Merge pull request #81 from matrix-org/dbkr/pk_sign

Add signing class to the pk module

8 files changed, 318 insertions, 8 deletions

diff --git a/Makefile b/Makefile
index 3269484..fe5ff35 100644
--- a/Makefile
+++ b/Makefile
@@ -86,9 +86,6 @@ CXXFLAGS += -Wall -Werror -std=c++11 -fPIC
 LDFLAGS += -Wall -Werror
 
 EMCCFLAGS = --closure 1 --memory-init-file 0 -s NO_FILESYSTEM=1 -s INVOKE_RUN=0 -s MODULARIZE=1
-# NO_BROWSER is kept for compatibility with emscripten 1.35.24, but is no
-# longer needed.
-EMCCFLAGS += -s NO_BROWSER=1
 
 # Olm generally doesn't need a lot of memory to encrypt / decrypt its usual
 # payloads (ie. Matrix messages), but we do need about 128K of heap to encrypt
diff --git a/include/olm/pk.h b/include/olm/pk.h
index c46baa0..8901621 100644
--- a/include/olm/pk.h
+++ b/include/olm/pk.h
@@ -1,4 +1,4 @@
-/* Copyright 2018 New Vector Ltd
+/* Copyright 2018, 2019 New Vector Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -207,6 +207,48 @@ size_t olm_pk_get_private_key(
     void *private_key, size_t private_key_length
 );
 
+typedef struct OlmPkSigning OlmPkSigning;
+
+/* The size of a signing object in bytes */
+size_t olm_pk_signing_size(void);
+
+/** Initialise a signing object using the supplied memory
+ *  The supplied memory must be at least olm_pk_signing_size() bytes */
+OlmPkSigning *olm_pk_signing(
+    void * memory
+);
+
+/** A null terminated string describing the most recent error to happen to a
+ * signing object */
+const char * olm_pk_signing_last_error(
+    OlmPkSigning * sign
+);
+
+/** Clears the memory used to back this signing object */
+size_t olm_clear_pk_signing(
+    OlmPkSigning *sign
+);
+
+/**
+ * Initialise the signing object with a public/private keypair from a seed
+ */
+size_t olm_pk_signing_key_from_seed(
+    OlmPkSigning * sign,
+    void * pubkey, size_t pubkey_length,
+    void * seed, size_t seed_length
+);
+
+size_t olm_pk_sign_seed_length(void);
+size_t olm_pk_sign_public_key_length(void);
+
+size_t olm_pk_signature_length();
+
+size_t olm_pk_sign(
+    OlmPkSigning *sign,
+    uint8_t const * message, size_t message_length,
+    uint8_t * signature, size_t signature_length
+);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/javascript/olm_pk.js b/javascript/olm_pk.js
index 81dbad4..80a57aa 100644
--- a/javascript/olm_pk.js
+++ b/javascript/olm_pk.js
@@ -271,3 +271,92 @@ PkDecryption.prototype['decrypt'] = restore_stack(function (
         }
     }
 })
+
+
+function PkSigning() {
+    var size = Module['_olm_pk_signing_size']();
+    this.buf = malloc(size);
+    this.ptr = Module['_olm_pk_signing'](this.buf);
+}
+
+function pk_signing_method(wrapped) {
+    return function() {
+        var result = wrapped.apply(this, arguments);
+        if (result === OLM_ERROR) {
+            var message = Pointer_stringify(
+                Module['_olm_pk_signing_last_error'](arguments[0])
+            );
+            throw new Error("OLM." + message);
+        }
+        return result;
+    }
+}
+
+PkSigning.prototype['free'] = function() {
+    Module['_olm_clear_pk_signing'](this.ptr);
+    free(this.ptr);
+}
+
+PkSigning.prototype['init_with_seed'] = restore_stack(function (seed) {
+    var seed_buffer = stack(seed.length);
+    Module['HEAPU8'].set(seed, seed_buffer);
+
+    var pubkey_length = pk_signing_method(
+        Module['_olm_pk_sign_public_key_length']
+    )();
+    var pubkey_buffer = stack(pubkey_length + NULL_BYTE_PADDING_LENGTH);
+    try {
+        pk_signing_method(Module['_olm_pk_signing_key_from_seed'])(
+            this.ptr,
+            pubkey_buffer, pubkey_length,
+            seed_buffer, seed.length
+        );
+    } finally {
+        // clear out our copy of the seed
+        bzero(seed_buffer, seed.length);
+    }
+    return Pointer_stringify(pubkey_buffer);
+});
+
+PkSigning.prototype['generate_seed'] = restore_stack(function () {
+    var random_length = pk_signing_method(
+        Module['_olm_pk_sign_seed_length']
+    )();
+    var random_buffer = random_stack(random_length);
+    var key_arr = new Uint8Array(
+        new Uint8Array(Module['HEAPU8'].buffer, random_buffer, random_length)
+    );
+    bzero(random_buffer, random_length);
+    return key_arr;
+});
+
+PkSigning.prototype['sign'] = restore_stack(function (message) {
+    // XXX: Should be able to sign any bytes rather than just strings,
+    // but this is consistent with encrypt for now.
+    //var message_buffer = stack(message.length);
+    //Module['HEAPU8'].set(message, message_buffer);
+    var message_buffer, message_length;
+
+    try {
+        message_length = lengthBytesUTF8(message)
+        message_buffer = malloc(message_length + 1);
+        stringToUTF8(message, message_buffer, message_length + 1);
+
+        var sig_length = pk_signing_method(
+            Module['_olm_pk_signature_length']
+        )();
+        var sig_buffer = stack(sig_length + NULL_BYTE_PADDING_LENGTH);
+        pk_signing_method(Module['_olm_pk_sign'])(
+            this.ptr,
+            message_buffer, message_length,
+            sig_buffer, sig_length
+        );
+        return Pointer_stringify(sig_buffer);
+    } finally {
+        if (message_buffer !== undefined) {
+            // don't leave a copy of the plaintext in the heap.
+            bzero(message_buffer, message_length + 1);
+            free(message_buffer);
+        }
+    }
+});
diff --git a/javascript/olm_post.js b/javascript/olm_post.js
index 3bf0d66..a3a3ef4 100644
--- a/javascript/olm_post.js
+++ b/javascript/olm_post.js
@@ -534,6 +534,7 @@ olm_exports["Session"] = Session;
 olm_exports["Utility"] = Utility;
 olm_exports["PkEncryption"] = PkEncryption;
 olm_exports["PkDecryption"] = PkDecryption;
+olm_exports["PkSigning"] = PkSigning;
 olm_exports["SAS"] = SAS;
 
