lib/libfetch/http.c

   1 /*-
   2  * Copyright (c) 2000-2011 Dag-Erling Smørgrav
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * The following copyright applies to the base64 code:
  31  *
  32  *-
  33  * Copyright 1997 Massachusetts Institute of Technology
  34  *
  35  * Permission to use, copy, modify, and distribute this software and
  36  * its documentation for any purpose and without fee is hereby
  37  * granted, provided that both the above copyright notice and this
  38  * permission notice appear in all copies, that both the above
  39  * copyright notice and this permission notice appear in all
  40  * supporting documentation, and that the name of M.I.T. not be used
  41  * in advertising or publicity pertaining to distribution of the
  42  * software without specific, written prior permission.  M.I.T. makes
  43  * no representations about the suitability of this software for any
  44  * purpose.  It is provided "as is" without express or implied
  45  * warranty.
  46  *
  47  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  48  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  49  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  50  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  51  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  52  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  53  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  54  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  55  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  56  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  57  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/socket.h>
  63 #include <sys/time.h>
  64
  65 #include <ctype.h>
  66 #include <err.h>
  67 #include <errno.h>
  68 #include <locale.h>
  69 #include <netdb.h>
  70 #include <stdarg.h>
  71 #include <stdio.h>
  72 #include <stdlib.h>
  73 #include <string.h>
  74 #include <time.h>
  75 #include <unistd.h>
  76
  77 #ifdef WITH_SSL
  78 #include <openssl/md5.h>
  79 #define MD5Init(c) MD5_Init(c)
  80 #define MD5Update(c, data, len) MD5_Update(c, data, len)
  81 #define MD5Final(md, c) MD5_Final(md, c)
  82 #else
  83 #include <md5.h>
  84 #endif
  85
  86 #include <netinet/in.h>
  87 #include <netinet/tcp.h>
  88
  89 #include "fetch.h"
  90 #include "common.h"
  91 #include "httperr.h"
  92
  93 /* Maximum number of redirects to follow */
  94 #define MAX_REDIRECT 20
  95
  96 /* Symbolic names for reply codes we care about */
  97 #define HTTP_OK                 200
  98 #define HTTP_PARTIAL            206
  99 #define HTTP_MOVED_PERM         301
 100 #define HTTP_MOVED_TEMP         302
 101 #define HTTP_SEE_OTHER          303
 102 #define HTTP_NOT_MODIFIED       304
 103 #define HTTP_USE_PROXY          305
 104 #define HTTP_TEMP_REDIRECT      307
 105 #define HTTP_PERM_REDIRECT      308
 106 #define HTTP_NEED_AUTH          401
 107 #define HTTP_NEED_PROXY_AUTH    407
 108 #define HTTP_BAD_RANGE          416
 109 #define HTTP_PROTOCOL_ERROR     999
 110
 111 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
 112                             || (xyz) == HTTP_MOVED_TEMP \
 113                             || (xyz) == HTTP_TEMP_REDIRECT \
 114                             || (xyz) == HTTP_USE_PROXY \
 115                             || (xyz) == HTTP_SEE_OTHER)
 116
 117 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
 118
 119
 120 /*****************************************************************************
 121  * I/O functions for decoding chunked streams
 122  */
 123
 124 struct httpio
 125 {
 126         conn_t          *conn;          /* connection */
 127         int              chunked;       /* chunked mode */
 128         char            *buf;           /* chunk buffer */
 129         size_t           bufsize;       /* size of chunk buffer */
 130         ssize_t          buflen;        /* amount of data currently in buffer */
 131         int              bufpos;        /* current read offset in buffer */
 132         int              eof;           /* end-of-file flag */
 133         int              error;         /* error flag */
 134         size_t           chunksize;     /* remaining size of current chunk */
 135 #ifndef NDEBUG
 136         size_t           total;
 137 #endif
 138 };
 139
 140 static int http_cmd(conn_t *, const char *, ...) __printflike(2, 3);
 141
 142 /*
 143  * Get next chunk header
 144  */
 145 static int
 146 http_new_chunk(struct httpio *io)
 147 {
 148         char *p;
 149
 150         if (fetch_getln(io->conn) == -1)
 151                 return (-1);
 152
 153         if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
 154                 return (-1);
 155
 156         for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
 157                 if (*p == ';')
 158                         break;
 159                 if (!isxdigit((unsigned char)*p))
 160                         return (-1);
 161                 if (isdigit((unsigned char)*p)) {
 162                         io->chunksize = io->chunksize * 16 +
 163                             *p - '0';
 164                 } else {
 165                         io->chunksize = io->chunksize * 16 +
 166                             10 + tolower((unsigned char)*p) - 'a';
 167                 }
 168         }
 169
 170 #ifndef NDEBUG
 171         if (fetchDebug) {
 172                 io->total += io->chunksize;
 173                 if (io->chunksize == 0)
 174                         fprintf(stderr, "%s(): end of last chunk\n", __func__);
 175                 else
 176                         fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
 177                             __func__, (unsigned long)io->chunksize,
 178                             (unsigned long)io->total);
 179         }
 180 #endif
 181
 182         return (io->chunksize);
 183 }
 184
 185 /*
 186  * Grow the input buffer to at least len bytes
 187  */
 188 static inline int
 189 http_growbuf(struct httpio *io, size_t len)
 190 {
 191         char *tmp;
 192
 193         if (io->bufsize >= len)
 194                 return (0);
 195
 196         if ((tmp = realloc(io->buf, len)) == NULL)
 197                 return (-1);
 198         io->buf = tmp;
 199         io->bufsize = len;
 200         return (0);
 201 }
 202
 203 /*
 204  * Fill the input buffer, do chunk decoding on the fly
 205  */
 206 static int
 207 http_fillbuf(struct httpio *io, size_t len)
 208 {
 209         ssize_t nbytes;
 210
 211         if (io->error)
 212                 return (-1);
 213         if (io->eof)
 214                 return (0);
 215
 216         if (io->chunked == 0) {
 217                 if (http_growbuf(io, len) == -1)
 218                         return (-1);
 219                 if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 220                         io->error = errno;
 221                         return (-1);
 222                 }
 223                 io->buflen = nbytes;
 224                 io->bufpos = 0;
 225                 return (io->buflen);
 226         }
 227
 228         if (io->chunksize == 0) {
 229                 switch (http_new_chunk(io)) {
 230                 case -1:
 231                         io->error = 1;
 232                         return (-1);
 233                 case 0:
 234                         io->eof = 1;
 235                         return (0);
 236                 }
 237         }
 238
 239         if (len > io->chunksize)
 240                 len = io->chunksize;
 241         if (http_growbuf(io, len) == -1)
 242                 return (-1);
 243         if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 244                 io->error = errno;
 245                 return (-1);
 246         }
 247         io->buflen = nbytes;
 248         io->chunksize -= io->buflen;
 249
 250         if (io->chunksize == 0) {
 251                 char endl[2];
 252
 253                 if (fetch_read(io->conn, endl, 2) != 2 ||
 254                     endl[0] != '\r' || endl[1] != '\n')
 255                         return (-1);
 256         }
 257
 258         io->bufpos = 0;
 259
 260         return (io->buflen);
 261 }
 262
 263 /*
 264  * Read function
 265  */
 266 static int
 267 http_readfn(void *v, char *buf, int len)
 268 {
 269         struct httpio *io = (struct httpio *)v;
 270         int l, pos;
 271
 272         if (io->error)
 273                 return (-1);
 274         if (io->eof)
 275                 return (0);
 276
 277         for (pos = 0; len > 0; pos += l, len -= l) {
 278                 /* empty buffer */
 279                 if (!io->buf || io->bufpos == io->buflen)
 280                         if (http_fillbuf(io, len) < 1)
 281                                 break;
 282                 l = io->buflen - io->bufpos;
 283                 if (len < l)
 284                         l = len;
 285                 memcpy(buf + pos, io->buf + io->bufpos, l);
 286                 io->bufpos += l;
 287         }
 288
 289         if (!pos && io->error) {
 290                 if (io->error == EINTR)
 291                         io->error = 0;
 292                 return (-1);
 293         }
 294         return (pos);
 295 }
 296
 297 /*
 298  * Write function
 299  */
 300 static int
 301 http_writefn(void *v, const char *buf, int len)
 302 {
 303         struct httpio *io = (struct httpio *)v;
 304
 305         return (fetch_write(io->conn, buf, len));
 306 }
 307
 308 /*
 309  * Close function
 310  */
 311 static int
 312 http_closefn(void *v)
 313 {
 314         struct httpio *io = (struct httpio *)v;
 315         int r;
 316
 317         r = fetch_close(io->conn);
 318         if (io->buf)
 319                 free(io->buf);
 320         free(io);
 321         return (r);
 322 }
 323
 324 /*
 325  * Wrap a file descriptor up
 326  */
 327 static FILE *
 328 http_funopen(conn_t *conn, int chunked)
 329 {
 330         struct httpio *io;
 331         FILE *f;
 332
 333         if ((io = calloc(1, sizeof(*io))) == NULL) {
 334                 fetch_syserr();
 335                 return (NULL);
 336         }
 337         io->conn = conn;
 338         io->chunked = chunked;
 339         f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
 340         if (f == NULL) {
 341                 fetch_syserr();
 342                 free(io);
 343                 return (NULL);
 344         }
 345         return (f);
 346 }
 347
 348
 349 /*****************************************************************************
 350  * Helper functions for talking to the server and parsing its replies
 351  */
 352
 353 /* Header types */
 354 typedef enum {
 355         hdr_syserror = -2,
 356         hdr_error = -1,
 357         hdr_end = 0,
 358         hdr_unknown = 1,
 359         hdr_content_length,
 360         hdr_content_range,
 361         hdr_last_modified,
 362         hdr_location,
 363         hdr_transfer_encoding,
 364         hdr_www_authenticate,
 365         hdr_proxy_authenticate,
 366 } hdr_t;
 367
 368 /* Names of interesting headers */
 369 static struct {
 370         hdr_t            num;
 371         const char      *name;
 372 } hdr_names[] = {
 373         { hdr_content_length,           "Content-Length" },
 374         { hdr_content_range,            "Content-Range" },
 375         { hdr_last_modified,            "Last-Modified" },
 376         { hdr_location,                 "Location" },
 377         { hdr_transfer_encoding,        "Transfer-Encoding" },
 378         { hdr_www_authenticate,         "WWW-Authenticate" },
 379         { hdr_proxy_authenticate,       "Proxy-Authenticate" },
 380         { hdr_unknown,                  NULL },
 381 };
 382
 383 /*
 384  * Send a formatted line; optionally echo to terminal
 385  */
 386 static int
 387 http_cmd(conn_t *conn, const char *fmt, ...)
