lib/libfetch/http.c

   1 /*-
   2  * Copyright (c) 2000-2013 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 int
 208 http_fillbuf(struct httpio *io, size_t len)
 209 {
 210         ssize_t nbytes;
 211
 212         if (io->error)
 213                 return (-1);
 214         if (io->eof)
 215                 return (0);
 216
 217         if (io->chunked == 0) {
 218                 if (http_growbuf(io, len) == -1)
 219                         return (-1);
 220                 if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 221                         io->error = errno;
 222                         return (-1);
 223                 }
 224                 io->buflen = nbytes;
 225                 io->bufpos = 0;
 226                 return (io->buflen);
 227         }
 228
 229         if (io->chunksize == 0) {
 230                 switch (http_new_chunk(io)) {
 231                 case -1:
 232                         io->error = 1;
 233                         return (-1);
 234                 case 0:
 235                         io->eof = 1;
 236                         return (0);
 237                 }
 238         }
 239
 240         if (len > io->chunksize)
 241                 len = io->chunksize;
 242         if (http_growbuf(io, len) == -1)
 243                 return (-1);
 244         if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
 245                 io->error = errno;
 246                 return (-1);
 247         }
 248         io->buflen = nbytes;
 249         io->chunksize -= io->buflen;
 250
 251         if (io->chunksize == 0) {
 252                 char endl[2];
 253
 254                 if (fetch_read(io->conn, endl, 2) != 2 ||
 255                     endl[0] != '\r' || endl[1] != '\n')
 256                         return (-1);
 257         }
 258
 259         io->bufpos = 0;
 260
 261         return (io->buflen);
 262 }
 263
 264 /*
 265  * Read function
 266  */
 267 static int
 268 http_readfn(void *v, char *buf, int len)
 269 {
 270         struct httpio *io = (struct httpio *)v;
 271         int l, pos;
 272
 273         if (io->error)
 274                 return (-1);
 275         if (io->eof)
 276                 return (0);
 277
 278         for (pos = 0; len > 0; pos += l, len -= l) {
 279                 /* empty buffer */
 280                 if (!io->buf || io->bufpos == io->buflen)
 281                         if (http_fillbuf(io, len) < 1)
 282                                 break;
 283                 l = io->buflen - io->bufpos;
 284                 if (len < l)
 285                         l = len;
 286                 memcpy(buf + pos, io->buf + io->bufpos, l);
 287                 io->bufpos += l;
 288         }
 289
 290         if (!pos && io->error) {
 291                 if (io->error == EINTR)
 292                         io->error = 0;
 293                 return (-1);
 294         }
 295         return (pos);
 296 }
 297
 298 /*
 299  * Write function
 300  */
 301 static int
 302 http_writefn(void *v, const char *buf, int len)
 303 {
 304         struct httpio *io = (struct httpio *)v;
 305
 306         return (fetch_write(io->conn, buf, len));
 307 }
 308
 309 /*
 310  * Close function
 311  */
 312 static int
 313 http_closefn(void *v)
 314 {
 315         struct httpio *io = (struct httpio *)v;
 316         int r;
 317
 318         r = fetch_close(io->conn);
 319         if (io->buf)
 320                 free(io->buf);
 321         free(io);
 322         return (r);
 323 }
 324
 325 /*
 326  * Wrap a file descriptor up
 327  */
 328 static FILE *
 329 http_funopen(conn_t *conn, int chunked)
 330 {
 331         struct httpio *io;
 332         FILE *f;
 333
 334         if ((io = calloc(1, sizeof(*io))) == NULL) {
 335                 fetch_syserr();
 336                 return (NULL);
 337         }
 338         io->conn = conn;
 339         io->chunked = chunked;
 340         f = funopen(io, http_readfn, http_writefn, NULL, http_closefn);
 341         if (f == NULL) {
 342                 fetch_syserr();
 343                 free(io);
 344                 return (NULL);
 345         }
 346         return (f);
 347 }
 348
 349
 350 /*****************************************************************************
 351  * Helper functions for talking to the server and parsing its replies
 352  */
 353
 354 /* Header types */
 355 typedef enum {
 356         hdr_syserror = -2,
 357         hdr_error = -1,
 358         hdr_end = 0,
 359         hdr_unknown = 1,
 360         hdr_content_length,
 361         hdr_content_range,
 362         hdr_last_modified,
 363         hdr_location,
 364         hdr_transfer_encoding,
 365         hdr_www_authenticate,
 366         hdr_proxy_authenticate,
 367 } hdr_t;
 368
 369 /* Names of interesting headers */
 370 static struct {
 371         hdr_t            num;
 372         const char      *name;
 373 } hdr_names[] = {
 374         { hdr_content_length,           "Content-Length" },
 375         { hdr_content_range,            "Content-Range" },
 376         { hdr_last_modified,            "Last-Modified" },
 377         { hdr_location,                 "Location" },
 378         { hdr_transfer_encoding,        "Transfer-Encoding" },
 379         { hdr_www_authenticate,         "WWW-Authenticate" },
 380         { hdr_proxy_authenticate,       "Proxy-Authenticate" },
 381         { hdr_unknown,                  NULL },
 382 };
 383
 384 /*
 385  * Send a formatted line; optionally echo to terminal
 386  */
 387 static int
 388 http_cmd(conn_t *conn, const char *fmt, ...)
 389 {
 390         va_list ap;
 391         size_t len;
 392         char *msg;
 393         int r;
 394
 395         va_start(ap, fmt);
 396         len = vasprintf(&msg, fmt, ap);
 397         va_end(ap);
 398
 399         if (msg == NULL) {
 400                 errno = ENOMEM;
 401                 fetch_syserr();
 402                 return (-1);
 403         }
 404
 405         r = fetch_putln(conn, msg, len);
 406         free(msg);
 407
 408         if (r == -1) {
 409                 fetch_syserr();
 410                 return (-1);
 411         }
 412
 413         return (0);
 414 }
 415
 416 /*
 417  * Get and parse status line
 418  */
 419 static int
 420 http_get_reply(conn_t *conn)
 421 {
 422         char *p;
 423
 424         if (fetch_getln(conn) == -1)
 425                 return (-1);
 426         /*
 427          * A valid status line looks like "HTTP/m.n xyz reason" where m
 428          * and n are the major and minor protocol version numbers and xyz
 429          * is the reply code.
 430          * Unfortunately, there are servers out there (NCSA 1.5.1, to name
 431          * just one) that do not send a version number, so we can't rely
 432          * on finding one, but if we do, insist on it being 1.0 or 1.1.
 433          * We don't care about the reason phrase.
 434          */
 435         if (strncmp(conn->buf, "HTTP", 4) != 0)
 436                 return (HTTP_PROTOCOL_ERROR);
 437         p = conn->buf + 4;
 438         if (*p == '/') {
 439                 if (p[1] != '1' || p[2] != '.' || (p[3] != '0' && p[3] != '1'))
 440                         return (HTTP_PROTOCOL_ERROR);
 441                 p += 4;
 442         }
 443         if (*p != ' ' ||
 444             !isdigit((unsigned char)p[1]) ||
 445             !isdigit((unsigned char)p[2]) ||
 446             !isdigit((unsigned char)p[3]))
 447                 return (HTTP_PROTOCOL_ERROR);
 448
 449         conn->err = (p[1] - '0') * 100 + (p[2] - '0') * 10 + (p[3] - '0');
 450         return (conn->err);
 451 }
 452
 453 /*
 454  * Check a header; if the type matches the given string, return a pointer
 455  * to the beginning of the value.
 456  */
 457 static const char *
 458 http_match(const char *str, const char *hdr)
 459 {
 460         while (*str && *hdr &&
 461             tolower((unsigned char)*str++) == tolower((unsigned char)*hdr++))
 462                 /* nothing */;
 463         if (*str || *hdr != ':')
 464                 return (NULL);
 465         while (*hdr && isspace((unsigned char)*++hdr))
 466                 /* nothing */;
 467         return (hdr);
 468 }
 469
 470
 471 /*
 472  * Get the next header and return the appropriate symbolic code.  We
 473  * need to read one line ahead for checking for a continuation line
 474  * belonging to the current header (continuation lines start with
 475  * white space).
