std.crypto.tls: validate previous certificate

This commit is contained in:
Andrew Kelley 2022-12-21 17:12:34 -07:00
parent 4f9f4575bd
commit 29475b4518
7 changed files with 679 additions and 622 deletions

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@ -177,8 +177,8 @@ const std = @import("std.zig");
pub const errors = @import("crypto/errors.zig");
pub const tls = @import("crypto/tls.zig");
pub const Der = @import("crypto/Der.zig");
pub const CertificateBundle = @import("crypto/CertificateBundle.zig");
pub const der = @import("crypto/der.zig");
pub const Certificate = @import("crypto/Certificate.zig");
test {
_ = aead.aegis.Aegis128L;
@ -269,8 +269,8 @@ test {
_ = random;
_ = errors;
_ = tls;
_ = Der;
_ = CertificateBundle;
_ = der;
_ = Certificate;
}
test "CSPRNG" {

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@ -0,0 +1,446 @@
buffer: []const u8,
index: u32,
pub const Bundle = @import("Certificate/Bundle.zig");
pub const Algorithm = enum {
sha1WithRSAEncryption,
sha224WithRSAEncryption,
sha256WithRSAEncryption,
sha384WithRSAEncryption,
sha512WithRSAEncryption,
pub const map = std.ComptimeStringMap(Algorithm, .{
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05 }, .sha1WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0B }, .sha256WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0C }, .sha384WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0D }, .sha512WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0E }, .sha224WithRSAEncryption },
});
pub fn Hash(comptime algorithm: Algorithm) type {
return switch (algorithm) {
.sha1WithRSAEncryption => crypto.hash.Sha1,
.sha224WithRSAEncryption => crypto.hash.sha2.Sha224,
.sha256WithRSAEncryption => crypto.hash.sha2.Sha256,
.sha384WithRSAEncryption => crypto.hash.sha2.Sha384,
.sha512WithRSAEncryption => crypto.hash.sha2.Sha512,
};
}
};
pub const AlgorithmCategory = enum {
rsaEncryption,
X9_62_id_ecPublicKey,
pub const map = std.ComptimeStringMap(AlgorithmCategory, .{
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01 }, .rsaEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x02, 0x01 }, .X9_62_id_ecPublicKey },
});
};
pub const Attribute = enum {
commonName,
serialNumber,
countryName,
localityName,
stateOrProvinceName,
organizationName,
organizationalUnitName,
organizationIdentifier,
pub const map = std.ComptimeStringMap(Attribute, .{
.{ &[_]u8{ 0x55, 0x04, 0x03 }, .commonName },
.{ &[_]u8{ 0x55, 0x04, 0x05 }, .serialNumber },
.{ &[_]u8{ 0x55, 0x04, 0x06 }, .countryName },
.{ &[_]u8{ 0x55, 0x04, 0x07 }, .localityName },
.{ &[_]u8{ 0x55, 0x04, 0x08 }, .stateOrProvinceName },
.{ &[_]u8{ 0x55, 0x04, 0x0A }, .organizationName },
.{ &[_]u8{ 0x55, 0x04, 0x0B }, .organizationalUnitName },
.{ &[_]u8{ 0x55, 0x04, 0x61 }, .organizationIdentifier },
});
};
pub const Parsed = struct {
certificate: Certificate,
issuer_slice: Slice,
subject_slice: Slice,
common_name_slice: Slice,
signature_slice: Slice,
signature_algorithm: Algorithm,
pub_key_algo: AlgorithmCategory,
pub_key_slice: Slice,
message_slice: Slice,
pub const Slice = der.Element.Slice;
pub fn slice(p: Parsed, s: Slice) []const u8 {
return p.certificate.buffer[s.start..s.end];
}
pub fn issuer(p: Parsed) []const u8 {
return p.slice(p.issuer_slice);
}
pub fn subject(p: Parsed) []const u8 {
return p.slice(p.subject_slice);
}
pub fn commonName(p: Parsed) []const u8 {
return p.slice(p.common_name_slice);
}
pub fn signature(p: Parsed) []const u8 {
return p.slice(p.signature_slice);
}
pub fn pubKey(p: Parsed) []const u8 {
return p.slice(p.pub_key_slice);
}
pub fn message(p: Parsed) []const u8 {
return p.slice(p.message_slice);
}
pub fn verify(parsed_subject: Parsed, parsed_issuer: Parsed) !void {
// Check that the subject's issuer name matches the issuer's
// subject name.
if (!mem.eql(u8, parsed_subject.issuer(), parsed_issuer.subject())) {
return error.CertificateIssuerMismatch;
}
// TODO check the time validity for the subject
// TODO check the time validity for the issuer
switch (parsed_subject.signature_algorithm) {
inline .sha1WithRSAEncryption,
.sha224WithRSAEncryption,
.sha256WithRSAEncryption,
.sha384WithRSAEncryption,
.sha512WithRSAEncryption,
=> |algorithm| return verifyRsa(
algorithm.Hash(),
parsed_subject.message(),
parsed_subject.signature(),
parsed_issuer.pub_key_algo,
parsed_issuer.pubKey(),
),
}
}
};
pub fn parse(cert: Certificate) !Parsed {
const cert_bytes = cert.buffer;
const certificate = try der.parseElement(cert_bytes, cert.index);
const tbs_certificate = try der.parseElement(cert_bytes, certificate.slice.start);
const version = try der.parseElement(cert_bytes, tbs_certificate.slice.start);
try checkVersion(cert_bytes, version);
const serial_number = try der.parseElement(cert_bytes, version.slice.end);
// RFC 5280, section 4.1.2.3:
// "This field MUST contain the same algorithm identifier as
// the signatureAlgorithm field in the sequence Certificate."
