lib/libfetch/http.c

   1 /*-
   2  * Copyright (c) 2000-2014 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 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 /*
  33  * The following copyright applies to the base64 code:
  34  *
  35  *-
  36  * Copyright 1997 Massachusetts Institute of Technology
  37  *
  38  * Permission to use, copy, modify, and distribute this software and
  39  * its documentation for any purpose and without fee is hereby
  40  * granted, provided that both the above copyright notice and this
  41  * permission notice appear in all copies, that both the above
  42  * copyright notice and this permission notice appear in all
  43  * supporting documentation, and that the name of M.I.T. not be used
  44  * in advertising or publicity pertaining to distribution of the
  45  * software without specific, written prior permission.  M.I.T. makes
  46  * no representations about the suitability of this software for any
  47  * purpose.  It is provided "as is" without express or implied
  48  * warranty.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
  51  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
  52  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  53  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
  54  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  55  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  56  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  57  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  58  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  59  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  60  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  */
  63
  64 #include <sys/param.h>
  65 #include <sys/socket.h>
  66 #include <sys/time.h>
  67
  68 #include <ctype.h>
  69 #include <err.h>
  70 #include <errno.h>
  71 #include <locale.h>
  72 #include <netdb.h>
  73 #include <stdarg.h>
  74 #include <stdio.h>
  75 #include <stdlib.h>
  76 #include <string.h>
  77 #include <time.h>
  78 #include <unistd.h>
  79
  80 #ifdef WITH_SSL
  81 #include <openssl/md5.h>
  82 #define MD5Init(c) MD5_Init(c)
  83 #define MD5Update(c, data, len) MD5_Update(c, data, len)
  84 #define MD5Final(md, c) MD5_Final(md, c)
  85 #else
  86 #include <md5.h>
  87 #endif
  88
  89 #include <netinet/in.h>
  90 #include <netinet/tcp.h>
  91
  92 #include "fetch.h"
  93 #include "common.h"
  94 #include "httperr.h"
  95
  96 /* Maximum number of redirects to follow */
  97 #define MAX_REDIRECT 20
  98
  99 /* Symbolic names for reply codes we care about */
 100 #define HTTP_OK                 200
 101 #define HTTP_PARTIAL            206
 102 #define HTTP_MOVED_PERM         301
 103 #define HTTP_MOVED_TEMP         302
 104 #define HTTP_SEE_OTHER          303
 105 #define HTTP_NOT_MODIFIED       304
 106 #define HTTP_USE_PROXY          305
 107 #define HTTP_TEMP_REDIRECT      307
 108 #define HTTP_PERM_REDIRECT      308
 109 #define HTTP_NEED_AUTH          401
 110 #define HTTP_NEED_PROXY_AUTH    407
 111 #define HTTP_BAD_RANGE          416
 112 #define HTTP_PROTOCOL_ERROR     999
 113
 114 #define HTTP_REDIRECT(xyz) ((xyz) == HTTP_MOVED_PERM \
 115                             || (xyz) == HTTP_MOVED_TEMP \
 116                             || (xyz) == HTTP_TEMP_REDIRECT \
 117                             || (xyz) == HTTP_USE_PROXY \
 118                             || (xyz) == HTTP_SEE_OTHER)
 119
 120 #define HTTP_ERROR(xyz) ((xyz) > 400 && (xyz) < 599)
 121
 122
 123 /*****************************************************************************
 124  * I/O functions for decoding chunked streams
 125  */
 126
 127 struct httpio
 128 {
 129         conn_t          *conn;          /* connection */
 130         int              chunked;       /* chunked mode */
 131         char            *buf;           /* chunk buffer */
 132         size_t           bufsize;       /* size of chunk buffer */
 133         ssize_t          buflen;        /* amount of data currently in buffer */
 134         int              bufpos;        /* current read offset in buffer */
 135         int              eof;           /* end-of-file flag */
 136         int              error;         /* error flag */
 137         size_t           chunksize;     /* remaining size of current chunk */
 138 #ifndef NDEBUG
 139         size_t           total;
 140 #endif
 141 };
 142
 143 /*
 144  * Get next chunk header
 145  */
 146 static int
 147 http_new_chunk(struct httpio *io)
 148 {
 149         char *p;
 150
 151         if (fetch_getln(io->conn) == -1)
 152                 return (-1);
 153
 154         if (io->conn->buflen < 2 || !isxdigit((unsigned char)*io->conn->buf))
 155                 return (-1);
 156
 157         for (p = io->conn->buf; *p && !isspace((unsigned char)*p); ++p) {
 158                 if (*p == ';')
 159                         break;
 160                 if (!isxdigit((unsigned char)*p))
 161                         return (-1);
 162                 if (isdigit((unsigned char)*p)) {
 163                         io->chunksize = io->chunksize * 16 +
 164                             *p - '0';
 165                 } else {
 166                         io->chunksize = io->chunksize * 16 +
 167                             10 + tolower((unsigned char)*p) - 'a';
 168                 }
 169         }
 170
 171 #ifndef NDEBUG
 172         if (fetchDebug) {
 173                 io->total += io->chunksize;
 174                 if (io->chunksize == 0)
 175                         fprintf(stderr, "%s(): end of last chunk\n", __func__);
 176                 else
 177                         fprintf(stderr, "%s(): new chunk: %lu (%lu)\n",
 178                             __func__, (unsigned long)io->chunksize,
 179                             (unsigned long)io->total);
 180         }
 181 #endif
 182
 183         return (io->chunksize);
 184 }
 185
 186 /*
 187  * Grow the input buffer to at least len bytes
 188  */
 189 static inline int
 190 http_growbuf(struct httpio *io, size_t len)
 191 {
 192         char *tmp;
 193
 194         if (io->bufsize >= len)
 195                 return (0);
 196
 197         if ((tmp = realloc(io->buf, len)) == NULL)
 198                 return (-1);
 199         io->buf = tmp;
 200         io->bufsize = len;
 201         return (0);
 202 }
 203
 204 /*
 205  * Fill the input buffer, do chunk decoding on the fly
 206  */
 207 static ssize_t
 208 http_fillbuf(struct httpio *io, size_t len)
 209 {
 210         ssize_t nbytes;
 211         char ch;
 212
 213         if (io->error)
 214                 return (-1);
 215         if (io->eof)
 216                 return (0);
 217
 218         if (io->chunked == 0) {
 219                 if (http_growbuf(io, len) == -1)
 220                         return (-1);
 221                 if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 222                         io->error = errno;
 223                         return (-1);
 224                 }
 225                 io->buflen = nbytes;
 226                 io->bufpos = 0;
 227                 return (io->buflen);
 228         }
 229
 230         if (io->chunksize == 0) {
 231                 switch (http_new_chunk(io)) {
 232                 case -1:
 233                         io->error = EPROTO;
 234                         return (-1);
 235                 case 0:
 236                         io->eof = 1;
 237                         return (0);
 238                 }
 239         }
 240
 241         if (len > io->chunksize)
 242                 len = io->chunksize;
 243         if (http_growbuf(io, len) == -1)
 244                 return (-1);
 245         if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 246                 io->error = errno;
 247                 return (-1);
 248         }
 249         io->buflen = nbytes;
 250         io->chunksize -= io->buflen;
 251
 252         if (io->chunksize == 0) {
 253                 if (fetch_read(io->conn, &ch, 1) != 1 || ch != '\r' ||
 254                     fetch_read(io->conn, &ch, 1) != 1 || ch != '\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 rlen;
 271
 272         if (io->error)
 273                 return (-1);
 274         if (io->eof)
 275                 return (0);
 276
 277         /* empty buffer */
 278         if (!io->buf || io->bufpos == io->buflen) {
 279                 if ((rlen = http_fillbuf(io, len)) < 0) {
 280                         if ((errno = io->error) == EINTR)
 281                                 io->error = 0;
 282                         return (-1);
 283                 } else if (rlen == 0) {
 284                         return (0);
 285                 }
 286         }
 287
 288         rlen = io->buflen - io->bufpos;
 289         if (len < rlen)
 290                 rlen = len;
 291         memcpy(buf, io->buf + io->bufpos, rlen);
 292         io->bufpos += rlen;
 293         return (rlen);
 294 }
 295
 296 /*
 297  * Write function
 298  */
 299 static int
 300 http_writefn(void *v, const char *buf, int len)
 301 {
 302         struct httpio *io = (struct httpio *)v;
 303
 304         return (fetch_write(io->conn, buf, len));
 305 }
 306
 307 /*
 308  * Close function
 309  */
 310 static int
 311 http_closefn(void *v)
 312 {
 313         struct httpio *io = (struct httpio *)v;
 314         int r;
 315
 316         r = fetch_close(io->conn);
 317         if (io->buf)
 318                 free(io->buf);
 319         free(io);
 320         return (r);
 321 }
 322
 323 /*
 324  * Wrap a file descriptor up
 325  */
 326 static FILE *
 327 http_funopen(conn_t *conn, int chunked)
 328 {
 329         struct httpio *io;
 330         FILE *f;
 331
 332         if ((io = calloc(1, sizeof(*io))) == NULL) {
 333                 fetch_syserr();
 334                 return (NULL);
 335         }
 336         io->conn = conn;
 337         io->chunked = chunked;
 338         f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
 339         if (f == NULL) {
 340                 fetch_syserr();
 341                 free(io);
 342                 return (NULL);
 343         }
 344         return (f);
 345 }
 346
 347
 348 /*****************************************************************************
 349  * Helper functions for talking to the server and parsing its replies
 350  */
 351
 352 /* Header types */
 353 typedef enum {
 354         hdr_syserror = -2,
 355         hdr_error = -1,
 356         hdr_end = 0,
 357         hdr_unknown = 1,
 358         hdr_content_length,
 359         hdr_content_range,
 360         hdr_last_modified,
 361         hdr_location,
 362         hdr_transfer_encoding,
 363         hdr_www_authenticate,
 364         hdr_proxy_authenticate,
 365 } hdr_t;
 366
 367 /* Names of interesting headers */
 368 static struct {
 369         hdr_t            num;
 370         const char      *name;
 371 } hdr_names[] = {
 372         { hdr_content_length,           "Content-Length" },
 373         { hdr_content_range,            "Content-Range" },
 374         { hdr_last_modified,            "Last-Modified" },
 375         { hdr_location,                 "Location" },
 376         { hdr_transfer_encoding,        "Transfer-Encoding" },
 377         { hdr_www_authenticate,         "WWW-Authenticate" },
 378         { hdr_proxy_authenticate,       "Proxy-Authenticate" },
 379         { hdr_unknown,                  NULL },
 380 };
 381
 382 /*
 383  * Send a formatted line; optionally echo to terminal
 384  */
 385 static int
 386 http_cmd(conn_t *conn, const char *fmt, ...)