 476  *
 477  * We get called with a fresh line already in the conn buffer, either
 478  * from the previous http_next_header() invocation, or, the first
 479  * time, from a fetch_getln() performed by our caller.
 480  *
 481  * This stops when we encounter an empty line (we dont read beyond the header
 482  * area).
 483  *
 484  * Note that the "headerbuf" is just a place to return the result. Its
 485  * contents are not used for the next call. This means that no cleanup
 486  * is needed when ie doing another connection, just call the cleanup when
 487  * fully done to deallocate memory.
 488  */
 489
 490 /* Limit the max number of continuation lines to some reasonable value */
 491 #define HTTP_MAX_CONT_LINES 10
 492
 493 /* Place into which to build a header from one or several lines */
 494 typedef struct {
 495         char    *buf;           /* buffer */
 496         size_t   bufsize;       /* buffer size */
 497         size_t   buflen;        /* length of buffer contents */
 498 } http_headerbuf_t;
 499
 500 static void
 501 init_http_headerbuf(http_headerbuf_t *buf)
 502 {
 503         buf->buf = NULL;
 504         buf->bufsize = 0;
 505         buf->buflen = 0;
 506 }
 507
 508 static void
 509 clean_http_headerbuf(http_headerbuf_t *buf)
 510 {
 511         if (buf->buf)
 512                 free(buf->buf);
 513         init_http_headerbuf(buf);
 514 }
 515
 516 /* Remove whitespace at the end of the buffer */
 517 static void
 518 http_conn_trimright(conn_t *conn)
 519 {
 520         while (conn->buflen &&
 521                isspace((unsigned char)conn->buf[conn->buflen - 1]))
 522                 conn->buflen--;
 523         conn->buf[conn->buflen] = '\0';
 524 }
 525
 526 static hdr_t
 527 http_next_header(conn_t *conn, http_headerbuf_t *hbuf, const char **p)
 528 {
 529         unsigned int i, len;
 530
 531         /*
 532          * Have to do the stripping here because of the first line. So
 533          * it's done twice for the subsequent lines. No big deal
 534          */
 535         http_conn_trimright(conn);
 536         if (conn->buflen == 0)
 537                 return (hdr_end);
 538
 539         /* Copy the line to the headerbuf */
 540         if (hbuf->bufsize < conn->buflen + 1) {
 541                 if ((hbuf->buf = realloc(hbuf->buf, conn->buflen + 1)) == NULL)
 542                         return (hdr_syserror);
 543                 hbuf->bufsize = conn->buflen + 1;
 544         }
 545         strcpy(hbuf->buf, conn->buf);
 546         hbuf->buflen = conn->buflen;
 547
 548         /*
 549          * Fetch possible continuation lines. Stop at 1st non-continuation
 550          * and leave it in the conn buffer
 551          */
 552         for (i = 0; i < HTTP_MAX_CONT_LINES; i++) {
 553                 if (fetch_getln(conn) == -1)
 554                         return (hdr_syserror);
 555
 556                 /*
 557                  * Note: we carry on the idea from the previous version
 558                  * that a pure whitespace line is equivalent to an empty
 559                  * one (so it's not continuation and will be handled when
 560                  * we are called next)
 561                  */
 562                 http_conn_trimright(conn);
 563                 if (conn->buf[0] != ' ' && conn->buf[0] != "\t"[0])
 564                         break;
 565
 566                 /* Got a continuation line. Concatenate to previous */
 567                 len = hbuf->buflen + conn->buflen;
 568                 if (hbuf->bufsize < len + 1) {
 569                         len *= 2;
 570                         if ((hbuf->buf = realloc(hbuf->buf, len + 1)) == NULL)
 571                                 return (hdr_syserror);
 572                         hbuf->bufsize = len + 1;
 573                 }
 574                 strcpy(hbuf->buf + hbuf->buflen, conn->buf);
 575                 hbuf->buflen += conn->buflen;
 576         }
 577
 578         /*
 579          * We could check for malformed headers but we don't really care.
 580          * A valid header starts with a token immediately followed by a
 581          * colon; a token is any sequence of non-control, non-whitespace
 582          * characters except "()<>@,;:\\\"{}".
 583          */
 584         for (i = 0; hdr_names[i].num != hdr_unknown; i++)
 585                 if ((*p = http_match(hdr_names[i].name, hbuf->buf)) != NULL)
 586                         return (hdr_names[i].num);
 587
 588         return (hdr_unknown);
 589 }
 590
 591 /**************************
 592  * [Proxy-]Authenticate header parsing
 593  */
 594
 595 /*
 596  * Read doublequote-delimited string into output buffer obuf (allocated
 597  * by caller, whose responsibility it is to ensure that it's big enough)
 598  * cp points to the first char after the initial '"'
 599  * Handles \ quoting
 600  * Returns pointer to the first char after the terminating double quote, or
 601  * NULL for error.
 602  */
 603 static const char *
 604 http_parse_headerstring(const char *cp, char *obuf)
 605 {
 606         for (;;) {
 607                 switch (*cp) {
 608                 case 0: /* Unterminated string */
 609                         *obuf = 0;
 610                         return (NULL);
 611                 case '"': /* Ending quote */
 612                         *obuf = 0;
 613                         return (++cp);
 614                 case '\\':
 615                         if (*++cp == 0) {
 616                                 *obuf = 0;
 617                                 return (NULL);
 618                         }
 619                         /* FALLTHROUGH */
 620                 default:
 621                         *obuf++ = *cp++;
 622                 }
 623         }
 624 }
 625
 626 /* Http auth challenge schemes */
 627 typedef enum {HTTPAS_UNKNOWN, HTTPAS_BASIC,HTTPAS_DIGEST} http_auth_schemes_t;
 628
 629 /* Data holder for a Basic or Digest challenge. */
 630 typedef struct {
 631         http_auth_schemes_t scheme;
 632         char    *realm;
 633         char    *qop;
 634         char    *nonce;
 635         char    *opaque;
 636         char    *algo;
 637         int      stale;
 638         int      nc; /* Nonce count */
 639 } http_auth_challenge_t;
 640
 641 static void
 642 init_http_auth_challenge(http_auth_challenge_t *b)
 643 {
 644         b->scheme = HTTPAS_UNKNOWN;
 645         b->realm = b->qop = b->nonce = b->opaque = b->algo = NULL;
 646         b->stale = b->nc = 0;
 647 }
 648
 649 static void
 650 clean_http_auth_challenge(http_auth_challenge_t *b)
 651 {
 652         if (b->realm)
 653                 free(b->realm);
 654         if (b->qop)
 655                 free(b->qop);
 656         if (b->nonce)
 657                 free(b->nonce);
 658         if (b->opaque)
 659                 free(b->opaque);
 660         if (b->algo)
 661                 free(b->algo);
 662         init_http_auth_challenge(b);
 663 }
 664
 665 /* Data holder for an array of challenges offered in an http response. */
 666 #define MAX_CHALLENGES 10
 667 typedef struct {
 668         http_auth_challenge_t *challenges[MAX_CHALLENGES];
 669         int     count; /* Number of parsed challenges in the array */
 670         int     valid; /* We did parse an authenticate header */
 671 } http_auth_challenges_t;
 672
 673 static void
 674 init_http_auth_challenges(http_auth_challenges_t *cs)
 675 {
 676         int i;
 677         for (i = 0; i < MAX_CHALLENGES; i++)
 678                 cs->challenges[i] = NULL;
 679         cs->count = cs->valid = 0;
 680 }
 681
 682 static void
 683 clean_http_auth_challenges(http_auth_challenges_t *cs)
 684 {
 685         int i;
 686         /* We rely on non-zero pointers being allocated, not on the count */
 687         for (i = 0; i < MAX_CHALLENGES; i++) {
 688                 if (cs->challenges[i] != NULL) {
 689                         clean_http_auth_challenge(cs->challenges[i]);
 690                         free(cs->challenges[i]);
 691                 }
 692         }
 693         init_http_auth_challenges(cs);
 694 }
 695
 696 /*
 697  * Enumeration for lexical elements. Separators will be returned as their own
 698  * ascii value
 699  */
 700 typedef enum {HTTPHL_WORD=256, HTTPHL_STRING=257, HTTPHL_END=258,
 701               HTTPHL_ERROR = 259} http_header_lex_t;
 702
 703 /*
 704  * Determine what kind of token comes next and return possible value
 705  * in buf, which is supposed to have been allocated big enough by
 706  * caller. Advance input pointer and return element type.
