/*************************************************************************** * _ _ ____ _ * Project ___| | | | _ \| | * / __| | | | |_) | | * | (__| |_| | _ <| |___ * \___|\___/|_| \_\_____| * * Copyright (C) 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.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. * * SPDX-License-Identifier: curl * ***************************************************************************/ #include "curl_setup.h" #include "urldata.h" #include #include #ifdef HAVE_LIBZ #include #endif #ifdef HAVE_BROTLI #if defined(__GNUC__) /* Ignore -Wvla warnings in brotli headers */ #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wvla" #endif #include #if defined(__GNUC__) #pragma GCC diagnostic pop #endif #endif #ifdef HAVE_ZSTD #include #endif #include "sendf.h" #include "http.h" #include "content_encoding.h" #include "strdup.h" #include "strcase.h" /* The last 3 #include files should be in this order */ #include "curl_printf.h" #include "curl_memory.h" #include "memdebug.h" #define CONTENT_ENCODING_DEFAULT "identity" #ifndef CURL_DISABLE_HTTP /* allow no more than 5 "chained" compression steps */ #define MAX_ENCODE_STACK 5 #define DSIZ CURL_MAX_WRITE_SIZE /* buffer size for decompressed data */ #ifdef HAVE_LIBZ /* 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 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 */ typedef enum { ZLIB_UNINIT, /* uninitialized */ ZLIB_INIT, /* initialized */ ZLIB_INFLATING, /* inflating started. */ ZLIB_EXTERNAL_TRAILER, /* reading external trailer */ ZLIB_GZIP_HEADER, /* reading gzip header */ ZLIB_GZIP_INFLATING, /* inflating gzip stream */ ZLIB_INIT_GZIP /* initialized in transparent gzip mode */ } zlibInitState; /* Deflate and gzip writer. */ struct zlib_writer { struct Curl_cwriter super; zlibInitState zlib_init; /* zlib init state */ uInt trailerlen; /* Remaining trailer byte count. */ z_stream z; /* State structure for zlib. */ }; 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 Curl_easy *data, z_stream *z) { 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(struct Curl_easy *data, z_stream *z, zlibInitState *zlib_init, CURLcode result) { if(*zlib_init == ZLIB_GZIP_HEADER) Curl_safefree(z->next_in); if(*zlib_init != ZLIB_UNINIT) { if(inflateEnd(z) != Z_OK && result == CURLE_OK) result = process_zlib_error(data, z); *zlib_init = ZLIB_UNINIT; } return result; } static CURLcode process_trailer(struct Curl_easy *data, struct zlib_writer *zp) { z_stream *z = &zp->z; CURLcode result = CURLE_OK; uInt len = z->avail_in < zp->trailerlen? z->avail_in: zp->trailerlen; /* Consume expected trailer bytes. Terminate stream if exhausted. Issue an error if unexpected bytes follow. */ zp->trailerlen -= len; z->avail_in -= len; z->next_in += len; if(z->avail_in) result = CURLE_WRITE_ERROR; if(result || !zp->trailerlen) result = exit_zlib(data, z, &zp->zlib_init, result); else { /* Only occurs for gzip with zlib < 1.2.0.4 or raw deflate. */ zp->zlib_init = ZLIB_EXTERNAL_TRAILER; } return result; } static CURLcode inflate_stream(struct Curl_easy *data, struct Curl_cwriter *writer, int type, zlibInitState started) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ uInt nread = z->avail_in; Bytef *orig_in = z->next_in; bool done = FALSE; CURLcode result = CURLE_OK; /* Curl_client_write status */ char *decomp; /* Put the decompressed data here. */ /* Check state. */ if(zp->zlib_init != ZLIB_INIT && zp->zlib_init != ZLIB_INFLATING && zp->zlib_init != ZLIB_INIT_GZIP && zp->zlib_init != ZLIB_GZIP_INFLATING) return exit_zlib(data, z, &zp->zlib_init, CURLE_WRITE_ERROR); /* Dynamically allocate a buffer for decompression because it's uncommonly large to hold on the stack */ decomp = malloc(DSIZ); if(!decomp) return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY); /* because the buffer size is fixed, iteratively decompress and transfer to the client via next_write function. */ while(!done) { int status; /* zlib status */ done = TRUE; /* (re)set buffer for decompressed output for every iteration */ z->next_out = (Bytef *) decomp; z->avail_out = DSIZ; #ifdef Z_BLOCK /* Z_BLOCK is only available in zlib ver. >= 1.2.0.5 */ status = inflate(z, Z_BLOCK); #else /* fallback for zlib ver. < 1.2.0.5 */ status = inflate(z, Z_SYNC_FLUSH); #endif /* Flush output data if some. */ if(z->avail_out != DSIZ) { if(status == Z_OK || status == Z_STREAM_END) { zp->zlib_init = started; /* Data started. */ result = Curl_cwriter_write(data, writer->next, type, decomp, DSIZ - z->avail_out); if(result) { exit_zlib(data, z, &zp->zlib_init, result); break; } } } /* Dispatch by inflate() status. */ switch(status) { case Z_OK: /* Always loop: there may be unflushed latched data in zlib state. */ done = FALSE; break; case Z_BUF_ERROR: /* No more data to flush: just exit loop. */ break; case Z_STREAM_END: result = process_trailer(data, zp); break; case Z_DATA_ERROR: /* some servers seem to not generate zlib headers, so this is an attempt to fix and continue anyway */ if(zp->zlib_init == ZLIB_INIT) { /* Do not use inflateReset2(): only available since zlib 1.2.3.4. */ (void) inflateEnd(z); /* don't care about the return code */ if(inflateInit2(z, -MAX_WBITS) == Z_OK) { z->next_in = orig_in; z->avail_in = nread; zp->zlib_init = ZLIB_INFLATING; zp->trailerlen = 4; /* Tolerate up to 4 unknown trailer bytes. */ done = FALSE; break; } zp->zlib_init = ZLIB_UNINIT; /* inflateEnd() already called. */ } result = exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z)); break; default: result = exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z)); break; } } free(decomp); /* We're about to leave this call so the `nread' data bytes won't be seen again. If we are in a state that would wrongly allow restart in raw mode at the next call, assume output has already started. */ if(nread && zp->zlib_init == ZLIB_INIT) zp->zlib_init = started; /* Cannot restart anymore. */ return result; } /* Deflate handler. */ static CURLcode deflate_do_init(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ /* Initialize zlib */ z->zalloc = (alloc_func) zalloc_cb; z->zfree = (free_func) zfree_cb; if(inflateInit(z) != Z_OK) return process_zlib_error(data, z); zp->zlib_init = ZLIB_INIT; return CURLE_OK; } static CURLcode deflate_do_write(struct Curl_easy *data, struct Curl_cwriter *writer, int type, const char *buf, size_t nbytes) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ if(!(type & CLIENTWRITE_BODY)) return Curl_cwriter_write(data, writer->next, type, buf, nbytes); /* Set the compressed input when this function is called */ z->next_in = (Bytef *) buf; z->avail_in = (uInt) nbytes; if(zp->zlib_init == ZLIB_EXTERNAL_TRAILER) return process_trailer(data, zp); /* Now uncompress the data */ return inflate_stream(data, writer, type, ZLIB_INFLATING); } static void deflate_do_close(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ exit_zlib(data, z, &zp->zlib_init, CURLE_OK); } static const struct Curl_cwtype deflate_encoding = { "deflate", NULL, deflate_do_init, deflate_do_write, deflate_do_close, sizeof(struct zlib_writer) }; /* Gzip handler. */ static CURLcode gzip_do_init(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ /* Initialize zlib */ 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(data, z); } zp->zlib_init = ZLIB_INIT_GZIP; /* Transparent gzip decompress state */ } else { /* we must parse the gzip header and trailer ourselves */ if(inflateInit2(z, -MAX_WBITS) != Z_OK) { return process_zlib_error(data, z); } zp->trailerlen = 8; /* A CRC-32 and a 32-bit input size (RFC 1952, 2.2) */ zp->zlib_init = ZLIB_INIT; /* Initial call state */ } return CURLE_OK; } #ifdef OLD_ZLIB_SUPPORT /* Skip over the gzip header */ typedef enum { GZIP_OK, GZIP_BAD, GZIP_UNDERFLOW } gzip_status; static gzip_status 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 static CURLcode gzip_do_write(struct Curl_easy *data, struct Curl_cwriter *writer, int type, const char *buf, size_t nbytes) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ if(!