 387 {
 388         va_list ap;
 389         size_t len;
 390         char *msg;
 391         int r;
 392
 393         va_start(ap, fmt);
 394         len = vasprintf(&msg, fmt, ap);
 395         va_end(ap);
 396
 397         if (msg == NULL) {
 398                 errno = ENOMEM;
 399                 fetch_syserr();
 400                 return (-1);
 401         }
 402
 403         r = fetch_putln(conn, msg, len);
 404         free(msg);
 405
 406         if (r == -1) {
 407                 fetch_syserr();
 408                 return (-1);
 409         }
 410
 411         return (0);
 412 }
 413
 414 /*
 415  * Get and parse status line
 416  */
 417 static int
 418 http_get_reply(conn_t *conn)
 419 {
 420         char *p;
 421
 422         if (fetch_getln(conn) == -1)
 423                 return (-1);
 424         /*
 425          * A valid status line looks like "HTTP/m.n xyz reason" where m
 426          * and n are the major and minor protocol version numbers and xyz
 427          * is the reply code.
 428          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
 429          * just one) that do not send a version number, so we can't rely
 430          * on finding one, but if we do, insist on it being 1.0 or 1.1.
 431          * We don't care about the reason phrase.
 432          */
 433         if (strncmp(conn->buf, "HTTP", 4) != 0)
 434                 return (HTTP_PROTOCOL_ERROR);
 435         p = conn->buf + 4;
 436         if (*p == '/') {
 437                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
 438                         return (HTTP_PROTOCOL_ERROR);
 439                 p += 4;
 440         }
 441         if (*p != ' ' ||
 442             !isdigit((unsigned char)p[1]) ||
 443             !isdigit((unsigned char)p[2]) ||
 444             !isdigit((unsigned char)p[3]))
 445                 return (HTTP_PROTOCOL_ERROR);
 446
 447         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
 448         return (conn->err);
 449 }
 450
 451 /*
 452  * Check a header; if the type matches the given string, return a pointer
 453  * to the beginning of the value.
 454  */
 455 static const char *
 456 http_match(const char *str, const char *hdr)
 457 {
 458         while (*str && *hdr &&
 459             tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
 460                 /* nothing */;
 461         if (*str || *hdr != ':')
 462                 return (NULL);
 463         while (*hdr && isspace((unsigned char)*++hdr))
 464                 /* nothing */;
 465         return (hdr);
 466 }
 467
 468
 469 /*
 470  * Get the next header and return the appropriate symbolic code.  We
 471  * need to read one line ahead for checking for a continuation line
 472  * belonging to the current header (continuation lines start with
 473  * white space).
 474  *
 475  * We get called with a fresh line already in the conn buffer, either
 476  * from the previous http_next_header() invocation, or, the first
 477  * time, from a fetch_getln() performed by our caller.
 478  *
 479  * This stops when we encounter an empty line (we dont read beyond the header
 480  * area).
 481  *
 482  * Note that the "headerbuf" is just a place to return the result. Its
 483  * contents are not used for the next call. This means that no cleanup
 484  * is needed when ie doing another connection, just call the cleanup when
 485  * fully done to deallocate memory.
 486  */
 487
 488 /* Limit the max number of continuation lines to some reasonable value */
 489 #define HTTP_MAX_CONT_LINES 10
 490
 491 /* Place into which to build a header from one or several lines */
 492 typedef struct {
 493         char    *buf;           /* buffer */
 494         size_t   bufsize;       /* buffer size */
 495         size_t   buflen;        /* length of buffer contents */
 496 } http_headerbuf_t;
 497
 498 static void
 499 init_http_headerbuf(http_headerbuf_t *buf)
 500 {
 501         buf->buf = NULL;
 502         buf->bufsize = 0;
 503         buf->buflen = 0;
 504 }
 505
 506 static void
 507 clean_http_headerbuf(http_headerbuf_t *buf)
 508 {
 509         if (buf->buf)
 510                 free(buf->buf);
 511         init_http_headerbuf(buf);
 512 }
 513
 514 /* Remove whitespace at the end of the buffer */
 515 static void
 516 http_conn_trimright(conn_t *conn)
 517 {
 518         while (conn->buflen &&
 519                isspace((unsigned char)conn->buf[conn->buflen - 1]))
 520                 conn->buflen--;
 521         conn->buf[conn->buflen] = '\0';
 522 }
 523
 524 static hdr_t
 525 http_next_header(conn_t *conn, http_headerbuf_t *hbuf, const char **p)
 526 {
 527         unsigned int i, len;
 528
 529         /*
 530          * Have to do the stripping here because of the first line. So
 531          * it's done twice for the subsequent lines. No big deal
 532          */
 533         http_conn_trimright(conn);
 534         if (conn->buflen == 0)
 535                 return (hdr_end);
 536
 537         /* Copy the line to the headerbuf */
 538         if (hbuf->bufsize < conn->buflen + 1) {
 539                 if ((hbuf->buf = realloc(hbuf->buf, conn->buflen + 1)) == NULL)
 540                         return (hdr_syserror);
 541                 hbuf->bufsize = conn->buflen + 1;
 542         }
 543         strcpy(hbuf->buf, conn->buf);
 544         hbuf->buflen = conn->buflen;
 545
 546         /*
 547          * Fetch possible continuation lines. Stop at 1st non-continuation
 548          * and leave it in the conn buffer
 549          */
 550         for (i = 0; i < HTTP_MAX_CONT_LINES; i++) {
 551                 if (fetch_getln(conn) == -1)
 552                         return (hdr_syserror);
 553
 554                 /*
 555                  * Note: we carry on the idea from the previous version
 556                  * that a pure whitespace line is equivalent to an empty
 557                  * one (so it's not continuation and will be handled when
 558                  * we are called next)
 559                  */
 560                 http_conn_trimright(conn);
 561                 if (conn->buf[0] != ' ' && conn->buf[0] != "\t"[0])
 562                         break;
 563
 564                 /* Got a continuation line. Concatenate to previous */
 565                 len = hbuf->buflen + conn->buflen;
 566                 if (hbuf->bufsize < len + 1) {
 567                         len *= 2;
 568                         if ((hbuf->buf = realloc(hbuf->buf, len + 1)) == NULL)
 569                                 return (hdr_syserror);
 570                         hbuf->bufsize = len + 1;
 571                 }
 572                 strcpy(hbuf->buf + hbuf->buflen, conn->buf);
 573                 hbuf->buflen += conn->buflen;
 574         }
 575
 576         /*
 577          * We could check for malformed headers but we don't really care.