 707  */
 708 static int
 709 http_header_lex(const char **cpp, char *buf)
 710 {
 711         size_t l;
 712         /* Eat initial whitespace */
 713         *cpp += strspn(*cpp, " \t");
 714         if (**cpp == 0)
 715                 return (HTTPHL_END);
 716
 717         /* Separator ? */
 718         if (**cpp == ',' || **cpp == '=')
 719                 return (*((*cpp)++));
 720
 721         /* String ? */
 722         if (**cpp == '"') {
 723                 *cpp = http_parse_headerstring(++*cpp, buf);
 724                 if (*cpp == NULL)
 725                         return (HTTPHL_ERROR);
 726                 return (HTTPHL_STRING);
 727         }
 728
 729         /* Read other token, until separator or whitespace */
 730         l = strcspn(*cpp, " \t,=");
 731         memcpy(buf, *cpp, l);
 732         buf[l] = 0;
 733         *cpp += l;
 734         return (HTTPHL_WORD);
 735 }
 736
 737 /*
 738  * Read challenges from http xxx-authenticate header and accumulate them
 739  * in the challenges list structure.
 740  *
 741  * Headers with multiple challenges are specified by rfc2617, but
 742  * servers (ie: squid) often send them in separate headers instead,
 743  * which in turn is forbidden by the http spec (multiple headers with
 744  * the same name are only allowed for pure comma-separated lists, see
 745  * rfc2616 sec 4.2).
 746  *
 747  * We support both approaches anyway
 748  */
 749 static int
 750 http_parse_authenticate(const char *cp, http_auth_challenges_t *cs)
 751 {
 752         int ret = -1;
 753         http_header_lex_t lex;
 754         char *key = malloc(strlen(cp) + 1);
 755         char *value = malloc(strlen(cp) + 1);
 756         char *buf = malloc(strlen(cp) + 1);
 757
 758         if (key == NULL || value == NULL || buf == NULL) {
 759                 fetch_syserr();
 760                 goto out;
 761         }
 762
 763         /* In any case we've seen the header and we set the valid bit */
 764         cs->valid = 1;
 765
 766         /* Need word first */
 767         lex = http_header_lex(&cp, key);
 768         if (lex != HTTPHL_WORD)
 769                 goto out;
 770
 771         /* Loop on challenges */
 772         for (; cs->count < MAX_CHALLENGES; cs->count++) {
 773                 cs->challenges[cs->count] =
 774                         malloc(sizeof(http_auth_challenge_t));
 775                 if (cs->challenges[cs->count] == NULL) {
 776                         fetch_syserr();
 777                         goto out;
 778                 }
 779                 init_http_auth_challenge(cs->challenges[cs->count]);
 780                 if (!strcasecmp(key, "basic")) {
 781                         cs->challenges[cs->count]->scheme = HTTPAS_BASIC;
 782                 } else if (!strcasecmp(key, "digest")) {
 783                         cs->challenges[cs->count]->scheme = HTTPAS_DIGEST;
 784                 } else {
 785                         cs->challenges[cs->count]->scheme = HTTPAS_UNKNOWN;
 786                         /*
 787                          * Continue parsing as basic or digest may
 788                          * follow, and the syntax is the same for
 789                          * all. We'll just ignore this one when
 790                          * looking at the list
 791                          */
 792                 }
 793
 794                 /* Loop on attributes */
 795                 for (;;) {
 796                         /* Key */
 797                         lex = http_header_lex(&cp, key);
 798                         if (lex != HTTPHL_WORD)
 799                                 goto out;
 800
 801                         /* Equal sign */
 802                         lex = http_header_lex(&cp, buf);
 803                         if (lex != '=')
 804                                 goto out;
 805
 806                         /* Value */
 807                         lex = http_header_lex(&cp, value);
 808                         if (lex != HTTPHL_WORD && lex != HTTPHL_STRING)
 809                                 goto out;
 810
 811                         if (!strcasecmp(key, "realm"))
 812                                 cs->challenges[cs->count]->realm =
 813                                         strdup(value);
 814                         else if (!strcasecmp(key, "qop"))
 815                                 cs->challenges[cs->count]->qop =
 816                                         strdup(value);
 817                         else if (!strcasecmp(key, "nonce"))
 818                                 cs->challenges[cs->count]->nonce =
 819                                         strdup(value);
 820                         else if (!strcasecmp(key, "opaque"))
 821                                 cs->challenges[cs->count]->opaque =
 822                                         strdup(value);
 823                         else if (!strcasecmp(key, "algorithm"))
 824                                 cs->challenges[cs->count]->algo =
 825                                         strdup(value);
 826                         else if (!strcasecmp(key, "stale"))
 827                                 cs->challenges[cs->count]->stale =
 828                                         strcasecmp(value, "no");
 829                         /* Else ignore unknown attributes */
 830
 831                         /* Comma or Next challenge or End */
 832                         lex = http_header_lex(&cp, key);
 833                         /*
 834                          * If we get a word here, this is the beginning of the
 835                          * next challenge. Break the attributes loop
 836                          */
 837                         if (lex == HTTPHL_WORD)
 838                                 break;
 839
 840                         if (lex == HTTPHL_END) {
 841                                 /* End while looking for ',' is normal exit */
 842                                 cs->count++;
 843                                 ret = 0;
 844                                 goto out;
 845                         }
 846                         /* Anything else is an error */
 847                         if (lex != ',')
 848                                 goto out;
 849
 850                 } /* End attributes loop */
 851         } /* End challenge loop */
 852
 853         /*
 854          * Challenges max count exceeded. This really can't happen
 855          * with normal data, something's fishy -> error
 856          */
 857
 858 out:
 859         if (key)
 860                 free(key);
 861         if (value)
 862                 free(value);
 863         if (buf)
 864                 free(buf);
 865         return (ret);
 866 }
 867
 868
 869 /*
 870  * Parse a last-modified header
 871  */
 872 static int
 873 http_parse_mtime(const char *p, time_t *mtime)
 874 {
 875         char locale[64], *r;
 876         struct tm tm;
 877
 878         strncpy(locale, setlocale(LC_TIME, NULL), sizeof(locale));
 879         setlocale(LC_TIME, "C");
 880         r = strptime(p, "%a, %d %b %Y %H:%M:%S GMT", &tm);
 881         /* XXX should add support for date-2 and date-3 */
 882         setlocale(LC_TIME, locale);
 883         if (r == NULL)
 884                 return (-1);
 885         DEBUG(fprintf(stderr, "last modified: [%04d-%02d-%02d "
 886                   "%02d:%02d:%02d]\n",
 887                   tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
 888                   tm.tm_hour, tm.tm_min, tm.tm_sec));
 889         *mtime = timegm(&tm);
 890         return (0);
 891 }
 892
 893 /*
 894  * Parse a content-length header
 895  */
 896 static int
 897 http_parse_length(const char *p, off_t *length)
 898 {
 899         off_t len;
 900
 901         for (len = 0; *p && isdigit((unsigned char)*p); ++p)
 902                 len = len * 10 + (*p - '0');
 903         if (*p)
 904                 return (-1);
 905         DEBUG(fprintf(stderr, "content length: [%lld]\n",
 906             (long long)len));
 907         *length = len;
 908         return (0);
 909 }
 910
 911 /*
 912  * Parse a content-range header
 913  */
 914 static int
 915 http_parse_range(const char *p, off_t *offset, off_t *length, off_t *size)
 916 {