const tbs_signature = try der.parseElement(cert_bytes, serial_number.slice.end);
const issuer = try der.parseElement(cert_bytes, tbs_signature.slice.end);
const validity = try der.parseElement(cert_bytes, issuer.slice.end);
const subject = try der.parseElement(cert_bytes, validity.slice.end);
const pub_key_info = try der.parseElement(cert_bytes, subject.slice.end);
const pub_key_signature_algorithm = try der.parseElement(cert_bytes, pub_key_info.slice.start);
const pub_key_algo_elem = try der.parseElement(cert_bytes, pub_key_signature_algorithm.slice.start);
const pub_key_algo = try parseAlgorithmCategory(cert_bytes, pub_key_algo_elem);
const pub_key_elem = try der.parseElement(cert_bytes, pub_key_signature_algorithm.slice.end);
const pub_key = try parseBitString(cert, pub_key_elem);
const rdn = try der.parseElement(cert_bytes, subject.slice.start);
const atav = try der.parseElement(cert_bytes, rdn.slice.start);
var common_name = der.Element.Slice.empty;
var atav_i = atav.slice.start;
while (atav_i < atav.slice.end) {
const ty_elem = try der.parseElement(cert_bytes, atav_i);
const ty = try parseAttribute(cert_bytes, ty_elem);
const val = try der.parseElement(cert_bytes, ty_elem.slice.end);
switch (ty) {
.commonName => common_name = val.slice,
else => {},
}
atav_i = val.slice.end;
}
const sig_algo = try der.parseElement(cert_bytes, tbs_certificate.slice.end);
const algo_elem = try der.parseElement(cert_bytes, sig_algo.slice.start);
const signature_algorithm = try parseAlgorithm(cert_bytes, algo_elem);
const sig_elem = try der.parseElement(cert_bytes, sig_algo.slice.end);
const signature = try parseBitString(cert, sig_elem);
return .{
.certificate = cert,
.common_name_slice = common_name,
.issuer_slice = issuer.slice,
.subject_slice = subject.slice,
.signature_slice = signature,
.signature_algorithm = signature_algorithm,
.message_slice = .{ .start = certificate.slice.start, .end = tbs_certificate.slice.end },
.pub_key_algo = pub_key_algo,
.pub_key_slice = pub_key,
};
}
pub fn verify(subject: Certificate, issuer: Certificate) !void {
const parsed_subject = try subject.parse();
const parsed_issuer = try issuer.parse();
return parsed_subject.verify(parsed_issuer);
}
pub fn contents(cert: Certificate, elem: der.Element) []const u8 {
return cert.buffer[elem.start..elem.end];
}
pub fn parseBitString(cert: Certificate, elem: der.Element) !der.Element.Slice {
if (elem.identifier.tag != .bitstring) return error.CertificateFieldHasWrongDataType;
if (cert.buffer[elem.slice.start] != 0) return error.CertificateHasInvalidBitString;
return .{ .start = elem.slice.start + 1, .end = elem.slice.end };
}
pub fn parseAlgorithm(bytes: []const u8, element: der.Element) !Algorithm {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return Algorithm.map.get(bytes[element.slice.start..element.slice.end]) orelse
return error.CertificateHasUnrecognizedAlgorithm;
}
pub fn parseAlgorithmCategory(bytes: []const u8, element: der.Element) !AlgorithmCategory {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return AlgorithmCategory.map.get(bytes[element.slice.start..element.slice.end]) orelse
return error.CertificateHasUnrecognizedAlgorithmCategory;
}
pub fn parseAttribute(bytes: []const u8, element: der.Element) !Attribute {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return Attribute.map.get(bytes[element.slice.start..element.slice.end]) orelse
return error.CertificateHasUnrecognizedAlgorithm;
}
fn verifyRsa(comptime Hash: type, message: []const u8, sig: []const u8, pub_key_algo: AlgorithmCategory, pub_key: []const u8) !void {
if (pub_key_algo != .rsaEncryption) return error.CertificateSignatureAlgorithmMismatch;
const pub_key_seq = try der.parseElement(pub_key, 0);
if (pub_key_seq.identifier.tag != .sequence) return error.CertificateFieldHasWrongDataType;
const modulus_elem = try der.parseElement(pub_key, pub_key_seq.slice.start);
if (modulus_elem.identifier.tag != .integer) return error.CertificateFieldHasWrongDataType;
const exponent_elem = try der.parseElement(pub_key, modulus_elem.slice.end);
if (exponent_elem.identifier.tag != .integer) return error.CertificateFieldHasWrongDataType;
// Skip over meaningless zeroes in the modulus.
const modulus_raw = pub_key[modulus_elem.slice.start..modulus_elem.slice.end];
const modulus_offset = for (modulus_raw) |byte, i| {
if (byte != 0) break i;
} else modulus_raw.len;
const modulus = modulus_raw[modulus_offset..];
const exponent = pub_key[exponent_elem.slice.start..exponent_elem.slice.end];
if (exponent.len > modulus.len) return error.CertificatePublicKeyInvalid;
if (sig.len != modulus.len) return error.CertificateSignatureInvalidLength;
const hash_der = switch (Hash) {
crypto.hash.Sha1 => [_]u8{
0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e,
0x03, 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14,
},
crypto.hash.sha2.Sha224 => [_]u8{
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, 0x05,
0x00, 0x04, 0x1c,
},
crypto.hash.sha2.Sha256 => [_]u8{
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
0x00, 0x04, 0x20,
},
crypto.hash.sha2.Sha384 => [_]u8{
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, 0x05,
0x00, 0x04, 0x30,
},
crypto.hash.sha2.Sha512 => [_]u8{
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05,
0x00, 0x04, 0x40,
},
else => @compileError("unreachable"),
};
var msg_hashed: [Hash.digest_length]u8 = undefined;
Hash.hash(message, &msg_hashed, .{});
switch (modulus.len) {
inline 128, 256, 512 => |modulus_len| {
const ps_len = modulus_len - (hash_der.len + msg_hashed.len) - 3;
const em: [modulus_len]u8 =
[2]u8{ 0, 1 } ++
([1]u8{0xff} ** ps_len) ++
[1]u8{0} ++
hash_der ++
msg_hashed;
const public_key = try rsa.PublicKey.fromBytes(exponent, modulus, rsa.poop);
const em_dec = try rsa.encrypt(modulus_len, sig[0..modulus_len].*, public_key, rsa.poop);
if (!mem.eql(u8, &em, &em_dec)) {
try std.testing.expectEqualSlices(u8, &em, &em_dec);
return error.CertificateSignatureInvalid;
}
},
else => {
return error.CertificateSignatureUnsupportedBitCount;
},
}
}
pub fn checkVersion(bytes: []const u8, version: der.Element) !void {
if (@bitCast(u8, version.identifier) != 0xa0 or
!mem.eql(u8, bytes[version.slice.start..version.slice.end], "\x02\x01\x02"))
{
return error.UnsupportedCertificateVersion;
}
}
const std = @import("../std.zig");
const crypto = std.crypto;
const mem = std.mem;
const der = std.crypto.der;
const Certificate = @This();
/// TODO: replace this with Frank's upcoming RSA implementation. the verify
/// function won't have the possibility of failure - it will either identify a
/// valid signature or an invalid signature.
