1 /*************************************************************************** 2 * _ _ ____ _ 3 * Project ___| | | | _ \| | 4 * / __| | | | |_) | | 5 * | (__| |_| | _ <| |___ 6 * \___|\___/|_| \_\_____| 7 * 8 * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel (at) 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 https://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 "curl_setup.h" 24 25 #ifdef HAVE_LIBZ 26 27 #include "urldata.h" 28 #include <curl/curl.h> 29 #include "sendf.h" 30 #include "content_encoding.h" 31 #include "strdup.h" 32 #include "curl_memory.h" 33 #include "memdebug.h" 34 35 /* Comment this out if zlib is always going to be at least ver. 1.2.0.4 36 (doing so will reduce code size slightly). */ 37 #define OLD_ZLIB_SUPPORT 1 38 39 #define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */ 40 41 #define GZIP_MAGIC_0 0x1f 42 #define GZIP_MAGIC_1 0x8b 43 44 /* gzip flag byte */ 45 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ 46 #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ 47 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 48 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 49 #define COMMENT 0x10 /* bit 4 set: file comment present */ 50 #define RESERVED 0xE0 /* bits 5..7: reserved */ 51 52 static voidpf 53 zalloc_cb(voidpf opaque, unsigned int items, unsigned int size) 54 { 55 (void) opaque; 56 /* not a typo, keep it calloc() */ 57 return (voidpf) calloc(items, size); 58 } 59 60 static void 61 zfree_cb(voidpf opaque, voidpf ptr) 62 { 63 (void) opaque; 64 free(ptr); 65 } 66 67 static CURLcode 68 process_zlib_error(struct connectdata *conn, z_stream *z) 69 { 70 struct Curl_easy *data = conn->data; 71 if(z->msg) 72 failf (data, "Error while processing content unencoding: %s", 73 z->msg); 74 else 75 failf (data, "Error while processing content unencoding: " 76 "Unknown failure within decompression software."); 77 78 return CURLE_BAD_CONTENT_ENCODING; 79 } 80 81 static CURLcode 82 exit_zlib(z_stream *z, zlibInitState *zlib_init, CURLcode result) 83 { 84 inflateEnd(z); 85 *zlib_init = ZLIB_UNINIT; 86 return result; 87 } 88 89 static CURLcode 90 inflate_stream(struct connectdata *conn, 91 struct SingleRequest *k) 92 { 93 int allow_restart = 1; 94 z_stream *z = &k->z; /* zlib state structure */ 95 uInt nread = z->avail_in; 96 Bytef *orig_in = z->next_in; 97 int status; /* zlib status */ 98 CURLcode result = CURLE_OK; /* Curl_client_write status */ 99 char *decomp; /* Put the decompressed data here. */ 100 101 /* Dynamically allocate a buffer for decompression because it's uncommonly 102 large to hold on the stack */ 103 decomp = malloc(DSIZ); 104 if(decomp == NULL) { 105 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 106 } 107 108 /* because the buffer size is fixed, iteratively decompress and transfer to 109 the client via client_write. */ 110 for(;;) { 111 /* (re)set buffer for decompressed output for every iteration */ 112 z->next_out = (Bytef *)decomp; 113 z->avail_out = DSIZ; 114 115 status = inflate(z, Z_SYNC_FLUSH); 116 if(status == Z_OK || status == Z_STREAM_END) { 117 allow_restart = 0; 118 if((DSIZ - z->avail_out) && (!k->ignorebody)) { 119 result = Curl_client_write(conn, CLIENTWRITE_BODY, decomp, 120 DSIZ - z->avail_out); 121 /* if !CURLE_OK, clean up, return */ 122 if(result) { 123 free(decomp); 124 return exit_zlib(z, &k->zlib_init, result); 125 } 126 } 127 128 /* Done? clean up, return */ 129 if(status == Z_STREAM_END) { 130 free(decomp); 131 if(inflateEnd(z) == Z_OK) 132 return exit_zlib(z, &k->zlib_init, result); 133 else 134 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 135 } 136 137 /* Done with these bytes, exit */ 138 139 /* status is always Z_OK at this point! */ 140 if(z->avail_in == 0) { 141 free(decomp); 142 return result; 143 } 144 } 145 else if(allow_restart && status == Z_DATA_ERROR) { 146 /* some servers seem to not generate zlib