 917         off_t first, last, len;
 918
 919         if (strncasecmp(p, "bytes ", 6) != 0)
 920                 return (-1);
 921         p += 6;
 922         if (*p == '*') {
 923                 first = last = -1;
 924                 ++p;
 925         } else {
 926                 for (first = 0; *p && isdigit((unsigned char)*p); ++p)
 927                         first = first * 10 + *p - '0';
 928                 if (*p != '-')
 929                         return (-1);
 930                 for (last = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 931                         last = last * 10 + *p - '0';
 932         }
 933         if (first > last || *p != '/')
 934                 return (-1);
 935         for (len = 0, ++p; *p && isdigit((unsigned char)*p); ++p)
 936                 len = len * 10 + *p - '0';
 937         if (*p || len < last - first + 1)
 938                 return (-1);
 939         if (first == -1) {
 940                 DEBUG(fprintf(stderr, "content range: [*/%lld]\n",
 941                     (long long)len));
 942                 *length = 0;
 943         } else {
 944                 DEBUG(fprintf(stderr, "content range: [%lld-%lld/%lld]\n",
 945                     (long long)first, (long long)last, (long long)len));
 946                 *length = last - first + 1;
 947         }
 948         *offset = first;
 949         *size = len;
 950         return (0);
 951 }
 952
 953
 954 /*****************************************************************************
 955  * Helper functions for authorization
 956  */
 957
 958 /*
 959  * Base64 encoding
 960  */
 961 static char *
 962 http_base64(const char *src)
 963 {
 964         static const char base64[] =
 965             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 966             "abcdefghijklmnopqrstuvwxyz"
 967             "0123456789+/";
 968         char *str, *dst;
 969         size_t l;
 970         int t, r;
 971
 972         l = strlen(src);
 973         if ((str = malloc(((l + 2) / 3) * 4 + 1)) == NULL)
 974                 return (NULL);
 975         dst = str;
 976         r = 0;
 977
 978         while (l >= 3) {
 979                 t = (src[0] << 16) | (src[1] << 8) | src[2];
 980                 dst[0] = base64[(t >> 18) & 0x3f];
 981                 dst[1] = base64[(t >> 12) & 0x3f];
 982                 dst[2] = base64[(t >> 6) & 0x3f];
 983                 dst[3] = base64[(t >> 0) & 0x3f];
 984                 src += 3; l -= 3;
 985                 dst += 4; r += 4;
 986         }
 987
 988         switch (l) {
 989         case 2:
 990                 t = (src[0] << 16) | (src[1] << 8);
 991                 dst[0] = base64[(t >> 18) & 0x3f];
 992                 dst[1] = base64[(t >> 12) & 0x3f];
 993                 dst[2] = base64[(t >> 6) & 0x3f];
 994                 dst[3] = '=';
 995                 dst += 4;
 996                 r += 4;
 997                 break;
 998         case 1:
 999                 t = src[0] << 16;
1000                 dst[0] = base64[(t >> 18) & 0x3f];
1001                 dst[1] = base64[(t >> 12) & 0x3f];
1002                 dst[2] = dst[3] = '=';
1003                 dst += 4;
1004                 r += 4;
1005                 break;
1006         case 0:
1007                 break;
1008         }
1009
1010         *dst = 0;
1011         return (str);
1012 }
1013
1014
1015 /*
1016  * Extract authorization parameters from environment value.
1017  * The value is like scheme:realm:user:pass
1018  */
1019 typedef struct {
1020         char    *scheme;
1021         char    *realm;
1022         char    *user;
1023         char    *password;
1024 } http_auth_params_t;
1025
1026 static void
1027 init_http_auth_params(http_auth_params_t *s)
1028 {
1029         s->scheme = s->realm = s->user = s->password = 0;
1030 }
1031
1032 static void
1033 clean_http_auth_params(http_auth_params_t *s)
1034 {
1035         if (s->scheme)
1036                 free(s->scheme);
1037         if (s->realm)
1038                 free(s->realm);
1039         if (s->user)
1040                 free(s->user);
1041         if (s->password)
1042                 free(s->password);
1043         init_http_auth_params(s);
1044 }
1045
1046 static int
1047 http_authfromenv(const char *p, http_auth_params_t *parms)
1048 {
1049         int ret = -1;
1050         char *v, *ve;
1051         char *str = strdup(p);
1052
1053         if (str == NULL) {
1054                 fetch_syserr();
1055                 return (-1);
1056         }
1057         v = str;
1058
1059         if ((ve = strchr(v, ':')) == NULL)
1060                 goto out;
1061
1062         *ve = 0;
1063         if ((parms->scheme = strdup(v)) == NULL) {
1064                 fetch_syserr();
1065                 goto out;
1066         }
1067         v = ve + 1;
1068
1069         if ((ve = strchr(v, ':')) == NULL)
1070                 goto out;
1071
1072         *ve = 0;
1073         if ((parms->realm = strdup(v)) == NULL) {
1074                 fetch_syserr();
1075                 goto out;
1076         }
1077         v = ve + 1;
1078
1079         if ((ve = strchr(v, ':')) == NULL)
1080                 goto out;
1081
1082         *ve = 0;
1083         if ((parms->user = strdup(v)) == NULL) {
1084                 fetch_syserr();
1085                 goto out;
1086         }
1087         v = ve + 1;
1088
1089
1090         if ((parms->password = strdup(v)) == NULL) {
1091                 fetch_syserr();
1092                 goto out;
1093         }
1094         ret = 0;
1095 out:
1096         if (ret == -1)
1097                 clean_http_auth_params(parms);
1098         if (str)
1099                 free(str);
1100         return (ret);
1101 }
1102
1103
1104 /*
1105  * Digest response: the code to compute the digest is taken from the
1106  * sample implementation in RFC2616
1107  */
1108 #define IN const
1109 #define OUT
1110
1111 #define HASHLEN 16
1112 typedef char HASH[HASHLEN];
1113 #define HASHHEXLEN 32
1114 typedef char HASHHEX[HASHHEXLEN+1];
1115
1116 static const char *hexchars = "0123456789abcdef";
1117 static void
1118 CvtHex(IN HASH Bin, OUT HASHHEX Hex)
1119 {
1120         unsigned short i;
1121         unsigned char j;
1122
1123         for (i = 0; i < HASHLEN; i++) {
1124                 j = (Bin[i] >> 4) & 0xf;
1125                 Hex[i*2] = hexchars[j];
1126                 j = Bin[i] & 0xf;
1127                 Hex[i*2+1] = hexchars[j];
1128         };
1129         Hex[HASHHEXLEN] = '\0';
1130 };
1131
1132 /* calculate H(A1) as per spec */
1133 static void
1134 DigestCalcHA1(
1135         IN char * pszAlg,
1136         IN char * pszUserName,
1137         IN char * pszRealm,
1138         IN char * pszPassword,
1139         IN char * pszNonce,
1140         IN char * pszCNonce,
1141         OUT HASHHEX SessionKey
1142         )
1143 {
1144         MD5_CTX Md5Ctx;
1145         HASH HA1;
1146
1147         MD5Init(&Md5Ctx);
1148         MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName));
1149         MD5Update(&Md5Ctx, ":", 1);
1150         MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm));
1151         MD5Update(&Md5Ctx, ":", 1);
1152         MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword));
1153         MD5Final(HA1, &Md5Ctx);
1154         if (strcasecmp(pszAlg, "md5-sess") == 0) {
1155
1156                 MD5Init(&Md5Ctx);
1157                 MD5Update(&Md5Ctx, HA1, HASHLEN);
1158                 MD5Update(&Md5Ctx, ":", 1);
1159                 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1160                 MD5Update(&Md5Ctx, ":", 1);
1161                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1162                 MD5Final(HA1, &Md5Ctx);
1163         };
1164         CvtHex(HA1, SessionKey);
1165 }
1166
1167 /* calculate request-digest/response-digest as per HTTP Digest spec */
1168 static void
1169 DigestCalcResponse(
1170         IN HASHHEX HA1,           /* H(A1) */
1171         IN char * pszNonce,       /* nonce from server */
1172         IN char * pszNonceCount,  /* 8 hex digits */
1173         IN char * pszCNonce,      /* client nonce */
1174         IN char * pszQop,         /* qop-value: "", "auth", "auth-int" */
1175         IN char * pszMethod,      /* method from the request */