 388 {
 389         va_list ap;
 390         size_t len;
 391         char *msg;
 392         int r;
 393
 394         va_start(ap, fmt);
 395         len = vasprintf(&msg, fmt, ap);
 396         va_end(ap);
 397
 398         if (msg == NULL) {
 399                 errno = ENOMEM;
 400                 fetch_syserr();
 401                 return (-1);
 402         }
 403
 404         r = fetch_putln(conn, msg, len);
 405         free(msg);
 406
 407         if (r == -1) {
 408                 fetch_syserr();
 409                 return (-1);
 410         }
 411
 412         return (0);
 413 }
 414
 415 /*
 416  * Get and parse status line
 417  */
 418 static int
 419 http_get_reply(conn_t *conn)
 420 {
 421         char *p;
 422
 423         if (fetch_getln(conn) == -1)
 424                 return (-1);
 425         /*
 426          * A valid status line looks like "HTTP/m.n xyz reason" where m
 427          * and n are the major and minor protocol version numbers and xyz
 428          * is the reply code.
 429          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
 430          * just one) that do not send a version number, so we can't rely
 431          * on finding one, but if we do, insist on it being 1.0 or 1.1.
 432          * We don't care about the reason phrase.
 433          */
 434         if (strncmp(conn->buf, "HTTP", 4) != 0)
 435                 return (HTTP_PROTOCOL_ERROR);
 436         p = conn->buf + 4;
 437         if (*p == '/') {
 438                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
 439                         return (HTTP_PROTOCOL_ERROR);
 440                 p += 4;
 441         }
 442         if (*p != ' ' ||
 443             !isdigit((unsigned char)p[1]) ||
 444             !isdigit((unsigned char)p[2]) ||
 445             !isdigit((unsigned char)p[3]))
 446                 return (HTTP_PROTOCOL_ERROR);
 447
 448         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
 449         return (conn->err);
 450 }
 451
 452 /*
 453  * Check a header; if the type matches the given string, return a pointer
 454  * to the beginning of the value.
 455  */
 456 static const char *
 457 http_match(const char *str, const char *hdr)
 458 {
 459         while (*str && *hdr &&
 460             tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
 461                 /* nothing */;
 462         if (*str || *hdr != ':')
 463                 return (NULL);
 464         while (*hdr && isspace((unsigned char)*++hdr))
 465                 /* nothing */;
 466         return (hdr);
 467 }
 468
 469
 470 /*
 471  * Get the next header and return the appropriate symbolic code.  We
 472  * need to read one line ahead for checking for a continuation line
 473  * belonging to the current header (continuation lines start with
 474  * white space).
 475  *
 476  * We get called with a fresh line already in the conn buffer, either
 477  * from the previous http_next_header() invocation, or, the first
 478  * time, from a fetch_getln() performed by our caller.
 479  *
 480  * This stops when we encounter an empty line (we dont read beyond the header
 481  * area).
 482  *
 483  * Note that the "headerbuf" is just a place to return the result. Its
 484  * contents are not used for the next call. This means that no cleanup
 485  * is needed when ie doing another connection, just call the cleanup when
 486  * fully done to deallocate memory.
 487  */
 488
 489 /* Limit the max number of continuation lines to some reasonable value */
 490 #define HTTP_MAX_CONT_LINES 10
 491
 492 /* Place into which to build a header from one or several lines */
 493 typedef struct {
 494         char    *buf;           /* buffer */
 495         size_t   bufsize;       /* buffer size */
 496         size_t   buflen;        /* length of buffer contents */
 497 } http_headerbuf_t;
 498
 499 static void
 500 init_http_headerbuf(http_headerbuf_t *buf)
 501 {
 502         buf->buf = NULL;
 503         buf->bufsize = 0;
 504         buf->buflen = 0;
 505 }
 506
 507 static void
 508 clean_http_headerbuf(http_headerbuf_t *buf)
 509 {
 510         if (buf->buf)
 511                 free(buf->buf);
 512         init_http_headerbuf(buf);
 513 }
 514
 515 /* Remove whitespace at the end of the buffer */
 516 static void
 517 http_conn_trimright(conn_t *conn)
 518 {
 519         while (conn->buflen &&
 520                isspace((unsigned char)conn->buf[conn->buflen - 1]))
 521                 conn->buflen--;
 522         conn->buf[conn->buflen] = '\0';
 523 }
 524
 525 static hdr_t
 526 http_next_header(conn_t *conn, http_headerbuf_t *hbuf, const char **p)
 527 {
 528         unsigned int i, len;
 529
 530         /*
 531          * Have to do the stripping here because of the first line. So
 532          * it's done twice for the subsequent lines. No big deal
 533          */
 534         http_conn_trimright(conn);
 535         if (conn->buflen == 0)
 536                 return (hdr_end);
 537
 538         /* Copy the line to the headerbuf */
 539         if (hbuf->bufsize < conn->buflen + 1) {
 540                 if ((hbuf->buf = realloc(hbuf->buf, conn->buflen + 1)) == NULL)
 541                         return (hdr_syserror);
 542                 hbuf->bufsize = conn->buflen + 1;
 543         }
 544         strcpy(hbuf->buf, conn->buf);
 545         hbuf->buflen = conn->buflen;
 546
 547         /*
 548          * Fetch possible continuation lines. Stop at 1st non-continuation
 549          * and leave it in the conn buffer
 550          */
 551         for (i = 0; i < HTTP_MAX_CONT_LINES; i++) {
 552                 if (fetch_getln(conn) == -1)
 553                         return (hdr_syserror);
 554
 555                 /*
 556                  * Note: we carry on the idea from the previous version
 557                  * that a pure whitespace line is equivalent to an empty
 558                  * one (so it's not continuation and will be handled when
 559                  * we are called next)
 560                  */
 561                 http_conn_trimright(conn);
 562                 if (conn->buf[0] != ' ' && conn->buf[0] != "\t"[0])
 563                         break;
 564
 565                 /* Got a continuation line. Concatenate to previous */
 566                 len = hbuf->buflen + conn->buflen;
 567                 if (hbuf->bufsize < len + 1) {
 568                         len *= 2;
 569                         if ((hbuf->buf = realloc(hbuf->buf, len + 1)) == NULL)
 570                                 return (hdr_syserror);
 571                         hbuf->bufsize = len + 1;
 572                 }
 573                 strcpy(hbuf->buf + hbuf->buflen, conn->buf);
 574                 hbuf->buflen += conn->buflen;
 575         }
 576
 577         /*
 578          * We could check for malformed headers but we don't really care.