 578          * A valid header starts with a token immediately followed by a
 579          * colon; a token is any sequence of non-control, non-whitespace
 580          * characters except "()<>@,;:\\\"{}".
 581          */
 582         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
 583                 if ((*p = http_match(hdr_names[i].name, hbuf->buf)) != NULL)
 584                         return (hdr_names[i].num);
 585
 586         return (hdr_unknown);
 587 }
 588
 589 /**************************
 590  * [Proxy-]Authenticate header parsing
 591  */
 592
 593 /*
 594  * Read doublequote-delimited string into output buffer obuf (allocated
 595  * by caller, whose responsibility it is to ensure that it's big enough)
 596  * cp points to the first char after the initial '"'
 597  * Handles \ quoting
 598  * Returns pointer to the first char after the terminating double quote, or
 599  * NULL for error.
 600  */
 601 static const char *
 602 http_parse_headerstring(const char *cp, char *obuf)
 603 {
 604         for (;;) {
 605                 switch (*cp) {
 606                 case 0: /* Unterminated string */
 607                         *obuf = 0;
 608                         return (NULL);
 609                 case '"': /* Ending quote */
 610                         *obuf = 0;
 611                         return (++cp);
 612                 case '\\':
 613                         if (*++cp == 0) {
 614                                 *obuf = 0;
 615                                 return (NULL);
 616                         }
 617                         /* FALLTHROUGH */
 618                 default:
 619                         *obuf++ = *cp++;
 620                 }
 621         }
 622 }
 623
 624 /* Http auth challenge schemes */
 625 typedef enum {HTTPAS_UNKNOWN, HTTPAS_BASIC,HTTPAS_DIGEST} http_auth_schemes_t;
 626
 627 /* Data holder for a Basic or Digest challenge. */
 628 typedef struct {
 629         http_auth_schemes_t scheme;
 630         char    *realm;
 631         char    *qop;
 632         char    *nonce;
 633         char    *opaque;
 634         char    *algo;
 635         int      stale;
 636         int      nc; /* Nonce count */
 637 } http_auth_challenge_t;
 638
 639 static void
 640 init_http_auth_challenge(http_auth_challenge_t *b)
 641 {
 642         b->scheme = HTTPAS_UNKNOWN;
 643         b->realm = b->qop = b->nonce = b->opaque = b->algo = NULL;
 644         b->stale = b->nc = 0;
 645 }
 646
 647 static void
 648 clean_http_auth_challenge(http_auth_challenge_t *b)
 649 {
 650         if (b->realm)
 651                 free(b->realm);
 652         if (b->qop)
 653                 free(b->qop);
 654         if (b->nonce)
 655                 free(b->nonce);
 656         if (b->opaque)
 657                 free(b->opaque);
 658         if (b->algo)
 659                 free(b->algo);
 660         init_http_auth_challenge(b);
 661 }
 662
 663 /* Data holder for an array of challenges offered in an http response. */
 664 #define MAX_CHALLENGES 10
 665 typedef struct {
 666         http_auth_challenge_t *challenges[MAX_CHALLENGES];
 667         int     count; /* Number of parsed challenges in the array */
 668         int     valid; /* We did parse an authenticate header */
 669 } http_auth_challenges_t;
 670
 671 static void
 672 init_http_auth_challenges(http_auth_challenges_t *cs)
 673 {
 674         int i;
 675         for (i = 0; i < MAX_CHALLENGES; i++)
 676                 cs->challenges[i] = NULL;
 677         cs->count = cs->valid = 0;
 678 }
 679
 680 static void
 681 clean_http_auth_challenges(http_auth_challenges_t *cs)
 682 {
 683         int i;
 684         /* We rely on non-zero pointers being allocated, not on the count */
 685         for (i = 0; i < MAX_CHALLENGES; i++) {
 686                 if (cs->challenges[i] != NULL) {
 687                         clean_http_auth_challenge(cs->challenges[i]);
 688                         free(cs->challenges[i]);
 689                 }
 690         }
 691         init_http_auth_challenges(cs);
 692 }
 693
 694 /*
 695  * Enumeration for lexical elements. Separators will be returned as their own
 696  * ascii value
 697  */
 698 typedef enum {HTTPHL_WORD=256, HTTPHL_STRING=257, HTTPHL_END=258,
 699               HTTPHL_ERROR = 259} http_header_lex_t;
 700
 701 /*
 702  * Determine what kind of token comes next and return possible value
 703  * in buf, which is supposed to have been allocated big enough by
 704  * caller. Advance input pointer and return element type.
 705  */
 706 static int
 707 http_header_lex(const char **cpp, char *buf)
 708 {
 709         size_t l;
 710         /* Eat initial whitespace */
 711         *cpp += strspn(*cpp, " \t");
 712         if (**cpp == 0)
 713                 return (HTTPHL_END);
 714
 715         /* Separator ? */
 716         if (**cpp == ',' || **cpp == '=')
 717                 return (*((*cpp)++));
 718
 719         /* String ? */
 720         if (**cpp == '"') {
 721                 *cpp = http_parse_headerstring(++*cpp, buf);
 722                 if (*cpp == NULL)
 723                         return (HTTPHL_ERROR);
 724                 return (HTTPHL_STRING);
 725         }
 726
 727         /* Read other token, until separator or whitespace */
 728         l = strcspn(*cpp, " \t,=");
 729         memcpy(buf, *cpp, l);
 730         buf[l] = 0;
 731         *cpp += l;
 732         return (HTTPHL_WORD);
 733 }
 734
 735 /*
 736  * Read challenges from http xxx-authenticate header and accumulate them
 737  * in the challenges list structure.
 738  *
 739  * Headers with multiple challenges are specified by rfc2617, but
 740  * servers (ie: squid) often send them in separate headers instead,
 741  * which in turn is forbidden by the http spec (multiple headers with
 742  * the same name are only allowed for pure comma-separated lists, see
 743  * rfc2616 sec 4.2).