(type & CLIENTWRITE_BODY)) return Curl_cwriter_write(data, writer->next, type, buf, nbytes); if(zp->zlib_init == ZLIB_INIT_GZIP) { /* Let zlib handle the gzip decompression entirely */ z->next_in = (Bytef *) buf; z->avail_in = (uInt) nbytes; /* Now uncompress the data */ return inflate_stream(data, writer, type, ZLIB_INIT_GZIP); } #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(data, z, &zp->zlib_init, CURLE_WRITE_ERROR); #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(zp->zlib_init) { /* Skip over gzip header? */ case ZLIB_INIT: { /* Initial call state */ ssize_t hlen; switch(check_gzip_header((unsigned char *) buf, nbytes, &hlen)) { case GZIP_OK: z->next_in = (Bytef *) buf + hlen; z->avail_in = (uInt) (nbytes - hlen); zp->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) nbytes; z->next_in = malloc(z->avail_in); if(!z->next_in) { return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY); } memcpy(z->next_in, buf, z->avail_in); zp->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(data, z, &zp->zlib_init, process_zlib_error(data, z)); } } break; case ZLIB_GZIP_HEADER: { /* Need more gzip header data state */ ssize_t hlen; z->avail_in += (uInt) nbytes; z->next_in = Curl_saferealloc(z->next_in, z->avail_in); if(!z->next_in) { return exit_zlib(data, z, &zp->zlib_init, CURLE_OUT_OF_MEMORY); } /* Append the new block of data to the previous one */ memcpy(z->next_in + z->avail_in - nbytes, buf, nbytes); 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 *) buf + hlen + nbytes - z->avail_in; z->avail_in = (uInt) (z->avail_in - hlen); zp->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: return exit_zlib(data, z, &zp->zlib_init, process_zlib_error(data, z)); } } break; case ZLIB_EXTERNAL_TRAILER: z->next_in = (Bytef *) buf; z->avail_in = (uInt) nbytes; return process_trailer(data, zp); case ZLIB_GZIP_INFLATING: default: /* Inflating stream state */ z->next_in = (Bytef *) buf; z->avail_in = (uInt) nbytes; 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(data, writer, type, ZLIB_GZIP_INFLATING); #endif } static void gzip_do_close(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zlib_writer *zp = (struct zlib_writer *) writer; z_stream *z = &zp->z; /* zlib state structure */ exit_zlib(data, z, &zp->zlib_init, CURLE_OK); } static const struct Curl_cwtype gzip_encoding = { "gzip", "x-gzip", gzip_do_init, gzip_do_write, gzip_do_close, sizeof(struct zlib_writer) }; #endif /* HAVE_LIBZ */ #ifdef HAVE_BROTLI /* Brotli writer. */ struct brotli_writer { struct Curl_cwriter super; BrotliDecoderState *br; /* State structure for brotli. */ }; static CURLcode brotli_map_error(BrotliDecoderErrorCode be) { switch(be) { case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE: case BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_META_NIBBLE: case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET: case BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME: case BROTLI_DECODER_ERROR_FORMAT_CL_SPACE: case BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE: case BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT: case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1: case BROTLI_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2: case BROTLI_DECODER_ERROR_FORMAT_TRANSFORM: case BROTLI_DECODER_ERROR_FORMAT_DICTIONARY: case BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS: case BROTLI_DECODER_ERROR_FORMAT_PADDING_1: case BROTLI_DECODER_ERROR_FORMAT_PADDING_2: #ifdef BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY case BROTLI_DECODER_ERROR_COMPOUND_DICTIONARY: #endif #ifdef BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET case BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET: #endif case BROTLI_DECODER_ERROR_INVALID_ARGUMENTS: return CURLE_BAD_CONTENT_ENCODING; case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES: case BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS: case BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP: case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_1: case BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2: case BROTLI_DECODER_ERROR_ALLOC_BLOCK_TYPE_TREES: return CURLE_OUT_OF_MEMORY; default: break; } return CURLE_WRITE_ERROR; } static CURLcode brotli_do_init(struct Curl_easy *data, struct Curl_cwriter *writer) { struct brotli_writer *bp = (struct brotli_writer *) writer; (void) data; bp->br = BrotliDecoderCreateInstance(NULL, NULL, NULL); return bp->br? CURLE_OK: CURLE_OUT_OF_MEMORY; } static CURLcode brotli_do_write(struct Curl_easy *data, struct Curl_cwriter *writer, int type, const char *buf, size_t nbytes) { struct brotli_writer *bp = (struct brotli_writer *) writer; const uint8_t *src = (const uint8_t *) buf; char *decomp; uint8_t *dst; size_t dstleft; CURLcode result = CURLE_OK; BrotliDecoderResult r = BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT; if(!