 579          * A valid header starts with a token immediately followed by a
 580          * colon; a token is any sequence of non-control, non-whitespace
 581          * characters except "()<>@,;:\\\"{}".
 582          */
 583         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
 584                 if ((*p = http_match(hdr_names[i].name, hbuf->buf)) != NULL)
 585                         return (hdr_names[i].num);
 586
 587         return (hdr_unknown);
 588 }
 589
 590 /**************************
 591  * [Proxy-]Authenticate header parsing
 592  */
 593
 594 /*
 595  * Read doublequote-delimited string into output buffer obuf (allocated
 596  * by caller, whose responsibility it is to ensure that it's big enough)
 597  * cp points to the first char after the initial '"'
 598  * Handles \ quoting
 599  * Returns pointer to the first char after the terminating double quote, or
 600  * NULL for error.
 601  */
 602 static const char *
 603 http_parse_headerstring(const char *cp, char *obuf)
 604 {
 605         for (;;) {
 606                 switch (*cp) {
 607                 case 0: /* Unterminated string */
 608                         *obuf = 0;
 609                         return (NULL);
 610                 case '"': /* Ending quote */
 611                         *obuf = 0;
 612                         return (++cp);
 613                 case '\\':
 614                         if (*++cp == 0) {
 615                                 *obuf = 0;
 616                                 return (NULL);
 617                         }
 618                         /* FALLTHROUGH */
 619                 default:
 620                         *obuf++ = *cp++;
 621                 }
 622         }
 623 }
 624
 625 /* Http auth challenge schemes */
 626 typedef enum {HTTPAS_UNKNOWN, HTTPAS_BASIC,HTTPAS_DIGEST} http_auth_schemes_t;
 627
 628 /* Data holder for a Basic or Digest challenge. */
 629 typedef struct {
 630         http_auth_schemes_t scheme;
 631         char    *realm;
 632         char    *qop;
 633         char    *nonce;
 634         char    *opaque;
 635         char    *algo;
 636         int      stale;
 637         int      nc; /* Nonce count */
 638 } http_auth_challenge_t;
 639
 640 static void
 641 init_http_auth_challenge(http_auth_challenge_t *b)
 642 {
 643         b->scheme = HTTPAS_UNKNOWN;
 644         b->realm = b->qop = b->nonce = b->opaque = b->algo = NULL;
 645         b->stale = b->nc = 0;
 646 }
 647
 648 static void
 649 clean_http_auth_challenge(http_auth_challenge_t *b)
 650 {
 651         if (b->realm)
 652                 free(b->realm);
 653         if (b->qop)
 654                 free(b->qop);
 655         if (b->nonce)
 656                 free(b->nonce);
 657         if (b->opaque)
 658                 free(b->opaque);
 659         if (b->algo)
 660                 free(b->algo);
 661         init_http_auth_challenge(b);
 662 }
 663
 664 /* Data holder for an array of challenges offered in an http response. */
 665 #define MAX_CHALLENGES 10
 666 typedef struct {
 667         http_auth_challenge_t *challenges[MAX_CHALLENGES];
 668         int     count; /* Number of parsed challenges in the array */
 669         int     valid; /* We did parse an authenticate header */
 670 } http_auth_challenges_t;
 671
 672 static void
 673 init_http_auth_challenges(http_auth_challenges_t *cs)
 674 {
 675         int i;
 676         for (i = 0; i < MAX_CHALLENGES; i++)
 677                 cs->challenges[i] = NULL;
 678         cs->count = cs->valid = 0;
 679 }
 680
 681 static void
 682 clean_http_auth_challenges(http_auth_challenges_t *cs)
 683 {
 684         int i;
 685         /* We rely on non-zero pointers being allocated, not on the count */
 686         for (i = 0; i < MAX_CHALLENGES; i++) {
 687                 if (cs->challenges[i] != NULL) {
 688                         clean_http_auth_challenge(cs->challenges[i]);
 689                         free(cs->challenges[i]);
 690                 }
 691         }
 692         init_http_auth_challenges(cs);
 693 }
 694
 695 /*
 696  * Enumeration for lexical elements. Separators will be returned as their own
 697  * ascii value
 698  */
 699 typedef enum {HTTPHL_WORD=256, HTTPHL_STRING=257, HTTPHL_END=258,
 700               HTTPHL_ERROR = 259} http_header_lex_t;
 701
 702 /*
 703  * Determine what kind of token comes next and return possible value
 704  * in buf, which is supposed to have been allocated big enough by
 705  * caller. Advance input pointer and return element type.
 706  */
 707 static int
 708 http_header_lex(const char **cpp, char *buf)
 709 {
 710         size_t l;
 711         /* Eat initial whitespace */
 712         *cpp += strspn(*cpp, " \t");
 713         if (**cpp == 0)
 714                 return (HTTPHL_END);
 715
 716         /* Separator ? */
 717         if (**cpp == ',' || **cpp == '=')
 718                 return (*((*cpp)++));
 719
 720         /* String ? */
 721         if (**cpp == '"') {
 722                 *cpp = http_parse_headerstring(++*cpp, buf);
 723                 if (*cpp == NULL)
 724                         return (HTTPHL_ERROR);
 725                 return (HTTPHL_STRING);
 726         }
 727
 728         /* Read other token, until separator or whitespace */
 729         l = strcspn(*cpp, " \t,=");
 730         memcpy(buf, *cpp, l);
 731         buf[l] = 0;
 732         *cpp += l;
 733         return (HTTPHL_WORD);
 734 }
 735
 736 /*
 737  * Read challenges from http xxx-authenticate header and accumulate them
 738  * in the challenges list structure.
 739  *
 740  * Headers with multiple challenges are specified by rfc2617, but
 741  * servers (ie: squid) often send them in separate headers instead,
 742  * which in turn is forbidden by the http spec (multiple headers with
 743  * the same name are only allowed for pure comma-separated lists, see
 744  * rfc2616 sec 4.2).