1176         IN char * pszDigestUri,   /* requested URL */
1177         IN HASHHEX HEntity,       /* H(entity body) if qop="auth-int" */
1178         OUT HASHHEX Response      /* request-digest or response-digest */
1179         )
1180 {
1181 /*      DEBUG(fprintf(stderr,
1182                       "Calc: HA1[%s] Nonce[%s] qop[%s] method[%s] URI[%s]\n",
1183                       HA1, pszNonce, pszQop, pszMethod, pszDigestUri));*/
1184         MD5_CTX Md5Ctx;
1185         HASH HA2;
1186         HASH RespHash;
1187         HASHHEX HA2Hex;
1188
1189         // calculate H(A2)
1190         MD5Init(&Md5Ctx);
1191         MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod));
1192         MD5Update(&Md5Ctx, ":", 1);
1193         MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri));
1194         if (strcasecmp(pszQop, "auth-int") == 0) {
1195                 MD5Update(&Md5Ctx, ":", 1);
1196                 MD5Update(&Md5Ctx, HEntity, HASHHEXLEN);
1197         };
1198         MD5Final(HA2, &Md5Ctx);
1199         CvtHex(HA2, HA2Hex);
1200
1201         // calculate response
1202         MD5Init(&Md5Ctx);
1203         MD5Update(&Md5Ctx, HA1, HASHHEXLEN);
1204         MD5Update(&Md5Ctx, ":", 1);
1205         MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce));
1206         MD5Update(&Md5Ctx, ":", 1);
1207         if (*pszQop) {
1208                 MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount));
1209                 MD5Update(&Md5Ctx, ":", 1);
1210                 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce));
1211                 MD5Update(&Md5Ctx, ":", 1);
1212                 MD5Update(&Md5Ctx, pszQop, strlen(pszQop));
1213                 MD5Update(&Md5Ctx, ":", 1);
1214         };
1215         MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN);
1216         MD5Final(RespHash, &Md5Ctx);
1217         CvtHex(RespHash, Response);
1218 }
1219
1220 /*
1221  * Generate/Send a Digest authorization header
1222  * This looks like: [Proxy-]Authorization: credentials
1223  *
1224  *  credentials      = "Digest" digest-response
1225  *  digest-response  = 1#( username | realm | nonce | digest-uri
1226  *                      | response | [ algorithm ] | [cnonce] |
1227  *                      [opaque] | [message-qop] |
1228  *                          [nonce-count]  | [auth-param] )
1229  *  username         = "username" "=" username-value
1230  *  username-value   = quoted-string
1231  *  digest-uri       = "uri" "=" digest-uri-value
1232  *  digest-uri-value = request-uri   ; As specified by HTTP/1.1
1233  *  message-qop      = "qop" "=" qop-value
1234  *  cnonce           = "cnonce" "=" cnonce-value
1235  *  cnonce-value     = nonce-value
1236  *  nonce-count      = "nc" "=" nc-value
1237  *  nc-value         = 8LHEX
1238  *  response         = "response" "=" request-digest
1239  *  request-digest = <"> 32LHEX <">
1240  */
1241 static int
1242 http_digest_auth(conn_t *conn, const char *hdr, http_auth_challenge_t *c,
1243                  http_auth_params_t *parms, struct url *url)
1244 {
1245         int r;
1246         char noncecount[10];
1247         char cnonce[40];
1248         char *options = 0;
1249
1250         if (!c->realm || !c->nonce) {
1251                 DEBUG(fprintf(stderr, "realm/nonce not set in challenge\n"));
1252                 return(-1);
1253         }
1254         if (!c->algo)
1255                 c->algo = strdup("");
1256
1257         if (asprintf(&options, "%s%s%s%s",
1258                      *c->algo? ",algorithm=" : "", c->algo,
1259                      c->opaque? ",opaque=" : "", c->opaque?c->opaque:"")== -1)
1260                 return (-1);
1261
1262         if (!c->qop) {
1263                 c->qop = strdup("");
1264                 *noncecount = 0;
1265                 *cnonce = 0;
1266         } else {
1267                 c->nc++;
1268                 sprintf(noncecount, "%08x", c->nc);
1269                 /* We don't try very hard with the cnonce ... */
1270                 sprintf(cnonce, "%x%lx", getpid(), (unsigned long)time(0));
1271         }
1272
1273         HASHHEX HA1;
1274         DigestCalcHA1(c->algo, parms->user, c->realm,
1275                       parms->password, c->nonce, cnonce, HA1);
1276         DEBUG(fprintf(stderr, "HA1: [%s]\n", HA1));
1277         HASHHEX digest;
1278         DigestCalcResponse(HA1, c->nonce, noncecount, cnonce, c->qop,
1279                            "GET", url->doc, "", digest);
1280
1281         if (c->qop[0]) {
1282                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1283                              "nonce=\"%s\",uri=\"%s\",response=\"%s\","
1284                              "qop=\"auth\", cnonce=\"%s\", nc=%s%s",
1285                              hdr, parms->user, c->realm,
1286                              c->nonce, url->doc, digest,
1287                              cnonce, noncecount, options);
1288         } else {
1289                 r = http_cmd(conn, "%s: Digest username=\"%s\",realm=\"%s\","
1290                              "nonce=\"%s\",uri=\"%s\",response=\"%s\"%s",
1291                              hdr, parms->user, c->realm,
1292                              c->nonce, url->doc, digest, options);
1293         }
1294         if (options)
1295                 free(options);
1296         return (r);
1297 }
1298
1299 /*
1300  * Encode username and password
1301  */
1302 static int
1303 http_basic_auth(conn_t *conn, const char *hdr, const char *usr, const char *pwd)
1304 {
1305         char *upw, *auth;
1306         int r;
1307
1308         DEBUG(fprintf(stderr, "basic: usr: [%s]\n", usr));
1309         DEBUG(fprintf(stderr, "basic: pwd: [%s]\n", pwd));
1310         if (asprintf(&upw, "%s:%s", usr, pwd) == -1)
1311                 return (-1);
1312         auth = http_base64(upw);
1313         free(upw);
1314         if (auth == NULL)
1315                 return (-1);
1316         r = http_cmd(conn, "%s: Basic %s", hdr, auth);
1317         free(auth);
1318         return (r);
1319 }
1320
1321 /*
1322  * Chose the challenge to answer and call the appropriate routine to
1323  * produce the header.
1324  */
1325 static int
1326 http_authorize(conn_t *conn, const char *hdr, http_auth_challenges_t *cs,
1327                http_auth_params_t *parms, struct url *url)
1328 {
1329         http_auth_challenge_t *basic = NULL;
1330         http_auth_challenge_t *digest = NULL;
1331         int i;
1332
1333         /* If user or pass are null we're not happy */
1334         if (!parms->user || !parms->password) {
1335                 DEBUG(fprintf(stderr, "NULL usr or pass\n"));
1336                 return (-1);
1337         }
1338
1339         /* Look for a Digest and a Basic challenge */
1340         for (i = 0; i < cs->count; i++) {
1341                 if (cs->challenges[i]->scheme == HTTPAS_BASIC)
1342                         basic = cs->challenges[i];
1343                 if (cs->challenges[i]->scheme == HTTPAS_DIGEST)
1344                         digest = cs->challenges[i];
1345         }
1346
1347         /* Error if "Digest" was specified and there is no Digest challenge */
1348         if (!digest && (parms->scheme &&
1349                         !strcasecmp(parms->scheme, "digest"))) {
1350                 DEBUG(fprintf(stderr,
1351                               "Digest auth in env, not supported by peer\n"));
1352                 return (-1);
1353         }
1354         /*
1355          * If "basic" was specified in the environment, or there is no Digest
1356          * challenge, do the basic thing. Don't need a challenge for this,
1357          * so no need to check basic!=NULL
1358          */
1359         if (!digest || (parms->scheme && !strcasecmp(parms->scheme,"basic")))
1360                 return (http_basic_auth(conn,hdr,parms->user,parms->password));
1361
1362         /* Else, prefer digest. We just checked that it's not NULL */
1363         return (http_digest_auth(conn, hdr, digest, parms, url));
1364 }
1365
1366 /*****************************************************************************
1367  * Helper functions for connecting to a server or proxy
1368  */
1369
1370 /*
1371  * Connect to the correct HTTP server or proxy.
