1/*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al. 9 * 10 * This software is licensed as described in the file COPYING, which 11 * you should have received as part of this distribution. The terms 12 * are also available at http://curl.haxx.se/docs/copyright.html. 13 * 14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell 15 * copies of the Software, and permit persons to whom the Software is 16 * furnished to do so, under the terms of the COPYING file. 17 * 18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY 19 * KIND, either express or implied. 20 * 21 ***************************************************************************/ 22 23#include "setup.h" 24 25#ifdef HAVE_LIBZ 26 27#include <stdlib.h> 28#include <string.h> 29 30#include "urldata.h" 31#include <curl/curl.h> 32#include "sendf.h" 33#include "content_encoding.h" 34#include "curl_memory.h" 35 36#include "memdebug.h" 37 38/* Comment this out if zlib is always going to be at least ver. 1.2.0.4 39 (doing so will reduce code size slightly). */ 40#define OLD_ZLIB_SUPPORT 1 41 42#define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */ 43 44#define GZIP_MAGIC_0 0x1f 45#define GZIP_MAGIC_1 0x8b 46 47/* gzip flag byte */ 48#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ 49#define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ 50#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 51#define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 52#define COMMENT 0x10 /* bit 4 set: file comment present */ 53#define RESERVED 0xE0 /* bits 5..7: reserved */ 54 55static CURLcode 56process_zlib_error(struct connectdata *conn, z_stream *z) 57{ 58 struct SessionHandle *data = conn->data; 59 if(z->msg) 60 failf (data, "Error while processing content unencoding: %s", 61 z->msg); 62 else 63 failf (data, "Error while processing content unencoding: " 64 "Unknown failure within decompression software."); 65 66 return CURLE_BAD_CONTENT_ENCODING; 67} 68 69static CURLcode 70exit_zlib(z_stream *z, zlibInitState *zlib_init, CURLcode result) 71{ 72 inflateEnd(z); 73 *zlib_init = ZLIB_UNINIT; 74 return result; 75} 76 77static CURLcode 78inflate_stream(struct connectdata *conn, 79 struct SingleRequest *k) 80{ 81 int allow_restart = 1; 82 z_stream *z = &k->z; /* zlib state structure */ 83 uInt nread = z->avail_in; 84 Bytef *orig_in = z->next_in; 85 int status; /* zlib status */ 86 CURLcode result = CURLE_OK; /* Curl_client_write status */ 87 char *decomp; /* Put the decompressed data here. */ 88 89 /* Dynamically allocate a buffer for decompression because it's uncommonly 90 large to hold on the stack */ 91 decomp = malloc(DSIZ); 92 if(decomp == NULL) { 93 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 94 } 95 96 /* because the buffer size is fixed, iteratively decompress and transfer to 97 the client via client_write. */ 98 for(;;) { 99 /* (re)set buffer for decompressed output for every iteration */ 100 z->next_out = (Bytef *)decomp; 101 z->avail_out = DSIZ; 102 103 status = inflate(z, Z_SYNC_FLUSH); 104 if(status == Z_OK || status == Z_STREAM_END) { 105 allow_restart = 0; 106 if((DSIZ - z->avail_out) && (!k->ignorebody)) { 107 result = Curl_client_write(conn, CLIENTWRITE_BODY, decomp, 108 DSIZ - z->avail_out); 109 /* if !CURLE_OK, clean up, return */ 110 if(result) { 111 free(decomp); 112 return exit_zlib(z, &k->zlib_init, result); 113 } 114 } 115 116 /* Done? clean up, return */ 117 if(status == Z_STREAM_END) { 118 free(decomp); 119 if(inflateEnd(z) == Z_OK) 120 return exit_zlib(z, &k->zlib_init, result); 121 else 122 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 123 } 124 125 /* Done with these bytes, exit */ 126 127 /* status is always Z_OK at this point! */ 128 if(z->avail_in == 0) { 129 free(decomp); 130 return result; 131 } 132 } 133 else if(allow_restart && status == Z_DATA_ERROR) { 134 /* some servers seem to not generate zlib headers, so this is an attempt 