 744  *
 745  * We support both approaches anyway
 746  */
 747 static int
 748 http_parse_authenticate(const char *cp, http_auth_challenges_t *cs)
 749 {
 750         int ret = -1;
 751         http_header_lex_t lex;
 752         char *key = malloc(strlen(cp) + 1);
 753         char *value = malloc(strlen(cp) + 1);
 754         char *buf = malloc(strlen(cp) + 1);
 755
 756         if (key == NULL || value == NULL || buf == NULL) {
 757                 fetch_syserr();
 758                 goto out;
 759         }
 760
 761         /* In any case we've seen the header and we set the valid bit */
 762         cs->valid = 1;
 763
 764         /* Need word first */
 765         lex = http_header_lex(&cp, key);
 766         if (lex != HTTPHL_WORD)
 767                 goto out;
 768
 769         /* Loop on challenges */
 770         for (; cs->count < MAX_CHALLENGES; cs->count++) {
 771                 cs->challenges[cs->count] =
 772                         malloc(sizeof(http_auth_challenge_t));
 773                 if (cs->challenges[cs->count] == NULL) {
 774                         fetch_syserr();
 775                         goto out;
 776                 }
 777                 init_http_auth_challenge(cs->challenges[cs->count]);
 778                 if (!strcasecmp(key, "basic")) {
 779                         cs->challenges[cs->count]->scheme = HTTPAS_BASIC;
 780                 } else if (!strcasecmp(key, "digest")) {
 781                         cs->challenges[cs->count]->scheme = HTTPAS_DIGEST;
 782                 } else {
 783                         cs->challenges[cs->count]->scheme = HTTPAS_UNKNOWN;
 784                         /*
 785                          * Continue parsing as basic or digest may
 786                          * follow, and the syntax is the same for
 787                          * all. We'll just ignore this one when
 788                          * looking at the list
 789                          */
 790                 }
 791
 792                 /* Loop on attributes */
 793                 for (;;) {
 794                         /* Key */
 795                         lex = http_header_lex(&cp, key);
 796                         if (lex != HTTPHL_WORD)
 797                                 goto out;
 798
 799                         /* Equal sign */
 800                         lex = http_header_lex(&cp, buf);
 801                         if (lex != '=')
 802                                 goto out;
 803
 804                         /* Value */
 805                         lex = http_header_lex(&cp, value);
 806                         if (lex != HTTPHL_WORD && lex != HTTPHL_STRING)
 807                                 goto out;
 808
 809                         if (!strcasecmp(key, "realm"))
 810                                 cs->challenges[cs->count]->realm =
 811                                         strdup(value);
 812                         else if (!strcasecmp(key, "qop"))
 813                                 cs->challenges[cs->count]->qop =
 814                                         strdup(value);
 815                         else if (!strcasecmp(key, "nonce"))
 816                                 cs->challenges[cs->count]->nonce =
 817                                         strdup(value);
 818                         else if (!strcasecmp(key, "opaque"))
 819                                 cs->challenges[cs->count]->opaque =
 820                                         strdup(value);
 821                         else if (!strcasecmp(key, "algorithm"))
 822                                 cs->challenges[cs->count]->algo =
 823                                         strdup(value);
 824                         else if (!strcasecmp(key, "stale"))
 825                                 cs->challenges[cs->count]->stale =
 826                                         strcasecmp(value, "no");
 827                         /* Else ignore unknown attributes */
 828
 829                         /* Comma or Next challenge or End */
 830                         lex = http_header_lex(&cp, key);
 831                         /*
 832                          * If we get a word here, this is the beginning of the
 833                          * next challenge. Break the attributes loop
 834                          */
 835                         if (lex == HTTPHL_WORD)
 836                                 break;
 837
 838                         if (lex == HTTPHL_END) {
 839                                 /* End while looking for ',' is normal exit */
 840                                 cs->count++;
 841                                 ret = 0;
 842                                 goto out;
 843                         }
 844                         /* Anything else is an error */
 845                         if (lex != ',')
 846                                 goto out;
 847
 848                 } /* End attributes loop */
 849         } /* End challenge loop */
 850
 851         /*
 852          * Challenges max count exceeded. This really can't happen
 853          * with normal data, something's fishy -> error
 854          */
 855
 856 out:
 857         if (key)
 858                 free(key);
 859         if (value)
 860                 free(value);
 861         if (buf)
 862                 free(buf);
 863         return (ret);
 864 }
 865
 866
 867 /*
 868  * Parse a last-modified header
 869  */
 870 static int
 871 http_parse_mtime(const char *p, time_t *mtime)
 872 {
 873         char locale[64], *r;
 874         struct tm tm;
 875
 876         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
 877         setlocale(LC_TIME, "C");
 878         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
 879         /* XXX should add support for date-2 and date-3 */
 880         setlocale(LC_TIME, locale);
 881         if (r == NULL)
 882                 return (-1);
 883         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
 884                   "%02d:%02d:%02d]\n",
 885                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 886                   tm.tm_hour, tm.tm_min, tm.tm_sec));
 887         *mtime = timegm(&tm);
 888         return (0);
 889 }
 890
 891 /*
 892  * Parse a content-length header
 893  */
 894 static int
 895 http_parse_length(const char *p, off_t *length)
 896 {
 897         off_t len;
 898
 899         for (len = 0; *p && isdigit((unsigned char)*p); ++p)
 900                 len = len * 10 + (*p - '0');
 901         if (*p)
 902                 return (-1);
 903         DEBUG(fprintf(stderr, "content length: [%lld]\n",
 904             (long long)len));
 905         *length = len;
 906         return (0);
 907 }
 908
 909 /*
 910  * Parse a content-range header
 911  */
 912 static int
 913 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
 914 {
 915         off_t first, last, len;
 916
 917         if (strncasecmp(p, "bytes ", 6) != 0)
 918                 return (-1);
 919         p += 6;
 920         if (*p == '*') {
 921                 first = last = -1;
 922                 ++p;
 923         } else {
 924                 for (first = 0; *p && isdigit((unsigned char)*p); ++p)
 925                         first = first * 10 + *p - '0';
 926                 if (*p != '-')
 927                         return (-1);
 928                 for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 929                         last = last * 10 + *p - '0';
 930         }
 931         if (first > last || *p != '/')
 932                 return (-1);
 933         for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 934                 len = len * 10 + *p - '0';
 935         if (*p || len < last - first + 1)
 936                 return (-1);
 937         if (first == -1) {
 938                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
 939                     (long long)len));
 940                 *length = 0;
 941         } else {
 942                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
 943                     (long long)first, (long long)last, (long long)len));
 944                 *length = last - first + 1;
 945         }
 946         *offset = first;
 947         *size = len;
 948         return (0);
 949 }
 950
 951
 952 /*****************************************************************************
 953  * Helper functions for authorization
 954  */
 955
 956 /*
 957  * Base64 encoding
 958  */
 959 static char *
 960 http_base64(const char *src)
 961 {
 962         static const char base64[] =
 963             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 964             "abcdefghijklmnopqrstuvwxyz"
 965             "0123456789+/";
 966         char *str, *dst;
 967         size_t l;
 968         int t, r;
 969
 970         l = strlen(src);
 971         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
 972                 return (NULL);
 973         dst = str;
 974         r = 0;
 975
 976         while (l >= 3) {
 977                 t = (src[0] << 16) | (src[1] << 8) | src[2];
 978                 dst[0] = base64[(t >> 18) & 0x3f];
 979                 dst[1] = base64[(t >> 12) & 0x3f];
 980                 dst[2] = base64[(t >> 6) & 0x3f];
 981                 dst[3] = base64[(t >> 0) & 0x3f];
 982                 src += 3; l -= 3;
 983                 dst += 4; r += 4;
 984         }
 985
 986         switch (l) {
 987         case 2:
 988                 t = (src[0] << 16) | (src[1] << 8);
 989                 dst[0] = base64[(t >> 18) & 0x3f];
 990                 dst[1] = base64[(t >> 12) & 0x3f];
 991                 dst[2] = base64[(t >> 6) & 0x3f];
 992                 dst[3] = '=';
 993                 dst += 4;
 994                 r += 4;
 995                 break;
 996         case 1:
 997                 t = src[0] << 16;
 998                 dst[0] = base64[(t >> 18) & 0x3f];
 999                 dst[1] = base64[(t >> 12) & 0x3f];
1000                 dst[2] = dst[3] = '=';
1001                 dst += 4;
1002                 r += 4;
1003                 break;
1004         case 0:
1005                 break;
1006         }
1007
1008         *dst = 0;
1009         return (str);
1010 }
1011
1012
1013 /*
1014  * Extract authorization parameters from environment value.
