From cfb10566fdb3093363fc39d21a8c5aa5c4deeeeb Mon Sep 17 00:00:00 2001 From: Rutger Broekhoff Date: Fri, 21 May 2021 00:16:17 +0200 Subject: Initial commit --- src/nkeys.zig | 518 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 518 insertions(+) create mode 100644 src/nkeys.zig (limited to 'src/nkeys.zig') diff --git a/src/nkeys.zig b/src/nkeys.zig new file mode 100644 index 0000000..7ce44f9 --- /dev/null +++ b/src/nkeys.zig @@ -0,0 +1,518 @@ +const std = @import("std"); +const ascii = std.ascii; +const base32 = @import("base32.zig"); +const crc16 = @import("crc16.zig"); +const crypto = std.crypto; +const Ed25519 = crypto.sign.Ed25519; +const mem = std.mem; +const testing = std.testing; + +const Error = error{ + InvalidPrefixByte, + InvalidEncoding, + InvalidSeed, + NoNKeySeedFound, + NoNKeyUserSeedFound, +}; + +pub fn fromText(text: []const u8) !Key { + if (!isValidEncoding(text)) return error.InvalidEncoding; + switch (text[0]) { + 'S' => { + // It's a seed. + if (text.len != text_seed_len) return error.InvalidSeed; + return Key{ .seed_key_pair = try fromSeed(text[0..text_seed_len]) }; + }, + 'P' => return error.InvalidEncoding, // unsupported for now + else => { + if (text.len != text_public_len) return error.InvalidEncoding; + return Key{ .public_key = try fromPublicKey(text[0..text_public_len]) }; + }, + } +} + +pub const Key = union(enum) { + seed_key_pair: SeedKeyPair, + public_key: PublicKey, + + const Self = @This(); + + pub fn publicKey(self: *const Self) !text_public { + return switch (self.*) { + .seed_key_pair => |*kp| try kp.publicKey(), + .public_key => |*pk| try pk.publicKey(), + }; + } + + pub fn intoPublicKey(self: *const Self) !PublicKey { + return switch (self.*) { + .seed_key_pair => |*kp| try kp.intoPublicKey(), + .public_key => |pk| pk, + }; + } + + pub fn verify( + self: *const Self, + msg: []const u8, + sig: [Ed25519.signature_length]u8, + ) !void { + return switch (self.*) { + .seed_key_pair => |*kp| try kp.verify(msg, sig), + .public_key => |*pk| try pk.verify(msg, sig), + }; + } + + pub fn wipe(self: *Self) void { + return switch (self.*) { + .seed_key_pair => |*kp| kp.wipe(), + .public_key => |*pk| pk.wipe(), + }; + } +}; + +pub const KeyTypePrefixByte = enum(u8) { + seed = 18 << 3, // S + private = 15 << 3, // P + unknown = 23 << 3, // U +}; + +pub const PublicPrefixByte = enum(u8) { + account = 0, // A + cluster = 2 << 3, // C + operator = 14 << 3, // O + server = 13 << 3, // N + user = 20 << 3, // U + + fn fromU8(b: u8) !PublicPrefixByte { + return switch (b) { + @enumToInt(PublicPrefixByte.server) => .server, + @enumToInt(PublicPrefixByte.cluster) => .cluster, + @enumToInt(PublicPrefixByte.operator) => .operator, + @enumToInt(PublicPrefixByte.account) => .account, + @enumToInt(PublicPrefixByte.user) => .user, + else => error.InvalidPrefixByte, + }; + } +}; + +pub const SeedKeyPair = struct { + const Self = @This(); + + seed: text_seed, + + pub fn init(prefix: PublicPrefixByte) !Self { + var raw_seed: [Ed25519.seed_length]u8 = undefined; + crypto.random.bytes(&raw_seed); + defer wipeBytes(&raw_seed); + + var seed = try encodeSeed(prefix, &raw_seed); + return Self{ .seed = seed }; + } + + pub fn initFromSeed(seed: *const text_seed) !Self { + var decoded = try decodeSeed(seed); + defer decoded.wipe(); + + return Self{ .seed = seed.