/// This code is borrowed from https://github.com/shiguredo/tls13-zig
/// which is licensed under the Apache License Version 2.0, January 2004
/// http://www.apache.org/licenses/
/// The code has been modified.
const rsa = struct {
const BigInt = std.math.big.int.Managed;
const PublicKey = struct {
n: BigInt,
e: BigInt,
pub fn deinit(self: *PublicKey) void {
self.n.deinit();
self.e.deinit();
}
pub fn fromBytes(pub_bytes: []const u8, modulus_bytes: []const u8, allocator: std.mem.Allocator) !PublicKey {
var _n = try BigInt.init(allocator);
errdefer _n.deinit();
try setBytes(&_n, modulus_bytes, allocator);
var _e = try BigInt.init(allocator);
errdefer _e.deinit();
try setBytes(&_e, pub_bytes, allocator);
return .{
.n = _n,
.e = _e,
};
}
};
fn encrypt(comptime modulus_len: usize, msg: [modulus_len]u8, public_key: PublicKey, allocator: std.mem.Allocator) ![modulus_len]u8 {
var m = try BigInt.init(allocator);
defer m.deinit();
try setBytes(&m, &msg, allocator);
if (m.order(public_key.n) != .lt) {
return error.MessageTooLong;
}
var e = try BigInt.init(allocator);
defer e.deinit();
try pow_montgomery(&e, &m, &public_key.e, &public_key.n, allocator);
var res: [modulus_len]u8 = undefined;
try toBytes(&res, &e, allocator);
return res;
}
fn setBytes(r: *BigInt, bytes: []const u8, allcator: std.mem.Allocator) !void {
try r.set(0);
var tmp = try BigInt.init(allcator);
defer tmp.deinit();
for (bytes) |b| {
try r.shiftLeft(r, 8);
try tmp.set(b);
try r.add(r, &tmp);
}
}
fn pow_montgomery(r: *BigInt, a: *const BigInt, x: *const BigInt, n: *const BigInt, allocator: std.mem.Allocator) !void {
var bin_raw: [512]u8 = undefined;
try toBytes(&bin_raw, x, allocator);
var i: usize = 0;
while (bin_raw[i] == 0x00) : (i += 1) {}
const bin = bin_raw[i..];
try r.set(1);
var r1 = try BigInt.init(allocator);
defer r1.deinit();
try BigInt.copy(&r1, a.toConst());
i = 0;
while (i < bin.len * 8) : (i += 1) {
if (((bin[i / 8] >> @intCast(u3, (7 - (i % 8)))) & 0x1) == 0) {
try BigInt.mul(&r1, r, &r1);
try mod(&r1, &r1, n, allocator);
try BigInt.sqr(r, r);
try mod(r, r, n, allocator);
} else {
try BigInt.mul(r, r, &r1);
try mod(r, r, n, allocator);
try BigInt.sqr(&r1, &r1);
try mod(&r1, &r1, n, allocator);
}
}
}
fn toBytes(out: []u8, a: *const BigInt, allocator: std.mem.Allocator) !void {
const Error = error{
BufferTooSmall,
};
var mask = try BigInt.initSet(allocator, 0xFF);
defer mask.deinit();
var tmp = try BigInt.init(allocator);
defer tmp.deinit();
var a_copy = try BigInt.init(allocator);
defer a_copy.deinit();
try a_copy.copy(a.toConst());
// Encoding into big-endian bytes
var i: usize = 0;
while (i < out.len) : (i += 1) {
try tmp.bitAnd(&a_copy, &mask);
const b = try tmp.to(u8);
out[out.len - i - 1] = b;
try a_copy.shiftRight(&a_copy, 8);
}
if (!a_copy.eqZero()) {
return Error.BufferTooSmall;
}
}
fn mod(rem: *BigInt, a: *const BigInt, n: *const BigInt, allocator: std.mem.Allocator) !void {
var q = try BigInt.init(allocator);
defer q.deinit();
try BigInt.divFloor(&q, rem, a, n);
}
// TODO: flush the toilet
const poop = std.heap.page_allocator;
};

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@ -0,0 +1,174 @@
//! A set of certificates. Typically pre-installed on every operating system,
//! these are "Certificate Authorities" used to validate SSL certificates.
//! This data structure stores certificates in DER-encoded form, all of them
//! concatenated together in the `bytes` array. The `map` field contains an
//! index from the DER-encoded subject name to the index of the containing
//! certificate within `bytes`.
/// The key is the contents slice of the subject.
map: std.HashMapUnmanaged(der.Element.Slice, u32, MapContext, std.hash_map.default_max_load_percentage) = .{},
bytes: std.ArrayListUnmanaged(u8) = .{},
pub fn verify(cb: Bundle, subject: Certificate.Parsed) !void {
const bytes_index = cb.find(subject.issuer()) orelse return error.IssuerNotFound;
const issuer_cert: Certificate = .{
.buffer = cb.bytes.items,
.index = bytes_index,
};
const issuer = try issuer_cert.parse();
try subject.verify(issuer);
}
/// The returned bytes become invalid after calling any of the rescan functions
/// or add functions.
pub fn find(cb: Bundle, subject_name: []const u8) ?u32 {
const Adapter = struct {
cb: Bundle,
pub fn hash(ctx: @This(), k: []const u8) u64 {
_ = ctx;
return std.hash_map.hashString(k);
}
pub fn eql(ctx: @This(), a: []const u8, b_key: der.Element.Slice) bool {
const b = ctx.cb.bytes.items[b_key.start..b_key.end];
return mem.eql(u8, a, b);
}
};
return cb.map.getAdapted(subject_name, Adapter{ .cb = cb });
}
pub fn deinit(cb: *Bundle, gpa: Allocator) void {
cb.map.deinit(gpa);
cb.bytes.deinit(gpa);
cb.* = undefined;
}
/// Empties the set of certificates and then scans the host operating system
/// file system standard locations for certificates.