1015  * The value is like scheme:realm:user:pass
1016  */
1017 typedef struct {
1018         char    *scheme;
1019         char    *realm;
1020         char    *user;
1021         char    *password;
1022 } http_auth_params_t;
1023
1024 static void
1025 init_http_auth_params(http_auth_params_t *s)
1026 {
1027         s->scheme = s->realm = s->user = s->password = 0;
1028 }
1029
1030 static void
1031 clean_http_auth_params(http_auth_params_t *s)
1032 {
1033         if (s->scheme)
1034                 free(s->scheme);
1035         if (s->realm)
1036                 free(s->realm);
1037         if (s->user)
1038                 free(s->user);
1039         if (s->password)
1040                 free(s->password);
1041         init_http_auth_params(s);
1042 }
1043
1044 static int
1045 http_authfromenv(const char *p, http_auth_params_t *parms)
1046 {
1047         int ret = -1;
1048         char *v, *ve;
1049         char *str = strdup(p);
1050
1051         if (str == NULL) {
1052                 fetch_syserr();
1053                 return (-1);
1054         }
1055         v = str;
1056
1057         if ((ve = strchr(v, ':')) == NULL)
1058                 goto out;
1059
1060         *ve = 0;
1061         if ((parms->scheme = strdup(v)) == NULL) {
1062                 fetch_syserr();
1063                 goto out;
1064         }
1065         v = ve + 1;
1066
1067         if ((ve = strchr(v, ':')) == NULL)
1068                 goto out;
1069
1070         *ve = 0;
1071         if ((parms->realm = strdup(v)) == NULL) {
1072                 fetch_syserr();
1073                 goto out;
1074         }
1075         v = ve + 1;
1076
1077         if ((ve = strchr(v, ':')) == NULL)
1078                 goto out;
1079
1080         *ve = 0;
1081         if ((parms->user = strdup(v)) == NULL) {
1082                 fetch_syserr();
1083                 goto out;
1084         }
1085         v = ve + 1;
1086
1087
1088         if ((parms->password = strdup(v)) == NULL) {
1089                 fetch_syserr();
1090                 goto out;
1091         }
1092         ret = 0;
1093 out:
1094         if (ret == -1)
1095                 clean_http_auth_params(parms);
1096         if (str)
1097                 free(str);
1098         return (ret);
1099 }
1100
1101
1102 /*
1103  * Digest response: the code to compute the digest is taken from the
1104  * sample implementation in RFC2616
1105  */
1106 #define IN const
1107 #define OUT
1108
1109 #define HASHLEN 16
1110 typedef char HASH[HASHLEN];
1111 #define HASHHEXLEN 32
1112 typedef char HASHHEX[HASHHEXLEN+1];
1113
1114 static const char *hexchars = "0123456789abcdef";
1115 static void
1116 CvtHex(IN HASH Bin, OUT HASHHEX Hex)
1117 {
1118         unsigned short i;
1119         unsigned char j;
1120
1121         for (i = 0; i < HASHLEN; i++) {
1122                 j = (Bin[i] >> 4) & 0xf;
1123                 Hex[i*2] = hexchars[j];
1124                 j = Bin[i] & 0xf;
1125                 Hex[i*2+1] = hexchars[j];
1126         };
1127         Hex[HASHHEXLEN] = '\0';
1128 };
1129
1130 /* calculate H(A1) as per spec */
1131 static void
1132 DigestCalcHA1(
1133         IN char * pszAlg,
1134         IN char * pszUserName,
1135         IN char * pszRealm,
1136         IN char * pszPassword,
1137         IN char * pszNonce,
1138         IN char * pszCNonce,
1139         OUT HASHHEX SessionKey
1140         )
1141 {
1142         MD5_CTX Md5Ctx;
1143         HASH HA1;
1144
1145         MD5Init(&Md5Ctx);
1146         MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName));
1147         MD5Update(&Md5Ctx, ":", 1);
1148         MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm));
1149         MD5Update(&Md5Ctx, ":", 1);
1150         MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword));
1151         MD5Final(HA1, &Md5Ctx);
1152         if (strcasecmp(pszAlg, "md5-sess") == 0) {
1153
1154                 MD5Init(&Md5Ctx);
1155                 MD5Update(&Md5Ctx, HA1, HASHLEN);
1156                 MD5Update(&Md5Ctx, ":", 1);
1157                 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1158                 MD5Update(&Md5Ctx, ":", 1);
1159                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1160                 MD5Final(HA1, &Md5Ctx);
1161         };
1162         CvtHex(HA1, SessionKey);
1163 }
1164
1165 /* calculate request-digest/response-digest as per HTTP Digest spec */
1166 static void
1167 DigestCalcResponse(
1168         IN HASHHEX HA1,           /* H(A1) */
1169         IN char * pszNonce,       /* nonce from server */
1170         IN char * pszNonceCount,  /* 8 hex digits */
1171         IN char * pszCNonce,      /* client nonce */
1172         IN char * pszQop,         /* qop-value: "", "auth", "auth-int" */
1173         IN char * pszMethod,      /* method from the request */
1174         IN char * pszDigestUri,   /* requested URL */
1175         IN HASHHEX HEntity,       /* H(entity body) if qop="auth-int" */
1176         OUT HASHHEX Response      /* request-digest or response-digest */
1177         )
1178 {
1179 /*      DEBUG(fprintf(stderr,
1180                       "Calc: HA1[%s] Nonce[%s] qop[%s] method[%s] URI[%s]\n",
1181                       HA1, pszNonce, pszQop, pszMethod, pszDigestUri));*/
1182         MD5_CTX Md5Ctx;
1183         HASH HA2;
1184         HASH RespHash;
1185         HASHHEX HA2Hex;
1186
1187         // calculate H(A2)
1188         MD5Init(&Md5Ctx);
1189         MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod));
1190         MD5Update(&Md5Ctx, ":", 1);
1191         MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri));
1192         if (strcasecmp(pszQop, "auth-int") == 0) {
1193                 MD5Update(&Md5Ctx, ":", 1);
1194                 MD5Update(&Md5Ctx, HEntity, HASHHEXLEN);
1195         };
1196         MD5Final(HA2, &Md5Ctx);
1197         CvtHex(HA2, HA2Hex);
1198
1199         // calculate response
1200         MD5Init(&Md5Ctx);
1201         MD5Update(&Md5Ctx, HA1, HASHHEXLEN);
1202         MD5Update(&Md5Ctx, ":", 1);
1203         MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1204         MD5Update(&Md5Ctx, ":", 1);
1205         if (*pszQop) {
1206                 MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount));
1207                 MD5Update(&Md5Ctx, ":", 1);
1208                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1209                 MD5Update(&Md5Ctx, ":", 1);
1210                 MD5Update(&Md5Ctx, pszQop, strlen(pszQop));
1211                 MD5Update(&Md5Ctx, ":", 1);
1212         };
1213         MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN);
1214         MD5Final(RespHash, &Md5Ctx);
1215         CvtHex(RespHash, Response);
1216 }
1217
1218 /*
1219  * Generate/Send a Digest authorization header
1220  * This looks like: [Proxy-]Authorization: credentials
1221  *
1222  *  credentials      = "Digest" digest-response
1223  *  digest-response  = 1#( username | realm | nonce | digest-uri
1224  *                      | response | [ algorithm ] | [cnonce] |
1225  *                      [opaque] | [message-qop] |
1226  *                          [nonce-count]  | [auth-param] )
1227  *  username         = "username" "=" username-value
1228  *  username-value   = quoted-string
1229  *  digest-uri       = "uri" "=" digest-uri-value
1230  *  digest-uri-value = request-uri   ; As specified by HTTP/1.1
1231  *  message-qop      = "qop" "=" qop-value
1232  *  cnonce           = "cnonce" "=" cnonce-value
1233  *  cnonce-value     = nonce-value
1234  *  nonce-count      = "nc" "=" nc-value
1235  *  nc-value         = 8LHEX
1236  *  response         = "response" "=" request-digest
1237  *  request-digest = <"> 32LHEX <">
1238  */
1239 static int
1240 http_digest_auth(conn_t *conn, const char *hdr, http_auth_challenge_t *c,
1241                  http_auth_params_t *parms, struct url *url)
1242 {
1243         int r;
1244         char noncecount[10];
1245         char cnonce[40];
1246         char *options = 0;
1247
1248         if (!c->realm || !c->nonce) {
1249                 DEBUG(fprintf(stderr, "realm/nonce not set in challenge\n"));
1250                 return(-1);
1251         }
1252         if (!c->algo)
1253                 c->algo = strdup("");
1254
1255         if (asprintf(&options, "%s%s%s%s",
1256                      *c->algo? ",algorithm=" : "", c->algo,
1257                      c->opaque? ",opaque=" : "", c->opaque?c->opaque:"")== -1)
1258                 return (-1);
1259
1260         if (!c->qop) {
1261                 c->qop = strdup("");
1262                 *noncecount = 0;
1263                 *cnonce = 0;
1264         } else {
1265                 c->nc++;
1266                 sprintf(noncecount, "%08x", c->nc);
1267                 /* We don't try very hard with the cnonce ... */
1268                 sprintf(cnonce, "%x%lx", getpid(), (unsigned long)time(0));
1269         }
1270
1271         HASHHEX HA1;
1272         DigestCalcHA1(c->algo, parms->user, c->realm,
1273                       parms->password, c->nonce, cnonce, HA1);
1274         DEBUG(fprintf(stderr, "HA1: [%s]\n", HA1));
1275         HASHHEX digest;
1276         DigestCalcResponse(HA1, c->nonce, noncecount, cnonce, c->qop,
1277                            "GET", url->doc, "", digest);
1278
1279         if (c->qop[0]) {
1280                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1281                              "nonce=\"%s\",uri=\"%s\",response=\"%s\","
1282                              "qop=\"auth\", cnonce=\"%s\", nc=%s%s",
1283                              hdr, parms->user, c->realm,
1284                              c->nonce, url->doc, digest,
1285                              cnonce, noncecount, options);
1286         } else {
1287                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1288                              "nonce=\"%s\",uri=\"%s\",response=\"%s\"%s",
1289                              hdr, parms->user, c->realm,
1290                              c->nonce, url->doc, digest, options);
1291         }
1292         if (options)
1293                 free(options);
1294         return (r);
1295 }
1296
1297 /*
1298  * Encode username and password
1299  */
1300 static int
1301 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
1302 {
1303         char *upw, *auth;
1304         int r;
1305
1306         DEBUG(fprintf(stderr, "basic: usr: [%s]\n", usr));
1307         DEBUG(fprintf(stderr, "basic: pwd: [%s]\n", pwd));
1308         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
1309                 return (-1);
1310         auth = http_base64(upw);
1311         free(upw);
1312         if (auth == NULL)
1313                 return (-1);
1314         r = http_cmd(conn, "%s: Basic %s", hdr, auth);
1315         free(auth);
1316         return (r);
1317 }
1318
1319 /*
1320  * Chose the challenge to answer and call the appropriate routine to
1321  * produce the header.
