From 0029cbbabe87d491fc046a55a629a6d556010baa Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Fri, 4 Jan 2008 21:30:33 +0200 Subject: [PATCH] Added support for flush marker, which will be in files that use LZMA_SYNC_FLUSH with encoder (not implemented yet). This is a new feature in the raw LZMA format, which isn't supported by old decoders. This shouldn't be a problem in practice, since lzma_alone_encoder() will not allow LZMA_SYNC_FLUSH, and thus not allow creating files on decodable with old decoders. Made lzma_decoder.c to require tab width of 4 characters if one wants to fit the code in 80 columns. This makes the code easier to read. --- src/liblzma/lzma/lzma_common.h | 4 + src/liblzma/lzma/lzma_decoder.c | 217 ++++++++++++++++++---------------------- 2 files changed, 104 insertions(+), 117 deletions(-) diff --git a/src/liblzma/lzma/lzma_common.h b/src/liblzma/lzma/lzma_common.h index 4ff59ae..d4873cf 100644 --- a/src/liblzma/lzma/lzma_common.h +++ b/src/liblzma/lzma/lzma_common.h @@ -81,6 +81,10 @@ // Price table size of Len Encoder #define LEN_PRICES (LEN_SYMBOLS << POS_STATES_BITS_MAX) +// Special lengths used together with distance == UINT32_MAX +#define LEN_SPECIAL_EOPM MATCH_MIN_LEN +#define LEN_SPECIAL_FLUSH (LEN_SPECIAL_EOPM + 1) + // Optimal - Number of entries in the optimum array. #define OPTS (1 << 12) diff --git a/src/liblzma/lzma/lzma_decoder.c b/src/liblzma/lzma/lzma_decoder.c index dda9417..037985c 100644 --- a/src/liblzma/lzma/lzma_decoder.c +++ b/src/liblzma/lzma/lzma_decoder.c @@ -18,6 +18,9 @@ // /////////////////////////////////////////////////////////////////////////////// +// NOTE: If you want to keep the line length in 80 characters, set +// tab width to 4 or less in your editor when editing this file. + #include "lzma_common.h" #include "lzma_decoder.h" #include "lz_decoder.h" @@ -44,21 +47,17 @@ do { \ if_bit_0(len_decoder.choice) { \ update_bit_0(len_decoder.choice); \ target = MATCH_MIN_LEN; \ - bittree_decode(target, \ - len_decoder.low[pos_state], LEN_LOW_BITS); \ + bittree_decode(target, len_decoder.low[pos_state], LEN_LOW_BITS); \ } else { \ update_bit_1(len_decoder.choice); \ if_bit_0(len_decoder.choice2) { \ update_bit_0(len_decoder.choice2); \ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS; \ - bittree_decode(target, len_decoder.mid[pos_state], \ - LEN_MID_BITS); \ + bittree_decode(target, len_decoder.mid[pos_state], LEN_MID_BITS); \ } else { \ update_bit_1(len_decoder.choice2); \ - target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS \ - + LEN_MID_SYMBOLS; \ - bittree_decode(target, len_decoder.high, \ - LEN_HIGH_BITS); \ + target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; \ + bittree_decode(target, len_decoder.high, LEN_HIGH_BITS); \ } \ } \ } while (0) @@ -76,15 +75,12 @@ do { \ if_bit_0(len_decoder.choice2) { \ update_bit_0_dummy(); \ target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS; \ - bittree_decode_dummy(target, \ - len_decoder.mid[pos_state], \ + bittree_decode_dummy(target, len_decoder.mid[pos_state], \ LEN_MID_BITS); \ } else { \ update_bit_1_dummy(); \ - target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS \ - + LEN_MID_SYMBOLS; \ - bittree_decode_dummy(target, len_decoder.high, \ - LEN_HIGH_BITS); \ + target = MATCH_MIN_LEN + LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS; \ + bittree_decode_dummy(target, len_decoder.high, LEN_HIGH_BITS); \ } \ } \ } while (0) @@ -151,6 +147,10 @@ struct lzma_coder_s { /// Length of a repeated match. lzma_length_decoder rep_match_len_decoder; + + /// True when we have produced at least one byte of output since the + /// beginning of the stream or the latest flush marker. + bool