pub fn rescan(cb: *Bundle, gpa: Allocator) !void {
switch (builtin.os.tag) {
.linux => return rescanLinux(cb, gpa),
else => @compileError("it is unknown where the root CA certificates live on this OS"),
}
}
pub fn rescanLinux(cb: *Bundle, gpa: Allocator) !void {
var dir = fs.openIterableDirAbsolute("/etc/ssl/certs", .{}) catch |err| switch (err) {
error.FileNotFound => return,
else => |e| return e,
};
defer dir.close();
cb.bytes.clearRetainingCapacity();
cb.map.clearRetainingCapacity();
var it = dir.iterate();
while (try it.next()) |entry| {
switch (entry.kind) {
.File, .SymLink => {},
else => continue,
}
try addCertsFromFile(cb, gpa, dir.dir, entry.name);
}
cb.bytes.shrinkAndFree(gpa, cb.bytes.items.len);
}
pub fn addCertsFromFile(
cb: *Bundle,
gpa: Allocator,
dir: fs.Dir,
sub_file_path: []const u8,
) !void {
var file = try dir.openFile(sub_file_path, .{});
defer file.close();
const size = try file.getEndPos();
// We borrow `bytes` as a temporary buffer for the base64-encoded data.
// This is possible by computing the decoded length and reserving the space
// for the decoded bytes first.
const decoded_size_upper_bound = size / 4 * 3;
try cb.bytes.ensureUnusedCapacity(gpa, decoded_size_upper_bound + size);
const end_reserved = cb.bytes.items.len + decoded_size_upper_bound;
const buffer = cb.bytes.allocatedSlice()[end_reserved..];
const end_index = try file.readAll(buffer);
const encoded_bytes = buffer[0..end_index];
const begin_marker = "-----BEGIN CERTIFICATE-----";
const end_marker = "-----END CERTIFICATE-----";
var start_index: usize = 0;
while (mem.indexOfPos(u8, encoded_bytes, start_index, begin_marker)) |begin_marker_start| {
const cert_start = begin_marker_start + begin_marker.len;
const cert_end = mem.indexOfPos(u8, encoded_bytes, cert_start, end_marker) orelse
return error.MissingEndCertificateMarker;
start_index = cert_end + end_marker.len;
const encoded_cert = mem.trim(u8, encoded_bytes[cert_start..cert_end], " \t\r\n");
const decoded_start = @intCast(u32, cb.bytes.items.len);
const dest_buf = cb.bytes.allocatedSlice()[decoded_start..];
cb.bytes.items.len += try base64.decode(dest_buf, encoded_cert);
const k = try cb.key(decoded_start);
const gop = try cb.map.getOrPutContext(gpa, k, .{ .cb = cb });
if (gop.found_existing) {
cb.bytes.items.len = decoded_start;
} else {
gop.value_ptr.* = decoded_start;
}
}
}
pub fn key(cb: Bundle, bytes_index: u32) !der.Element.Slice {
const bytes = cb.bytes.items;
const certificate = try der.parseElement(bytes, bytes_index);
const tbs_certificate = try der.parseElement(bytes, certificate.slice.start);
const version = try der.parseElement(bytes, tbs_certificate.slice.start);
try Certificate.checkVersion(bytes, version);
const serial_number = try der.parseElement(bytes, version.slice.end);
const signature = try der.parseElement(bytes, serial_number.slice.end);
const issuer = try der.parseElement(bytes, signature.slice.end);
const validity = try der.parseElement(bytes, issuer.slice.end);
const subject = try der.parseElement(bytes, validity.slice.end);
return subject.slice;
}
const builtin = @import("builtin");
const std = @import("../../std.zig");
const fs = std.fs;
const mem = std.mem;
const crypto = std.crypto;
const Allocator = std.mem.Allocator;
const der = std.crypto.der;
const Certificate = std.crypto.Certificate;
const Bundle = @This();
const base64 = std.base64.standard.decoderWithIgnore(" \t\r\n");
const MapContext = struct {
cb: *const Bundle,
pub fn hash(ctx: MapContext, k: der.Element.Slice) u64 {
return std.hash_map.hashString(ctx.cb.bytes.items[k.start..k.end]);
}
pub fn eql(ctx: MapContext, a: der.Element.Slice, b: der.Element.Slice) bool {
const bytes = ctx.cb.bytes.items;
return mem.eql(
u8,
bytes[a.start..a.end],
bytes[b.start..b.end],
);
}
};
test "scan for OS-provided certificates" {
if (builtin.os.tag == .wasi) return error.SkipZigTest;
var bundle: Bundle = .{};
defer bundle.deinit(std.testing.allocator);
try bundle.rescan(std.testing.allocator);
}

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@ -1,593 +0,0 @@
//! A set of certificates. Typically pre-installed on every operating system,
//! these are "Certificate Authorities" used to validate SSL certificates.
//! This data structure stores certificates in DER-encoded form, all of them
//! concatenated together in the `bytes` array. The `map` field contains an
//! index from the DER-encoded subject name to the index of the containing
//! certificate within `bytes`.
map: std.HashMapUnmanaged(Key, u32, MapContext, std.hash_map.default_max_load_percentage) = .{},
bytes: std.ArrayListUnmanaged(u8) = .{},
pub const Key = struct {
subject_start: u32,
subject_end: u32,
};
pub fn verify(cb: CertificateBundle, subject: Certificate.Parsed) !void {
const bytes_index = cb.find(subject.issuer) orelse return error.IssuerNotFound;
const issuer_cert: Certificate = .{
.buffer = cb.bytes.items,
.index = bytes_index,
};
const issuer = try issuer_cert.parse();
try subject.verify(issuer);
}
/// The returned bytes become invalid after calling any of the rescan functions
/// or add functions.
pub fn find(cb: CertificateBundle, subject_name: []const u8) ?u32 {
const Adapter = struct {
cb: CertificateBundle,
pub fn hash(ctx: @This(), k: []const u8) u64 {
_ = ctx;
return std.hash_map.hashString(k);
}
pub fn eql(ctx: @This(), a: []const u8, b_key: Key) bool {
const b = ctx.cb.bytes.items[b_key.subject_start..b_key.subject_end];
return mem.eql(u8, a, b);
}
};
return cb.map.getAdapted(subject_name, Adapter{ .cb = cb });
}
pub fn deinit(cb: *CertificateBundle, gpa: Allocator) void {
cb.map.deinit(gpa);
cb.bytes.deinit(gpa);
cb.* = undefined;
}
/// Empties the set of certificates and then scans the host operating system
/// file system standard locations for certificates.