(type & CLIENTWRITE_BODY)) return Curl_cwriter_write(data, writer->next, type, buf, nbytes); if(!bp->br) return CURLE_WRITE_ERROR; /* Stream already ended. */ decomp = malloc(DSIZ); if(!decomp) return CURLE_OUT_OF_MEMORY; while((nbytes || r == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT) && result == CURLE_OK) { dst = (uint8_t *) decomp; dstleft = DSIZ; r = BrotliDecoderDecompressStream(bp->br, &nbytes, &src, &dstleft, &dst, NULL); result = Curl_cwriter_write(data, writer->next, type, decomp, DSIZ - dstleft); if(result) break; switch(r) { case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT: case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT: break; case BROTLI_DECODER_RESULT_SUCCESS: BrotliDecoderDestroyInstance(bp->br); bp->br = NULL; if(nbytes) result = CURLE_WRITE_ERROR; break; default: result = brotli_map_error(BrotliDecoderGetErrorCode(bp->br)); break; } } free(decomp); return result; } static void brotli_do_close(struct Curl_easy *data, struct Curl_cwriter *writer) { struct brotli_writer *bp = (struct brotli_writer *) writer; (void) data; if(bp->br) { BrotliDecoderDestroyInstance(bp->br); bp->br = NULL; } } static const struct Curl_cwtype brotli_encoding = { "br", NULL, brotli_do_init, brotli_do_write, brotli_do_close, sizeof(struct brotli_writer) }; #endif #ifdef HAVE_ZSTD /* Zstd writer. */ struct zstd_writer { struct Curl_cwriter super; ZSTD_DStream *zds; /* State structure for zstd. */ void *decomp; }; static CURLcode zstd_do_init(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zstd_writer *zp = (struct zstd_writer *) writer; (void)data; zp->zds = ZSTD_createDStream(); zp->decomp = NULL; return zp->zds ? CURLE_OK : CURLE_OUT_OF_MEMORY; } static CURLcode zstd_do_write(struct Curl_easy *data, struct Curl_cwriter *writer, int type, const char *buf, size_t nbytes) { CURLcode result = CURLE_OK; struct zstd_writer *zp = (struct zstd_writer *) writer; ZSTD_inBuffer in; ZSTD_outBuffer out; size_t errorCode; if(!(type & CLIENTWRITE_BODY)) return Curl_cwriter_write(data, writer->next, type, buf, nbytes); if(!zp->decomp) { zp->decomp = malloc(DSIZ); if(!zp->decomp) return CURLE_OUT_OF_MEMORY; } in.pos = 0; in.src = buf; in.size = nbytes; for(;;) { out.pos = 0; out.dst = zp->decomp; out.size = DSIZ; errorCode = ZSTD_decompressStream(zp->zds, &out, &in); if(ZSTD_isError(errorCode)) { return CURLE_BAD_CONTENT_ENCODING; } if(out.pos > 0) { result = Curl_cwriter_write(data, writer->next, type, zp->decomp, out.pos); if(result) break; } if((in.pos == nbytes) && (out.pos < out.size)) break; } return result; } static void zstd_do_close(struct Curl_easy *data, struct Curl_cwriter *writer) { struct zstd_writer *zp = (struct zstd_writer *) writer; (void)data; if(zp->decomp) { free(zp->decomp); zp->decomp = NULL; } if(zp->zds) { ZSTD_freeDStream(zp->zds); zp->zds = NULL; } } static const struct Curl_cwtype zstd_encoding = { "zstd", NULL, zstd_do_init, zstd_do_write, zstd_do_close, sizeof(struct zstd_writer) }; #endif /* Identity handler. */ static const struct Curl_cwtype identity_encoding = { "identity", "none", Curl_cwriter_def_init, Curl_cwriter_def_write, Curl_cwriter_def_close, sizeof(struct Curl_cwriter) }; /* supported general content decoders. */ static const struct Curl_cwtype * const general_unencoders[] = { &identity_encoding, #ifdef HAVE_LIBZ &deflate_encoding, &gzip_encoding, #endif #ifdef HAVE_BROTLI &brotli_encoding, #endif #ifdef HAVE_ZSTD &zstd_encoding, #endif NULL }; /* supported content decoders only for transfer encodings */ static const struct Curl_cwtype * const transfer_unencoders[] = { #ifndef CURL_DISABLE_HTTP &Curl_httpchunk_unencoder, #endif NULL }; /* Provide a list of comma-separated names of supported encodings. */ void Curl_all_content_encodings(char *buf, size_t blen) { size_t len = 0; const