has_produced_output; }; @@ -176,23 +176,19 @@ decode_dummy(const lzma_coder *restrict coder, update_bit_0_dummy(); const probability *subcoder = literal_get_subcoder( - coder->literal_coder, - now_pos, lz_get_byte(coder->lz, 0)); + coder->literal_coder, now_pos, lz_get_byte(coder->lz, 0)); uint32_t symbol = 1; if (!is_char_state(state)) { // Decode literal with match byte. assert(rep0 != UINT32_MAX); - uint32_t match_byte - = lz_get_byte(coder->lz, rep0); + uint32_t match_byte = lz_get_byte(coder->lz, rep0); do { match_byte <<= 1; - const uint32_t match_bit - = match_byte & 0x100; - const uint32_t subcoder_index = 0x100 - + match_bit + symbol; + const uint32_t match_bit = match_byte & 0x100; + const uint32_t subcoder_index = 0x100 + match_bit + symbol; if_bit_0(subcoder[subcoder_index]) { update_bit_0_dummy(); @@ -231,11 +227,10 @@ decode_dummy(const lzma_coder *restrict coder, length_decode_dummy(len, coder->len_decoder, pos_state); update_match(state); - const uint32_t len_to_pos_state - = get_len_to_pos_state(len); + const uint32_t len_to_pos_state = get_len_to_pos_state(len); uint32_t pos_slot = 0; - bittree_decode_dummy(pos_slot, coder->pos_slot_decoder[ - len_to_pos_state], POS_SLOT_BITS); + bittree_decode_dummy(pos_slot, + coder->pos_slot_decoder[len_to_pos_state], POS_SLOT_BITS); assert(pos_slot <= 63); if (pos_slot >= START_POS_MODEL_INDEX) { @@ -247,22 +242,16 @@ decode_dummy(const lzma_coder *restrict coder, assert(direct_bits <= 5); rep0 <<= direct_bits; assert(rep0 <= 96); - // -1 is fine, because - // bittree_reverse_decode() - // starts from table index [1] - // (not [0]). - assert((int32_t)(rep0 - pos_slot - 1) - >= -1); - assert((int32_t)(rep0 - pos_slot - 1) - <= 82); + // -1 is fine, because bittree_reverse_decode() + // starts from table index [1] (not [0]). + assert((int32_t)(rep0 - pos_slot - 1) >= -1); + assert((int32_t)(rep0 - pos_slot - 1) <= 82); // We add the result to rep0, so rep0 // must not be part of second argument // of the macro. - const int32_t offset - = rep0 - pos_slot - 1; - bittree_reverse_decode_dummy( - coder->pos_decoders + offset, - direct_bits); + const int32_t offset = rep0 - pos_slot - 1; + bittree_reverse_decode_dummy(coder->pos_decoders + offset, + direct_bits); } else { assert(pos_slot >= 14); assert(direct_bits >= 6); @@ -270,9 +259,8 @@ decode_dummy(const lzma_coder *restrict coder, assert(direct_bits >= 2); rc_decode_direct_dummy(direct_bits); - bittree_reverse_decode_dummy( - coder->pos_align_decoder, - ALIGN_BITS); + bittree_reverse_decode_dummy(coder->pos_align_decoder, + ALIGN_BITS); } } @@ -282,8 +270,7 @@ decode_dummy(const lzma_coder *restrict coder, if_bit_0(coder->is_rep0[state]) { update_bit_0_dummy(); - if_bit_0(coder->is_rep0_long[state][ - pos_state]) { + if_bit_0(coder->is_rep0_long[state][pos_state]) { update_bit_0_dummy(); break; } else { @@ -306,18 +293,13 @@ decode_dummy(const lzma_coder *restrict coder, } } - length_decode_dummy(len, coder->rep_match_len_decoder, - pos_state); + length_decode_dummy(len, coder->rep_match_len_decoder, pos_state); } } while (0); rc_normalize(); - // Validate the buffer position. - if (in_pos_local > in_size) - return false; - - return true; + return in_pos_local <= in_size; } @@ -351,6 +333,7 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // Misc uint32_t now_pos = coder->now_pos; + bool has_produced_output = coder->has_produced_output; // Variables derived from decoder settings const uint32_t pos_mask = coder->pos_mask; @@ -363,10 +346,10 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, in_limit = in_size - REQUIRED_IN_BUFFER_SIZE; - while (coder->lz.pos < coder->lz.limit && (in_pos_local < in_limit - || (has_safe_buffer && decode_dummy( - coder, in, in_pos_local, in_size, - rc, state, rep0, now_pos)))) { + while (coder->lz.pos < coder->lz.limit + && (in_pos_local < in_limit || (has_safe_buffer + && decode_dummy(coder, in, in_pos_local, in_size, + rc, state, rep0, now_pos)))) { ///////////////////// // Actual decoding // @@ -379,8 +362,7 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // It's a literal i.e. a single 8-bit byte. - probability *subcoder = literal_get_subcoder( - coder->literal_coder, + probability *subcoder = literal_get_subcoder(coder->literal_coder, now_pos, lz_get_byte(coder->lz, 0)); uint32_t symbol = 1; @@ -388,25 +370,20 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // Decode literal with match byte. assert(rep0 != UINT32_MAX); - uint32_t match_byte - = lz_get_byte(coder->lz, rep0); + uint32_t match_byte = lz_get_byte(coder->lz, rep0); do { match_byte <<= 1; - const uint32_t match_bit - = match_byte & 0x100; - const uint32_t subcoder_index = 0x100 - + match_bit + symbol; + const uint32_t match_bit = match_byte & 0x100; + const uint32_t subcoder_index = 0x100 + match_bit + symbol; if_bit_0(subcoder[subcoder_index]) { - update_bit_0(subcoder[ - subcoder_index]); + update_bit_0(subcoder[subcoder_index]); symbol <<= 1; if (match_bit != 0) break; } else { - update_bit_1(subcoder[ - subcoder_index]); + update_bit_1(subcoder[subcoder_index]); symbol = (symbol << 1) | 1; if (match_bit == 0) break; @@ -431,6 +408,7 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, coder->lz.dict[coder->lz.pos++] = (uint8_t)(symbol); ++now_pos; update_char(state); + has_produced_output = true; continue; } @@ -460,11 +438,10 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, update_match(state); - const uint32_t len_to_pos_state - = get_len_to_pos_state(len); + const uint32_t len_to_pos_state = get_len_to_pos_state(len); uint32_t pos_slot = 0; - bittree_decode(pos_slot, coder->pos_slot_decoder[ - len_to_pos_state], POS_SLOT_BITS); + bittree_decode(pos_slot, + coder->pos_slot_decoder[len_to_pos_state], POS_SLOT_BITS); assert(pos_slot <= 63); if (pos_slot >= START_POS_MODEL_INDEX) { @@ -480,18 +457,14 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // bittree_reverse_decode() // starts from table index [1] // (not [0]). - assert((int32_t)(rep0 - pos_slot - 1) - >= -1); - assert((int32_t)(rep0 - pos_slot - 1) - <= 82); + assert((int32_t)(rep0 - pos_slot - 1) >= -1); + assert((int32_t)(rep0 - pos_slot - 1) <= 82); // We add the result to rep0, so rep0 // must not be part of second argument // of the macro. - const int32_t offset - = rep0 - pos_slot - 1; - bittree_reverse_decode(rep0, - coder->pos_decoders + offset, - direct_bits); + const int32_t offset = rep0 - pos_slot - 1; + bittree_reverse_decode(rep0, coder->pos_decoders + offset, + direct_bits); } else { assert(pos_slot >= 14); assert(direct_bits >= 6); @@ -500,14 +473,33 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, rc_decode_direct(rep0, direct_bits); rep0 <<= ALIGN_BITS; - bittree_reverse_decode(rep0, - coder->pos_align_decoder, - ALIGN_BITS); + bittree_reverse_decode(rep0, coder->pos_align_decoder, + ALIGN_BITS); if (rep0 == UINT32_MAX) { - // End of Payload Marker found. - coder->lz.eopm_detected = true; - break; + if (len == LEN_SPECIAL_EOPM) { + // End of Payload Marker found. + coder->lz.eopm_detected = true; + break; + + } else if (len == LEN_SPECIAL_FLUSH) { + // Flush marker detected. We must have produced + // at least one byte of output since the previous + // flush marker or the beginning of the stream. + // This is to prevent hanging the decoder with + // malicious input files. + if (!coder->has_produced_output) + return true; + + coder->has_produced_output = false; + + rc_reset(rc); + if (!rc_read_init(&rc, in, &in_pos_local, in_size)) + break; + + } else { + return true; + } } } } else { @@ -529,10 +521,8 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // The distance is rep0. - if_bit_0(coder->is_rep0_long[state][ - pos_state]) { - update_bit_0(coder->is_rep0_long[ - state][pos_state]); + if_bit_0(coder->is_rep0_long[state][pos_state]) { + update_bit_0(coder->is_rep0_long[state][pos_state]); // Repeating exactly one byte. For // simplicity, it is done here inline @@ -544,24 +534,21 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // Security/sanity checks. See the end // of the main loop for explanation // of these. - if ((rep0 >= coder->lz.pos - && !coder->lz.is_full) - || in_pos_local - > in_size) - goto error; + if ((rep0 >= coder->lz.pos && !coder->lz.is_full) + || in_pos_local > in_size) + return true; // Repeat one byte and start a new // decoding loop. coder->lz.dict[coder->lz.pos] - = lz_get_byte( - coder->lz, rep0); + = lz_get_byte(coder->lz, rep0); ++coder->lz.pos; ++now_pos; + has_produced_output = true; continue; } else { - update_bit_1(coder->is_rep0_long[ - state][pos_state]); + update_bit_1(coder->is_rep0_long[state][pos_state]); // Repeating more than one byte at // distance of rep0. @@ -584,12 +571,10 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, update_bit_1(coder->is_rep1[state]); if_bit_0(coder->is_rep2[state]) { - update_bit_0(coder->is_rep2[ - state]); + update_bit_0(coder->is_rep2[state]); distance = rep2; } else { - update_bit_1(coder->is_rep2[ - state]); + update_bit_1(coder->is_rep2[state]); distance = rep3; rep3 = rep2; } @@ -602,8 +587,7 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, } // Decode the length of the repeated match. - length_decode(len, coder->rep_match_len_decoder, - pos_state); + length_decode(len, coder->rep_match_len_decoder, pos_state); update_rep(state); } @@ -619,15 +603,16 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, assert(len <= MATCH_MAX_LEN); now_pos += len; + has_produced_output = true; // Validate the buffer position to avoid buffer overflows // on corrupted input data. if (in_pos_local > in_size) - goto error; + return true; // Repeat len bytes from distance of rep0. if (!lzma_lz_out_repeat(&coder->lz, rep0, len)) - goto error; + return true; } rc_normalize(); @@ -649,12 +634,10 @@ decode_real(lzma_coder *restrict coder, const uint8_t *restrict in, // Misc coder->now_pos = now_pos; + coder->has_produced_output = has_produced_output; *in_pos = in_pos_local; return false; - -error: - return true; } @@ -766,20 +749,20 @@ lzma_lzma_decoder_init(lzma_next_coder *next, lzma_allocator *allocator, bit_reset(next->coder->rep_match_len_decoder.choice2); for (uint32_t pos_state = 0; pos_state < num_pos_states; ++pos_state) { - bittree_reset(next->coder->len_decoder.low[pos_state], + bittree_reset(next->coder->len_decoder.low[pos_state], LEN_LOW_BITS); + bittree_reset(next->coder->len_decoder.mid[pos_state], LEN_MID_BITS); + + bittree_reset(next->coder->rep_match_len_decoder.low[pos_state], LEN_LOW_BITS); - bittree_reset(next->coder->len_decoder.mid[pos_state], + bittree_reset(next->coder->rep_match_len_decoder.mid[pos_state], LEN_MID_BITS); - - bittree_reset(next->coder->rep_match_len_decoder.low[ - pos_state], LEN_LOW_BITS); - bittree_reset(next->coder->rep_match_len_decoder.mid[ - pos_state], LEN_MID_BITS); } bittree_reset(next->coder->len_decoder.high, LEN_HIGH_BITS); bittree_reset(next->coder->rep_match_len_decoder.high, LEN_HIGH_BITS); + next->coder->has_produced_output = false; + // Initialize the next decoder in the chain, if any. { const lzma_ret ret = lzma_next_filter_init(&next->coder->next, -- 2.7.4