1322  */
1323 static int
1324 http_authorize(conn_t *conn, const char *hdr, http_auth_challenges_t *cs,
1325                http_auth_params_t *parms, struct url *url)
1326 {
1327         http_auth_challenge_t *basic = NULL;
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 and a Basic challenge */
1338         for (i = 0; i < cs->count; i++) {
1339                 if (cs->challenges[i]->scheme == HTTPAS_BASIC)
1340                         basic = cs->challenges[i];
1341                 if (cs->challenges[i]->scheme == HTTPAS_DIGEST)
1342                         digest = cs->challenges[i];
1343         }
1344
1345         /* Error if "Digest" was specified and there is no Digest challenge */
1346         if (!digest && (parms->scheme &&
1347                         !strcasecmp(parms->scheme, "digest"))) {
1348                 DEBUG(fprintf(stderr,
1349                               "Digest auth in env, not supported by peer\n"));
1350                 return (-1);
1351         }
1352         /*
1353          * If "basic" was specified in the environment, or there is no Digest
1354          * challenge, do the basic thing. Don't need a challenge for this,
1355          * so no need to check basic!=NULL
1356          */
1357         if (!digest || (parms->scheme && !strcasecmp(parms->scheme,"basic")))
1358                 return (http_basic_auth(conn,hdr,parms->user,parms->password));
1359
1360         /* Else, prefer digest. We just checked that it's not NULL */
1361         return (http_digest_auth(conn, hdr, digest, parms, url));
1362 }
1363
1364 /*****************************************************************************
1365  * Helper functions for connecting to a server or proxy
1366  */
1367
1368 /*
1369  * Connect to the correct HTTP server or proxy.
1370  */
1371 static conn_t *
1372 http_connect(struct url *URL, struct url *purl, const char *flags)
1373 {
1374         struct url *curl;
1375         conn_t *conn;
1376         int verbose;
1377         int af, val;
1378
1379 #ifdef INET6
1380         af = AF_UNSPEC;
1381 #else
1382         af = AF_INET;
1383 #endif
1384
1385         verbose = CHECK_FLAG('v');
1386         if (CHECK_FLAG('4'))
1387                 af = AF_INET;
1388 #ifdef INET6
1389         else if (CHECK_FLAG('6'))
1390                 af = AF_INET6;
1391 #endif
1392
1393         curl = (purl != NULL) ? purl : URL;
1394
1395         if ((conn = fetch_connect(curl->host, curl->port, af, verbose)) == NULL)
1396                 /* fetch_connect() has already set an error code */
1397                 return (NULL);
1398         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 && purl) {
1399                 http_cmd(conn, "CONNECT %s:%d HTTP/1.1",
1400                     URL->host, URL->port);
1401                 http_cmd(conn, "Host: %s:%d",
1402                     URL->host, URL->port);
1403                 http_cmd(conn, "");
1404                 if (http_get_reply(conn) != HTTP_OK) {
1405                         fetch_close(conn);
1406                         return (NULL);
1407                 }
1408                 http_get_reply(conn);
1409         }
1410         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
1411             fetch_ssl(conn, URL, verbose) == -1) {
1412                 fetch_close(conn);
1413                 /* grrr */
1414                 errno = EAUTH;
1415                 fetch_syserr();
1416                 return (NULL);
1417         }
1418
1419         val = 1;
1420         setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
1421
1422         return (conn);
1423 }
1424
1425 static struct url *
1426 http_get_proxy(struct url * url, const char *flags)
1427 {
1428         struct url *purl;
1429         char *p;
1430
1431         if (flags != NULL && strchr(flags, 'd') != NULL)
1432                 return (NULL);
1433         if (fetch_no_proxy_match(url->host))
1434                 return (NULL);
1435         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1436             *p && (purl = fetchParseURL(p))) {
1437                 if (!*purl->scheme)
1438                         strcpy(purl->scheme, SCHEME_HTTP);
1439                 if (!purl->port)
1440                         purl->port = fetch_default_proxy_port(purl->scheme);
1441                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1442                         return (purl);
1443                 fetchFreeURL(purl);
1444         }
1445         return (NULL);
1446 }
1447
1448 static void
1449 http_print_html(FILE *out, FILE *in)
1450 {
1451         size_t len;
1452         char *line, *p, *q;
1453         int comment, tag;
1454
1455         comment = tag = 0;
1456         while ((line = fgetln(in, &len)) != NULL) {
1457                 while (len && isspace((unsigned char)line[len - 1]))
1458                         --len;
1459                 for (p = q = line; q < line + len; ++q) {
1460                         if (comment && *q == '-') {
1461                                 if (q + 2 < line + len &&
1462                                     strcmp(q, "-->") == 0) {
1463                                         tag = comment = 0;
1464                                         q += 2;
1465                                 }
1466                         } else if (tag && !comment && *q == '>') {
1467                                 p = q + 1;
1468                                 tag = 0;
1469                         } else if (!tag && *q == '<') {
1470                                 if (q > p)
1471                                         fwrite(p, q - p, 1, out);
1472                                 tag = 1;
1473                                 if (q + 3 < line + len &&
1474                                     strcmp(q, "<!--") == 0) {
1475                                         comment = 1;
1476                                         q += 3;
1477                                 }
1478                         }
1479                 }
1480                 if (!tag && q > p)
1481                         fwrite(p, q - p, 1, out);
1482                 fputc('\n', out);
1483         }
1484 }
1485
1486
1487 /*****************************************************************************
1488  * Core
1489  */
1490
1491 /*
1492  * Send a request and process the reply
1493  *
1494  * XXX This function is way too long, the do..while loop should be split
1495  * XXX off into a separate function.