 olm_exports["get_library_version"] = restore_stack(function() {
diff --git a/javascript/test/olm.spec.js b/javascript/test/olm.spec.js
index 77dd712..a698314 100644
--- a/javascript/test/olm.spec.js
+++ b/javascript/test/olm.spec.js
@@ -34,7 +34,6 @@ describe("olm", function() {
     beforeEach(function(done) {
         // This should really be in a beforeAll, but jasmine-node
         // doesn't support that
-        debugger;
         Olm.init().then(function() {
             aliceAccount = new Olm.Account();
             bobAccount = new Olm.Account();
diff --git a/javascript/test/pk.spec.js b/javascript/test/pk.spec.js
index b4b119e..f212b96 100644
--- a/javascript/test/pk.spec.js
+++ b/javascript/test/pk.spec.js
@@ -1,5 +1,5 @@
 /*
-Copyright 2018 New Vector Ltd
+Copyright 2018, 2019 New Vector Ltd
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -19,12 +19,13 @@ limitations under the License.
 var Olm = require('../olm');
 
 describe("pk", function() {
-    var encryption, decryption;
+    var encryption, decryption, signing;
 
     beforeEach(function(done) {
         Olm.init().then(function() {
             encryption = new Olm.PkEncryption();
             decryption = new Olm.PkDecryption();
+            signing = new Olm.PkSigning();
 
             done();
         });
@@ -39,6 +40,10 @@ describe("pk", function() {
             decryption.free();
             decryption = undefined;
         }
+        if (signing !== undefined) {
+            signing.free();
+            signing = undefined;
+        }
     });
 
     it('should import & export keys from private parts', function () {
@@ -89,4 +94,29 @@ describe("pk", function() {
         expect(decrypted).toEqual(TEST_TEXT);
         new_decryption.free();
     });
+
+    it('should sign and verify', function () {
+        var seed = new Uint8Array([
+            0x77, 0x07, 0x6D, 0x0A, 0x73, 0x18, 0xA5, 0x7D,
+            0x3C, 0x16, 0xC1, 0x72, 0x51, 0xB2, 0x66, 0x45,
+            0xDF, 0x4C, 0x2F, 0x87, 0xEB, 0xC0, 0x99, 0x2A,
+            0xB1, 0x77, 0xFB, 0xA5, 0x1D, 0xB9, 0x2C, 0x2A
+        ]);
+
+        var TEST_TEXT = "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.";
+        //var seed = signing.generate_seed();
+        var pubkey = signing.init_with_seed(seed);
+        var sig = signing.sign(TEST_TEXT);
+
+        var util = new Olm.Utility();
+        util.ed25519_verify(pubkey, TEST_TEXT, sig);
+        var verifyFailure;
+        try {
+            util.ed25519_verify(pubkey, TEST_TEXT, 'p' + sig.slice(1));
+        } catch (e) {
+            verifyFailure = e;
+        }
+        expect(verifyFailure).not.toBeNull();
+        util.free();
+    });
 });
diff --git a/src/pk.cpp b/src/pk.cpp
index 8db958a..111e54b 100644
--- a/src/pk.cpp
+++ b/src/pk.cpp
@@ -1,4 +1,4 @@
-/* Copyright 2018 New Vector Ltd
+/* Copyright 2018, 2019 New Vector Ltd
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -409,4 +409,86 @@ size_t olm_pk_get_private_key(
     return olm_pk_private_key_length();
 }
 
