authorgravatar for 4678790+dweiller@users.noreply.github.comDominic <4678790+dweiller@users.noreply.github.com> 2023-02-03 15:35:30+11:00
committergravatar for 4678790+dweiller@users.noreply.github.comDominic <4678790+dweiller@users.noreply.github.com> 2023-02-20 09:09:06+11:00
log1c509f483aef8b826f02ffc7ab8d1f2cfcec0d36
tree697a1d231ef9bc57444ce84f35035ffa8800b094
parent596a97fb556a380d9f3780363ee07fc5dfaf43c2

std.compress.zstandard: fix crashes

2 files changed, 10 insertions(+), 6 deletions(-)

lib/std/compress/zstandard/decode/block.zig+2
......@@ -981,6 +981,8 @@ fn decodeStreams(size_format: u2, stream_data: []const u8) !LiteralsSection.Stre
981981 const stream_3_start = stream_2_start + stream_2_length;
982982 const stream_4_start = stream_3_start + stream_3_length;
983983
984 if (stream_data.len < stream_4_start) return error.MalformedLiteralsSection;
985
984986 return .{ .four = .{
985987 stream_data[stream_1_start .. stream_1_start + stream_1_length],
986988 stream_data[stream_2_start .. stream_2_start + stream_2_length],
lib/std/compress/zstandard/decode/huffman.zig+8-6
......@@ -59,7 +59,7 @@ fn assignWeights(huff_bits: *readers.ReverseBitReader, accuracy_log: usize, entr
5959 var even_state: u32 = huff_bits.readBitsNoEof(u32, accuracy_log) catch return error.MalformedHuffmanTree;
6060 var odd_state: u32 = huff_bits.readBitsNoEof(u32, accuracy_log) catch return error.MalformedHuffmanTree;
6161
62 while (i < 255) {
62 while (i < 254) {
6363 const even_data = entries[even_state];
6464 var read_bits: usize = 0;
6565 const even_bits = huff_bits.readBits(u32, even_data.bits, &read_bits) catch unreachable;
......@@ -78,7 +78,7 @@ fn assignWeights(huff_bits: *readers.ReverseBitReader, accuracy_log: usize, entr
7878 weights[i] = std.math.cast(u4, odd_data.symbol) orelse return error.MalformedHuffmanTree;
7979 i += 1;
8080 if (read_bits < odd_data.bits) {
81 if (i == 256) return error.MalformedHuffmanTree;
81 if (i == 255) return error.MalformedHuffmanTree;
8282 weights[i] = std.math.cast(u4, entries[even_state].symbol) orelse return error.MalformedHuffmanTree;
8383 i += 1;
8484 break;
......@@ -147,16 +147,18 @@ fn assignSymbols(weight_sorted_prefixed_symbols: []LiteralsSection.HuffmanTree.P
147147}
148148
149149fn buildHuffmanTree(weights: *[256]u4, symbol_count: usize) error{MalformedHuffmanTree}!LiteralsSection.HuffmanTree {
150 var weight_power_sum: u16 = 0;
150 var weight_power_sum_big: u32 = 0;
151151 for (weights[0 .. symbol_count - 1]) |value| {
152152 if (value > 0) {
153 weight_power_sum += @as(u16, 1) << (value - 1);
153 weight_power_sum_big += @as(u16, 1) << (value - 1);
154154 }
155155 }
156 if (weight_power_sum >= 1 << 11) return error.MalformedHuffmanTree;
156 if (weight_power_sum_big >= 1 << 11) return error.MalformedHuffmanTree;
157 const weight_power_sum = @intCast(u16, weight_power_sum_big);
157158
158159 // advance to next power of two (even if weight_power_sum is a power of 2)
159 const max_number_of_bits = std.math.log2_int(u16, weight_power_sum) + 1;
160 // TODO: is it valid to have weight_power_sum == 0?
161 const max_number_of_bits = if (weight_power_sum == 0) 1 else std.math.log2_int(u16, weight_power_sum) + 1;
160162 const next_power_of_two = @as(u16, 1) << max_number_of_bits;
161163 weights[symbol_count - 1] = std.math.log2_int(u16, next_power_of_two - weight_power_sum) + 1;
162164