1372  */
1373 static conn_t *
1374 http_connect(struct url *URL, struct url *purl, const char *flags)
1375 {
1376         struct url *curl;
1377         conn_t *conn;
1378         int verbose;
1379         int af, val;
1380
1381 #ifdef INET6
1382         af = AF_UNSPEC;
1383 #else
1384         af = AF_INET;
1385 #endif
1386
1387         verbose = CHECK_FLAG('v');
1388         if (CHECK_FLAG('4'))
1389                 af = AF_INET;
1390 #ifdef INET6
1391         else if (CHECK_FLAG('6'))
1392                 af = AF_INET6;
1393 #endif
1394
1395         curl = (purl != NULL) ? purl : URL;
1396
1397         if ((conn = fetch_connect(curl->host, curl->port, af, verbose)) == NULL)
1398                 /* fetch_connect() has already set an error code */
1399                 return (NULL);
1400         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 && purl) {
1401                 http_cmd(conn, "CONNECT %s:%d HTTP/1.1",
1402                     URL->host, URL->port);
1403                 http_cmd(conn, "Host: %s:%d",
1404                     URL->host, URL->port);
1405                 http_cmd(conn, "");
1406                 if (http_get_reply(conn) != HTTP_OK) {
1407                         fetch_close(conn);
1408                         return (NULL);
1409                 }
1410                 http_get_reply(conn);
1411         }
1412         if (strcasecmp(URL->scheme, SCHEME_HTTPS) == 0 &&
1413             fetch_ssl(conn, URL, verbose) == -1) {
1414                 fetch_close(conn);
1415                 /* grrr */
1416                 errno = EAUTH;
1417                 fetch_syserr();
1418                 return (NULL);
1419         }
1420
1421         val = 1;
1422         setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val, sizeof(val));
1423
1424         return (conn);
1425 }
1426
1427 static struct url *
1428 http_get_proxy(struct url * url, const char *flags)
1429 {
1430         struct url *purl;
1431         char *p;
1432
1433         if (flags != NULL && strchr(flags, 'd') != NULL)
1434                 return (NULL);
1435         if (fetch_no_proxy_match(url->host))
1436                 return (NULL);
1437         if (((p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1438             *p && (purl = fetchParseURL(p))) {
1439                 if (!*purl->scheme)
1440                         strcpy(purl->scheme, SCHEME_HTTP);
1441                 if (!purl->port)
1442                         purl->port = fetch_default_proxy_port(purl->scheme);
1443                 if (strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1444                         return (purl);
1445                 fetchFreeURL(purl);
1446         }
1447         return (NULL);
1448 }
1449
1450 static void
1451 http_print_html(FILE *out, FILE *in)
1452 {
1453         size_t len;
1454         char *line, *p, *q;
1455         int comment, tag;
1456
1457         comment = tag = 0;
1458         while ((line = fgetln(in, &len)) != NULL) {
1459                 while (len && isspace((unsigned char)line[len - 1]))
1460                         --len;
1461                 for (p = q = line; q < line + len; ++q) {
1462                         if (comment && *q == '-') {
1463                                 if (q + 2 < line + len &&
1464                                     strcmp(q, "-->") == 0) {
1465                                         tag = comment = 0;
1466                                         q += 2;
1467                                 }
1468                         } else if (tag && !comment && *q == '>') {
1469                                 p = q + 1;
1470                                 tag = 0;
1471                         } else if (!tag && *q == '<') {
1472                                 if (q > p)
1473                                         fwrite(p, q - p, 1, out);
1474                                 tag = 1;
1475                                 if (q + 3 < line + len &&
1476                                     strcmp(q, "<!--") == 0) {
1477                                         comment = 1;
1478                                         q += 3;
1479                                 }
1480                         }
1481                 }
1482                 if (!tag && q > p)
1483                         fwrite(p, q - p, 1, out);
1484                 fputc('\n', out);
1485         }
1486 }
1487
1488
1489 /*****************************************************************************
1490  * Core
1491  */
1492
1493 /*
1494  * Send a request and process the reply
1495  *
1496  * XXX This function is way too long, the do..while loop should be split
1497  * XXX off into a separate function.
1498  */
1499 FILE *
1500 http_request(struct url *URL, const char *op, struct url_stat *us,
1501         struct url *purl, const char *flags)
1502 {
1503         char timebuf[80];
1504         char hbuf[MAXHOSTNAMELEN + 7], *host;
1505         conn_t *conn;
1506         struct url *url, *new;
1507         int chunked, direct, ims, noredirect, verbose;
1508         int e, i, n, val;
1509         off_t offset, clength, length, size;
1510         time_t mtime;
1511         const char *p;
1512         FILE *f;
1513         hdr_t h;
1514         struct tm *timestruct;
1515         http_headerbuf_t headerbuf;
1516         http_auth_challenges_t server_challenges;
1517         http_auth_challenges_t proxy_challenges;
1518
1519         /* The following calls don't allocate anything */
1520         init_http_headerbuf(&headerbuf);
1521         init_http_auth_challenges(&server_challenges);
1522         init_http_auth_challenges(&proxy_challenges);
1523
1524         direct = CHECK_FLAG('d');
1525         noredirect = CHECK_FLAG('A');
1526         verbose = CHECK_FLAG('v');
1527         ims = CHECK_FLAG('i');
1528
1529         if (direct && purl) {
1530                 fetchFreeURL(purl);
1531                 purl = NULL;
1532         }
1533
1534         /* try the provided URL first */
1535         url = URL;
1536
1537         n = MAX_REDIRECT;
1538         i = 0;
1539
1540         e = HTTP_PROTOCOL_ERROR;
1541         do {
1542                 new = NULL;
1543                 chunked = 0;
1544                 offset = 0;
1545                 clength = -1;
1546                 length = -1;
1547                 size = -1;
1548                 mtime = 0;
1549
1550                 /* check port */
1551                 if (!url->port)
1552                         url->port = fetch_default_port(url->scheme);
1553
1554                 /* were we redirected to an FTP URL? */
1555                 if (purl == NULL && strcmp(url->scheme, SCHEME_FTP) == 0) {
1556                         if (strcmp(op, "GET") == 0)
1557                                 return (ftp_request(url, "RETR", us, purl, flags));
1558                         else if (strcmp(op, "HEAD") == 0)
1559                                 return (ftp_request(url, "STAT", us, purl, flags));
1560                 }
1561
1562                 /* connect to server or proxy */
1563                 if ((conn = http_connect(url, purl, flags)) == NULL)
1564                         goto ouch;
1565
1566                 host = url->host;
1567 #ifdef INET6
1568                 if (strchr(url->host, ':')) {
1569                         snprintf(hbuf, sizeof(hbuf), "[%s]", url->host);
1570                         host = hbuf;
1571                 }
1572 #endif
1573                 if (url->port != fetch_default_port(url->scheme)) {
1574                         if (host != hbuf) {
1575                                 strcpy(hbuf, host);
1576                                 host = hbuf;
1577                         }
1578                         snprintf(hbuf + strlen(hbuf),
1579                             sizeof(hbuf) - strlen(hbuf), ":%d", url->port);
1580                 }
1581
1582                 /* send request */
1583                 if (verbose)
1584                         fetch_info("requesting %s://%s%s",
1585                             url->scheme, host, url->doc);
1586                 if (purl && strcasecmp(URL->scheme, SCHEME_HTTPS) != 0) {
1587                         http_cmd(conn, "%s %s://%s%s HTTP/1.1",
1588                             op, url->scheme, host, url->doc);
1589                 } else {
1590                         http_cmd(conn, "%s %s HTTP/1.1",
1591                             op, url->doc);
1592                 }
1593
1594                 if (ims && url->ims_time) {
1595                         timestruct = gmtime((time_t *)&url->ims_time);
1596                         (void)strftime(timebuf, 80, "%a, %d %b %Y %T GMT",
1597                             timestruct);
1598                         if (verbose)
1599                                 fetch_info("If-Modified-Since: %s", timebuf);
1600                         http_cmd(conn, "If-Modified-Since: %s", timebuf);
1601                 }
1602                 /* virtual host */
1603                 http_cmd(conn, "Host: %s", host);
1604
1605                 /*
1606                  * Proxy authorization: we only send auth after we received
1607                  * a 407 error. We do not first try basic anyway (changed
1608                  * when support was added for digest-auth)
1609                  */
1610                 if (purl && proxy_challenges.valid) {
1611                         http_auth_params_t aparams;
1612                         init_http_auth_params(&aparams);
1613                         if (*purl->user || *purl->pwd) {
1614                                 aparams.user = purl->user ?