pub fn rescan(cb: *CertificateBundle, gpa: Allocator) !void {
switch (builtin.os.tag) {
.linux => return rescanLinux(cb, gpa),
else => @compileError("it is unknown where the root CA certificates live on this OS"),
}
}
pub fn rescanLinux(cb: *CertificateBundle, gpa: Allocator) !void {
var dir = fs.openIterableDirAbsolute("/etc/ssl/certs", .{}) catch |err| switch (err) {
error.FileNotFound => return,
else => |e| return e,
};
defer dir.close();
cb.bytes.clearRetainingCapacity();
cb.map.clearRetainingCapacity();
var it = dir.iterate();
while (try it.next()) |entry| {
switch (entry.kind) {
.File, .SymLink => {},
else => continue,
}
try addCertsFromFile(cb, gpa, dir.dir, entry.name);
}
cb.bytes.shrinkAndFree(gpa, cb.bytes.items.len);
}
pub fn addCertsFromFile(
cb: *CertificateBundle,
gpa: Allocator,
dir: fs.Dir,
sub_file_path: []const u8,
) !void {
var file = try dir.openFile(sub_file_path, .{});
defer file.close();
const size = try file.getEndPos();
// We borrow `bytes` as a temporary buffer for the base64-encoded data.
// This is possible by computing the decoded length and reserving the space
// for the decoded bytes first.
const decoded_size_upper_bound = size / 4 * 3;
try cb.bytes.ensureUnusedCapacity(gpa, decoded_size_upper_bound + size);
const end_reserved = cb.bytes.items.len + decoded_size_upper_bound;
const buffer = cb.bytes.allocatedSlice()[end_reserved..];
const end_index = try file.readAll(buffer);
const encoded_bytes = buffer[0..end_index];
const begin_marker = "-----BEGIN CERTIFICATE-----";
const end_marker = "-----END CERTIFICATE-----";
var start_index: usize = 0;
while (mem.indexOfPos(u8, encoded_bytes, start_index, begin_marker)) |begin_marker_start| {
const cert_start = begin_marker_start + begin_marker.len;
const cert_end = mem.indexOfPos(u8, encoded_bytes, cert_start, end_marker) orelse
return error.MissingEndCertificateMarker;
start_index = cert_end + end_marker.len;
const encoded_cert = mem.trim(u8, encoded_bytes[cert_start..cert_end], " \t\r\n");
const decoded_start = @intCast(u32, cb.bytes.items.len);
const dest_buf = cb.bytes.allocatedSlice()[decoded_start..];
cb.bytes.items.len += try base64.decode(dest_buf, encoded_cert);
const k = try cb.key(decoded_start);
const gop = try cb.map.getOrPutContext(gpa, k, .{ .cb = cb });
if (gop.found_existing) {
cb.bytes.items.len = decoded_start;
} else {
gop.value_ptr.* = decoded_start;
}
}
}
pub fn key(cb: CertificateBundle, bytes_index: u32) !Key {
const bytes = cb.bytes.items;
const certificate = try Der.parseElement(bytes, bytes_index);
const tbs_certificate = try Der.parseElement(bytes, certificate.start);
const version = try Der.parseElement(bytes, tbs_certificate.start);
try checkVersion(bytes, version);
const serial_number = try Der.parseElement(bytes, version.end);
const signature = try Der.parseElement(bytes, serial_number.end);
const issuer = try Der.parseElement(bytes, signature.end);
const validity = try Der.parseElement(bytes, issuer.end);
const subject = try Der.parseElement(bytes, validity.end);
return .{
.subject_start = subject.start,
.subject_end = subject.end,
};
}
pub const Certificate = struct {
buffer: []const u8,
index: u32,
pub const Algorithm = enum {
sha1WithRSAEncryption,
sha224WithRSAEncryption,
sha256WithRSAEncryption,
sha384WithRSAEncryption,
sha512WithRSAEncryption,
pub const map = std.ComptimeStringMap(Algorithm, .{
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x05 }, .sha1WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0B }, .sha256WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0C }, .sha384WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0D }, .sha512WithRSAEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x0E }, .sha224WithRSAEncryption },
});
pub fn Hash(comptime algorithm: Algorithm) type {
return switch (algorithm) {
.sha1WithRSAEncryption => crypto.hash.Sha1,
.sha224WithRSAEncryption => crypto.hash.sha2.Sha224,
.sha256WithRSAEncryption => crypto.hash.sha2.Sha256,
.sha384WithRSAEncryption => crypto.hash.sha2.Sha384,
.sha512WithRSAEncryption => crypto.hash.sha2.Sha512,
};
}
};
pub const AlgorithmCategory = enum {
rsaEncryption,
X9_62_id_ecPublicKey,
pub const map = std.ComptimeStringMap(AlgorithmCategory, .{
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01 }, .rsaEncryption },
.{ &[_]u8{ 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x02, 0x01 }, .X9_62_id_ecPublicKey },
});
};
pub const Attribute = enum {
commonName,
serialNumber,
countryName,
localityName,
stateOrProvinceName,
organizationName,
organizationalUnitName,
organizationIdentifier,
pub const map = std.ComptimeStringMap(Attribute, .{
.{ &[_]u8{ 0x55, 0x04, 0x03 }, .commonName },
.{ &[_]u8{ 0x55, 0x04, 0x05 }, .serialNumber },
.{ &[_]u8{ 0x55, 0x04, 0x06 }, .countryName },
.{ &[_]u8{ 0x55, 0x04, 0x07 }, .localityName },
.{ &[_]u8{ 0x55, 0x04, 0x08 }, .stateOrProvinceName },
.{ &[_]u8{ 0x55, 0x04, 0x0A }, .organizationName },
.{ &[_]u8{ 0x55, 0x04, 0x0B }, .organizationalUnitName },
.{ &[_]u8{ 0x55, 0x04, 0x61 }, .organizationIdentifier },
});
};
pub const Parsed = struct {
certificate: Certificate,
issuer: []const u8,
subject: []const u8,
common_name: []const u8,
signature: []const u8,
signature_algorithm: Algorithm,
message: []const u8,
pub_key_algo: AlgorithmCategory,
pub_key: []const u8,
pub fn verify(subject: Parsed, issuer: Parsed) !void {
// Check that the subject's issuer name matches the issuer's
// subject name.
