbsd.org>
   4  * Copyright (c) 2013 Florian Obser <florian@openbsd.org>
   5  *
   6  * Permission to use, copy, modify, and 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 "got_compat.h"
  20
  21 #include <arpa/inet.h>
  22 #include <sys/queue.h>
  23 #include <sys/socket.h>
  24 #include <sys/types.h>
  25 #include <sys/uio.h>
  26
  27 #include <errno.h>
  28 #include <event.h>
  29 #include <imsg.h>
  30 #include <stdarg.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <time.h>
  35 #include <unistd.h>
  36
  37 #include "got_error.h"
  38 #include "got_reference.h"
  39
  40 #include "gotwebd.h"
  41 #include "log.h"
  42 #include "tmpl.h"
  43
  44 size_t   fcgi_parse_record(uint8_t *, size_t, struct request *);
  45 void     fcgi_parse_begin_request(uint8_t *, uint16_t, struct request *,
  46             uint16_t);
  47 void     fcgi_parse_params(uint8_t *, uint16_t, struct request *, uint16_t);
  48 int      fcgi_send_response(struct request *, int, const void *, size_t);
  49
  50 void     dump_fcgi_request_body(const char *, struct fcgi_record_header *);
  51 void     dump_fcgi_record_header(const char *, struct fcgi_record_header *);
  52 void     dump_fcgi_begin_request_body(const char *,
  53             struct fcgi_begin_request_body *);
  54 void     dump_fcgi_end_request_body(const char *,
  55             struct fcgi_end_request_body *);
  56
  57 extern int       cgi_inflight;
  58 extern volatile int client_cnt;
  59
  60 void
  61 fcgi_request(int fd, short events, void *arg)
  62 {
  63         struct request *c = arg;
  64         ssize_t n;
  65         size_t parsed = 0;
  66
  67         n = read(fd, c->buf + c->buf_pos + c->buf_len,
  68             FCGI_RECORD_SIZE - c->buf_pos - c->buf_len);
  69
  70         switch (n) {
  71         case -1:
  72                 switch (errno) {
  73                 case EINTR:
  74                 case EAGAIN:
  75                         return;
  76                 default:
  77                         goto fail;
  78                 }
  79                 break;
  80
  81         case 0:
  82                 log_info("closed connection");
  83                 goto fail;
  84         default:
  85                 break;
  86         }
  87
  88         c->buf_len += n;
  89
  90         /*
  91          * Parse the records as they are received. Per the FastCGI
  92          * specification, the server need only receive the FastCGI
  93          * parameter records in full; it is free to begin execution
  94          * at that point, which is what happens here.
  95          */
  96         do {
  97                 parsed = fcgi_parse_record(c->buf + c->buf_pos, c->buf_len, c);
  98                 if (parsed != 0) {
  99                         c->buf_pos += parsed;
 100                         c->buf_len -= parsed;
 101                 }
 102
 103                 /* drop the parsed record */
 104                 if (parsed != 0 && c->buf_len > 0) {
 105                         memmove(c->buf, c->buf + c->buf_pos, c->buf_len);
 106                         c->buf_pos = 0;
 107                 }
 108         } while (parsed > 0 && c->buf_len > 0);
 109
 110         return;
 111 fail:
 112         fcgi_cleanup_request(c);
 113 }
 114
 115 size_t
 116 fcgi_parse_record(uint8_t *buf, size_t n, struct request *c)
 117 {
 118         struct fcgi_record_header *h;
 119
 120         if (n < sizeof(struct fcgi_record_header))
 121                 return 0;
 122
 123         h = (struct fcgi_record_header*) buf;
 124
 125         dump_fcgi_record_header("", h);
 126
 127         if (n < sizeof(struct fcgi_record_header) + ntohs(h->content_len)
 128             + h->padding_len)
 129                 return 0;
 130
 131         dump_fcgi_request_body("", h);
 132
 133         if (h->version != 1)
 134                 log_warn("wrong version");
 135
 136         switch (h->type) {
 137         case FCGI_BEGIN_REQUEST:
 138                 fcgi_parse_begin_request(buf +
 139                     sizeof(struct fcgi_record_header),
 140                     ntohs(h->content_len), c, ntohs(h->id));
 141                 break;
 142         case FCGI_PARAMS:
 143                 fcgi_parse_params(buf + sizeof(struct fcgi_record_header),
 144                     ntohs(h->content_len), c, ntohs(h->id));
 145                 break;
 146         case FCGI_STDIN:
 147         case FCGI_ABORT_REQUEST:
 148                 fcgi_create_end_record(c);
 149                 fcgi_cleanup_request(c);
 150                 return 0;
 151         default:
 152                 log_warn("unimplemented type %d", h->type);
 153                 break;
 154         }
 155
 156         return (sizeof(struct fcgi_record_header) + ntohs(h->content_len)
 157             + h->padding_len);
 158 }
 159
 160 void
 161 fcgi_parse_begin_request(uint8_t *buf, uint16_t n,
 162     struct request *c, uint16_t id)
 163 {
 164         /* XXX -- FCGI_CANT_MPX_CONN */
 165         if (c->request_started) {
 166                 log_warn("unexpected FCGI_BEGIN_REQUEST, ignoring");
 167                 return;
 168         }
 169
 170         if (n != sizeof(struct fcgi_begin_request_body)) {
 171                 log_warn("wrong size %d != %lu", n,