* }; + } + + fn rawSeed(self: *const Self) ![Ed25519.seed_length]u8 { + return (try decodeSeed(&self.seed)).seed; + } + + fn keys(self: *const Self) !Ed25519.KeyPair { + return Ed25519.KeyPair.create(try rawSeed(self)); + } + + pub fn privateKey(self: *const Self) !text_private { + var kp = try self.keys(); + defer wipeKeyPair(&kp); + return try encodePrivate(&kp.secret_key); + } + + pub fn publicKey(self: *const Self) !text_public { + var decoded = try decodeSeed(&self.seed); + defer decoded.wipe(); + var kp = try Ed25519.KeyPair.create(decoded.seed); + defer wipeKeyPair(&kp); + return try encodePublic(decoded.prefix, &kp.public_key); + } + + pub fn intoPublicKey(self: *const Self) !PublicKey { + var decoded = try decodeSeed(&self.seed); + var kp = try Ed25519.KeyPair.create(decoded.seed); + defer wipeKeyPair(&kp); + return PublicKey{ + .prefix = decoded.prefix, + .key = kp.public_key, + }; + } + + pub fn sign( + self: *const Self, + msg: []const u8, + ) ![Ed25519.signature_length]u8 { + var kp = try self.keys(); + defer wipeKeyPair(&kp); + return try Ed25519.sign(msg, kp, null); + } + + pub fn verify( + self: *const Self, + msg: []const u8, + sig: [Ed25519.signature_length]u8, + ) !void { + var kp = try self.keys(); + defer wipeKeyPair(&kp); + try Ed25519.verify(sig, msg, kp.public_key); + } + + pub fn wipe(self: *Self) void { + wipeBytes(&self.seed); + } + + fn wipeKeyPair(kp: *Ed25519.KeyPair) void { + wipeBytes(&kp.secret_key); + } +}; + +fn wipeBytes(bs: []u8) void { + for (bs) |*b| b.* = 0; +} + +pub const PublicKey = struct { + const Self = @This(); + + prefix: PublicPrefixByte, + key: [Ed25519.public_length]u8, + + pub fn publicKey(self: *const Self) !text_public { + return try encodePublic(self.prefix, &self.key); + } + + pub fn verify( + self: *const Self, + msg: []const u8, + sig: [Ed25519.signature_length]u8, + ) !void { + try Ed25519.verify(sig, msg, self.key); + } + + pub fn wipe(self: *Self) void { + self.prefix = .user; + std.crypto.random.bytes(&self.key); + } +}; + +// One prefix byte, two CRC bytes +const binary_private_size = 1 + Ed25519.secret_length + 2; +// One prefix byte, two CRC bytes +const binary_public_size = 1 + Ed25519.public_length + 2; +// Two prefix bytes, two CRC bytes +const binary_seed_size = 2 + Ed25519.seed_length + 2; + +pub const text_private_len = base32.encodedLen(binary_private_size); +pub const text_public_len = base32.encodedLen(binary_public_size); +pub const text_seed_len = base32.encodedLen(binary_seed_size); + +pub const text_private = [text_private_len]u8; +pub const text_public = [text_public_len]u8; +pub const text_seed = [text_seed_len]u8; + +pub fn encodePublic(prefix: PublicPrefixByte, key: *const [Ed25519.public_length]u8) !text_public { + return encode(1, key.len, &[_]u8{@enumToInt(prefix)}, key); +} + +pub fn encodePrivate(key: *const [Ed25519.secret_length]u8) !text_private { + return encode(1, key.len, &[_]u8{@enumToInt(KeyTypePrefixByte.private)}, key); +} + +fn EncodedKey(comptime prefix_len: usize, comptime data_len: usize) type { + return [base32.encodedLen(prefix_len + data_len + 2)]u8; +} + +fn encode( + comptime prefix_len: usize, + comptime data_len: usize, + prefix: *const [prefix_len]u8, + data: *const [data_len]u8, +) !EncodedKey(prefix_len, data_len) { + var buf: [prefix_len + data_len + 2]u8 = undefined; + defer wipeBytes(&buf); + + mem.copy(u8, &buf, prefix[0..]); + mem.copy(u8, buf[prefix_len..], data[0..]); + var off = prefix_len + data_len; + var checksum = crc16.make(buf[0..off]); + mem.writeIntLittle(u16, buf[buf.len - 2 .. buf.len], checksum); + + var text: EncodedKey(prefix_len, data_len) = undefined; + std.debug.assert(base32.encode(&buf, &text) == text.len); + + return text; +} + +pub fn encodeSeed(prefix: PublicPrefixByte, src: *const [Ed25519.seed_length]u8) !text_seed { + var full_prefix = [_]u8{ + @enumToInt(KeyTypePrefixByte.seed) | (@enumToInt(prefix) >> 5), + (@enumToInt(prefix) & 0b00011111) << 3, + }; + return encode(full_prefix.len, src.len, &full_prefix, src); +} + +pub fn decodePrivate(text: *const text_private) ![Ed25519.secret_length]u8 { + var decoded = try decode(1, Ed25519.secret_length, text); + defer wipeBytes(&decoded.data); + if (decoded.prefix[0] != @enumToInt(KeyTypePrefixByte.private)) + return error.InvalidPrefixByte; + return decoded.data; +} + +pub fn decodePublic(prefix: PublicPrefixByte, text: *const text_public) ![Ed25519.public_length]u8 { + var decoded = try