| author |  Dominic <4678790+dweiller@users.noreply.github.com> 2023-02-06 13:19:24+11:00 |
| committer | Dominic <4678790+dweiller@users.noreply.github.com> 2023-02-20 09:09:06+11:00 |
| log | 98bbd959b08db4d66a9ae68ce3fe4196594c6d9e |
| tree | b5cd9926fba54cbfbb4b22d89eaafab14dc0a72a |
| parent | ece52e0771560726a72a11cfafb59bb1dc9ad221 |
std.compress.zstandard: improve block size validation
2 files changed, 8 insertions(+), 2 deletions(-)
lib- std
- compress
- zstandard
- decode
- decompress.zig
lib/std/compress/zstandard/decode/block.zig+5-1
| ... | ... | @@ -594,9 +594,9 @@ pub fn decodeBlock( |
| 594 | 594 | block_header: frame.Zstandard.Block.Header, |
| 595 | 595 | decode_state: *DecodeState, |
| 596 | 596 | consumed_count: *usize, |
| 597 | block_size_max: usize, | |
| 597 | 598 | written_count: usize, |
| 598 | 599 | ) (error{DestTooSmall} || Error)!usize { |
| 599 | const block_size_max = @min(1 << 17, dest[written_count..].len); // 128KiB | |
| 600 | 600 | const block_size = block_header.block_size; |
| 601 | 601 | if (block_size_max < block_size) return error.BlockSizeOverMaximum; |
| 602 | 602 | switch (block_header.block_type) { |
| ... | ... | @@ -805,6 +805,7 @@ pub fn decodeBlockReader( |
| 805 | 805 | |
| 806 | 806 | try decode_state.prepare(block_reader, literals, sequences_header); |
| 807 | 807 | |
| 808 | var bytes_written: usize = 0; | |
| 808 | 809 | if (sequences_header.sequence_count > 0) { |
| 809 | 810 | if (sequence_buffer.len < block_reader_limited.bytes_left) |
| 810 | 811 | return error.SequenceBufferTooSmall; |
| ... | ... | @@ -825,6 +826,7 @@ pub fn decodeBlockReader( |
| 825 | 826 | i == sequences_header.sequence_count - 1, |
| 826 | 827 | ) catch return error.MalformedCompressedBlock; |
| 827 | 828 | sequence_size_limit -= decompressed_size; |
| 829 | bytes_written += decompressed_size; | |
| 828 | 830 | } |
| 829 | 831 | } |
| 830 | 832 | |
| ... | ... | @@ -832,8 +834,10 @@ pub fn decodeBlockReader( |
| 832 | 834 | const len = literals.header.regenerated_size - decode_state.literal_written_count; |
| 833 | 835 | decode_state.decodeLiteralsRingBuffer(dest, len) catch |
| 834 | 836 | return error.MalformedCompressedBlock; |
| 837 | bytes_written += len; | |
| 835 | 838 | } |
| 836 | 839 | |
| 840 | if (bytes_written > block_size_max) return error.BlockSizeOverMaximum; | |
| 837 | 841 | decode_state.literal_written_count = 0; |
| 838 | 842 | assert(block_reader.readByte() == error.EndOfStream); |
| 839 | 843 | }, |
lib/std/compress/zstandard/decompress.zig+3-1
| ... | ... | @@ -236,6 +236,7 @@ pub fn decodeZstandardFrame( |
| 236 | 236 | src[consumed_count..], |
| 237 | 237 | &consumed_count, |
| 238 | 238 | if (frame_context.hasher_opt) |*hasher| hasher else null, |
| 239 | frame_context.block_size_max, | |
| 239 | 240 | ) catch |err| switch (err) { |
| 240 | 241 | error.DestTooSmall => return error.BadContentSize, |
| 241 | 242 | inline else => |e| return e, |
| ... | ... | @@ -376,7 +377,6 @@ pub fn decodeZstandardFrameArrayList( |
| 376 | 377 | block_header = try block.decodeBlockHeaderSlice(src[consumed_count..]); |
| 377 | 378 | consumed_count += 3; |
| 378 | 379 | }) { |
| 379 | if (block_header.block_size > frame_context.block_size_max) return error.BlockSizeOverMaximum; | |
| 380 | 380 | const written_size = try block.decodeBlockRingBuffer( |
| 381 | 381 | &ring_buffer, |
| 382 | 382 | src[consumed_count..], |
| ... | ... | @@ -420,6 +420,7 @@ fn decodeFrameBlocks( |
| 420 | 420 | src: []const u8, |
| 421 | 421 | consumed_count: *usize, |
| 422 | 422 | hash: ?*std.hash.XxHash64, |
| 423 | block_size_max: usize, | |
| 423 | 424 | ) (error{ EndOfStream, DestTooSmall } || block.Error)!usize { |
| 424 | 425 | // These tables take 7680 bytes |
| 425 | 426 | var literal_fse_data: [types.compressed_block.table_size_max.literal]Table.Fse = undefined; |
| ... | ... | @@ -441,6 +442,7 @@ fn decodeFrameBlocks( |
| 441 | 442 | block_header, |
| 442 | 443 | &decode_state, |
| 443 | 444 | &bytes_read, |
| 445 | block_size_max, | |
| 444 | 446 | written_count, |
| 445 | 447 | ); |
| 446 | 448 | if (hash) |hash_state| hash_state.update(dest[written_count .. written_count + written_size]); |