lib/libfetch/http.c

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