decode(1, Ed25519.public_length, text); + if (decoded.data[0] != @enumToInt(prefix)) + return error.InvalidPrefixByte; + return decoded.data; +} + +fn DecodedNKey(comptime prefix_len: usize, comptime data_len: usize) type { + return struct { + prefix: [prefix_len]u8, + data: [data_len]u8, + }; +} + +fn decode( + comptime prefix_len: usize, + comptime data_len: usize, + text: *const [base32.encodedLen(prefix_len + data_len + 2)]u8, +) !DecodedNKey(prefix_len, data_len) { + var raw: [prefix_len + data_len + 2]u8 = undefined; + defer wipeBytes(&raw); + std.debug.assert((try base32.decode(text[0..], &raw)) == raw.len); + + var checksum = mem.readIntLittle(u16, raw[raw.len - 2 .. raw.len]); + try crc16.validate(raw[0 .. raw.len - 2], checksum); + + return DecodedNKey(prefix_len, data_len){ + .prefix = raw[0..prefix_len].*, + .data = raw[prefix_len .. raw.len - 2].*, + }; +} + +pub const DecodedSeed = struct { + const Self = @This(); + + prefix: PublicPrefixByte, + seed: [Ed25519.seed_length]u8, + + pub fn wipe(self: *Self) void { + self.prefix = .account; + wipeBytes(&self.seed); + } +}; + +pub fn decodeSeed(text: *const text_seed) !DecodedSeed { + var decoded = try decode(2, Ed25519.seed_length, text); + defer wipeBytes(&decoded.data); // gets copied + + var key_ty_prefix = decoded.prefix[0] & 0b11111000; + var entity_ty_prefix = (decoded.prefix[0] & 0b00000111) << 5 | ((decoded.prefix[1] & 0b11111000) >> 3); + + if (key_ty_prefix != @enumToInt(KeyTypePrefixByte.seed)) + return error.InvalidSeed; + + return DecodedSeed{ + .prefix = try PublicPrefixByte.fromU8(entity_ty_prefix), + .seed = decoded.data, + }; +} + +pub fn fromPublicKey(text: *const text_public) !PublicKey { + var decoded = try decode(1, Ed25519.public_length, text); + defer wipeBytes(&decoded.data); // gets copied + + return PublicKey{ + .prefix = try PublicPrefixByte.fromU8(decoded.prefix[0]), + .key = decoded.data, + }; +} + +pub fn fromSeed(text: *const text_seed) !SeedKeyPair { + var res = try decodeSeed(text); + wipeBytes(&res.seed); + return SeedKeyPair{ .seed = text.* }; +} + +pub fn isValidEncoding(text: []const u8) bool { + if (text.len < 4) return false; + var made_crc: u16 = 0; + var dec = base32.Decoder{}; + var crc_buf: [2]u8 = undefined; + var crc_buf_len: u8 = 0; + var expect_len: usize = base32.decodedLen(text.len); + var wrote_n_total: usize = 0; + for (text) |c, i| { + var b = (dec.read(c) catch return false) orelse continue; + wrote_n_total += 1; + if (crc_buf_len == 2) made_crc = crc16.update(made_crc, &.{crc_buf[0]}); + crc_buf[0] = crc_buf[1]; + crc_buf[1] = b; + if (crc_buf_len != 2) crc_buf_len += 1; + } + if (dec.out_off != 0 and wrote_n_total < expect_len) { + if (crc_buf_len == 2) made_crc = crc16.update(made_crc, &.{crc_buf[0]}); + crc_buf[0] = crc_buf[1]; + crc_buf[1] = dec.buf; + if (crc_buf_len != 2) crc_buf_len += 1; + } + if (crc_buf_len != 2) unreachable; + var got_crc = mem.readIntLittle(u16, &crc_buf); + return made_crc == got_crc; +} + +pub fn isValidSeed(text: *const text_seed) bool { + var res = decodeSeed(text) catch return false; + wipeBytes(&res.seed); + return true; +} + +pub fn isValidPublicKey(text: *const text_public, with_type: ?PublicPrefixByte) bool { + var res = decode(1, Ed25519.public_length, text) catch return false; + var public = PublicPrefixByte.fromU8(res.data[0]) catch return false; + return if (with_type) |ty| public == ty else true; +} + +pub fn fromRawSeed(prefix: PublicPrefixByte, raw_seed: *const [Ed25519.seed_length]u8) !SeedKeyPair { + return SeedKeyPair{ .seed = try encodeSeed(prefix, raw_seed) }; +} + +pub fn getNextLine(text: []const u8, off: *usize) ?[]const u8 { + if (off.* <= text.len) return null; + var newline_pos = mem.indexOfPos(u8, text, off.*, "\n") orelse return null; + var start = off.*; + var end = newline_pos; + if (newline_pos > 0 and text[newline_pos - 1] == '\r') end -= 1; + off.