 745  *
 746  * We support both approaches anyway
 747  */
 748 static int
 749 http_parse_authenticate(const char *cp, http_auth_challenges_t *cs)
 750 {
 751         int ret = -1;
 752         http_header_lex_t lex;
 753         char *key = malloc(strlen(cp) + 1);
 754         char *value = malloc(strlen(cp) + 1);
 755         char *buf = malloc(strlen(cp) + 1);
 756
 757         if (key == NULL || value == NULL || buf == NULL) {
 758                 fetch_syserr();
 759                 goto out;
 760         }
 761
 762         /* In any case we've seen the header and we set the valid bit */
 763         cs->valid = 1;
 764
 765         /* Need word first */
 766         lex = http_header_lex(&cp, key);
 767         if (lex != HTTPHL_WORD)
 768                 goto out;
 769
 770         /* Loop on challenges */
 771         for (; cs->count < MAX_CHALLENGES; cs->count++) {
 772                 cs->challenges[cs->count] =
 773                         malloc(sizeof(http_auth_challenge_t));
 774                 if (cs->challenges[cs->count] == NULL) {
 775                         fetch_syserr();
 776                         goto out;
 777                 }
 778                 init_http_auth_challenge(cs->challenges[cs->count]);
 779                 if (!strcasecmp(key, "basic")) {
 780                         cs->challenges[cs->count]->scheme = HTTPAS_BASIC;
 781                 } else if (!strcasecmp(key, "digest")) {
 782                         cs->challenges[cs->count]->scheme = HTTPAS_DIGEST;
 783                 } else {
 784                         cs->challenges[cs->count]->scheme = HTTPAS_UNKNOWN;
 785                         /*
 786                          * Continue parsing as basic or digest may
 787                          * follow, and the syntax is the same for
 788                          * all. We'll just ignore this one when
 789                          * looking at the list
 790                          */
 791                 }
 792
 793                 /* Loop on attributes */
 794                 for (;;) {
 795                         /* Key */
 796                         lex = http_header_lex(&cp, key);
 797                         if (lex != HTTPHL_WORD)
 798                                 goto out;
 799
 800                         /* Equal sign */
 801                         lex = http_header_lex(&cp, buf);
 802                         if (lex != '=')
 803                                 goto out;
 804
 805                         /* Value */
 806                         lex = http_header_lex(&cp, value);
 807                         if (lex != HTTPHL_WORD && lex != HTTPHL_STRING)
 808                                 goto out;
 809
 810                         if (!strcasecmp(key, "realm"))
 811                                 cs->challenges[cs->count]->realm =
 812                                         strdup(value);
 813                         else if (!strcasecmp(key, "qop"))
 814                                 cs->challenges[cs->count]->qop =
 815                                         strdup(value);
 816                         else if (!strcasecmp(key, "nonce"))
 817                                 cs->challenges[cs->count]->nonce =
 818                                         strdup(value);
 819                         else if (!strcasecmp(key, "opaque"))
 820                                 cs->challenges[cs->count]->opaque =
 821                                         strdup(value);
 822                         else if (!strcasecmp(key, "algorithm"))
 823                                 cs->challenges[cs->count]->algo =
 824                                         strdup(value);
 825                         else if (!strcasecmp(key, "stale"))
 826                                 cs->challenges[cs->count]->stale =
 827                                         strcasecmp(value, "no");
 828                         /* Else ignore unknown attributes */
 829
 830                         /* Comma or Next challenge or End */
 831                         lex = http_header_lex(&cp, key);
 832                         /*
 833                          * If we get a word here, this is the beginning of the
 834                          * next challenge. Break the attributes loop
 835                          */
 836                         if (lex == HTTPHL_WORD)
 837                                 break;
 838
 839                         if (lex == HTTPHL_END) {
 840                                 /* End while looking for ',' is normal exit */
 841                                 cs->count++;
 842                                 ret = 0;
 843                                 goto out;
 844                         }
 845                         /* Anything else is an error */
 846                         if (lex != ',')
 847                                 goto out;
 848
 849                 } /* End attributes loop */
 850         } /* End challenge loop */
 851
 852         /*
 853          * Challenges max count exceeded. This really can't happen
 854          * with normal data, something's fishy -> error
 855          */
 856
 857 out:
 858         if (key)
 859                 free(key);
 860         if (value)
 861                 free(value);
 862         if (buf)
 863                 free(buf);
 864         return (ret);
 865 }
 866
 867
 868 /*
 869  * Parse a last-modified header
 870  */
 871 static int
 872 http_parse_mtime(const char *p, time_t *mtime)
 873 {
 874         char locale[64], *r;
 875         struct tm tm;
 876
 877         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
 878         setlocale(LC_TIME, "C");
 879         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
 880         /* XXX should add support for date-2 and date-3 */
 881         setlocale(LC_TIME, locale);
 882         if (r == NULL)
 883                 return (-1);
 884         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
 885                   "%02d:%02d:%02d]\n",
 886                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 887                   tm.tm_hour, tm.tm_min, tm.tm_sec));
 888         *mtime = timegm(&tm);
 889         return (0);
 890 }
 891
 892 /*
 893  * Parse a content-length header
 894  */
 895 static int
 896 http_parse_length(const char *p, off_t *length)
 897 {
 898         off_t len;
 899
 900         for (len = 0; *p && isdigit((unsigned char)*p); ++p)
 901                 len = len * 10 + (*p - '0');
 902         if (*p)
 903                 return (-1);
 904         DEBUG(fprintf(stderr, "content length: [%lld]\n",
 905             (long long)len));
 906         *length = len;
 907         return (0);
 908 }
 909
 910 /*
 911  * Parse a content-range header
 912  */
 913 static int
 914 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
 915 {
 916         off_t first, last, len;
 917
 918         if (strncasecmp(p, "bytes ", 6) != 0)
 919                 return (-1);
 920         p += 6;
 921         if (*p == '*') {
 922                 first = last = -1;
 923                 ++p;
 924         } else {
 925                 for (first = 0; *p && isdigit((unsigned char)*p); ++p)
 926                         first = first * 10 + *p - '0';
 927                 if (*p != '-')
 928                         return (-1);
 929                 for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 930                         last = last * 10 + *p - '0';
 931         }
 932         if (first > last || *p != '/')
 933                 return (-1);
 934         for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 935                 len = len * 10 + *p - '0';
 936         if (*p || len < last - first + 1)
 937                 return (-1);
 938         if (first == -1) {
 939                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
 940                     (long long)len));
 941                 *length = 0;
 942         } else {
 943                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
 944                     (long long)first, (long long)last, (long long)len));
 945                 *length = last - first + 1;
 946         }
 947         *offset = first;
 948         *size = len;
 949         return (0);
 950 }
 951
 952
 953 /*****************************************************************************
 954  * Helper functions for authorization
 955  */
 956
 957 /*
 958  * Base64 encoding
 959  */
 960 static char *
 961 http_base64(const char *src)
 962 {
 963         static const char base64[] =
 964             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 965             "abcdefghijklmnopqrstuvwxyz"
 966             "0123456789+/";
 967         char *str, *dst;
 968         size_t l;
 969         int t, r;
 970
 971         l = strlen(src);
 972         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
 973                 return (NULL);
 974         dst = str;
 975         r = 0;
 976
 977         while (l >= 3) {
 978                 t = (src[0] << 16) | (src[1] << 8) | src[2];
 979                 dst[0] = base64[(t >> 18) & 0x3f];
 980                 dst[1] = base64[(t >> 12) & 0x3f];
 981                 dst[2] = base64[(t >> 6) & 0x3f];
 982                 dst[3] = base64[(t >> 0) & 0x3f];
 983                 src += 3; l -= 3;
 984                 dst += 4; r += 4;
 985         }
 986
 987         switch (l) {
 988         case 2:
 989                 t = (src[0] << 16) | (src[1] << 8);
 990                 dst[0] = base64[(t >> 18) & 0x3f];
 991                 dst[1] = base64[(t >> 12) & 0x3f];
 992                 dst[2] = base64[(t >> 6) & 0x3f];
 993                 dst[3] = '=';
 994                 dst += 4;
 995                 r += 4;
 996                 break;
 997         case 1:
 998                 t = src[0] << 16;
 999                 dst[0] = base64[(t >> 18) & 0x3f];
1000                 dst[1] = base64[(t >> 12) & 0x3f];
1001                 dst[2] = dst[3] = '=';
1002                 dst += 4;
1003                 r += 4;
1004                 break;
1005         case 0:
1006                 break;
1007         }
1008
1009         *dst = 0;
1010         return (str);
1011 }
1012
1013
1014 /*
1015  * Extract authorization parameters from environment value.