1496  */
1497 FILE *
1498 http_request(struct url *URL, const char *op, struct url_stat *us,
1499         struct url *purl, const char *flags)
1500 {
1501         char timebuf[80];
1502         char hbuf[MAXHOSTNAMELEN + 7], *host;
1503         conn_t *conn;
1504         struct url *url, *new;
1505         int chunked, direct, ims, noredirect, verbose;
1506         int e, i, n, val;
1507         off_t offset, clength, length, size;
1508         time_t mtime;
1509         const char *p;
1510         FILE *f;
1511         hdr_t h;
1512         struct tm *timestruct;
1513         http_headerbuf_t headerbuf;
1514         http_auth_challenges_t server_challenges;
1515         http_auth_challenges_t proxy_challenges;
1516
1517         /* The following calls don't allocate anything */
1518         init_http_headerbuf(&headerbuf);
1519         init_http_auth_challenges(&server_challenges);
1520         init_http_auth_challenges(&proxy_challenges);
1521
1522         direct = CHECK_FLAG('d');
1523         noredirect = CHECK_FLAG('A');
1524         verbose = CHECK_FLAG('v');
1525         ims = CHECK_FLAG('i');
1526
1527         if (direct && purl) {
1528                 fetchFreeURL(purl);
1529                 purl = NULL;
1530         }
1531
1532         /* try the provided URL first */
1533         url = URL;
1534
1535         n = MAX_REDIRECT;
1536         i = 0;
1537
1538         e = HTTP_PROTOCOL_ERROR;
1539         do {
1540                 new = NULL;
1541                 chunked = 0;
1542                 offset = 0;
1543                 clength = -1;
1544                 length = -1;
1545                 size = -1;
1546                 mtime = 0;
1547
1548                 /* check port */
1549                 if (!url->port)
1550                         url->port = fetch_default_port(url->scheme);
1551
1552                 /* were we redirected to an FTP URL? */
1553                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
1554                         if (strcmp(op, "GET") == 0)
1555                                 return (ftp_request(url, "RETR", us, purl, flags));
1556                         else if (strcmp(op, "HEAD") == 0)
1557                                 return (ftp_request(url, "STAT", us, purl, flags));
1558                 }
1559
1560                 /* connect to server or proxy */
1561                 if ((conn = http_connect(url, purl, flags)) == NULL)
1562                         goto ouch;
1563
1564                 host = url->host;
1565 #ifdef INET6
1566                 if (strchr(url->host, ':')) {
1567                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
1568                         host = hbuf;
1569                 }
1570 #endif
1571                 if (url->port != fetch_default_port(url->scheme)) {
1572                         if (host != hbuf) {
1573                                 strcpy(hbuf, host);
1574                                 host = hbuf;
1575                         }
1576                         snprintf(hbuf + strlen(hbuf),
1577                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
1578                 }
1579
1580                 /* send request */
1581                 if (verbose)
1582                         fetch_info("requesting %s://%s%s",
1583                             url->scheme, host, url->doc);
1584                 if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
1585                         http_cmd(conn, "%s %s://%s%s HTTP/1.1",
1586                             op, url->scheme, host, url->doc);
1587                 } else {
1588                         http_cmd(conn, "%s %s HTTP/1.1",
1589                             op, url->doc);
1590                 }
1591
1592                 if (ims && url->ims_time) {
1593                         timestruct = gmtime((time_t *)&url->ims_time);
1594                         (void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
1595                             timestruct);
1596                         if (verbose)
1597                                 fetch_info("If-Modified-Since: %s", timebuf);
1598                         http_cmd(conn, "If-Modified-Since: %s", timebuf);
1599                 }
1600                 /* virtual host */
1601                 http_cmd(conn, "Host: %s", host);
1602
1603                 /*
1604                  * Proxy authorization: we only send auth after we received
1605                  * a 407 error. We do not first try basic anyway (changed
1606                  * when support was added for digest-auth)
1607                  */
1608                 if (purl && proxy_challenges.valid) {
1609                         http_auth_params_t aparams;
1610                         init_http_auth_params(&aparams);
1611                         if (*purl->user || *purl->pwd) {
1612                                 aparams.user = purl->user ?
1613                                         strdup(purl->user) : strdup("");
1614                                 aparams.password = purl->pwd?
1615                                         strdup(purl->pwd) : strdup("");
1616                         } else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL &&
1617                                    *p != '\0') {
1618                                 if (http_authfromenv(p, &aparams) < 0) {
1619                                         http_seterr(HTTP_NEED_PROXY_AUTH);
1620                                         goto ouch;
1621                                 }
1622                         }
1623                         http_authorize(conn, "Proxy-Authorization",
1624                                        &proxy_challenges, &aparams, url);
1625                         clean_http_auth_params(&aparams);
1626                 }
1627
1628                 /*
1629                  * Server authorization: we never send "a priori"
1630                  * Basic auth, which used to be done if user/pass were
1631                  * set in the url. This would be weird because we'd send the
1632                  * password in the clear even if Digest is finally to be
1633                  * used (it would have made more sense for the
1634                  * pre-digest version to do this when Basic was specified
1635                  * in the environment)
1636                  */
1637                 if (server_challenges.valid) {
1638                         http_auth_params_t aparams;
1639                         init_http_auth_params(&aparams);
1640                         if (*url->user || *url->pwd) {
1641                                 aparams.user = url->user ?
1642                                         strdup(url->user) : strdup("");
1643                                 aparams.password = url->pwd ?
1644                                         strdup(url->pwd) : strdup("");
1645                         } else if ((p = getenv("HTTP_AUTH")) != NULL &&
1646                                    *p != '\0') {
1647                                 if (http_authfromenv(p, &aparams) < 0) {
1648                                         http_seterr(HTTP_NEED_AUTH);
1649                                         goto ouch;
1650                                 }
1651                         } else if (fetchAuthMethod &&
1652                                    fetchAuthMethod(url) == 0) {
1653                                 aparams.user = url->user ?
1654                                         strdup(url->user) : strdup("");
1655                                 aparams.password = url->pwd ?
1656                                         strdup(url->pwd) : strdup("");
1657                         } else {
1658                                 http_seterr(HTTP_NEED_AUTH);
1659                                 goto ouch;
1660                         }
1661                         http_authorize(conn, "Authorization",
1662                                        &server_challenges, &aparams, url);
1663                         clean_http_auth_params(&aparams);
1664                 }
1665
1666                 /* other headers */
1667                 if ((p = getenv("HTTP_ACCEPT")) != NULL) {
1668                         if (*p != '\0')
1669                                 http_cmd(conn, "Accept: %s", p);
1670                 } else {
1671                         http_cmd(conn, "Accept: */*");
1672                 }
1673                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
1674                         if (strcasecmp(p, "auto") == 0)
1675                                 http_cmd(conn, "Referer: %s://%s%s",
1676                                     url->scheme, host, url->doc);
1677                         else
1678                                 http_cmd(conn, "Referer: %s", p);
1679                 }
1680                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
1681                         http_cmd(conn, "User-Agent: %s", p);
1682                 else
1683                         http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
1684                 if (url->offset > 0)
1685                         http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
1686                 http_cmd(conn, "Connection: close");
1687                 http_cmd(conn, "");
1688
1689                 /*
1690                  * Force the queued request to be dispatched.  Normally, one
1691                  * would do this with shutdown(2) but squid proxies can be
1692                  * configured to disallow such half-closed connections.  To
1693                  * be compatible with such configurations, fiddle with socket
1694                  * options to force the pending data to be written.
1695                  */
1696                 val = 0;
1697                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
1698                            sizeof(val));
1699                 val = 1;
1700                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
1701                            sizeof(val));
1702
1703                 /* get reply */
1704                 switch (http_get_reply(conn)) {
1705                 case HTTP_OK:
1706                 case HTTP_PARTIAL:
1707                 case HTTP_NOT_MODIFIED:
1708                         /* fine */
1709                         break;
1710                 case HTTP_MOVED_PERM:
1711                 case HTTP_MOVED_TEMP:
1712                 case HTTP_SEE_OTHER:
1713                 case HTTP_USE_PROXY:
1714                         /*
1715                          * Not so fine, but we still have to read the
1716                          * headers to get the new location.
1717                          */
1718                         break;
1719                 case HTTP_NEED_AUTH:
1720                         if (server_challenges.valid) {
1721                                 /*
1722                                  * We already sent out authorization code,
1723                                  * so there's nothing more we can do.
1724                                  */
1725                                 http_seterr(conn->err);
1726                                 goto ouch;
1727                         }
1728                         /* try again, but send the password this time */
1729                         if (verbose)
1730                                 fetch_info("server requires authorization");
1731                         break;
1732                 case HTTP_NEED_PROXY_AUTH:
1733                         if (proxy_challenges.valid) {
1734                                 /*
1735                                  * We already sent our proxy
1736                                  * authorization code, so there's
1737                                  * nothing more we can do. */
1738                                 http_seterr(conn->err);
1739                                 goto ouch;
1740                         }
1741                         /* try again, but send the password this time */
1742                         if (verbose)
1743                                 fetch_info("proxy requires authorization");
1744                         break;
1745                 case HTTP_BAD_RANGE:
1746                         /*
1747                          * This can happen if we ask for 0 bytes because
1748                          * we already have the whole file.  Consider this
1749                          * a success for now, and check sizes later.
1750                          */
1751                         break;
1752                 case HTTP_PROTOCOL_ERROR:
1753                         /* fall through */
1754                 case -1:
1755                         fetch_syserr();
1756                         goto ouch;
1757                 default:
1758                         http_seterr(conn->err);
1759                         if (!verbose)
1760                                 goto ouch;
1761                         /* fall through so we can get the full error message */
1762                 }
1763
1764                 /* get headers. http_next_header expects one line readahead */
1765                 if (fetch_getln(conn) == -1) {
1766                         fetch_syserr();
1767                         goto ouch;
1768                 }
1769                 do {
1770                         switch ((h = http_next_header(conn, &headerbuf, &p))) {
1771                         case hdr_syserror:
1772                                 fetch_syserr();
1773                                 goto ouch;
1774                         case hdr_error:
1775                                 http_seterr(HTTP_PROTOCOL_ERROR);
1776                                 goto ouch;
1777                         case hdr_content_length:
1778                                 http_parse_length(p, &clength);
1779                                 break;
1780                         case hdr_content_range:
1781                                 http_parse_range(p, &offset, &length, &size);
1782                                 break;
1783                         case hdr_last_modified:
1784                                 http_parse_mtime(p, &mtime);
1785                                 break;
1786                         case hdr_location:
1787                                 if (!HTTP_REDIRECT(conn->err))
1788                                         break;
1789                                 /*
1790                                  * if the A flag is set, we don't follow
1791                                  * temporary redirects.