* = newline_pos + 1; + return text[start..end]; +} + +// `line` must not contain CR or LF characters. +pub fn isKeySectionBarrier(line: []const u8) bool { + return line.len >= 6 and mem.startsWith(u8, line, "---") and mem.endsWith(u8, line, "---"); +} + +pub fn areKeySectionContentsValid(contents: []const u8) bool { + const allowed_chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.="; + + for (contents) |c| { + var is_c_allowed = false; + for (allowed_chars) |allowed_c| { + if (c == allowed_c) { + is_c_allowed = true; + break; + } + } + if (!is_c_allowed) return false; + } + + return true; +} + +pub fn findKeySection(text: []const u8, off: *usize) ?[]const u8 { + // Skip all space + // Lines end with \n, but \r\n is also fine + // Contents of the key may consist of abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.= + // However, if a line seems to be in the form of ---stuff---, the section is ended. + // A newline must be present at the end of the key footer + // See https://regex101.com/r/pEaqcJ/1 for a weird edge case in the github.com/nats-io/nkeys library + // Another weird edge case: https://regex101.com/r/Xmqj1h/1 + while (true) { + var opening_line = getNextLine(text, off) orelse return null; + if (!isKeySectionBarrier(opening_line)) continue; + + var contents_line = getNextLine(text, off) orelse return null; + if (!areKeySectionContentsValid(contents_line)) continue; + + var closing_line = getNextLine(text, off) orelse return null; + if (!isKeySectionBarrier(closing_line)) continue; + + return contents_line; + } +} + +pub fn parseDecoratedJwt(contents: []const u8) ![]const u8 { + var current_off: usize = 0; + return findKeySection(contents, ¤t_off) orelse return contents; +} + +fn validNKey(text: []const u8) bool { + var valid_prefix = + mem.startsWith(u8, text, "SO") or + mem.startsWith(u8, text, "SA") or + mem.startsWith(u8, text, "SU"); + var valid_len = text.len >= text_seed_len; + return valid_prefix and valid_len; +} + +fn findNKey(text: []const u8) ?[]const u8 { + var current_off: usize = 0; + while (true) { + var line = getNextLine(text, ¤t_off) orelse return null; + for (line) |c, i| { + if (!ascii.isSpace(c)) { + if (validNKey(line[i..])) return line[i..]; + break; + } + } + } +} + +pub fn parseDecoratedNKey(contents: []const u8) !SeedKeyPair { + var current_off: usize = 0; + + var seed: ?[]const u8 = null; + if (findKeySection(contents, ¤t_off) != null) + seed = findKeySection(contents, ¤t_off); + if (seed != null) + seed = findNKey(contents) orelse return error.NoNKeySeedFound; + if (!validNKey(seed.?)) + return error.NoNKeySeedFound; + return fromSeed(contents[0..text_seed_len]); +} + +pub fn parseDecoratedUserNKey(contents: []const u8) !SeedKeyPair { + var key = try parseDecoratedNKey(contents); + if (!mem.startsWith(u8, &key.seed, "SU")) return error.NoNKeyUserSeedFound; + defer key.wipe(); + return key; +} + +test { + testing.refAllDecls(@This()); + testing.refAllDecls(Key); + testing.refAllDecls(SeedKeyPair); + testing.refAllDecls(PublicKey); +} + +test { + var key_pair = try SeedKeyPair.init(PublicPrefixByte.server); + defer key_pair.wipe(); + + var decoded_seed = try decodeSeed(&key_pair.seed); + var encoded_second_time = try encodeSeed(decoded_seed.prefix, &decoded_seed.seed); + try testing.expectEqualSlices(u8, &key_pair.seed, &encoded_second_time); + try testing.expect(isValidEncoding(&key_pair.seed)); + + var pub_key_str_a = try key_pair.publicKey(); + var priv_key_str = try key_pair.privateKey(); + try testing.expect(pub_key_str_a.len != 0); + try testing.expect(priv_key_str.len != 0); + try testing.expect(isValidEncoding(&pub_key_str_a)); + try testing.expect(isValidEncoding(&priv_key_str)); + wipeBytes(&priv_key_str); + + var pub_key = try key_pair.intoPublicKey(); + var pub_key_str_b = try pub_key.publicKey(); + try testing.expectEqualSlices(u8, &pub_key_str_a, &pub_key_str_b); +} -- cgit v1.2.3