1016  * The value is like scheme:realm:user:pass
1017  */
1018 typedef struct {
1019         char    *scheme;
1020         char    *realm;
1021         char    *user;
1022         char    *password;
1023 } http_auth_params_t;
1024
1025 static void
1026 init_http_auth_params(http_auth_params_t *s)
1027 {
1028         s->scheme = s->realm = s->user = s->password = 0;
1029 }
1030
1031 static void
1032 clean_http_auth_params(http_auth_params_t *s)
1033 {
1034         if (s->scheme)
1035                 free(s->scheme);
1036         if (s->realm)
1037                 free(s->realm);
1038         if (s->user)
1039                 free(s->user);
1040         if (s->password)
1041                 free(s->password);
1042         init_http_auth_params(s);
1043 }
1044
1045 static int
1046 http_authfromenv(const char *p, http_auth_params_t *parms)
1047 {
1048         int ret = -1;
1049         char *v, *ve;
1050         char *str = strdup(p);
1051
1052         if (str == NULL) {
1053                 fetch_syserr();
1054                 return (-1);
1055         }
1056         v = str;
1057
1058         if ((ve = strchr(v, ':')) == NULL)
1059                 goto out;
1060
1061         *ve = 0;
1062         if ((parms->scheme = strdup(v)) == NULL) {
1063                 fetch_syserr();
1064                 goto out;
1065         }
1066         v = ve + 1;
1067
1068         if ((ve = strchr(v, ':')) == NULL)
1069                 goto out;
1070
1071         *ve = 0;
1072         if ((parms->realm = strdup(v)) == NULL) {
1073                 fetch_syserr();
1074                 goto out;
1075         }
1076         v = ve + 1;
1077
1078         if ((ve = strchr(v, ':')) == NULL)
1079                 goto out;
1080
1081         *ve = 0;
1082         if ((parms->user = strdup(v)) == NULL) {
1083                 fetch_syserr();
1084                 goto out;
1085         }
1086         v = ve + 1;
1087
1088
1089         if ((parms->password = strdup(v)) == NULL) {
1090                 fetch_syserr();
1091                 goto out;
1092         }
1093         ret = 0;
1094 out:
1095         if (ret == -1)
1096                 clean_http_auth_params(parms);
1097         if (str)
1098                 free(str);
1099         return (ret);
1100 }
1101
1102
1103 /*
1104  * Digest response: the code to compute the digest is taken from the
1105  * sample implementation in RFC2616
1106  */
1107 #define IN const
1108 #define OUT
1109
1110 #define HASHLEN 16
1111 typedef char HASH[HASHLEN];
1112 #define HASHHEXLEN 32
1113 typedef char HASHHEX[HASHHEXLEN+1];
1114
1115 static const char *hexchars = "0123456789abcdef";
1116 static void
1117 CvtHex(IN HASH Bin, OUT HASHHEX Hex)
1118 {
1119         unsigned short i;
1120         unsigned char j;
1121
1122         for (i = 0; i < HASHLEN; i++) {
1123                 j = (Bin[i] >> 4) & 0xf;
1124                 Hex[i*2] = hexchars[j];
1125                 j = Bin[i] & 0xf;
1126                 Hex[i*2+1] = hexchars[j];
1127         };
1128         Hex[HASHHEXLEN] = '\0';
1129 };
1130
1131 /* calculate H(A1) as per spec */
1132 static void
1133 DigestCalcHA1(
1134         IN char * pszAlg,
1135         IN char * pszUserName,
1136         IN char * pszRealm,
1137         IN char * pszPassword,
1138         IN char * pszNonce,
1139         IN char * pszCNonce,
1140         OUT HASHHEX SessionKey
1141         )
1142 {
1143         MD5_CTX Md5Ctx;
1144         HASH HA1;
1145
1146         MD5Init(&Md5Ctx);
1147         MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName));
1148         MD5Update(&Md5Ctx, ":", 1);
1149         MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm));
1150         MD5Update(&Md5Ctx, ":", 1);
1151         MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword));
1152         MD5Final(HA1, &Md5Ctx);
1153         if (strcasecmp(pszAlg, "md5-sess") == 0) {
1154
1155                 MD5Init(&Md5Ctx);
1156                 MD5Update(&Md5Ctx, HA1, HASHLEN);
1157                 MD5Update(&Md5Ctx, ":", 1);
1158                 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1159                 MD5Update(&Md5Ctx, ":", 1);
1160                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1161                 MD5Final(HA1, &Md5Ctx);
1162         };
1163         CvtHex(HA1, SessionKey);
1164 }
1165
1166 /* calculate request-digest/response-digest as per HTTP Digest spec */
1167 static void
1168 DigestCalcResponse(
1169         IN HASHHEX HA1,           /* H(A1) */
1170         IN char * pszNonce,       /* nonce from server */
1171         IN char * pszNonceCount,  /* 8 hex digits */
1172         IN char * pszCNonce,      /* client nonce */
1173         IN char * pszQop,         /* qop-value: "", "auth", "auth-int" */
1174         IN char * pszMethod,      /* method from the request */
1175         IN char * pszDigestUri,   /* requested URL */
1176         IN HASHHEX HEntity,       /* H(entity body) if qop="auth-int" */
1177         OUT HASHHEX Response      /* request-digest or response-digest */
1178         )
1179 {
1180 /*      DEBUG(fprintf(stderr,
1181                       "Calc: HA1[%s] Nonce[%s] qop[%s] method[%s] URI[%s]\n",
1182                       HA1, pszNonce, pszQop, pszMethod, pszDigestUri));*/
1183         MD5_CTX Md5Ctx;
1184         HASH HA2;
1185         HASH RespHash;
1186         HASHHEX HA2Hex;
1187
1188         // calculate H(A2)
1189         MD5Init(&Md5Ctx);
1190         MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod));
1191         MD5Update(&Md5Ctx, ":", 1);
1192         MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri));
1193         if (strcasecmp(pszQop, "auth-int") == 0) {
1194                 MD5Update(&Md5Ctx, ":", 1);
1195                 MD5Update(&Md5Ctx, HEntity, HASHHEXLEN);
1196         };
1197         MD5Final(HA2, &Md5Ctx);
1198         CvtHex(HA2, HA2Hex);
1199
1200         // calculate response
1201         MD5Init(&Md5Ctx);
1202         MD5Update(&Md5Ctx, HA1, HASHHEXLEN);
1203         MD5Update(&Md5Ctx, ":", 1);
1204         MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1205         MD5Update(&Md5Ctx, ":", 1);
1206         if (*pszQop) {
1207                 MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount));
1208                 MD5Update(&Md5Ctx, ":", 1);
1209                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1210                 MD5Update(&Md5Ctx, ":", 1);
1211                 MD5Update(&Md5Ctx, pszQop, strlen(pszQop));
1212                 MD5Update(&Md5Ctx, ":", 1);
1213         };
1214         MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN);
1215         MD5Final(RespHash, &Md5Ctx);
1216         CvtHex(RespHash, Response);
1217 }
1218
1219 /*
1220  * Generate/Send a Digest authorization header
1221  * This looks like: [Proxy-]Authorization: credentials
1222  *
1223  *  credentials      = "Digest" digest-response
1224  *  digest-response  = 1#( username | realm | nonce | digest-uri
1225  *                      | response | [ algorithm ] | [cnonce] |
1226  *                      [opaque] | [message-qop] |
1227  *                          [nonce-count]  | [auth-param] )
1228  *  username         = "username" "=" username-value
1229  *  username-value   = quoted-string
1230  *  digest-uri       = "uri" "=" digest-uri-value
1231  *  digest-uri-value = request-uri   ; As specified by HTTP/1.1
1232  *  message-qop      = "qop" "=" qop-value
1233  *  cnonce           = "cnonce" "=" cnonce-value
1234  *  cnonce-value     = nonce-value
1235  *  nonce-count      = "nc" "=" nc-value
1236  *  nc-value         = 8LHEX
1237  *  response         = "response" "=" request-digest
1238  *  request-digest = <"> 32LHEX <">
1239  */
1240 static int
1241 http_digest_auth(conn_t *conn, const char *hdr, http_auth_challenge_t *c,
1242                  http_auth_params_t *parms, struct url *url)
1243 {
1244         int r;
1245         char noncecount[10];
1246         char cnonce[40];
1247         char *options = 0;
1248
1249         if (!c->realm || !c->nonce) {
1250                 DEBUG(fprintf(stderr, "realm/nonce not set in challenge\n"));
1251                 return(-1);
1252         }
1253         if (!c->algo)
1254                 c->algo = strdup("");
1255
1256         if (asprintf(&options, "%s%s%s%s",
1257                      *c->algo? ",algorithm=" : "", c->algo,
1258                      c->opaque? ",opaque=" : "", c->opaque?c->opaque:"")== -1)
1259                 return (-1);
1260
1261         if (!c->qop) {
1262                 c->qop = strdup("");
1263                 *noncecount = 0;
1264                 *cnonce = 0;
1265         } else {
1266                 c->nc++;
1267                 sprintf(noncecount, "%08x", c->nc);
1268                 /* We don't try very hard with the cnonce ... */
1269                 sprintf(cnonce, "%x%lx", getpid(), (unsigned long)time(0));
1270         }
1271
1272         HASHHEX HA1;
1273         DigestCalcHA1(c->algo, parms->user, c->realm,
1274                       parms->password, c->nonce, cnonce, HA1);
1275         DEBUG(fprintf(stderr, "HA1: [%s]\n", HA1));
1276         HASHHEX digest;
1277         DigestCalcResponse(HA1, c->nonce, noncecount, cnonce, c->qop,
1278                            "GET", url->doc, "", digest);
1279
1280         if (c->qop[0]) {
1281                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1282                              "nonce=\"%s\",uri=\"%s\",response=\"%s\","
1283                              "qop=\"auth\", cnonce=\"%s\", nc=%s%s",
1284                              hdr, parms->user, c->realm,
1285                              c->nonce, url->doc, digest,
1286                              cnonce, noncecount, options);
1287         } else {
1288                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1289                              "nonce=\"%s\",uri=\"%s\",response=\"%s\"%s",
1290                              hdr, parms->user, c->realm,
1291                              c->nonce, url->doc, digest, options);
1292         }
1293         if (options)
1294                 free(options);
1295         return (r);
1296 }
1297
1298 /*
1299  * Encode username and password
1300  */
1301 static int
1302 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
1303 {
1304         char *upw, *auth;
1305         int r;
1306
1307         DEBUG(fprintf(stderr, "basic: usr: [%s]\n", usr));
1308         DEBUG(fprintf(stderr, "basic: pwd: [%s]\n", pwd));
1309         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
1310                 return (-1);
1311         auth = http_base64(upw);
1312         free(upw);
1313         if (auth == NULL)
1314                 return (-1);
1315         r = http_cmd(conn, "%s: Basic %s", hdr, auth);
1316         free(auth);
1317         return (r);
1318 }
1319
1320 /*
1321  * Chose the challenge to answer and call the appropriate routine to
1322  * produce the header.
