Detect and report invalid stream earlier. PiperOrigin-RevId: 876128553
diff --git a/c/dec/decode.c b/c/dec/decode.c index e87e7f5..19c7e02 100644 --- a/c/dec/decode.c +++ b/c/dec/decode.c
@@ -1176,7 +1176,7 @@ /* Decodes a command or literal and updates block type ring-buffer. Reads 3..54 bits. */ -static BROTLI_INLINE BROTLI_BOOL DecodeBlockTypeAndLength( +static BROTLI_INLINE BrotliDecoderErrorCode DecodeBlockTypeAndLength( int safe, BrotliDecoderState* s, int tree_type) { brotli_reg_t max_block_type = s->num_block_types[tree_type]; const HuffmanCode* type_tree = &s->block_type_trees[ @@ -1187,7 +1187,7 @@ brotli_reg_t* ringbuffer = &s->block_type_rb[tree_type * 2]; brotli_reg_t block_type; if (max_block_type <= 1) { - return BROTLI_FALSE; + return BROTLI_DECODER_ERROR_FORMAT_BLOCK_SWITCH; } /* Read 0..15 + 3..39 bits. */ @@ -1197,11 +1197,13 @@ } else { BrotliBitReaderState memento; BrotliBitReaderSaveState(br, &memento); - if (!SafeReadSymbol(type_tree, br, &block_type)) return BROTLI_FALSE; + if (!SafeReadSymbol(type_tree, br, &block_type)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } if (!SafeReadBlockLength(s, &s->block_length[tree_type], len_tree, br)) { s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE; BrotliBitReaderRestoreState(br, &memento); - return BROTLI_FALSE; + return BROTLI_DECODER_NEEDS_MORE_INPUT; } } @@ -1217,7 +1219,7 @@ } ringbuffer[0] = ringbuffer[1]; ringbuffer[1] = block_type; - return BROTLI_TRUE; + return BROTLI_DECODER_SUCCESS; } static BROTLI_INLINE void DetectTrivialLiteralBlockTypes( @@ -1254,59 +1256,65 @@ /* Decodes the block type and updates the state for literal context. Reads 3..54 bits. */ -static BROTLI_INLINE BROTLI_BOOL DecodeLiteralBlockSwitchInternal( +static BROTLI_INLINE BrotliDecoderErrorCode DecodeLiteralBlockSwitchInternal( int safe, BrotliDecoderState* s) { - if (!DecodeBlockTypeAndLength(safe, s, 0)) { - return BROTLI_FALSE; + BrotliDecoderErrorCode result = DecodeBlockTypeAndLength(safe, s, 0); + if (result != BROTLI_DECODER_SUCCESS) { + return result; } PrepareLiteralDecoding(s); - return BROTLI_TRUE; + return BROTLI_DECODER_SUCCESS; } -static void BROTLI_NOINLINE DecodeLiteralBlockSwitch(BrotliDecoderState* s) { - DecodeLiteralBlockSwitchInternal(0, s); +static BROTLI_NOINLINE BrotliDecoderErrorCode +DecodeLiteralBlockSwitch(BrotliDecoderState* s) { + return DecodeLiteralBlockSwitchInternal(0, s); } -static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeLiteralBlockSwitch( +static BROTLI_NOINLINE BrotliDecoderErrorCode SafeDecodeLiteralBlockSwitch( BrotliDecoderState* s) { return DecodeLiteralBlockSwitchInternal(1, s); } /* Block switch for insert/copy length. Reads 3..54 bits. */ -static BROTLI_INLINE BROTLI_BOOL DecodeCommandBlockSwitchInternal( +static BROTLI_INLINE BrotliDecoderErrorCode DecodeCommandBlockSwitchInternal( int safe, BrotliDecoderState* s) { - if (!DecodeBlockTypeAndLength(safe, s, 1)) { - return BROTLI_FALSE; + BrotliDecoderErrorCode result = DecodeBlockTypeAndLength(safe, s, 1); + if (result != BROTLI_DECODER_SUCCESS) { + return result; } s->htree_command = s->insert_copy_hgroup.htrees[s->block_type_rb[3]]; - return BROTLI_TRUE; + return BROTLI_DECODER_SUCCESS; } -static void BROTLI_NOINLINE DecodeCommandBlockSwitch(BrotliDecoderState* s) { - DecodeCommandBlockSwitchInternal(0, s); +static BROTLI_NOINLINE BrotliDecoderErrorCode +DecodeCommandBlockSwitch(BrotliDecoderState* s) { + return DecodeCommandBlockSwitchInternal(0, s); } -static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeCommandBlockSwitch( - BrotliDecoderState* s) { +static BROTLI_NOINLINE BrotliDecoderErrorCode +SafeDecodeCommandBlockSwitch(BrotliDecoderState* s) { return