135 to fix and continue anyway */ 136 137 (void) inflateEnd(z); /* don't care about the return code */ 138 if(inflateInit2(z, -MAX_WBITS) != Z_OK) { 139 free(decomp); 140 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 141 } 142 z->next_in = orig_in; 143 z->avail_in = nread; 144 allow_restart = 0; 145 continue; 146 } 147 else { /* Error; exit loop, handle below */ 148 free(decomp); 149 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 150 } 151 } 152 /* Will never get here */ 153} 154 155CURLcode 156Curl_unencode_deflate_write(struct connectdata *conn, 157 struct SingleRequest *k, 158 ssize_t nread) 159{ 160 z_stream *z = &k->z; /* zlib state structure */ 161 162 /* Initialize zlib? */ 163 if(k->zlib_init == ZLIB_UNINIT) { 164 z->zalloc = (alloc_func)Z_NULL; 165 z->zfree = (free_func)Z_NULL; 166 z->opaque = 0; 167 z->next_in = NULL; 168 z->avail_in = 0; 169 if(inflateInit(z) != Z_OK) 170 return process_zlib_error(conn, z); 171 k->zlib_init = ZLIB_INIT; 172 } 173 174 /* Set the compressed input when this function is called */ 175 z->next_in = (Bytef *)k->str; 176 z->avail_in = (uInt)nread; 177 178 /* Now uncompress the data */ 179 return inflate_stream(conn, k); 180} 181 182#ifdef OLD_ZLIB_SUPPORT 183/* Skip over the gzip header */ 184static enum { 185 GZIP_OK, 186 GZIP_BAD, 187 GZIP_UNDERFLOW 188} check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen) 189{ 190 int method, flags; 191 const ssize_t totallen = len; 192 193 /* The shortest header is 10 bytes */ 194 if(len < 10) 195 return GZIP_UNDERFLOW; 196 197 if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1)) 198 return GZIP_BAD; 199 200 method = data[2]; 201 flags = data[3]; 202 203 if(method != Z_DEFLATED || (flags & RESERVED) != 0) { 204 /* Can't handle this compression method or unknown flag */ 205 return GZIP_BAD; 206 } 207 208 /* Skip over time, xflags, OS code and all previous bytes */ 209 len -= 10; 210 data += 10; 211 212 if(flags & EXTRA_FIELD) { 213 ssize_t extra_len; 214 215 if(len < 2) 216 return GZIP_UNDERFLOW; 217 218 extra_len = (data[1] << 8) | data[0]; 219 220 if(len < (extra_len+2)) 221 return GZIP_UNDERFLOW; 222 223 len -= (extra_len + 2); 224 data += (extra_len + 2); 225 } 226 227 if(flags & ORIG_NAME) { 228 /* Skip over NUL-terminated file name */ 229 while(len && *data) { 230 --len; 231 ++data; 232 } 233 if(!len || *data) 234 return GZIP_UNDERFLOW; 235 236 /* Skip over the NUL */ 237 --len; 238 ++data; 239 } 240 241 if(flags & COMMENT) { 242 /* Skip over NUL-terminated comment */ 243 while(len && *data) { 244 --len; 245 ++data; 246 } 247 if(!len || *data) 248 return GZIP_UNDERFLOW; 249 250 /* Skip over the NUL */ 251 --len; 252 } 253 254 if(flags & HEAD_CRC) { 255 if(len < 2) 256 return GZIP_UNDERFLOW; 257 258 len -= 2; 259 } 260 261 *headerlen = totallen - len; 262 return GZIP_OK; 263} 264#endif 265 266CURLcode 267Curl_unencode_gzip_write(struct connectdata *conn, 268 struct SingleRequest *k, 269 ssize_t nread) 270{ 271 z_stream *z = &k->z; /* zlib state structure */ 272 273 /* Initialize zlib? */ 274 if(k->zlib_init == ZLIB_UNINIT) { 275 z->zalloc = (alloc_func)Z_NULL; 276 z->zfree = (free_func)Z_NULL; 277 z->opaque = 0; 278 z->next_in = NULL; 279 z->avail_in = 0; 280 281 if(strcmp(zlibVersion(), "1.2.0.4") >= 0) { 282 /* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */ 283 if(inflateInit2(z, MAX_WBITS+32) != Z_OK) { 284 return process_zlib_error(conn, z); 285 } 286 k->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */ 287 } 288 else { 289 /* we must parse the gzip header ourselves */ 290 if(inflateInit2(z, -MAX_WBITS) != Z_OK) { 291 return process_zlib_error(conn, z); 292 } 293 k->zlib_init = ZLIB_INIT; /* Initial call state */ 294 } 295 } 296 297 if(k->zlib_init == ZLIB_INIT_GZIP) { 298 /* Let zlib handle the gzip decompression entirely */ 299 z->next_in = (Bytef *)k->str; 300 z->avail_in = (uInt)nread; 301 /* Now uncompress the