1323  */
1324 static int
1325 http_authorize(conn_t *conn, const char *hdr, http_auth_challenges_t *cs,
1326                http_auth_params_t *parms, struct url *url)
1327 {
1328         http_auth_challenge_t *digest = NULL;
1329         int i;
1330
1331         /* If user or pass are null we're not happy */
1332         if (!parms->user || !parms->password) {
1333                 DEBUG(fprintf(stderr, "NULL usr or pass\n"));
1334                 return (-1);
1335         }
1336
1337         /* Look for a Digest */
1338         for (i = 0; i < cs->count; i++) {
1339                 if (cs->challenges[i]->scheme == HTTPAS_DIGEST)
1340                         digest = cs->challenges[i];
1341         }
1342
1343         /* Error if "Digest" was specified and there is no Digest challenge */
1344         if (!digest && (parms->scheme &&
1345                         !strcasecmp(parms->scheme, "digest"))) {
1346                 DEBUG(fprintf(stderr,
1347                               "Digest auth in env, not supported by peer\n"));
1348                 return (-1);
1349         }
1350         /*
1351          * If "basic" was specified in the environment, or there is no Digest
1352          * challenge, do the basic thing. Don't need a challenge for this,
1353          * so no need to check basic!=NULL
1354          */
1355         if (!digest || (parms->scheme && !strcasecmp(parms->scheme,"basic")))
1356                 return (http_basic_auth(conn,hdr,parms->user,parms->password));
1357
1358         /* Else, prefer digest. We just checked that it's not NULL */
1359         return (http_digest_auth(conn, hdr, digest, parms, url));
1360 }
1361
1362 /*****************************************************************************
1363  * Helper functions for connecting to a server or proxy
1364  */
1365
1366 /*
1367  * Connect to the correct HTTP server or proxy.
1368  */
1369 static conn_t *
1370 http_connect(struct url *URL, struct url *purl, const char *flags)
1371 {
1372         conn_t *conn;
1373         int verbose;
1374         int af, val;
1375
1376 #ifdef INET6
1377         af = AF_UNSPEC;
1378 #else
1379         af = AF_INET;
1380 #endif
1381
1382         verbose = CHECK_FLAG('v');
1383         if (CHECK_FLAG('4'))
1384                 af = AF_INET;
1385 #ifdef INET6
1386         else if (CHECK_FLAG('6'))
1387                 af = AF_INET6;
1388 #endif
1389
1390         if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
1391                 URL = purl;
1392         } else if (strcasecmp(URL->scheme, SCHEME_FTP) == 0) {
1393                 /* can't talk http to an ftp server */
1394                 /* XXX should set an error code */
1395                 return (NULL);
1396         }
1397
1398         if ((conn = fetch_connect(URL->host, URL->port, af, verbose)) == NULL)
1399                 /* fetch_connect() has already set an error code */
1400                 return (NULL);
1401         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
1402             fetch_ssl(conn, verbose) == -1) {
1403                 fetch_close(conn);
1404                 /* grrr */
1405                 errno = EAUTH;
1406                 fetch_syserr();
1407                 return (NULL);
1408         }
1409
1410         val = 1;
1411         setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
1412
1413         return (conn);
1414 }
1415
1416 static struct url *
1417 http_get_proxy(struct url * url, const char *flags)
1418 {
1419         struct url *purl;
1420         char *p;
1421
1422         if (flags != NULL && strchr(flags, 'd') != NULL)
1423                 return (NULL);
1424         if (fetch_no_proxy_match(url->host))
1425                 return (NULL);
1426         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1427             *p && (purl = fetchParseURL(p))) {
1428                 if (!*purl->scheme)
1429                         strcpy(purl->scheme, SCHEME_HTTP);
1430                 if (!purl->port)
1431                         purl->port = fetch_default_proxy_port(purl->scheme);
1432                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1433                         return (purl);
1434                 fetchFreeURL(purl);
1435         }
1436         return (NULL);
1437 }
1438
1439 static void
1440 http_print_html(FILE *out, FILE *in)
1441 {
1442         size_t len;
1443         char *line, *p, *q;
1444         int comment, tag;
1445
1446         comment = tag = 0;
1447         while ((line = fgetln(in, &len)) != NULL) {
1448                 while (len && isspace((unsigned char)line[len - 1]))
1449                         --len;
1450                 for (p = q = line; q < line + len; ++q) {
1451                         if (comment && *q == '-') {
1452                                 if (q + 2 < line + len &&
1453                                     strcmp(q, "-->") == 0) {
1454                                         tag = comment = 0;
1455                                         q += 2;
1456                                 }
1457                         } else if (tag && !comment && *q == '>') {
1458                                 p = q + 1;
1459                                 tag = 0;
1460                         } else if (!tag && *q == '<') {
1461                                 if (q > p)
1462                                         fwrite(p, q - p, 1, out);
1463                                 tag = 1;
1464                                 if (q + 3 < line + len &&
1465                                     strcmp(q, "<!--") == 0) {
1466                                         comment = 1;
1467                                         q += 3;
1468                                 }
1469                         }
1470                 }
1471                 if (!tag && q > p)
1472                         fwrite(p, q - p, 1, out);
1473                 fputc('\n', out);
1474         }
1475 }
1476
1477
1478 /*****************************************************************************
1479  * Core
1480  */
1481
1482 /*
1483  * Send a request and process the reply
1484  *
1485  * XXX This function is way too long, the do..while loop should be split
1486  * XXX off into a separate function.