DecodeCommandBlockSwitchInternal(1, s); } /* Block switch for distance codes. Reads 3..54 bits. */ -static BROTLI_INLINE BROTLI_BOOL DecodeDistanceBlockSwitchInternal( +static BROTLI_INLINE BrotliDecoderErrorCode DecodeDistanceBlockSwitchInternal( int safe, BrotliDecoderState* s) { - if (!DecodeBlockTypeAndLength(safe, s, 2)) { - return BROTLI_FALSE; + BrotliDecoderErrorCode result = DecodeBlockTypeAndLength(safe, s, 2); + if (result != BROTLI_DECODER_SUCCESS) { + return result; } s->dist_context_map_slice = s->dist_context_map + (s->block_type_rb[5] << BROTLI_DISTANCE_CONTEXT_BITS); s->dist_htree_index = s->dist_context_map_slice[s->distance_context]; - return BROTLI_TRUE; + return BROTLI_DECODER_SUCCESS; } -static void BROTLI_NOINLINE DecodeDistanceBlockSwitch(BrotliDecoderState* s) { - DecodeDistanceBlockSwitchInternal(0, s); +static BROTLI_NOINLINE BrotliDecoderErrorCode +DecodeDistanceBlockSwitch(BrotliDecoderState* s) { + return DecodeDistanceBlockSwitchInternal(0, s); } static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeDistanceBlockSwitch( @@ -1940,6 +1948,9 @@ return BrotliCheckInputAmount(br); } +/* NB: METHOD should return BROTLI_FALSE only in case there is not enough input; + in case of "unsafe" execution, when input is guaranteed to be sufficient, + result is ignored. */ #define BROTLI_SAFE(METHOD) \ { \ if (safe) { \ @@ -1952,6 +1963,22 @@ } \ } +/* NB: METHOD should return BROTLI_DECODER_SUCCESS, BROTLI_DECODER_ERROR_*, or + BROTLI_DECODER_NEEDS_MORE_INPUT; the later two break the processing. */ +#define BROTLI_SAFE_WITH_STATUS(METHOD) \ + { \ + BrotliDecoderErrorCode status; \ + if (safe) { \ + status = Safe##METHOD; \ + } else { \ + status = METHOD; \ + } \ + if (status != BROTLI_DECODER_SUCCESS) { \ + result = status; \ + goto saveStateAndReturn; \ + } \ + } + static BROTLI_INLINE BrotliDecoderErrorCode ProcessCommandsInternal( int safe, BrotliDecoderState* s) { int pos = s->pos; @@ -1991,7 +2018,7 @@ goto saveStateAndReturn; } if (BROTLI_PREDICT_FALSE(s->block_length[1] == 0)) { - BROTLI_SAFE(DecodeCommandBlockSwitch(s)); + BROTLI_SAFE_WITH_STATUS(DecodeCommandBlockSwitch(s)); goto CommandBegin; } /* Read the insert/copy length in the command. */ @@ -2136,7 +2163,7 @@ } else { /* Read distance code in the command, unless it was implicitly zero. */ if (BROTLI_PREDICT_FALSE(s->block_length[2] == 0)) { - BROTLI_SAFE(DecodeDistanceBlockSwitch(s)); + BROTLI_SAFE_WITH_STATUS(DecodeDistanceBlockSwitch(s)); } BROTLI_SAFE(ReadDistance(s, br)); } @@ -2330,7 +2357,7 @@ } NextLiteralBlock: - BROTLI_SAFE(DecodeLiteralBlockSwitch(s)); + BROTLI_SAFE_WITH_STATUS(DecodeLiteralBlockSwitch(s)); goto CommandInner; saveStateAndReturn: @@ -2552,6 +2579,8 @@ if (result != BROTLI_DECODER_SUCCESS) { break; } + BROTLI_DCHECK(s->meta_block_remaining_len <= + (int)BROTLI_BLOCK_SIZE_CAP); BROTLI_LOG_UINT(s->is_last_metablock); BROTLI_LOG_UINT(s->meta_block_remaining_len); BROTLI_LOG_UINT(s->is_metadata);
diff --git a/c/include/brotli/decode.h b/c/include/brotli/decode.h index 8d436db..10d01e3 100644 --- a/c/include/brotli/decode.h +++ b/c/include/brotli/decode.h
@@ -85,9 +85,7 @@ BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_1, -14) SEPARATOR \ BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_2, -15) SEPARATOR \ BROTLI_ERROR_CODE(_ERROR_FORMAT_, DISTANCE, -16) SEPARATOR \ - \ - /* -17 code is reserved */ \ - \ + BROTLI_ERROR_CODE(_ERROR_FORMAT_, BLOCK_SWITCH, -17) SEPARATOR \ BROTLI_ERROR_CODE(_ERROR_, COMPOUND_DICTIONARY, -18) SEPARATOR \ BROTLI_ERROR_CODE(_ERROR_, DICTIONARY_NOT_SET, -19) SEPARATOR \ BROTLI_ERROR_CODE(_ERROR_, INVALID_ARGUMENTS, -20) SEPARATOR \