1792                                  */
1793                                 if (noredirect &&
1794                                     conn->err != HTTP_MOVED_PERM &&
1795                                     conn->err != HTTP_PERM_REDIRECT &&
1796                                     conn->err != HTTP_USE_PROXY) {
1797                                         n = 1;
1798                                         break;
1799                                 }
1800                                 if (new)
1801                                         free(new);
1802                                 if (verbose)
1803                                         fetch_info("%d redirect to %s", conn->err, p);
1804                                 if (*p == '/')
1805                                         /* absolute path */
1806                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1807                                             url->user, url->pwd);
1808                                 else
1809                                         new = fetchParseURL(p);
1810                                 if (new == NULL) {
1811                                         /* XXX should set an error code */
1812                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1813                                         goto ouch;
1814                                 }
1815
1816                                 /* Only copy credentials if the host matches */
1817                                 if (!strcmp(new->host, url->host) && !*new->user && !*new->pwd) {
1818                                         strcpy(new->user, url->user);
1819                                         strcpy(new->pwd, url->pwd);
1820                                 }
1821                                 new->offset = url->offset;
1822                                 new->length = url->length;
1823                                 break;
1824                         case hdr_transfer_encoding:
1825                                 /* XXX weak test*/
1826                                 chunked = (strcasecmp(p, "chunked") == 0);
1827                                 break;
1828                         case hdr_www_authenticate:
1829                                 if (conn->err != HTTP_NEED_AUTH)
1830                                         break;
1831                                 if (http_parse_authenticate(p, &server_challenges) == 0)
1832                                         ++n;
1833                                 break;
1834                         case hdr_proxy_authenticate:
1835                                 if (conn->err != HTTP_NEED_PROXY_AUTH)
1836                                         break;
1837                                 if (http_parse_authenticate(p, &proxy_challenges) == 0)
1838                                         ++n;
1839                                 break;
1840                         case hdr_end:
1841                                 /* fall through */
1842                         case hdr_unknown:
1843                                 /* ignore */
1844                                 break;
1845                         }
1846                 } while (h > hdr_end);
1847
1848                 /* we need to provide authentication */
1849                 if (conn->err == HTTP_NEED_AUTH ||
1850                     conn->err == HTTP_NEED_PROXY_AUTH) {
1851                         e = conn->err;
1852                         if ((conn->err == HTTP_NEED_AUTH &&
1853                              !server_challenges.valid) ||
1854                             (conn->err == HTTP_NEED_PROXY_AUTH &&
1855                              !proxy_challenges.valid)) {
1856                                 /* 401/7 but no www/proxy-authenticate ?? */
1857                                 DEBUG(fprintf(stderr, "401/7 and no auth header\n"));
1858                                 goto ouch;
1859                         }
1860                         fetch_close(conn);
1861                         conn = NULL;
1862                         continue;
1863                 }
1864
1865                 /* requested range not satisfiable */
1866                 if (conn->err == HTTP_BAD_RANGE) {
1867                         if (url->offset == size && url->length == 0) {
1868                                 /* asked for 0 bytes; fake it */
1869                                 offset = url->offset;
1870                                 clength = -1;
1871                                 conn->err = HTTP_OK;
1872                                 break;
1873                         } else {
1874                                 http_seterr(conn->err);
1875                                 goto ouch;
1876                         }
1877                 }
1878
1879                 /* we have a hit or an error */
1880                 if (conn->err == HTTP_OK
1881                     || conn->err == HTTP_NOT_MODIFIED
1882                     || conn->err == HTTP_PARTIAL
1883                     || HTTP_ERROR(conn->err))
1884                         break;
1885
1886                 /* all other cases: we got a redirect */
1887                 e = conn->err;
1888                 clean_http_auth_challenges(&server_challenges);
1889                 fetch_close(conn);
1890                 conn = NULL;
1891                 if (!new) {
1892                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1893                         break;
1894                 }
1895                 if (url != URL)
1896                         fetchFreeURL(url);
1897                 url = new;
1898         } while (++i < n);
1899
1900         /* we failed, or ran out of retries */
1901         if (conn == NULL) {
1902                 http_seterr(e);
1903                 goto ouch;
1904         }
1905
1906         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1907                   " size %lld, clength %lld\n",
1908                   (long long)offset, (long long)length,
1909                   (long long)size, (long long)clength));
1910
1911         if (conn->err == HTTP_NOT_MODIFIED) {
1912                 http_seterr(HTTP_NOT_MODIFIED);
1913                 return (NULL);
1914         }
1915
1916         /* check for inconsistencies */
1917         if (clength != -1 && length != -1 && clength != length) {
1918                 http_seterr(HTTP_PROTOCOL_ERROR);
1919                 goto ouch;
1920         }
1921         if (clength == -1)
1922                 clength = length;
1923         if (clength != -1)
1924                 length = offset + clength;
1925         if (length != -1 && size != -1 && length != size) {
1926                 http_seterr(HTTP_PROTOCOL_ERROR);
1927                 goto ouch;
1928         }
1929         if (size == -1)
1930                 size = length;
1931
1932         /* fill in stats */
1933         if (us) {
1934                 us->size = size;
1935                 us->atime = us->mtime = mtime;
1936         }
1937
1938         /* too far? */
1939         if (URL->offset > 0 && offset > URL->offset) {
1940                 http_seterr(HTTP_PROTOCOL_ERROR);
1941                 goto ouch;
1942         }
1943
1944         /* report back real offset and size */
1945         URL->offset = offset;
1946         URL->length = clength;
1947
1948         /* wrap it up in a FILE */
1949         if ((f = http_funopen(conn, chunked)) == NULL) {
1950                 fetch_syserr();
1951                 goto ouch;
1952         }
1953
1954         if (url != URL)
1955                 fetchFreeURL(url);
1956         if (purl)
1957                 fetchFreeURL(purl);
1958
1959         if (HTTP_ERROR(conn->err)) {
1960                 http_print_html(stderr, f);
1961                 fclose(f);
1962                 f = NULL;
1963         }
1964         clean_http_headerbuf(&headerbuf);
1965         clean_http_auth_challenges(&server_challenges);
1966         clean_http_auth_challenges(&proxy_challenges);
1967         return (f);
1968
1969 ouch:
1970         if (url != URL)
1971                 fetchFreeURL(url);
1972         if (purl)
1973                 fetchFreeURL(purl);
1974         if (conn != NULL)
1975                 fetch_close(conn);
1976         clean_http_headerbuf(&headerbuf);
1977         clean_http_auth_challenges(&server_challenges);
1978         clean_http_auth_challenges(&proxy_challenges);
1979         return (NULL);
1980 }
1981
1982
1983 /*****************************************************************************
1984  * Entry points
1985  */
1986
1987 /*
1988  * Retrieve and stat a file by HTTP
1989  */
1990 FILE *
1991 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1992 {
1993         return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1994 }
1995
1996 /*
1997  * Retrieve a file by HTTP
1998  */
1999 FILE *
2000 fetchGetHTTP(struct url *URL, const char *flags)
2001 {
2002         return (fetchXGetHTTP(URL, NULL, flags));
2003 }
2004
2005 /*
2006  * Store a file by HTTP
2007  */
2008 FILE *
2009 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
2010 {
2011         warnx("fetchPutHTTP(): not implemented");
2012         return (NULL);
2013 }
2014
2015 /*
2016  * Get an HTTP document's metadata
2017  */
2018 int
2019 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
2020 {
2021         FILE *f;
2022
2023         f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
2024         if (f == NULL)
2025                 return (-1);
2026         fclose(f);
2027         return (0);
2028 }
2029
2030 /*
2031  * List a directory
2032  */
2033 struct url_ent *
2034 fetchListHTTP(struct url *url __unused, const char *flags __unused)
2035 {
2036         warnx("fetchListHTTP(): not implemented");
2037         return (NULL);
2038 }