1487  */
1488 FILE *
1489 http_request(struct url *URL, const char *op, struct url_stat *us,
1490         struct url *purl, const char *flags)
1491 {
1492         char timebuf[80];
1493         char hbuf[MAXHOSTNAMELEN + 7], *host;
1494         conn_t *conn;
1495         struct url *url, *new;
1496         int chunked, direct, ims, noredirect, verbose;
1497         int e, i, n, val;
1498         off_t offset, clength, length, size;
1499         time_t mtime;
1500         const char *p;
1501         FILE *f;
1502         hdr_t h;
1503         struct tm *timestruct;
1504         http_headerbuf_t headerbuf;
1505         http_auth_challenges_t server_challenges;
1506         http_auth_challenges_t proxy_challenges;
1507
1508         /* The following calls don't allocate anything */
1509         init_http_headerbuf(&headerbuf);
1510         init_http_auth_challenges(&server_challenges);
1511         init_http_auth_challenges(&proxy_challenges);
1512
1513         direct = CHECK_FLAG('d');
1514         noredirect = CHECK_FLAG('A');
1515         verbose = CHECK_FLAG('v');
1516         ims = CHECK_FLAG('i');
1517
1518         if (direct && purl) {
1519                 fetchFreeURL(purl);
1520                 purl = NULL;
1521         }
1522
1523         /* try the provided URL first */
1524         url = URL;
1525
1526         n = MAX_REDIRECT;
1527         i = 0;
1528
1529         e = HTTP_PROTOCOL_ERROR;
1530         do {
1531                 new = NULL;
1532                 chunked = 0;
1533                 offset = 0;
1534                 clength = -1;
1535                 length = -1;
1536                 size = -1;
1537                 mtime = 0;
1538
1539                 /* check port */
1540                 if (!url->port)
1541                         url->port = fetch_default_port(url->scheme);
1542
1543                 /* were we redirected to an FTP URL? */
1544                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
1545                         if (strcmp(op, "GET") == 0)
1546                                 return (ftp_request(url, "RETR", us, purl, flags));
1547                         else if (strcmp(op, "HEAD") == 0)
1548                                 return (ftp_request(url, "STAT", us, purl, flags));
1549                 }
1550
1551                 /* connect to server or proxy */
1552                 if ((conn = http_connect(url, purl, flags)) == NULL)
1553                         goto ouch;
1554
1555                 host = url->host;
1556 #ifdef INET6
1557                 if (strchr(url->host, ':')) {
1558                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
1559                         host = hbuf;
1560                 }
1561 #endif
1562                 if (url->port != fetch_default_port(url->scheme)) {
1563                         if (host != hbuf) {
1564                                 strcpy(hbuf, host);
1565                                 host = hbuf;
1566                         }
1567                         snprintf(hbuf + strlen(hbuf),
1568                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
1569                 }
1570
1571                 /* send request */
1572                 if (verbose)
1573                         fetch_info("requesting %s://%s%s",
1574                             url->scheme, host, url->doc);
1575                 if (purl) {
1576                         http_cmd(conn, "%s %s://%s%s HTTP/1.1",
1577                             op, url->scheme, host, url->doc);
1578                 } else {
1579                         http_cmd(conn, "%s %s HTTP/1.1",
1580                             op, url->doc);
1581                 }
1582
1583                 if (ims && url->ims_time) {
1584                         timestruct = gmtime((time_t *)&url->ims_time);
1585                         (void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
1586                             timestruct);
1587                         if (verbose)
1588                                 fetch_info("If-Modified-Since: %s", timebuf);
1589                         http_cmd(conn, "If-Modified-Since: %s", timebuf);
1590                 }
1591                 /* virtual host */
1592                 http_cmd(conn, "Host: %s", host);
1593
1594                 /*
1595                  * Proxy authorization: we only send auth after we received
1596                  * a 407 error. We do not first try basic anyway (changed
1597                  * when support was added for digest-auth)
1598                  */
1599                 if (purl && proxy_challenges.valid) {
1600                         http_auth_params_t aparams;
1601                         init_http_auth_params(&aparams);
1602                         if (*purl->user || *purl->pwd) {
1603                                 aparams.user = purl->user ?
1604                                         strdup(purl->user) : strdup("");
1605                                 aparams.password = purl->pwd?
1606                                         strdup(purl->pwd) : strdup("");
1607                         } else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL &&
1608                                    *p != '\0') {
1609                                 if (http_authfromenv(p, &aparams) < 0) {
1610                                         http_seterr(HTTP_NEED_PROXY_AUTH);
1611                                         goto ouch;
1612                                 }
1613                         }
1614                         http_authorize(conn, "Proxy-Authorization",
1615                                        &proxy_challenges, &aparams, url);
1616                         clean_http_auth_params(&aparams);
1617                 }
1618
1619                 /*
1620                  * Server authorization: we never send "a priori"
1621                  * Basic auth, which used to be done if user/pass were
1622                  * set in the url. This would be weird because we'd send the
1623                  * password in the clear even if Digest is finally to be
1624                  * used (it would have made more sense for the
1625                  * pre-digest version to do this when Basic was specified
1626                  * in the environment)
1627                  */
1628                 if (server_challenges.valid) {
1629                         http_auth_params_t aparams;
1630                         init_http_auth_params(&aparams);
1631                         if (*url->user || *url->pwd) {
1632                                 aparams.user = url->user ?
1633                                         strdup(url->user) : strdup("");
1634                                 aparams.password = url->pwd ?
1635                                         strdup(url->pwd) : strdup("");
1636                         } else if ((p = getenv("HTTP_AUTH")) != NULL &&
1637                                    *p != '\0') {
1638                                 if (http_authfromenv(p, &aparams) < 0) {
1639                                         http_seterr(HTTP_NEED_AUTH);
1640                                         goto ouch;
1641                                 }
1642                         } else if (fetchAuthMethod &&
1643                                    fetchAuthMethod(url) == 0) {
1644                                 aparams.user = url->user ?
1645                                         strdup(url->user) : strdup("");
1646                                 aparams.password = url->pwd ?
1647                                         strdup(url->pwd) : strdup("");
1648                         } else {
1649                                 http_seterr(HTTP_NEED_AUTH);
1650                                 goto ouch;
1651                         }
1652                         http_authorize(conn, "Authorization",
1653                                        &server_challenges, &aparams, url);
1654                         clean_http_auth_params(&aparams);
1655                 }
1656
1657                 /* other headers */
1658                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
1659                         if (strcasecmp(p, "auto") == 0)
1660                                 http_cmd(conn, "Referer: %s://%s%s",
1661                                     url->scheme, host, url->doc);
1662                         else
1663                                 http_cmd(conn, "Referer: %s", p);
1664                 }
1665                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
1666                         http_cmd(conn, "User-Agent: %s", p);
1667                 else
1668                         http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
1669                 if (url->offset > 0)
1670                         http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
1671                 http_cmd(conn, "Connection: close");
1672                 http_cmd(conn, "%s", "");
1673
1674                 /*
1675                  * Force the queued request to be dispatched.  Normally, one
1676                  * would do this with shutdown(2) but squid proxies can be
1677                  * configured to disallow such half-closed connections.  To
1678                  * be compatible with such configurations, fiddle with socket
1679                  * options to force the pending data to be written.
1680                  */
1681                 val = 0;
1682                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
1683                            sizeof(val));
1684                 val = 1;
1685                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
1686                            sizeof(val));
1687
1688                 /* get reply */
1689                 switch (http_get_reply(conn)) {
1690                 case HTTP_OK:
1691                 case HTTP_PARTIAL:
1692                 case HTTP_NOT_MODIFIED:
1693                         /* fine */
1694                         break;
1695                 case HTTP_MOVED_PERM:
1696                 case HTTP_MOVED_TEMP:
1697                 case HTTP_SEE_OTHER:
1698                 case HTTP_USE_PROXY:
1699                         /*
1700                          * Not so fine, but we still have to read the
1701                          * headers to get the new location.
1702                          */
1703                         break;
1704                 case HTTP_NEED_AUTH:
1705                         if (server_challenges.valid) {
1706                                 /*
1707                                  * We already sent out authorization code,
1708                                  * so there's nothing more we can do.
1709                                  */
1710                                 http_seterr(conn->err);
1711                                 goto ouch;
1712                         }
1713                         /* try again, but send the password this time */
1714                         if (verbose)
1715                                 fetch_info("server requires authorization");
1716                         break;
1717                 case HTTP_NEED_PROXY_AUTH:
1718                         if (proxy_challenges.valid) {
1719                                 /*
1720                                  * We already sent our proxy
1721                                  * authorization code, so there's
1722                                  * nothing more we can do. */
1723                                 http_seterr(conn->err);
1724                                 goto ouch;
1725                         }
1726                         /* try again, but send the password this time */
1727                         if (verbose)
1728                                 fetch_info("proxy requires authorization");
1729                         break;
1730                 case HTTP_BAD_RANGE:
1731                         /*
1732                          * This can happen if we ask for 0 bytes because
1733                          * we already have the whole file.  Consider this
1734                          * a success for now, and check sizes later.
1735                          */
1736                         break;
1737                 case HTTP_PROTOCOL_ERROR:
1738                         /* fall through */
1739                 case -1:
1740                         fetch_syserr();
1741                         goto ouch;
1742                 default:
1743                         http_seterr(conn->err);
1744                         if (!verbose)
1745                                 goto ouch;
1746                         /* fall through so we can get the full error message */
1747                 }
1748
1749                 /* get headers. http_next_header expects one line readahead */
1750                 if (fetch_getln(conn) == -1) {
1751                     fetch_syserr();
1752                     goto ouch;
1753                 }
1754                 do {
1755                     switch ((h = http_next_header(conn, &headerbuf, &p))) {
1756                         case hdr_syserror:
1757                                 fetch_syserr();
1758                                 goto ouch;
1759                         case hdr_error:
1760                                 http_seterr(HTTP_PROTOCOL_ERROR);
1761                                 goto ouch;
1762                         case hdr_content_length:
1763                                 http_parse_length(p, &clength);
1764                                 break;
1765                         case hdr_content_range:
1766                                 http_parse_range(p, &offset, &length, &size);
1767                                 break;
1768                         case hdr_last_modified:
1769                                 http_parse_mtime(p, &mtime);
1770                                 break;
1771                         case hdr_location:
1772                                 if (!HTTP_REDIRECT(conn->err))
1773                                         break;
1774                                 /*
1775                                  * if the A flag is set, we don't follow
1776                                  * temporary redirects.