1615                                         strdup(purl->user) : strdup("");
1616                                 aparams.password = purl->pwd?
1617                                         strdup(purl->pwd) : strdup("");
1618                         } else if ((p = getenv("HTTP_PROXY_AUTH")) != NULL &&
1619                                    *p != '\0') {
1620                                 if (http_authfromenv(p, &aparams) < 0) {
1621                                         http_seterr(HTTP_NEED_PROXY_AUTH);
1622                                         goto ouch;
1623                                 }
1624                         }
1625                         http_authorize(conn, "Proxy-Authorization",
1626                                        &proxy_challenges, &aparams, url);
1627                         clean_http_auth_params(&aparams);
1628                 }
1629
1630                 /*
1631                  * Server authorization: we never send "a priori"
1632                  * Basic auth, which used to be done if user/pass were
1633                  * set in the url. This would be weird because we'd send the
1634                  * password in the clear even if Digest is finally to be
1635                  * used (it would have made more sense for the
1636                  * pre-digest version to do this when Basic was specified
1637                  * in the environment)
1638                  */
1639                 if (server_challenges.valid) {
1640                         http_auth_params_t aparams;
1641                         init_http_auth_params(&aparams);
1642                         if (*url->user || *url->pwd) {
1643                                 aparams.user = url->user ?
1644                                         strdup(url->user) : strdup("");
1645                                 aparams.password = url->pwd ?
1646                                         strdup(url->pwd) : strdup("");
1647                         } else if ((p = getenv("HTTP_AUTH")) != NULL &&
1648                                    *p != '\0') {
1649                                 if (http_authfromenv(p, &aparams) < 0) {
1650                                         http_seterr(HTTP_NEED_AUTH);
1651                                         goto ouch;
1652                                 }
1653                         } else if (fetchAuthMethod &&
1654                                    fetchAuthMethod(url) == 0) {
1655                                 aparams.user = url->user ?
1656                                         strdup(url->user) : strdup("");
1657                                 aparams.password = url->pwd ?
1658                                         strdup(url->pwd) : strdup("");
1659                         } else {
1660                                 http_seterr(HTTP_NEED_AUTH);
1661                                 goto ouch;
1662                         }
1663                         http_authorize(conn, "Authorization",
1664                                        &server_challenges, &aparams, url);
1665                         clean_http_auth_params(&aparams);
1666                 }
1667
1668                 /* other headers */
1669                 if ((p = getenv("HTTP_ACCEPT")) != NULL) {
1670                         if (*p != '\0')
1671                                 http_cmd(conn, "Accept: %s", p);
1672                 } else {
1673                         http_cmd(conn, "Accept: */*");
1674                 }
1675                 if ((p = getenv("HTTP_REFERER")) != NULL && *p != '\0') {
1676                         if (strcasecmp(p, "auto") == 0)
1677                                 http_cmd(conn, "Referer: %s://%s%s",
1678                                     url->scheme, host, url->doc);
1679                         else
1680                                 http_cmd(conn, "Referer: %s", p);
1681                 }
1682                 if ((p = getenv("HTTP_USER_AGENT")) != NULL && *p != '\0')
1683                         http_cmd(conn, "User-Agent: %s", p);
1684                 else
1685                         http_cmd(conn, "User-Agent: %s " _LIBFETCH_VER, getprogname());
1686                 if (url->offset > 0)
1687                         http_cmd(conn, "Range: bytes=%lld-", (long long)url->offset);
1688                 http_cmd(conn, "Connection: close");
1689                 http_cmd(conn, "");
1690
1691                 /*
1692                  * Force the queued request to be dispatched.  Normally, one
1693                  * would do this with shutdown(2) but squid proxies can be
1694                  * configured to disallow such half-closed connections.  To
1695                  * be compatible with such configurations, fiddle with socket
1696                  * options to force the pending data to be written.
1697                  */
1698                 val = 0;
1699                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NOPUSH, &val,
1700                            sizeof(val));
1701                 val = 1;
1702                 setsockopt(conn->sd, IPPROTO_TCP, TCP_NODELAY, &val,
1703                            sizeof(val));
1704
1705                 /* get reply */
1706                 switch (http_get_reply(conn)) {
1707                 case HTTP_OK:
1708                 case HTTP_PARTIAL:
1709                 case HTTP_NOT_MODIFIED:
1710                         /* fine */
1711                         break;
1712                 case HTTP_MOVED_PERM:
1713                 case HTTP_MOVED_TEMP:
1714                 case HTTP_SEE_OTHER:
1715                 case HTTP_USE_PROXY:
1716                         /*
1717                          * Not so fine, but we still have to read the
1718                          * headers to get the new location.
1719                          */
1720                         break;
1721                 case HTTP_NEED_AUTH:
1722                         if (server_challenges.valid) {
1723                                 /*
1724                                  * We already sent out authorization code,
1725                                  * so there's nothing more we can do.
1726                                  */
1727                                 http_seterr(conn->err);
1728                                 goto ouch;
1729                         }
1730                         /* try again, but send the password this time */
1731                         if (verbose)
1732                                 fetch_info("server requires authorization");
1733                         break;
1734                 case HTTP_NEED_PROXY_AUTH:
1735                         if (proxy_challenges.valid) {
1736                                 /*
1737                                  * We already sent our proxy
1738                                  * authorization code, so there's
1739                                  * nothing more we can do. */
1740                                 http_seterr(conn->err);
1741                                 goto ouch;
1742                         }
1743                         /* try again, but send the password this time */
1744                         if (verbose)
1745                                 fetch_info("proxy requires authorization");
1746                         break;
1747                 case HTTP_BAD_RANGE:
1748                         /*
1749                          * This can happen if we ask for 0 bytes because
1750                          * we already have the whole file.  Consider this
1751                          * a success for now, and check sizes later.
1752                          */
1753                         break;
1754                 case HTTP_PROTOCOL_ERROR:
1755                         /* fall through */
1756                 case -1:
1757                         fetch_syserr();
1758                         goto ouch;
1759                 default:
1760                         http_seterr(conn->err);
1761                         if (!verbose)
1762                                 goto ouch;
1763                         /* fall through so we can get the full error message */
1764                 }
1765
1766                 /* get headers. http_next_header expects one line readahead */
1767                 if (fetch_getln(conn) == -1) {
1768                         fetch_syserr();
1769                         goto ouch;
1770                 }
1771                 do {
1772                         switch ((h = http_next_header(conn, &headerbuf, &p))) {
1773                         case hdr_syserror:
1774                                 fetch_syserr();
1775                                 goto ouch;
1776                         case hdr_error:
1777                                 http_seterr(HTTP_PROTOCOL_ERROR);
1778                                 goto ouch;
1779                         case hdr_content_length:
1780                                 http_parse_length(p, &clength);
1781                                 break;
1782                         case hdr_content_range:
1783                                 http_parse_range(p, &offset, &length, &size);
1784                                 break;
1785                         case hdr_last_modified:
1786                                 http_parse_mtime(p, &mtime);
1787                                 break;
1788                         case hdr_location:
1789                                 if (!HTTP_REDIRECT(conn->err))
1790                                         break;
1791                                 /*
1792                                  * if the A flag is set, we don't follow
1793                                  * temporary redirects.