if (!mem.eql(u8, subject.issuer, issuer.subject)) {
return error.CertificateIssuerMismatch;
}
// TODO check the time validity for the subject
// TODO check the time validity for the issuer
switch (subject.signature_algorithm) {
inline .sha1WithRSAEncryption,
.sha224WithRSAEncryption,
.sha256WithRSAEncryption,
.sha384WithRSAEncryption,
.sha512WithRSAEncryption,
=> |algorithm| return verifyRsa(
algorithm.Hash(),
subject.message,
subject.signature,
issuer.pub_key_algo,
issuer.pub_key,
),
}
}
};
pub fn parse(cert: Certificate) !Parsed {
const cert_bytes = cert.buffer;
const certificate = try Der.parseElement(cert_bytes, cert.index);
const tbs_certificate = try Der.parseElement(cert_bytes, certificate.start);
const version = try Der.parseElement(cert_bytes, tbs_certificate.start);
try checkVersion(cert_bytes, version);
const serial_number = try Der.parseElement(cert_bytes, version.end);
// RFC 5280, section 4.1.2.3:
// "This field MUST contain the same algorithm identifier as
// the signatureAlgorithm field in the sequence Certificate."
const tbs_signature = try Der.parseElement(cert_bytes, serial_number.end);
const issuer = try Der.parseElement(cert_bytes, tbs_signature.end);
const validity = try Der.parseElement(cert_bytes, issuer.end);
const subject = try Der.parseElement(cert_bytes, validity.end);
const pub_key_info = try Der.parseElement(cert_bytes, subject.end);
const pub_key_signature_algorithm = try Der.parseElement(cert_bytes, pub_key_info.start);
const pub_key_algo_elem = try Der.parseElement(cert_bytes, pub_key_signature_algorithm.start);
const pub_key_algo = try parseAlgorithmCategory(cert_bytes, pub_key_algo_elem);
const pub_key_elem = try Der.parseElement(cert_bytes, pub_key_signature_algorithm.end);
const pub_key = try parseBitString(cert, pub_key_elem);
const rdn = try Der.parseElement(cert_bytes, subject.start);
const atav = try Der.parseElement(cert_bytes, rdn.start);
var common_name: []const u8 = &.{};
var atav_i = atav.start;
while (atav_i < atav.end) {
const ty_elem = try Der.parseElement(cert_bytes, atav_i);
const ty = try parseAttribute(cert_bytes, ty_elem);
const val = try Der.parseElement(cert_bytes, ty_elem.end);
switch (ty) {
.commonName => common_name = cert.contents(val),
else => {},
}
atav_i = val.end;
}
const sig_algo = try Der.parseElement(cert_bytes, tbs_certificate.end);
const algo_elem = try Der.parseElement(cert_bytes, sig_algo.start);
const signature_algorithm = try parseAlgorithm(cert_bytes, algo_elem);
const sig_elem = try Der.parseElement(cert_bytes, sig_algo.end);
const signature = try parseBitString(cert, sig_elem);
return .{
.certificate = cert,
.common_name = common_name,
.issuer = cert.contents(issuer),
.subject = cert.contents(subject),
.signature = signature,
.signature_algorithm = signature_algorithm,
.message = cert_bytes[certificate.start..tbs_certificate.end],
.pub_key_algo = pub_key_algo,
.pub_key = pub_key,
};
}
pub fn verify(subject: Certificate, issuer: Certificate) !void {
const parsed_subject = try subject.parse();
const parsed_issuer = try issuer.parse();
return parsed_subject.verify(parsed_issuer);
}
pub fn contents(cert: Certificate, elem: Der.Element) []const u8 {
return cert.buffer[elem.start..elem.end];
}
pub fn parseBitString(cert: Certificate, elem: Der.Element) ![]const u8 {
if (elem.identifier.tag != .bitstring) return error.CertificateFieldHasWrongDataType;
if (cert.buffer[elem.start] != 0) return error.CertificateHasInvalidBitString;
return cert.buffer[elem.start + 1 .. elem.end];
}
pub fn parseAlgorithm(bytes: []const u8, element: Der.Element) !Algorithm {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return Algorithm.map.get(bytes[element.start..element.end]) orelse
return error.CertificateHasUnrecognizedAlgorithm;
}
pub fn parseAlgorithmCategory(bytes: []const u8, element: Der.Element) !AlgorithmCategory {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return AlgorithmCategory.map.get(bytes[element.start..element.end]) orelse {
std.debug.print("unrecognized algorithm category: {}\n", .{std.fmt.fmtSliceHexLower(bytes[element.start..element.end])});
return error.CertificateHasUnrecognizedAlgorithmCategory;
};
}
pub fn parseAttribute(bytes: []const u8, element: Der.Element) !Attribute {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return Attribute.map.get(bytes[element.start..element.end]) orelse
return error.CertificateHasUnrecognizedAlgorithm;
}
fn verifyRsa(comptime Hash: type, message: []const u8, sig: []const u8, pub_key_algo: AlgorithmCategory, pub_key: []const u8) !void {
if (pub_key_algo != .rsaEncryption) return error.CertificateSignatureAlgorithmMismatch;
const pub_key_seq = try Der.parseElement(pub_key, 0);
if (pub_key_seq.identifier.tag != .sequence) return error.CertificateFieldHasWrongDataType;
const modulus_elem = try Der.parseElement(pub_key, pub_key_seq.start);
if (modulus_elem.identifier.tag != .integer) return error.CertificateFieldHasWrongDataType;
const exponent_elem = try Der.parseElement(pub_key, modulus_elem.end);
if (exponent_elem.identifier.tag != .integer) return error.CertificateFieldHasWrongDataType;
// Skip over meaningless zeroes in the modulus.