1777                                  */
1778                                 if (noredirect &&
1779                                     conn->err != HTTP_MOVED_PERM &&
1780                                     conn->err != HTTP_PERM_REDIRECT &&
1781                                     conn->err != HTTP_USE_PROXY) {
1782                                         n = 1;
1783                                         break;
1784                                 }
1785                                 if (new)
1786                                         free(new);
1787                                 if (verbose)
1788                                         fetch_info("%d redirect to %s", conn->err, p);
1789                                 if (*p == '/')
1790                                         /* absolute path */
1791                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1792                                             url->user, url->pwd);
1793                                 else
1794                                         new = fetchParseURL(p);
1795                                 if (new == NULL) {
1796                                         /* XXX should set an error code */
1797                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1798                                         goto ouch;
1799                                 }
1800
1801                                 /* Only copy credentials if the host matches */
1802                                 if (!strcmp(new->host, url->host) && !*new->user && !*new->pwd) {
1803                                         strcpy(new->user, url->user);
1804                                         strcpy(new->pwd, url->pwd);
1805                                 }
1806                                 new->offset = url->offset;
1807                                 new->length = url->length;
1808                                 break;
1809                         case hdr_transfer_encoding:
1810                                 /* XXX weak test*/
1811                                 chunked = (strcasecmp(p, "chunked") == 0);
1812                                 break;
1813                         case hdr_www_authenticate:
1814                                 if (conn->err != HTTP_NEED_AUTH)
1815                                         break;
1816                                 if (http_parse_authenticate(p, &server_challenges) == 0)
1817                                         ++n;
1818                                 break;
1819                         case hdr_proxy_authenticate:
1820                                 if (conn->err != HTTP_NEED_PROXY_AUTH)
1821                                         break;
1822                                 if (http_parse_authenticate(p, &proxy_challenges) == 0)
1823                                         ++n;
1824                                 break;
1825                         case hdr_end:
1826                                 /* fall through */
1827                         case hdr_unknown:
1828                                 /* ignore */
1829                                 break;
1830                         }
1831                 } while (h > hdr_end);
1832
1833                 /* we need to provide authentication */
1834                 if (conn->err == HTTP_NEED_AUTH ||
1835                     conn->err == HTTP_NEED_PROXY_AUTH) {
1836                         e = conn->err;
1837                         if ((conn->err == HTTP_NEED_AUTH &&
1838                              !server_challenges.valid) ||
1839                             (conn->err == HTTP_NEED_PROXY_AUTH &&
1840                              !proxy_challenges.valid)) {
1841                                 /* 401/7 but no www/proxy-authenticate ?? */
1842                                 DEBUG(fprintf(stderr, "401/7 and no auth header\n"));
1843                                 goto ouch;
1844                         }
1845                         fetch_close(conn);
1846                         conn = NULL;
1847                         continue;
1848                 }
1849
1850                 /* requested range not satisfiable */
1851                 if (conn->err == HTTP_BAD_RANGE) {
1852                         if (url->offset == size && url->length == 0) {
1853                                 /* asked for 0 bytes; fake it */
1854                                 offset = url->offset;
1855                                 clength = -1;
1856                                 conn->err = HTTP_OK;
1857                                 break;
1858                         } else {
1859                                 http_seterr(conn->err);
1860                                 goto ouch;
1861                         }
1862                 }
1863
1864                 /* we have a hit or an error */
1865                 if (conn->err == HTTP_OK
1866                     || conn->err == HTTP_NOT_MODIFIED
1867                     || conn->err == HTTP_PARTIAL
1868                     || HTTP_ERROR(conn->err))
1869                         break;
1870
1871                 /* all other cases: we got a redirect */
1872                 e = conn->err;
1873                 clean_http_auth_challenges(&server_challenges);
1874                 fetch_close(conn);
1875                 conn = NULL;
1876                 if (!new) {
1877                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1878                         break;
1879                 }
1880                 if (url != URL)
1881                         fetchFreeURL(url);
1882                 url = new;
1883         } while (++i < n);
1884
1885         /* we failed, or ran out of retries */
1886         if (conn == NULL) {
1887                 http_seterr(e);
1888                 goto ouch;
1889         }
1890
1891         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1892                   " size %lld, clength %lld\n",
1893                   (long long)offset, (long long)length,
1894                   (long long)size, (long long)clength));
1895
1896         if (conn->err == HTTP_NOT_MODIFIED) {
1897                 http_seterr(HTTP_NOT_MODIFIED);
1898                 return (NULL);
1899         }
1900
1901         /* check for inconsistencies */
1902         if (clength != -1 && length != -1 && clength != length) {
1903                 http_seterr(HTTP_PROTOCOL_ERROR);
1904                 goto ouch;
1905         }
1906         if (clength == -1)
1907                 clength = length;
1908         if (clength != -1)
1909                 length = offset + clength;
1910         if (length != -1 && size != -1 && length != size) {
1911                 http_seterr(HTTP_PROTOCOL_ERROR);
1912                 goto ouch;
1913         }
1914         if (size == -1)
1915                 size = length;
1916
1917         /* fill in stats */
1918         if (us) {
1919                 us->size = size;
1920                 us->atime = us->mtime = mtime;
1921         }
1922
1923         /* too far? */
1924         if (URL->offset > 0 && offset > URL->offset) {
1925                 http_seterr(HTTP_PROTOCOL_ERROR);
1926                 goto ouch;
1927         }
1928
1929         /* report back real offset and size */
1930         URL->offset = offset;
1931         URL->length = clength;
1932
1933         /* wrap it up in a FILE */
1934         if ((f = http_funopen(conn, chunked)) == NULL) {
1935                 fetch_syserr();
1936                 goto ouch;
1937         }
1938
1939         if (url != URL)
1940                 fetchFreeURL(url);
1941         if (purl)
1942                 fetchFreeURL(purl);
1943
1944         if (HTTP_ERROR(conn->err)) {
1945                 http_print_html(stderr, f);
1946                 fclose(f);
1947                 f = NULL;
1948         }
1949         clean_http_headerbuf(&headerbuf);
1950         clean_http_auth_challenges(&server_challenges);
1951         clean_http_auth_challenges(&proxy_challenges);
1952         return (f);
1953
1954 ouch:
1955         if (url != URL)
1956                 fetchFreeURL(url);
1957         if (purl)
1958                 fetchFreeURL(purl);
1959         if (conn != NULL)
1960                 fetch_close(conn);
1961         clean_http_headerbuf(&headerbuf);
1962         clean_http_auth_challenges(&server_challenges);
1963         clean_http_auth_challenges(&proxy_challenges);
1964         return (NULL);
1965 }
1966
1967
1968 /*****************************************************************************
1969  * Entry points
1970  */
1971
1972 /*
1973  * Retrieve and stat a file by HTTP
1974  */
1975 FILE *
1976 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1977 {
1978         return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1979 }
1980
1981 /*
1982  * Retrieve a file by HTTP
1983  */
1984 FILE *
1985 fetchGetHTTP(struct url *URL, const char *flags)
1986 {
1987         return (fetchXGetHTTP(URL, NULL, flags));
1988 }
1989
1990 /*
1991  * Store a file by HTTP
1992  */
1993 FILE *
1994 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
1995 {
1996         warnx("fetchPutHTTP(): not implemented");
1997         return (NULL);
1998 }
1999
2000 /*
2001  * Get an HTTP document's metadata
2002  */
2003 int
2004 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
2005 {
2006         FILE *f;
2007
2008         f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
2009         if (f == NULL)
2010                 return (-1);
2011         fclose(f);
2012         return (0);
2013 }
2014
2015 /*
2016  * List a directory
2017  */
2018 struct url_ent *
2019 fetchListHTTP(struct url *url __unused, const char *flags __unused)
2020 {
2021         warnx("fetchListHTTP(): not implemented");
2022         return (NULL);
2023 }