data */ 302 return inflate_stream(conn, k); 303 } 304 305#ifndef OLD_ZLIB_SUPPORT 306 /* Support for old zlib versions is compiled away and we are running with 307 an old version, so return an error. */ 308 return exit_zlib(z, &k->zlib_init, CURLE_FUNCTION_NOT_FOUND); 309 310#else 311 /* This next mess is to get around the potential case where there isn't 312 * enough data passed in to skip over the gzip header. If that happens, we 313 * malloc a block and copy what we have then wait for the next call. If 314 * there still isn't enough (this is definitely a worst-case scenario), we 315 * make the block bigger, copy the next part in and keep waiting. 316 * 317 * This is only required with zlib versions < 1.2.0.4 as newer versions 318 * can handle the gzip header themselves. 319 */ 320 321 switch (k->zlib_init) { 322 /* Skip over gzip header? */ 323 case ZLIB_INIT: 324 { 325 /* Initial call state */ 326 ssize_t hlen; 327 328 switch (check_gzip_header((unsigned char *)k->str, nread, &hlen)) { 329 case GZIP_OK: 330 z->next_in = (Bytef *)k->str + hlen; 331 z->avail_in = (uInt)(nread - hlen); 332 k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ 333 break; 334 335 case GZIP_UNDERFLOW: 336 /* We need more data so we can find the end of the gzip header. It's 337 * possible that the memory block we malloc here will never be freed if 338 * the transfer abruptly aborts after this point. Since it's unlikely 339 * that circumstances will be right for this code path to be followed in 340 * the first place, and it's even more unlikely for a transfer to fail 341 * immediately afterwards, it should seldom be a problem. 342 */ 343 z->avail_in = (uInt)nread; 344 z->next_in = malloc(z->avail_in); 345 if(z->next_in == NULL) { 346 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 347 } 348 memcpy(z->next_in, k->str, z->avail_in); 349 k->zlib_init = ZLIB_GZIP_HEADER; /* Need more gzip header data state */ 350 /* We don't have any data to inflate yet */ 351 return CURLE_OK; 352 353 case GZIP_BAD: 354 default: 355 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 356 } 357 358 } 359 break; 360 361 case ZLIB_GZIP_HEADER: 362 { 363 /* Need more gzip header data state */ 364 ssize_t hlen; 365 unsigned char *oldblock = z->next_in; 366 367 z->avail_in += (uInt)nread; 368 z->next_in = realloc(z->next_in, z->avail_in); 369 if(z->next_in == NULL) { 370 free(oldblock); 371 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 372 } 373 /* Append the new block of data to the previous one */ 374 memcpy(z->next_in + z->avail_in - nread, k->str, nread); 375 376 switch (check_gzip_header(z->next_in, z->avail_in, &hlen)) { 377 case GZIP_OK: 378 /* This is the zlib stream data */ 379 free(z->next_in); 380 /* Don't point into the malloced block since we just freed it */ 381 z->next_in = (Bytef *)k->str + hlen + nread - z->avail_in; 382 z->avail_in = (uInt)(z->avail_in - hlen); 383 k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ 384 break; 385 386 case GZIP_UNDERFLOW: 387 /* We still don't have any data to inflate! */ 388 return CURLE_OK; 389 390 case GZIP_BAD: 391 default: 392 free(z->next_in); 393 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 394 } 395 396 } 397 break; 398 399 case ZLIB_GZIP_INFLATING: 400 default: 401 /* Inflating stream state */ 402 z->next_in = (Bytef *)k->str; 403 z->avail_in = (uInt)nread; 404 break; 405 } 406 407 if(z->avail_in == 0) { 408 /* We don't have any data to inflate; wait until next time */ 409 return CURLE_OK; 410 } 411 412 /* We've parsed the header, now uncompress the data */ 413 return inflate_stream(conn, k); 414#endif 415} 416 417void Curl_unencode_cleanup(struct connectdata *conn) 418{ 419 struct SessionHandle *data = conn->data; 420 struct SingleRequest *k = &data->req; 421 z_stream *z = &k->z; 422 if(k->zlib_init != ZLIB_UNINIT) 423 (void) exit_zlib(z, &k->zlib_init, CURLE_OK); 424} 425 426#endif /* HAVE_LIBZ */ 427