struct Curl_cwtype * const *cep; const struct Curl_cwtype *ce; DEBUGASSERT(buf); DEBUGASSERT(blen); buf[0] = 0; for(cep = general_unencoders; *cep; cep++) { ce = *cep; if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT)) len += strlen(ce->name) + 2; } if(!len) { if(blen >= sizeof(CONTENT_ENCODING_DEFAULT)) strcpy(buf, CONTENT_ENCODING_DEFAULT); } else if(blen > len) { char *p = buf; for(cep = general_unencoders; *cep; cep++) { ce = *cep; if(!strcasecompare(ce->name, CONTENT_ENCODING_DEFAULT)) { strcpy(p, ce->name); p += strlen(p); *p++ = ','; *p++ = ' '; } } p[-2] = '\0'; } } /* Deferred error dummy writer. */ static CURLcode error_do_init(struct Curl_easy *data, struct Curl_cwriter *writer) { (void)data; (void)writer; return CURLE_OK; } static CURLcode error_do_write(struct Curl_easy *data, struct Curl_cwriter *writer, int type, const char *buf, size_t nbytes) { char all[256]; (void)Curl_all_content_encodings(all, sizeof(all)); (void) writer; (void) buf; (void) nbytes; if(!(type & CLIENTWRITE_BODY)) return Curl_cwriter_write(data, writer->next, type, buf, nbytes); failf(data, "Unrecognized content encoding type. " "libcurl understands %s content encodings.", all); return CURLE_BAD_CONTENT_ENCODING; } static void error_do_close(struct Curl_easy *data, struct Curl_cwriter *writer) { (void) data; (void) writer; } static const struct Curl_cwtype error_writer = { "ce-error", NULL, error_do_init, error_do_write, error_do_close, sizeof(struct Curl_cwriter) }; /* Find the content encoding by name. */ static const struct Curl_cwtype *find_unencode_writer(const char *name, size_t len, Curl_cwriter_phase phase) { const struct Curl_cwtype * const *cep; if(phase == CURL_CW_TRANSFER_DECODE) { for(cep = transfer_unencoders; *cep; cep++) { const struct Curl_cwtype *ce = *cep; if((strncasecompare(name, ce->name, len) && !ce->name[len]) || (ce->alias && strncasecompare(name, ce->alias, len) && !ce->alias[len])) return ce; } } /* look among the general decoders */ for(cep = general_unencoders; *cep; cep++) { const struct Curl_cwtype *ce = *cep; if((strncasecompare(name, ce->name, len) && !ce->name[len]) || (ce->alias && strncasecompare(name, ce->alias, len) && !ce->alias[len])) return ce; } return NULL; } /* Set-up the unencoding stack from the Content-Encoding header value. * See RFC 7231 section 3.1.2.2. */ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data, const char *enclist, int is_transfer) { Curl_cwriter_phase phase = is_transfer? CURL_CW_TRANSFER_DECODE:CURL_CW_CONTENT_DECODE; CURLcode result; do { const char *name; size_t namelen; /* Parse a single encoding name. */ while(ISBLANK(*enclist) || *enclist == ',') enclist++; name = enclist; for(namelen = 0; *enclist && *enclist != ','; enclist++) if(!ISSPACE(*enclist)) namelen = enclist - name + 1; if(namelen) { const struct Curl_cwtype *cwt; struct Curl_cwriter *writer; /* if we skip the decoding in this phase, do not look further. * Exception is "chunked" transfer-encoding which always must happen */ if((is_transfer && !data->set.http_transfer_encoding && (namelen != 7 || !strncasecompare(name, "chunked", 7))) || (!is_transfer && data->set.http_ce_skip)) { /* not requested, ignore */ return CURLE_OK; } if(Curl_cwriter_count(data, phase) + 1 >= MAX_ENCODE_STACK) { failf(data, "Reject response due to more than %u content encodings", MAX_ENCODE_STACK); return CURLE_BAD_CONTENT_ENCODING; } cwt = find_unencode_writer(name, namelen, phase); if(!cwt) cwt = &error_writer; /* Defer error at use. */ result = Curl_cwriter_create(&writer, data, cwt, phase); if(result) return result; result = Curl_cwriter_add(data, writer); if(result) { Curl_cwriter_free(data, writer); return result; } } } while(*enclist); return CURLE_OK; } #else /* Stubs for builds without HTTP. */ CURLcode Curl_build_unencoding_stack(struct Curl_easy *data, const char *enclist, int is_transfer) { (void) data; (void) enclist; (void) is_transfer; return CURLE_NOT_BUILT_IN; } void Curl_all_content_encodings(char *buf, size_t blen) { DEBUGASSERT(buf); DEBUGASSERT(blen); if(blen < sizeof(CONTENT_ENCODING_DEFAULT)) buf[0] = 0; else strcpy(buf, CONTENT_ENCODING_DEFAULT); } #endif /* CURL_DISABLE_HTTP */