1794                                  */
1795                                 if (noredirect &&
1796                                     conn->err != HTTP_MOVED_PERM &&
1797                                     conn->err != HTTP_PERM_REDIRECT &&
1798                                     conn->err != HTTP_USE_PROXY) {
1799                                         n = 1;
1800                                         break;
1801                                 }
1802                                 if (new)
1803                                         free(new);
1804                                 if (verbose)
1805                                         fetch_info("%d redirect to %s", conn->err, p);
1806                                 if (*p == '/')
1807                                         /* absolute path */
1808                                         new = fetchMakeURL(url->scheme, url->host, url->port, p,
1809                                             url->user, url->pwd);
1810                                 else
1811                                         new = fetchParseURL(p);
1812                                 if (new == NULL) {
1813                                         /* XXX should set an error code */
1814                                         DEBUG(fprintf(stderr, "failed to parse new URL\n"));
1815                                         goto ouch;
1816                                 }
1817
1818                                 /* Only copy credentials if the host matches */
1819                                 if (!strcmp(new->host, url->host) && !*new->user && !*new->pwd) {
1820                                         strcpy(new->user, url->user);
1821                                         strcpy(new->pwd, url->pwd);
1822                                 }
1823                                 new->offset = url->offset;
1824                                 new->length = url->length;
1825                                 break;
1826                         case hdr_transfer_encoding:
1827                                 /* XXX weak test*/
1828                                 chunked = (strcasecmp(p, "chunked") == 0);
1829                                 break;
1830                         case hdr_www_authenticate:
1831                                 if (conn->err != HTTP_NEED_AUTH)
1832                                         break;
1833                                 if (http_parse_authenticate(p, &server_challenges) == 0)
1834                                         ++n;
1835                                 break;
1836                         case hdr_proxy_authenticate:
1837                                 if (conn->err != HTTP_NEED_PROXY_AUTH)
1838                                         break;
1839                                 if (http_parse_authenticate(p, &proxy_challenges) == 0)
1840                                         ++n;
1841                                 break;
1842                         case hdr_end:
1843                                 /* fall through */
1844                         case hdr_unknown:
1845                                 /* ignore */
1846                                 break;
1847                         }
1848                 } while (h > hdr_end);
1849
1850                 /* we need to provide authentication */
1851                 if (conn->err == HTTP_NEED_AUTH ||
1852                     conn->err == HTTP_NEED_PROXY_AUTH) {
1853                         e = conn->err;
1854                         if ((conn->err == HTTP_NEED_AUTH &&
1855                              !server_challenges.valid) ||
1856                             (conn->err == HTTP_NEED_PROXY_AUTH &&
1857                              !proxy_challenges.valid)) {
1858                                 /* 401/7 but no www/proxy-authenticate ?? */
1859                                 DEBUG(fprintf(stderr, "401/7 and no auth header\n"));
1860                                 goto ouch;
1861                         }
1862                         fetch_close(conn);
1863                         conn = NULL;
1864                         continue;
1865                 }
1866
1867                 /* requested range not satisfiable */
1868                 if (conn->err == HTTP_BAD_RANGE) {
1869                         if (url->offset == size && url->length == 0) {
1870                                 /* asked for 0 bytes; fake it */
1871                                 offset = url->offset;
1872                                 clength = -1;
1873                                 conn->err = HTTP_OK;
1874                                 break;
1875                         } else {
1876                                 http_seterr(conn->err);
1877                                 goto ouch;
1878                         }
1879                 }
1880
1881                 /* we have a hit or an error */
1882                 if (conn->err == HTTP_OK
1883                     || conn->err == HTTP_NOT_MODIFIED
1884                     || conn->err == HTTP_PARTIAL
1885                     || HTTP_ERROR(conn->err))
1886                         break;
1887
1888                 /* all other cases: we got a redirect */
1889                 e = conn->err;
1890                 clean_http_auth_challenges(&server_challenges);
1891                 fetch_close(conn);
1892                 conn = NULL;
1893                 if (!new) {
1894                         DEBUG(fprintf(stderr, "redirect with no new location\n"));
1895                         break;
1896                 }
1897                 if (url != URL)
1898                         fetchFreeURL(url);
1899                 url = new;
1900         } while (++i < n);
1901
1902         /* we failed, or ran out of retries */
1903         if (conn == NULL) {
1904                 http_seterr(e);
1905                 goto ouch;
1906         }
1907
1908         DEBUG(fprintf(stderr, "offset %lld, length %lld,"
1909                   " size %lld, clength %lld\n",
1910                   (long long)offset, (long long)length,
1911                   (long long)size, (long long)clength));
1912
1913         if (conn->err == HTTP_NOT_MODIFIED) {
1914                 http_seterr(HTTP_NOT_MODIFIED);
1915                 return (NULL);
1916         }
1917
1918         /* check for inconsistencies */
1919         if (clength != -1 && length != -1 && clength != length) {
1920                 http_seterr(HTTP_PROTOCOL_ERROR);
1921                 goto ouch;
1922         }
1923         if (clength == -1)
1924                 clength = length;
1925         if (clength != -1)
1926                 length = offset + clength;
1927         if (length != -1 && size != -1 && length != size) {
1928                 http_seterr(HTTP_PROTOCOL_ERROR);
1929                 goto ouch;
1930         }
1931         if (size == -1)
1932                 size = length;
1933
1934         /* fill in stats */
1935         if (us) {
1936                 us->size = size;
1937                 us->atime = us->mtime = mtime;
1938         }
1939
1940         /* too far? */
1941         if (URL->offset > 0 && offset > URL->offset) {
1942                 http_seterr(HTTP_PROTOCOL_ERROR);
1943                 goto ouch;
1944         }
1945
1946         /* report back real offset and size */
1947         URL->offset = offset;
1948         URL->length = clength;
1949
1950         /* wrap it up in a FILE */
1951         if ((f = http_funopen(conn, chunked)) == NULL) {
1952                 fetch_syserr();
1953                 goto ouch;
1954         }
1955
1956         if (url != URL)
1957                 fetchFreeURL(url);
1958         if (purl)
1959                 fetchFreeURL(purl);
1960
1961         if (HTTP_ERROR(conn->err)) {
1962                 http_print_html(stderr, f);
1963                 fclose(f);
1964                 f = NULL;
1965         }
1966         clean_http_headerbuf(&headerbuf);
1967         clean_http_auth_challenges(&server_challenges);
1968         clean_http_auth_challenges(&proxy_challenges);
1969         return (f);
1970
1971 ouch:
1972         if (url != URL)
1973                 fetchFreeURL(url);
1974         if (purl)
1975                 fetchFreeURL(purl);
1976         if (conn != NULL)
1977                 fetch_close(conn);
1978         clean_http_headerbuf(&headerbuf);
1979         clean_http_auth_challenges(&server_challenges);
1980         clean_http_auth_challenges(&proxy_challenges);
1981         return (NULL);
1982 }
1983
1984
1985 /*****************************************************************************
1986  * Entry points
1987  */
1988
1989 /*
1990  * Retrieve and stat a file by HTTP
1991  */
1992 FILE *
1993 fetchXGetHTTP(struct url *URL, struct url_stat *us, const char *flags)
1994 {
1995         return (http_request(URL, "GET", us, http_get_proxy(URL, flags), flags));
1996 }
1997
1998 /*
1999  * Retrieve a file by HTTP
2000  */
2001 FILE *
2002 fetchGetHTTP(struct url *URL, const char *flags)
2003 {
2004         return (fetchXGetHTTP(URL, NULL, flags));
2005 }
2006
2007 /*
2008  * Store a file by HTTP
2009  */
2010 FILE *
2011 fetchPutHTTP(struct url *URL __unused, const char *flags __unused)
2012 {
2013         warnx("fetchPutHTTP(): not implemented");
2014         return (NULL);
2015 }
2016
2017 /*
2018  * Get an HTTP document's metadata
2019  */
2020 int
2021 fetchStatHTTP(struct url *URL, struct url_stat *us, const char *flags)
2022 {
2023         FILE *f;
2024
2025         f = http_request(URL, "HEAD", us, http_get_proxy(URL, flags), flags);
2026         if (f == NULL)
2027                 return (-1);
2028         fclose(f);
2029         return (0);
2030 }
2031
2032 /*
2033  * List a directory
2034  */
2035 struct url_ent *
2036 fetchListHTTP(struct url *url __unused, const char *flags __unused)
2037 {
2038         warnx("fetchListHTTP(): not implemented");
2039         return (NULL);
2040 }