/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 1998 - 2016, Daniel Stenberg, , et al. * * This software is licensed as described in the file COPYING, which * you should have received as part of this distribution. The terms * are also available at https://curl.haxx.se/docs/copyright.html. * * You may opt to use, copy, modify, merge, publish, distribute and/or sell * copies of the Software, and permit persons to whom the Software is * furnished to do so, under the terms of the COPYING file. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ***************************************************************************/ #include "curl_setup.h" #ifdef HAVE_LIBZ #include "urldata.h" #include #include "sendf.h" #include "content_encoding.h" #include "strdup.h" #include "curl_memory.h" #include "memdebug.h" /* Comment this out if zlib is always going to be at least ver. 1.2.0.4 (doing so will reduce code size slightly). */ #define OLD_ZLIB_SUPPORT 1 #define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */ #define GZIP_MAGIC_0 0x1f #define GZIP_MAGIC_1 0x8b /* gzip flag byte */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ #define COMMENT 0x10 /* bit 4 set: file comment present */ #define RESERVED 0xE0 /* bits 5..7: reserved */ static voidpf zalloc_cb(voidpf opaque, unsigned int items, unsigned int size) { (void) opaque; /* not a typo, keep it calloc() */ return (voidpf) calloc(items, size); } static void zfree_cb(voidpf opaque, voidpf ptr) { (void) opaque; free(ptr); } static CURLcode process_zlib_error(struct connectdata *conn, z_stream *z) { struct Curl_easy *data = conn->data; if(z->msg) failf (data, "Error while processing content unencoding: %s", z->msg); else failf (data, "Error while processing content unencoding: " "Unknown failure within decompression software."); return CURLE_BAD_CONTENT_ENCODING; } static CURLcode exit_zlib(z_stream *z, zlibInitState *zlib_init, CURLcode result) { inflateEnd(z); *zlib_init = ZLIB_UNINIT; return result; } static CURLcode inflate_stream(struct connectdata *conn, struct SingleRequest *k) { int allow_restart = 1; z_stream *z = &k->z; /* zlib state structure */ uInt nread = z->avail_in; Bytef *orig_in = z->next_in; int status; /* zlib status */ CURLcode result = CURLE_OK; /* Curl_client_write status */ char *decomp; /* Put the decompressed data here. */ /* Dynamically allocate a buffer for decompression because it's uncommonly large to hold on the stack */ decomp = malloc(DSIZ); if(decomp == NULL) { return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); } /* because the buffer size is fixed, iteratively decompress and transfer to the client via client_write. */ for(;;) { /* (re)set buffer for decompressed output for every iteration */ z->next_out = (Bytef *)decomp; z->avail_out = DSIZ; status = inflate(z, Z_SYNC_FLUSH); if(status == Z_OK || status == Z_STREAM_END) { allow_restart = 0; if((DSIZ - z->avail_out) && (!k->ignorebody)) { result = Curl_client_write(conn, CLIENTWRITE_BODY, decomp, DSIZ - z->avail_out); /* if !CURLE_OK, clean up, return */ if(result) { free(decomp); return exit_zlib(z, &k->zlib_init, result); } } /* Done? clean up, return */ if(status == Z_STREAM_END) { free(decomp); if(inflateEnd(z) == Z_OK) return exit_zlib(z, &k->zlib_init, result); else return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); } /* Done with these bytes, exit */ /* status is always Z_OK at this point! */ if(z->avail_in == 0) { free(decomp); return result; } } else if(allow_restart && status == Z_DATA_ERROR) { /* some servers seem to not generate zlib headers, so this is an attempt to fix and continue anyway */ (void) inflateEnd(z); /* don't care about the return code */ if(inflateInit2(z, -MAX_WBITS) != Z_OK) { free(decomp); return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); } z->next_in = orig_in; z->avail_in = nread; allow_restart = 0; continue; } else { /* Error; exit loop, handle below */ free(decomp); return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); } } /* Will never get here */ } CURLcode Curl_unencode_deflate_write(struct connectdata *conn, struct SingleRequest *k, ssize_t nread) { z_stream *z = &k->z; /* zlib state structure */ /* Initialize zlib? */ if(k->zlib_init == ZLIB_UNINIT) { memset(z, 0, sizeof(z_stream)); z->zalloc = (alloc_func)zalloc_cb; z->zfree = (free_func)zfree_cb; if(inflateInit(z) != Z_OK) return process_zlib_error(conn, z); k->zlib_init = ZLIB_INIT; } /* Set the compressed input when this function is called */ z->next_in = (Bytef *)k->str; z->avail_in = (uInt)nread; /* Now uncompress the data */ return inflate_stream(conn, k); } #ifdef OLD_ZLIB_SUPPORT /* Skip over the gzip header */ static enum { GZIP_OK, GZIP_BAD, GZIP_UNDERFLOW } check_gzip_header(unsigned char const *data, ssize_t len, ssize_t *headerlen) { int method, flags; const ssize_t totallen = len; /* The shortest header is 10 bytes */ if(len < 10) return GZIP_UNDERFLOW; if((data[0] != GZIP_MAGIC_0) || (data[1] != GZIP_MAGIC_1)) return GZIP_BAD; method = data[2]; flags = data[3]; if(method != Z_DEFLATED || (flags & RESERVED) != 0) { /* Can't handle this compression method or unknown