std.crypto: enhance Certificate security

lib/std/crypto.zig

@@ -195,6 +195,8 @@ pub const errors = @import("crypto/errors.zig");
 pub const tls = @import("crypto/tls.zig");
 pub const Certificate = @import("crypto/Certificate.zig");
 
+pub const rsa = @import("crypto/rsa.zig");
+
 /// Side-channels mitigations.
 pub const SideChannelsMitigations = enum {
     /// No additional side-channel mitigations are applied.
@@ -307,6 +309,8 @@ test {
     _ = errors;
     _ = tls;
     _ = Certificate;
+    _ = rsa;
+    _ = @import("crypto/oid.zig");
 }
 
 test "CSPRNG" {

lib/std/crypto/25519/ed25519.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const der = @import("../der.zig");
 const crypto = std.crypto;
 const debug = std.debug;
 const fmt = std.fmt;
@@ -213,6 +214,26 @@ pub const Ed25519 = struct {
             };
         }
 
+        pub fn fromDer(bytes: []const u8) !Signature {
+            var parser = der.Parser{ .bytes = bytes };
+            const seq = try parser.expectSequence();
+            defer parser.seek(seq.slice.end);
+
+            const r = try parser.expectPrimitive(.integer);
+            if (r.slice.len() > Curve.encoded_length) return error.InvalidScalar;
+            const s = try parser.expectPrimitive(.integer);
+            if (s.slice.len() > @sizeOf(CompressedScalar)) return error.InvalidScalar;
+
+            if (parser.index != seq.slice.end) return error.InvalidSequence;
+            if (parser.index != parser.bytes.len) return error.InvalidSequence;
+
+            var res = std.mem.zeroInit(Signature, .{});
+            @memcpy(res.r[res.r.len - parser.view(r).len ..], parser.view(r));
+            @memcpy(res.s[res.r.len - parser.view(s).len ..], parser.view(s));
+
+            return res;
+        }
+
         /// Create a Verifier for incremental verification of a signature.
         pub fn verifier(self: Signature, public_key: PublicKey) (NonCanonicalError || EncodingError || IdentityElementError)!Verifier {
             return Verifier.init(self, public_key);

lib/std/crypto/25519/x25519.zig

@@ -19,15 +19,19 @@ pub const X25519 = struct {
     pub const public_length = 32;
     /// Length (in bytes) of the output of the DH function.
     pub const shared_length = 32;
-    /// Seed (for key pair creation) length in bytes.
-    pub const seed_length = 32;
+
+    pub const PublicKey = [public_length]u8;
+    pub const SecretKey = [secret_length]u8;
 
     /// An X25519 key pair.
     pub const KeyPair = struct {
         /// Public part.
-        public_key: [public_length]u8,
+        public_key: PublicKey,
         /// Secret part.
-        secret_key: [secret_length]u8,
+        secret_key: SecretKey,
+
+        /// Seed (for key pair creation) length in bytes.
+        pub const seed_length = 32;
 
         /// Create a new key pair using an optional seed.
         pub fn create(seed: ?[seed_length]u8) IdentityElementError!KeyPair {