 172                     sizeof(struct fcgi_begin_request_body));
 173                 return;
 174         }
 175
 176         c->request_started = 1;
 177         c->id = id;
 178 }
 179
 180 void
 181 fcgi_parse_params(uint8_t *buf, uint16_t n, struct request *c, uint16_t id)
 182 {
 183         uint32_t name_len, val_len;
 184         uint8_t *val;
 185
 186         if (!c->request_started) {
 187                 log_warn("FCGI_PARAMS without FCGI_BEGIN_REQUEST, ignoring");
 188                 return;
 189         }
 190
 191         if (c->id != id) {
 192                 log_warn("unexpected id, ignoring");
 193                 return;
 194         }
 195
 196         if (n == 0) {
 197                 gotweb_process_request(c);
 198                 template_flush(c->tp);
 199                 return;
 200         }
 201
 202         while (n > 0) {
 203                 if (buf[0] >> 7 == 0) {
 204                         name_len = buf[0];
 205                         n--;
 206                         buf++;
 207                 } else {
 208                         if (n > 3) {
 209                                 name_len = ((buf[0] & 0x7f) << 24) +
 210                                     (buf[1] << 16) + (buf[2] << 8) + buf[3];
 211                                 n -= 4;
 212                                 buf += 4;
 213                         } else
 214                                 return;
 215                 }
 216
 217                 if (n == 0)
 218                         return;
 219
 220                 if (buf[0] >> 7 == 0) {
 221                         val_len = buf[0];
 222                         n--;
 223                         buf++;
 224                 } else {
 225                         if (n > 3) {
 226                                 val_len = ((buf[0] & 0x7f) << 24) +
 227                                         (buf[1] << 16) + (buf[2] << 8) +
 228                                         buf[3];
 229                                 n -= 4;
 230                                 buf += 4;
 231                         } else
 232                                 return;
 233                 }
 234
 235                 if (n < name_len + val_len)
 236                         return;
 237
 238                 val = buf + name_len;
 239
 240                 if (val_len < MAX_QUERYSTRING &&
 241                     name_len == 12 &&
 242                     strncmp(buf, "QUERY_STRING", 12) == 0) {
 243                         memcpy(c->querystring, val, val_len);
 244                         c->querystring[val_len] = '\0';
 245                 }
 246
 247                 if (val_len < MAX_DOCUMENT_URI &&
 248                     name_len == 12 &&
 249                     strncmp(buf, "DOCUMENT_URI", 12) == 0) {
 250                         memcpy(c->document_uri, val, val_len);
 251                         c->document_uri[val_len] = '\0';
 252                 }
 253
 254                 if (val_len < MAX_SERVER_NAME &&
 255                     name_len == 11 &&
 256                     strncmp(buf, "SERVER_NAME", 11) == 0) {
 257                         memcpy(c->server_name, val, val_len);
 258                         c->server_name[val_len] = '\0';
 259                 }
 260
 261                 if (name_len == 5 &&
 262                     strncmp(buf, "HTTPS", 5) == 0)
 263                         c->https = 1;
 264
 265                 buf += name_len + val_len;
 266                 n -= name_len - val_len;
 267         }
 268 }
 269
 270 void
 271 fcgi_timeout(int fd, short events, void *arg)
 272 {
 273         fcgi_cleanup_request((struct request*) arg);
 274 }
 275
 276 static int
 277 send_response(struct request *c, int type, const uint8_t *data,
 278     size_t len)
 279 {
 280         static const uint8_t padding[FCGI_PADDING_SIZE];
 281         struct fcgi_record_header header;
 282         struct iovec iov[3];
 283         struct timespec ts;
 284         ssize_t nw;
 285         size_t padded_len, tot;
 286         int i, err = 0, th = 2000;
 287
 288         ts.tv_sec = 0;
 289         ts.tv_nsec = 50;
 290
 291         memset(&header, 0, sizeof(header));
 292         header.version = 1;
 293         header.type = type;
 294         header.id = htons(c->id);
 295         header.content_len = htons(len);
 296
 297         /* The FastCGI spec suggests to align the output buffer */
 298         tot = sizeof(header) + len;
 299         padded_len = FCGI_ALIGN(tot);
 300         if (padded_len > tot) {
 301                 header.padding_len = padded_len - tot;
 302                 tot += header.padding_len;
 303         }
 304
 305         iov[0].iov_base = &header;
 306         iov[0].iov_len = sizeof(header);
 307
 308         iov[1].iov_base = (void *)data;
 309         iov[1].iov_len = len;
 310
 311         iov[2].iov_base = (void *)padding;
 312         iov[2].iov_len = header.padding_len;
 313
 314         dump_fcgi_record_header("resp ", &header);
 315
 316         /*
 317          * XXX: add some simple write heuristics here
 318          * On slower VMs, spotty connections, etc., we don't want to go right to
 319          * disconnect. Let's at least try to write the data a few times before
 320          * giving up.