flag */ return GZIP_BAD; } /* Skip over time, xflags, OS code and all previous bytes */ len -= 10; data += 10; if(flags & EXTRA_FIELD) { ssize_t extra_len; if(len < 2) return GZIP_UNDERFLOW; extra_len = (data[1] << 8) | data[0]; if(len < (extra_len+2)) return GZIP_UNDERFLOW; len -= (extra_len + 2); data += (extra_len + 2); } if(flags & ORIG_NAME) { /* Skip over NUL-terminated file name */ while(len && *data) { --len; ++data; } if(!len || *data) return GZIP_UNDERFLOW; /* Skip over the NUL */ --len; ++data; } if(flags & COMMENT) { /* Skip over NUL-terminated comment */ while(len && *data) { --len; ++data; } if(!len || *data) return GZIP_UNDERFLOW; /* Skip over the NUL */ --len; } if(flags & HEAD_CRC) { if(len < 2) return GZIP_UNDERFLOW; len -= 2; } *headerlen = totallen - len; return GZIP_OK; } #endif CURLcode Curl_unencode_gzip_write(struct connectdata *conn, struct SingleRequest *k, ssize_t nread) { z_stream *z = &k->z; /* zlib state structure */ /* Initialize zlib? */ if(k->zlib_init == ZLIB_UNINIT) { memset(z, 0, sizeof(z_stream)); z->zalloc = (alloc_func)zalloc_cb; z->zfree = (free_func)zfree_cb; if(strcmp(zlibVersion(), "1.2.0.4") >= 0) { /* zlib ver. >= 1.2.0.4 supports transparent gzip decompressing */ if(inflateInit2(z, MAX_WBITS+32) != Z_OK) { return process_zlib_error(conn, z); } k->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */ } else { /* we must parse the gzip header ourselves */ if(inflateInit2(z, -MAX_WBITS) != Z_OK) { return process_zlib_error(conn, z); } k->zlib_init = ZLIB_INIT; /* Initial call state */ } } if(k->zlib_init == ZLIB_INIT_GZIP) { /* Let zlib handle the gzip decompression entirely */ z->next_in = (Bytef *)k->str; z->avail_in = (uInt)nread; /* Now uncompress the data */ return inflate_stream(conn, k); } #ifndef OLD_ZLIB_SUPPORT /* Support for old zlib versions is compiled away and we are running with an old version, so return an error. */ return exit_zlib(z, &k->zlib_init, CURLE_FUNCTION_NOT_FOUND); #else /* This next mess is to get around the potential case where there isn't * enough data passed in to skip over the gzip header. If that happens, we * malloc a block and copy what we have then wait for the next call. If * there still isn't enough (this is definitely a worst-case scenario), we * make the block bigger, copy the next part in and keep waiting. * * This is only required with zlib versions < 1.2.0.4 as newer versions * can handle the gzip header themselves. */ switch (k->zlib_init) { /* Skip over gzip header? */ case ZLIB_INIT: { /* Initial call state */ ssize_t hlen; switch (check_gzip_header((unsigned char *)k->str, nread, &hlen)) { case GZIP_OK: z->next_in = (Bytef *)k->str + hlen; z->avail_in = (uInt)(nread - hlen); k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ break; case GZIP_UNDERFLOW: /* We need more data so we can find the end of the gzip header. It's * possible that the memory block we malloc here will never be freed if * the transfer abruptly aborts after this point. Since it's unlikely * that circumstances will be right for this code path to be followed in * the first place, and it's even more unlikely for a transfer to fail * immediately afterwards, it should seldom be a problem. */ z->avail_in = (uInt)nread; z->next_in = malloc(z->avail_in); if(z->next_in == NULL) { return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); } memcpy(z->next_in, k->str, z->avail_in); k->zlib_init = ZLIB_GZIP_HEADER; /* Need more gzip header data state */ /* We don't have any data to inflate yet */ return CURLE_OK; case GZIP_BAD: default: return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); } } break; case ZLIB_GZIP_HEADER: { /* Need more gzip header data state */ ssize_t hlen; z->avail_in += (uInt)nread; z->next_in = Curl_saferealloc(z->next_in, z->avail_in); if(z->next_in == NULL) { return exit_zlib(z, &k->zlib_init, CURLE_OUT_OF_MEMORY); } /* Append the new block of data to the previous one */ memcpy(z->next_in + z->avail_in - nread, k->str, nread); switch (check_gzip_header(z->next_in, z->avail_in, &hlen)) { case GZIP_OK: /* This is the zlib stream data */ free(z->next_in); /* Don't point into the malloced block since we just freed it */ z->next_in = (Bytef *)k->str + hlen + nread - z->avail_in; z->avail_in = (uInt)(z->avail_in - hlen); k->zlib_init = ZLIB_GZIP_INFLATING; /* Inflating stream state */ break; case GZIP_UNDERFLOW: /* We still don't have any data to inflate! */ return CURLE_OK; case GZIP_BAD: default: free(z->next_in); return exit_zlib(z, &k->zlib_init, process_zlib_error(conn, z)); } } break; case ZLIB_GZIP_INFLATING: default: /* Inflating stream state */ z->next_in = (Bytef *)k->str; z->avail_in = (uInt)nread; break; } if(z->avail_in == 0) { /* We don't have any data to inflate; wait until next time */ return CURLE_OK; } /* We've parsed the header, now uncompress the data */ return inflate_stream(conn, k); #endif } void Curl_unencode_cleanup(struct connectdata *conn) { struct Curl_easy *data = conn->data; struct SingleRequest *k = &data->req; z_stream *z = &k->z; if(k->zlib_init != ZLIB_UNINIT) (void) exit_zlib(z, &k->zlib_init, CURLE_OK); } #endif /* HAVE_LIBZ */