const modulus_raw = pub_key[modulus_elem.start..modulus_elem.end];
const modulus_offset = for (modulus_raw) |byte, i| {
if (byte != 0) break i;
} else modulus_raw.len;
const modulus = modulus_raw[modulus_offset..];
const exponent = pub_key[exponent_elem.start..exponent_elem.end];
if (exponent.len > modulus.len) return error.CertificatePublicKeyInvalid;
if (sig.len != modulus.len) return error.CertificateSignatureInvalidLength;
const hash_der = switch (Hash) {
crypto.hash.Sha1 => [_]u8{
0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e,
0x03, 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14,
},
crypto.hash.sha2.Sha224 => [_]u8{
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, 0x05,
0x00, 0x04, 0x1c,
},
crypto.hash.sha2.Sha256 => [_]u8{
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
0x00, 0x04, 0x20,
},
crypto.hash.sha2.Sha384 => [_]u8{
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, 0x05,
0x00, 0x04, 0x30,
},
crypto.hash.sha2.Sha512 => [_]u8{
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05,
0x00, 0x04, 0x40,
},
else => @compileError("unreachable"),
};
var msg_hashed: [Hash.digest_length]u8 = undefined;
Hash.hash(message, &msg_hashed, .{});
switch (modulus.len) {
inline 128, 256, 512 => |modulus_len| {
const ps_len = modulus_len - (hash_der.len + msg_hashed.len) - 3;
const em: [modulus_len]u8 =
[2]u8{ 0, 1 } ++
([1]u8{0xff} ** ps_len) ++
[1]u8{0} ++
hash_der ++
msg_hashed;
const public_key = try rsa.PublicKey.fromBytes(exponent, modulus, rsa.poop);
const em_dec = try rsa.encrypt(modulus_len, sig[0..modulus_len].*, public_key, rsa.poop);
if (!mem.eql(u8, &em, &em_dec)) {
try std.testing.expectEqualSlices(u8, &em, &em_dec);
return error.CertificateSignatureInvalid;
}
},
else => {
return error.CertificateSignatureUnsupportedBitCount;
},
}
}
};
fn checkVersion(bytes: []const u8, version: Der.Element) !void {
if (@bitCast(u8, version.identifier) != 0xa0 or
!mem.eql(u8, bytes[version.start..version.end], "\x02\x01\x02"))
{
return error.UnsupportedCertificateVersion;
}
}
const builtin = @import("builtin");
const std = @import("../std.zig");
const fs = std.fs;
const mem = std.mem;
const crypto = std.crypto;
const Allocator = std.mem.Allocator;
const Der = std.crypto.Der;
const CertificateBundle = @This();
const base64 = std.base64.standard.decoderWithIgnore(" \t\r\n");
const MapContext = struct {
cb: *const CertificateBundle,
pub fn hash(ctx: MapContext, k: Key) u64 {
return std.hash_map.hashString(ctx.cb.bytes.items[k.subject_start..k.subject_end]);
}
pub fn eql(ctx: MapContext, a: Key, b: Key) bool {
const bytes = ctx.cb.bytes.items;
return mem.eql(
u8,
bytes[a.subject_start..a.subject_end],
bytes[b.subject_start..b.subject_end],
);
}
};
test "scan for OS-provided certificates" {
if (builtin.os.tag == .wasi) return error.SkipZigTest;
var bundle: CertificateBundle = .{};
defer bundle.deinit(std.testing.allocator);
try bundle.rescan(std.testing.allocator);
}
/// TODO: replace this with Frank's upcoming RSA implementation. the verify
/// function won't have the possibility of failure - it will either identify a
/// valid signature or an invalid signature.
/// This code is borrowed from https://github.com/shiguredo/tls13-zig
/// which is licensed under the Apache License Version 2.0, January 2004
/// http://www.apache.org/licenses/
/// The code has been modified.
const rsa = struct {
const BigInt = std.math.big.int.Managed;
const PublicKey = struct {
n: BigInt,
e: BigInt,
pub fn deinit(self: *PublicKey) void {
self.n.deinit();
self.e.deinit();
}
pub fn fromBytes(pub_bytes: []const u8, modulus_bytes: []const u8, allocator: std.mem.Allocator) !PublicKey {
var _n = try BigInt.init(allocator);
errdefer _n.deinit();
try setBytes(&_n, modulus_bytes, allocator);
var _e = try BigInt.init(allocator);
errdefer _e.deinit();
try setBytes(&_e, pub_bytes, allocator);
return .{
.n = _n,
.e = _e,
};
}
};
fn encrypt(comptime modulus_len: usize, msg: [modulus_len]u8, public_key: PublicKey, allocator: std.mem.Allocator) ![modulus_len]u8 {
var m = try BigInt.init(allocator);
defer m.deinit();
try setBytes(&m, &msg, allocator);
if (m.order(public_key.n) != .lt) {
return error.MessageTooLong;
}
var e = try BigInt.init(allocator);
defer e.deinit();
try pow_montgomery(&e, &m, &public_key.e, &public_key.n, allocator);
var res: [modulus_len]u8 = undefined;
try toBytes(&res, &e, allocator);
return res;
}
fn setBytes(r: *BigInt, bytes: []const u8, allcator: std.mem.Allocator) !void {
try r.set(0);
var tmp = try BigInt.init(allcator);
defer tmp.deinit();
for (bytes) |b| {
try r.shiftLeft(r, 8);
try tmp.set(b);
try r.add(r, &tmp);
}
}
fn pow_montgomery(r: *BigInt, a: *const BigInt, x: *const BigInt, n: *const BigInt, allocator: std.mem.Allocator) !void {
var bin_raw: [512]u8 = undefined;
try toBytes(&bin_raw, x, allocator);
var i: usize = 0;
while (bin_raw[i] == 0x00) : (i += 1) {}
const bin = bin_raw[i..];
try r.set(1);
var r1 = try BigInt.init(allocator);
defer r1.deinit();
try BigInt.copy(&r1, a.toConst());
i = 0;
while (i < bin.len * 8) : (i += 1) {
if (((bin[i / 8] >> @intCast(u3, (7 - (i % 8)))) & 0x1) == 0) {
try BigInt.mul(&r1, r, &r1);
try mod(&r1, &r1, n, allocator);
try BigInt.sqr(r, r);
try mod(r, r, n, allocator);
} else {
try BigInt.mul(r, r, &r1);
try mod(r, r, n, allocator);
try BigInt.sqr(&r1, &r1);
try mod(&r1, &r1, n, allocator);
}
}
}
fn toBytes(out: []u8, a: *const BigInt, allocator: std.mem.Allocator) !void {
const Error = error{
BufferTooSmall,
};
var mask = try BigInt.initSet(allocator, 0xFF);
defer mask.deinit();
var tmp = try BigInt.init(allocator);
defer tmp.deinit();
var a_copy = try BigInt.init(allocator);
defer a_copy.deinit();
try a_copy.copy(a.toConst());
// Encoding into big-endian bytes
var i: usize = 0;
while (i < out.len) : (i += 1) {
try tmp.bitAnd(&a_copy, &mask);
const b = try tmp.to(u8);