 321          */
 322         while (tot > 0) {
 323                 nw = writev(c->fd, iov, nitems(iov));
 324                 if (nw == 0) {
 325                         c->sock->client_status = CLIENT_DISCONNECT;
 326                         break;
 327                 }
 328                 if (nw == -1) {
 329                         err++;
 330                         if (errno == EAGAIN && err < th) {
 331                                 nanosleep(&ts, NULL);
 332                                 continue;
 333                         }
 334                         log_warn("%s: write failure", __func__);
 335                         c->sock->client_status = CLIENT_DISCONNECT;
 336                         return -1;
 337                 }
 338
 339                 if (nw != tot)
 340                         log_warnx("%s: partial write: %zu vs %zu", __func__,
 341                             nw, tot);
 342
 343                 tot -= nw;
 344                 for (i = 0; i < nitems(iov); ++i) {
 345                         if (nw < iov[i].iov_len) {
 346                                 iov[i].iov_base += nw;
 347                                 iov[i].iov_len -= nw;
 348                                 break;
 349                         }
 350                         nw -= iov[i].iov_len;
 351                         iov[i].iov_len = 0;
 352                 }
 353         }
 354
 355         return 0;
 356 }
 357
 358 int
 359 fcgi_send_response(struct request *c, int type, const void *data,
 360     size_t len)
 361 {
 362         if (c->sock->client_status == CLIENT_DISCONNECT)
 363                 return -1;
 364
 365         while (len > FCGI_CONTENT_SIZE) {
 366                 if (send_response(c, type, data, len) == -1)
 367                         return -1;
 368
 369                 data += FCGI_CONTENT_SIZE;
 370                 len -= FCGI_CONTENT_SIZE;
 371         }
 372
 373         if (len == 0)
 374                 return 0;
 375
 376         return send_response(c, type, data, len);
 377 }
 378
 379 int
 380 fcgi_write(void *arg, const void *buf, size_t len)
 381 {
 382         struct request  *c = arg;
 383
 384         return fcgi_send_response(c, FCGI_STDOUT, buf, len);
 385 }
 386
 387 void
 388 fcgi_create_end_record(struct request *c)
 389 {
 390         struct fcgi_end_request_body end_request;
 391
 392         memset(&end_request, 0, sizeof(end_request));
 393         end_request.app_status = htonl(0); /* script status */
 394         end_request.protocol_status = FCGI_REQUEST_COMPLETE;
 395
 396         fcgi_send_response(c, FCGI_END_REQUEST, &end_request,
 397             sizeof(end_request));
 398 }
 399
 400 void
 401 fcgi_cleanup_request(struct request *c)
 402 {
 403         cgi_inflight--;
 404         client_cnt--;
 405
 406         evtimer_del(&c->tmo);
 407         if (event_initialized(&c->ev))
 408                 event_del(&c->ev);
 409
 410         close(c->fd);
 411         template_free(c->tp);
 412         if (c->t != NULL)
 413                 gotweb_free_transport(c->t);
 414         free(c);
 415 }
 416
 417 void
 418 dump_fcgi_request_body(const char *p, struct fcgi_record_header *h)
 419 {
 420         if (h->type == FCGI_BEGIN_REQUEST)
 421                 dump_fcgi_begin_request_body(p,
 422                     (struct fcgi_begin_request_body *)(h + 1));
 423         else if (h->type == FCGI_END_REQUEST)
 424                 dump_fcgi_end_request_body(p,
 425                     (struct fcgi_end_request_body *)(h + 1));
 426 }
 427
 428 void
 429 dump_fcgi_record_header(const char* p, struct fcgi_record_header *h)
 430 {
 431         log_debug("%sversion:         %d", p, h->version);
 432         log_debug("%stype:            %d", p, h->type);
 433         log_debug("%srequestId:       %d", p, ntohs(h->id));
 434         log_debug("%scontentLength:   %d", p, ntohs(h->content_len));
 435         log_debug("%spaddingLength:   %d", p, h->padding_len);
 436         log_debug("%sreserved:        %d", p, h->reserved);
 437 }
 438
 439 void
 440 dump_fcgi_begin_request_body(const char *p, struct fcgi_begin_request_body *b)
 441 {
 442         log_debug("%srole             %d", p, ntohs(b->role));
 443         log_debug("%sflags            %d", p, b->flags);
 444 }
 445
 446 void
 447 dump_fcgi_end_request_body(const char *p, struct fcgi_end_request_body *b)
 448 {
 449         log_debug("%sappStatus:       %d", p, ntohl(b->app_status));
 450         log_debug("%sprotocolStatus:  %d", p, b->protocol_status);
 451 }