headers, so this is an attempt 147 to fix and continue anyway */ 148 149 (void) inflateEnd(z); /* don't care about the return code */ 150 if(inflateInit2(z, -MAX_WBITS) != Z_OK) { 151 free(decomp); 152 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 153 } 154 z->next_in = orig_in; 155 z->avail_in = nread; 156 allow_restart = 0; 157 continue; 158 } 159 else { /* Error; exit loop, handle below */ 160 free(decomp); 161 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 162 } 163 } 164 /* Will never get here */ 165 } 166 167 CURLcode 168 Curl_unencode_deflate_write(struct connectdata *conn, 169 struct SingleRequest *k, 170 ssize_t nread) 171 { 172 z_stream *z = &k->z; /* zlib state structure */ 173 174 /* Initialize zlib? */ 175 if(k->zlib_init == ZLIB_UNINIT) { 176 memset(z, 0, sizeof(z_stream)); 177 z->zalloc = (alloc_func)zalloc_cb; 178 z->zfree = (free_func)zfree_cb; 179 180 if(inflateInit(z) != Z_OK) 181 return process_zlib_error(conn, z); 182 k->zlib_init = ZLIB_INIT; 183 } 184 185 /* Set the compressed input when this function is called */ 186 z->next_in = (Bytef *)k->str; 187 z->avail_in = (uInt)nread; 188 189 /* Now uncompress the data */ 190 return inflate_stream(conn, k); 191 } 192 193 #ifdef OLD_ZLIB_SUPPORT 194 /* Skip over the gzip header */ 195 static enum { 196 GZIP_OK, 197 GZIP_BAD, 198 GZIP_UNDERFLOW 199 } check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen) 200 { 201 int method, flags; 202 const ssize_t totallen = len; 203 204 /* The shortest header is 10 bytes */ 205 if(len < 10) 206 return GZIP_UNDERFLOW; 207 208 if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1)) 209 return GZIP_BAD; 210 211 method = data[2]; 212 flags = data[3]; 213 214 if(method != Z_DEFLATED || (flags & RESERVED) != 0) { 215 /* Can't handle this compression method or unknown flag */ 216 return GZIP_BAD; 217 } 218 219 /* Skip over time, xflags, OS code and all previous bytes */ 220 len -= 10; 221 data += 10; 222 223 if(flags & EXTRA_FIELD) { 224 ssize_t extra_len; 225 226 if(len < 2) 227 return GZIP_UNDERFLOW; 228 229 extra_len = (data[1] << 8) | data[0]; 230 231 if(len < (extra_len+2)) 232 return GZIP_UNDERFLOW; 233 234 len -= (extra_len + 2); 235 data += (extra_len + 2); 236 } 237 238 if(flags & ORIG_NAME) { 239 /* Skip over NUL-terminated file name */ 240 while(len && *data) { 241 --len; 242 ++data; 243 } 244 if(!len || *data) 245 return GZIP_UNDERFLOW; 246 247 /* Skip over the NUL */ 248 --len; 249 ++data; 250 } 251 252 if(flags & COMMENT) { 253 /* Skip over NUL-terminated comment */ 254 while(len && *data) { 255 --len; 256 ++data; 257 } 258 if(!len || *data) 259 return GZIP_UNDERFLOW; 260 261 /* Skip over the NUL */ 262 --len; 263 } 264 265 if(flags & HEAD_CRC) { 266 if(len < 2) 267 return GZIP_UNDERFLOW; 268 269 len -= 2; 270 } 271 272 *headerlen = totallen - len; 273 return GZIP_OK; 274 } 275 #endif 276 277 CURLcode 278 Curl_unencode_gzip_write(struct connectdata *conn, 279 struct SingleRequest *k, 280 ssize_t nread) 281 { 282 z_stream *z = &k->z; /* zlib state structure */ 283 284 /* Initialize zlib? */ 285 if(k->zlib_init == ZLIB_UNINIT) { 286 memset(z, 0, sizeof(z_stream)); 287 z->zalloc = (alloc_func)zalloc_cb; 288 z->zfree = (free_func)zfree_cb; 289 290 if(strcmp(zlibVersion(), "1.2.0.4") >= 0) { 291 /* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */ 292 if(inflateInit2(z, MAX_WBITS+32) != Z_OK) { 293 return process_zlib_error(conn, z); 294 } 295 k->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */ 296 } 297 else { 298 /* we must parse the gzip header ourselves */ 299 if(inflateInit2(z, -MAX_WBITS) != Z_OK) { 300 return process_zlib_error(conn, z); 301 } 302 k->zlib_init = ZLIB_INIT; /* Initial call state */ 303 } 304 } 305 306 if(k->zlib_init == ZLIB_INIT_GZIP) { 307 /* Let zlib handle the gzip decompression entirely */ 308 z->next_in = (Bytef *)k->str; 309 z->avail_in = (uInt)nread; 310 /* Now uncompress the data */ 311 return inflate_stream(conn, k); 312 } 313 314 #ifndef OLD_ZLIB_SUPPORT 315 /* Support for old zlib versions is compiled away and we are running with 316 an old version, so return an error. */ 317 return exit_zlib(z, &k->zlib_init, CURLE_FUNCTION_NOT_FOUND); 318 319 #else 320 /* This next mess is to get around the potential case where there isn't 321 * enough data passed in to skip over the gzip header. If that happens, we 322 * malloc a block and copy what we have then wait for the next call. If 323 * there still isn't enough (this is definitely a worst-case scenario), we 324 * make the block bigger, copy the next part in and keep waiting. 325 * 326 * This is only required with zlib versions < 1.2.0.4 as newer versions 327 * can handle the gzip header themselves. 328 */ 329 330 switch (k->zlib_init) { 331 /* Skip over gzip header? */ 332 case ZLIB_INIT: 333 { 334 /* Initial call state */ 335 ssize_t hlen; 336 337 switch (check_gzip_header((unsigned char *)k->str, nread, &hlen)) { 338 case GZIP_OK: 339 z->next_in = (Bytef *)k->str + hlen; 340 z->avail_in = (uInt)(nread - hlen); 341 k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ 342 break; 343 344 case GZIP_UNDERFLOW: 345 /* We need more data so we can find the end of the gzip header. It's 346 * possible that the memory block we malloc here will never be freed if 347 * the transfer abruptly aborts after this point. Since it's unlikely 348 * that circumstances will be right for this code path to be followed in 349 * the first place, and it's even more unlikely for a transfer to fail 350 * immediately afterwards, it should seldom be a problem. 351 */ 352 z->avail_in = (uInt)nread; 353 z->next_in = malloc(z->avail_in); 354 if(z->next_in == NULL) { 355 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 356 } 357 memcpy(z->next_in, k->str, z->avail_in); 358 k->zlib_init = ZLIB_GZIP_HEADER; /* Need more gzip header data state */ 359 /* We don't have any data to inflate yet */ 360 return CURLE_OK; 361 362 case GZIP_BAD: 363 default: 364 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 365 } 366 367 } 368 break; 369 370 case ZLIB_GZIP_HEADER: 371 { 372 /* Need more gzip header data state */ 373 ssize_t hlen; 374 z->avail_in += (uInt)nread; 375 z->next_in = Curl_saferealloc(z->next_in, z->avail_in); 376 if(z->next_in == NULL) { 377 return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); 378 } 379 /* Append the new block of data to the previous one */ 380 memcpy(z->next_in + z->avail_in - nread, k->str, nread); 381 382 switch (check_gzip_header(z->next_in, z->avail_in, &hlen)) { 383 case GZIP_OK: 384 /* This is the zlib stream data */ 385 free(z->next_in); 386 /* Don't point into the malloced block since we just freed it */ 387 z->next_in = (Bytef *)k->str + hlen + nread - z->avail_in; 388 z->avail_in = (uInt)(z->avail_in - hlen); 389 k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ 390 break; 391 392 case GZIP_UNDERFLOW: 393 /* We still don't have any data to inflate! */ 394 return CURLE_OK; 395 396 case GZIP_BAD: 397 default: 398 free(z->next_in); 399 return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); 400 } 401 402 } 403 break; 404 405 case ZLIB_GZIP_INFLATING: 406 default: 407 /* Inflating stream state */ 408 z->next_in = (Bytef *)k->str; 409 z->avail_in = (uInt)nread; 410 break; 411 } 412 413 if(z->avail_in == 0) { 414 /* We don't have any data to inflate; wait until next time */ 415 return CURLE_OK; 416 } 417 418 /* We've parsed the header, now uncompress the data */ 419 return inflate_stream(conn, k); 420 #endif 421 } 422 423 void Curl_unencode_cleanup(struct connectdata *conn) 424 { 425 struct Curl_easy *data = conn->data; 426 struct SingleRequest *k = &data->req; 427 z_stream *z = &k->z; 428 if(k->zlib_init != ZLIB_UNINIT) 429 (void) exit_zlib(z, &k->zlib_init, CURLE_OK); 430 } 431 432 #endif /* HAVE_LIBZ */ 433