out[out.len - i - 1] = b;
try a_copy.shiftRight(&a_copy, 8);
}
if (!a_copy.eqZero()) {
return Error.BufferTooSmall;
}
}
fn mod(rem: *BigInt, a: *const BigInt, n: *const BigInt, allocator: std.mem.Allocator) !void {
var q = try BigInt.init(allocator);
defer q.deinit();
try BigInt.divFloor(&q, rem, a, n);
}
// TODO: flush the toilet
const poop = std.heap.page_allocator;
};

View File

@ -99,8 +99,14 @@ pub const Oid = enum {
pub const Element = struct {
identifier: Identifier,
start: u32,
end: u32,
slice: Slice,
pub const Slice = struct {
start: u32,
end: u32,
pub const empty: Slice = .{ .start = 0, .end = 0 };
};
};
pub const ParseElementError = error{CertificateHasFieldWithInvalidLength};
@ -114,8 +120,10 @@ pub fn parseElement(bytes: []const u8, index: u32) ParseElementError!Element {
if ((size_byte >> 7) == 0) {
return .{
.identifier = identifier,
.start = i,
.end = i + size_byte,
.slice = .{
.start = i,
.end = i + size_byte,
},
};
}
@ -132,8 +140,10 @@ pub fn parseElement(bytes: []const u8, index: u32) ParseElementError!Element {
return .{
.identifier = identifier,
.start = i,
.end = i + long_form_size,
.slice = .{
.start = i,
.end = i + long_form_size,
},
};
}
@ -145,9 +155,9 @@ pub const ParseObjectIdError = error{
pub fn parseObjectId(bytes: []const u8, element: Element) ParseObjectIdError!Oid {
if (element.identifier.tag != .object_identifier)
return error.CertificateFieldHasWrongDataType;
return Oid.map.get(bytes[element.start..element.end]) orelse
return Oid.map.get(bytes[element.slice.start..element.slice.end]) orelse
return error.CertificateHasUnrecognizedObjectId;
}
const std = @import("../std.zig");
const Der = @This();
const der = @This();

View File

@ -1,6 +1,5 @@
const std = @import("../../std.zig");
const tls = std.crypto.tls;
const Der = std.crypto.Der;
const Client = @This();
const net = std.net;
const mem = std.mem;
@ -18,7 +17,7 @@ const int2 = tls.int2;
const int3 = tls.int3;
const array = tls.array;
const enum_array = tls.enum_array;
const Certificate = crypto.CertificateBundle.Certificate;
const Certificate = crypto.Certificate;
application_cipher: ApplicationCipher,
read_seq: u64,
@ -30,7 +29,7 @@ partially_read_len: u15,
eof: bool,
/// `host` is only borrowed during this function call.
pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []const u8) !Client {
pub fn init(stream: net.Stream, ca_bundle: Certificate.Bundle, host: []const u8) !Client {
const host_len = @intCast(u16, host.len);
var random_buffer: [128]u8 = undefined;
@ -298,9 +297,19 @@ pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []con
break :i end;
};
// This is used for two purposes:
// * Detect whether a certificate is the first one presented, in which case
// we need to verify the host name.
// * Flip back and forth between the two cleartext buffers in order to keep
// the previous certificate in memory so that it can be verified by the
// next one.
var cert_index: usize = 0;
var read_seq: u64 = 0;
var validated_cert = false;
var is_subsequent_cert = false;
var prev_cert: Certificate.Parsed = undefined;
// Set to true once a trust chain has been established from the first
// certificate to a root CA.
var cert_verification_done = false;
var cleartext_bufs: [2][8000]u8 = undefined;
while (true) {
const end_hdr = i + 5;
@ -328,7 +337,8 @@ pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []con
if (handshake_buf[i] != 0x01) return error.TlsUnexpectedMessage;
},
.application_data => {
var cleartext_buf: [8000]u8 = undefined;
const cleartext_buf = &cleartext_bufs[cert_index % 2];
const cleartext = switch (handshake_cipher) {
inline else => |*p| c: {
const P = @TypeOf(p.*);
@ -393,7 +403,7 @@ pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []con
switch (handshake_cipher) {
inline else => |*p| p.transcript_hash.update(wrapped_handshake),
}
if (validated_cert) break :cert;
if (cert_verification_done) break :cert;
var hs_i: u32 = 0;
const cert_req_ctx_len = handshake[hs_i];
hs_i += 1;
@ -411,12 +421,22 @@ pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []con
.index = hs_i,
};
const subject = try subject_cert.parse();
if (!is_subsequent_cert) {
is_subsequent_cert = true;
if (mem.eql(u8, subject.common_name, host)) {
if (cert_index > 0) {
if (prev_cert.verify(subject)) |_| {
std.debug.print("previous certificate verified\n", .{});
} else |err| {
std.debug.print("unable to validate previous cert: {s}\n", .{
@errorName(err),
});
}
} else {
// Verify the host on the first certificate.
const common_name = subject.commonName();
if (mem.eql(u8, common_name, host)) {
std.debug.print("exact host match\n", .{});
} else if (mem.startsWith(u8, subject.common_name, "*.") and
mem.eql(u8, subject.common_name[2..], host))
} else if (mem.startsWith(u8, common_name, "*.") and
(mem.endsWith(u8, host, common_name[1..]) or
mem.eql(u8, common_name[2..], host)))
{
std.debug.print("wildcard host match\n", .{});
} else {
@ -427,17 +447,17 @@ pub fn init(stream: net.Stream, ca_bundle: crypto.CertificateBundle, host: []con
if (ca_bundle.verify(subject)) |_| {
std.debug.print("found a root CA cert matching issuer. verification success!\n", .{});
validated_cert = true;
cert_verification_done = true;
break :cert;
} else |err| {
std.debug.print("unable to validate cert against system root CAs: {s}\n", .{
@errorName(err),
});
// TODO handle a certificate
// signing chain that ends in a
// root-validated one.
}
prev_cert = subject;
cert_index += 1;
hs_i = end_cert;
const total_ext_size = mem.readIntBig(u16, handshake[hs_i..][0..2]);
hs_i += 2;

View File

@ -7,7 +7,7 @@ const Client = @This();
allocator: std.mem.Allocator,
headers: std.ArrayListUnmanaged(u8) = .{},
active_requests: usize = 0,
ca_bundle: std.crypto.CertificateBundle = .{},
ca_bundle: std.crypto.Certificate.Bundle = .{},
pub const Request = struct {
client: *Client,