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Diffstat (limited to 'src/common/compress_lzma.c')
| -rw-r--r-- | src/common/compress_lzma.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/src/common/compress_lzma.c b/src/common/compress_lzma.c new file mode 100644 index 0000000000..051c59ba2d --- /dev/null +++ b/src/common/compress_lzma.c @@ -0,0 +1,361 @@ +/* Copyright (c) 2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2017, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file compress_lzma.c + * \brief Compression backend for LZMA. + * + * This module should never be invoked directly. Use the compress module + * instead. + **/ + +#include "orconfig.h" + +#include "util.h" +#include "torlog.h" +#include "compress.h" +#include "compress_lzma.h" + +#ifdef HAVE_LZMA +#include <lzma.h> +#endif + +/** The maximum amount of memory we allow the LZMA decoder to use, in bytes. */ +#define MEMORY_LIMIT (16 * 1024 * 1024) + +/** Total number of bytes allocated for LZMA state. */ +static atomic_counter_t total_lzma_allocation; + +#ifdef HAVE_LZMA +/** Given <b>level</b> return the memory level. */ +static int +memory_level(compression_level_t level) +{ + switch (level) { + default: + case BEST_COMPRESSION: + case HIGH_COMPRESSION: return 6; + case MEDIUM_COMPRESSION: return 4; + case LOW_COMPRESSION: return 2; + } +} + +/** Convert a given <b>error</b> to a human readable error string. */ +static const char * +lzma_error_str(lzma_ret error) +{ + switch (error) { + case LZMA_OK: + return "Operation completed successfully"; + case LZMA_STREAM_END: + return "End of stream"; + case LZMA_NO_CHECK: + return "Input stream lacks integrity check"; + case LZMA_UNSUPPORTED_CHECK: + return "Unable to calculate integrity check"; + case LZMA_GET_CHECK: + return "Integrity check available"; + case LZMA_MEM_ERROR: + return "Unable to allocate memory"; + case LZMA_MEMLIMIT_ERROR: + return "Memory limit reached"; + case LZMA_FORMAT_ERROR: + return "Unknown file format"; + case LZMA_OPTIONS_ERROR: + return "Unsupported options"; + case LZMA_DATA_ERROR: + return "Corrupt input data"; + case LZMA_BUF_ERROR: + return "Unable to progress"; + case LZMA_PROG_ERROR: + return "Programming error"; + default: + return "Unknown LZMA error"; + } +} +#endif /* defined(HAVE_LZMA) */ + +/** Return 1 if LZMA compression is supported; otherwise 0. */ +int +tor_lzma_method_supported(void) +{ +#ifdef HAVE_LZMA + return 1; +#else + return 0; +#endif +} + +/** Return a string representation of the version of the currently running + * version of liblzma. Returns NULL if LZMA is unsupported. */ +const char * +tor_lzma_get_version_str(void) +{ +#ifdef HAVE_LZMA + return lzma_version_string(); +#else + return NULL; +#endif +} + +/** Return a string representation of the version of liblzma used at + * compilation time. Returns NULL if LZMA is unsupported. */ +const char * +tor_lzma_get_header_version_str(void) +{ +#ifdef HAVE_LZMA + return LZMA_VERSION_STRING; +#else + return NULL; +#endif +} + +/** Internal LZMA state for incremental compression/decompression. + * The body of this struct is not exposed. */ +struct tor_lzma_compress_state_t { +#ifdef HAVE_LZMA + lzma_stream stream; /**< The LZMA stream. */ +#endif + + int compress; /**< True if we are compressing; false if we are inflating */ + + /** Number of bytes read so far. Used to detect compression bombs. */ + size_t input_so_far; + /** Number of bytes written so far. Used to detect compression bombs. */ + size_t output_so_far; + + /** Approximate number of bytes allocated for this object. */ + size_t allocation; +}; + +#ifdef HAVE_LZMA +/** Return an approximate number of bytes stored in memory to hold the LZMA + * encoder/decoder state. */ +static size_t +tor_lzma_state_size_precalc(int compress, compression_level_t level) +{ + uint64_t memory_usage; + + if (compress) + memory_usage = lzma_easy_encoder_memusage(memory_level(level)); + else + memory_usage = lzma_easy_decoder_memusage(memory_level(level)); + + if (memory_usage == UINT64_MAX) { + // LCOV_EXCL_START + log_warn(LD_GENERAL, "Unsupported compression level passed to LZMA %s", + compress ? "encoder" : "decoder"); + goto err; + // LCOV_EXCL_STOP + } + + if (memory_usage + sizeof(tor_lzma_compress_state_t) > SIZE_MAX) + memory_usage = SIZE_MAX; + else + memory_usage += sizeof(tor_lzma_compress_state_t); + + return (size_t)memory_usage; + + // LCOV_EXCL_START + err: + return 0; + // LCOV_EXCL_STOP +} +#endif /* defined(HAVE_LZMA) */ + +/** Construct and return a tor_lzma_compress_state_t object using + * <b>method</b>. If <b>compress</b>, it's for compression; otherwise it's for + * decompression. */ +tor_lzma_compress_state_t * +tor_lzma_compress_new(int compress, + compress_method_t method, + compression_level_t level) +{ + tor_assert(method == LZMA_METHOD); + +#ifdef HAVE_LZMA + tor_lzma_compress_state_t *result; + lzma_ret retval; + lzma_options_lzma stream_options; + + // Note that we do not explicitly initialize the lzma_stream object here, + // since the LZMA_STREAM_INIT "just" initializes all members to 0, which is + // also what `tor_malloc_zero()` does. + result = tor_malloc_zero(sizeof(tor_lzma_compress_state_t)); + result->compress = compress; + result->allocation = tor_lzma_state_size_precalc(compress, level); + + if (compress) { + lzma_lzma_preset(&stream_options, memory_level(level)); + + retval = lzma_alone_encoder(&result->stream, &stream_options); + + if (retval != LZMA_OK) { + // LCOV_EXCL_START + log_warn(LD_GENERAL, "Error from LZMA encoder: %s (%u).", + lzma_error_str(retval), retval); + goto err; + // LCOV_EXCL_STOP + } + } else { + retval = lzma_alone_decoder(&result->stream, MEMORY_LIMIT); + + if (retval != LZMA_OK) { + // LCOV_EXCL_START + log_warn(LD_GENERAL, "Error from LZMA decoder: %s (%u).", + lzma_error_str(retval), retval); + goto err; + // LCOV_EXCL_STOP + } + } + + atomic_counter_add(&total_lzma_allocation, result->allocation); + return result; + + /* LCOV_EXCL_START */ + err: + tor_free(result); + return NULL; + /* LCOV_EXCL_STOP */ +#else /* !(defined(HAVE_LZMA)) */ + (void)compress; + (void)method; + (void)level; + + return NULL; +#endif /* defined(HAVE_LZMA) */ +} + +/** Compress/decompress some bytes using <b>state</b>. Read up to + * *<b>in_len</b> bytes from *<b>in</b>, and write up to *<b>out_len</b> bytes + * to *<b>out</b>, adjusting the values as we go. If <b>finish</b> is true, + * we've reached the end of the input. + * + * Return TOR_COMPRESS_DONE if we've finished the entire + * compression/decompression. + * Return TOR_COMPRESS_OK if we're processed everything from the input. + * Return TOR_COMPRESS_BUFFER_FULL if we're out of space on <b>out</b>. + * Return TOR_COMPRESS_ERROR if the stream is corrupt. + */ +tor_compress_output_t +tor_lzma_compress_process(tor_lzma_compress_state_t *state, + char **out, size_t *out_len, + const char **in, size_t *in_len, + int finish) +{ +#ifdef HAVE_LZMA + lzma_ret retval; + lzma_action action; + + tor_assert(state != NULL); + tor_assert(*in_len <= UINT_MAX); + tor_assert(*out_len <= UINT_MAX); + + state->stream.next_in = (unsigned char *)*in; + state->stream.avail_in = *in_len; + state->stream.next_out = (unsigned char *)*out; + state->stream.avail_out = *out_len; + + action = finish ? LZMA_FINISH : LZMA_RUN; + + retval = lzma_code(&state->stream, action); + + state->input_so_far += state->stream.next_in - ((unsigned char *)*in); + state->output_so_far += state->stream.next_out - ((unsigned char *)*out); + + *out = (char *)state->stream.next_out; + *out_len = state->stream.avail_out; + *in = (const char *)state->stream.next_in; + *in_len = state->stream.avail_in; + + if (! state->compress && + tor_compress_is_compression_bomb(state->input_so_far, + state->output_so_far)) { + log_warn(LD_DIR, "Possible compression bomb; abandoning stream."); + return TOR_COMPRESS_ERROR; + } + + switch (retval) { + case LZMA_OK: + if (state->stream.avail_out == 0 || finish) + return TOR_COMPRESS_BUFFER_FULL; + + return TOR_COMPRESS_OK; + + case LZMA_BUF_ERROR: + if (state->stream.avail_in == 0 && !finish) + return TOR_COMPRESS_OK; + + return TOR_COMPRESS_BUFFER_FULL; + + case LZMA_STREAM_END: + return TOR_COMPRESS_DONE; + + // We list all the possible values of `lzma_ret` here to silence the + // `switch-enum` warning and to detect if a new member was added. + case LZMA_NO_CHECK: + case LZMA_UNSUPPORTED_CHECK: + case LZMA_GET_CHECK: + case LZMA_MEM_ERROR: + case LZMA_MEMLIMIT_ERROR: + case LZMA_FORMAT_ERROR: + case LZMA_OPTIONS_ERROR: + case LZMA_DATA_ERROR: + case LZMA_PROG_ERROR: + default: + log_warn(LD_GENERAL, "LZMA %s didn't finish: %s.", + state->compress ? "compression" : "decompression", + lzma_error_str(retval)); + return TOR_COMPRESS_ERROR; + } +#else /* !(defined(HAVE_LZMA)) */ + (void)state; + (void)out; + (void)out_len; + (void)in; + (void)in_len; + (void)finish; + return TOR_COMPRESS_ERROR; +#endif /* defined(HAVE_LZMA) */ +} + +/** Deallocate <b>state</b>. */ +void +tor_lzma_compress_free_(tor_lzma_compress_state_t *state) +{ + if (state == NULL) + return; + + atomic_counter_sub(&total_lzma_allocation, state->allocation); + +#ifdef HAVE_LZMA + lzma_end(&state->stream); +#endif + + tor_free(state); +} + +/** Return the approximate number of bytes allocated for <b>state</b>. */ +size_t +tor_lzma_compress_state_size(const tor_lzma_compress_state_t *state) +{ + tor_assert(state != NULL); + return state->allocation; +} + +/** Return the approximate number of bytes allocated for all LZMA states. */ +size_t +tor_lzma_get_total_allocation(void) +{ + return atomic_counter_get(&total_lzma_allocation); +} + +/** Initialize the lzma module */ +void +tor_lzma_init(void) +{ + atomic_counter_init(&total_lzma_allocation); +} + |