+struct OlmPkSigning {
+    OlmErrorCode last_error;
+    _olm_ed25519_key_pair key_pair;
+};
+
+size_t olm_pk_signing_size(void) {
+    return sizeof(OlmPkSigning);
+}
+
+OlmPkSigning *olm_pk_signing(void * memory) {
+    olm::unset(memory, sizeof(OlmPkSigning));
+    return new(memory) OlmPkSigning;
+}
+
+const char * olm_pk_signing_last_error(OlmPkSigning * sign) {
+    auto error = sign->last_error;
+    return _olm_error_to_string(error);
+}
+
+size_t olm_clear_pk_signing(OlmPkSigning *sign) {
+    /* Clear the memory backing the signing */
+    olm::unset(sign, sizeof(OlmPkSigning));
+    /* Initialise a fresh signing object in case someone tries to use it */
+    new(sign) OlmPkSigning();
+    return sizeof(OlmPkSigning);
+}
+
+size_t olm_pk_sign_seed_length(void) {
+    return ED25519_RANDOM_LENGTH;
+}
+
+size_t olm_pk_sign_public_key_length(void) {
+    return olm::encode_base64_length(ED25519_PUBLIC_KEY_LENGTH);
+}
+
+size_t olm_pk_signing_key_from_seed(
+    OlmPkSigning * signing,
+    void * pubkey, size_t pubkey_length,
+    void * seed, size_t seed_length
+) {
+    if (pubkey_length < olm_pk_sign_public_key_length()) {
+        signing->last_error =
+            OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
+        return std::size_t(-1);
+    }
+    if (seed_length < olm_pk_sign_seed_length()) {
+        signing->last_error =
+            OlmErrorCode::OLM_INPUT_BUFFER_TOO_SMALL;
+        return std::size_t(-1);
+    }
+
+    _olm_crypto_ed25519_generate_key((uint8_t *) seed, &signing->key_pair);
+    olm::encode_base64(
+        (const uint8_t *)signing->key_pair.public_key.public_key,
+        ED25519_PUBLIC_KEY_LENGTH,
+        (uint8_t *)pubkey
+    );
+    return 0;
+}
+
+size_t olm_pk_signature_length() {
+    return olm::encode_base64_length(ED25519_SIGNATURE_LENGTH);
+}
+
+size_t olm_pk_sign(
+    OlmPkSigning *signing,
+    uint8_t const * message, size_t message_length,
+    uint8_t * signature, size_t signature_length
+) {
+    if (signature_length < olm_pk_signature_length()) {
+        signing->last_error = OlmErrorCode::OLM_OUTPUT_BUFFER_TOO_SMALL;
+        return std::size_t(-1);
+    }
+    uint8_t *raw_sig = signature + olm_pk_signature_length() - ED25519_SIGNATURE_LENGTH;
+    _olm_crypto_ed25519_sign(
+        &signing->key_pair,
+        message, message_length, raw_sig
+    );
+    olm::encode_base64(raw_sig, ED25519_SIGNATURE_LENGTH, signature);
+    return olm_pk_signature_length();
+}
+
 }
diff --git a/tests/test_pk.cpp b/tests/test_pk.cpp
index 42cc8c9..874710b 100644
--- a/tests/test_pk.cpp
+++ b/tests/test_pk.cpp
@@ -163,4 +163,74 @@ free(ciphertext);
 free(plaintext_buffer);
 
 }
+
+{ /* Signing Test Case 1 */
+
+TestCase test_case("Public Key Signing");
+
+std::uint8_t signing_buffer[olm_pk_signing_size()];
+OlmPkSigning *signing = olm_pk_signing(signing_buffer);
+
+std::uint8_t seed[32] = {
+    0x77, 0x07, 0x6D, 0x0A, 0x73, 0x18, 0xA5, 0x7D,
+    0x3C, 0x16, 0xC1, 0x72, 0x51, 0xB2, 0x66, 0x45,
+    0xDF, 0x4C, 0x2F, 0x87, 0xEB, 0xC0, 0x99, 0x2A,
+    0xB1, 0x77, 0xFB, 0xA5, 0x1D, 0xB9, 0x2C, 0x2A
+};
+
+//const std::uint8_t *pub_key = (std::uint8_t *) "hSDwCYkwp1R0i33ctD73Wg2/Og0mOBr066SpjqqbTmoK";
+
+char pubkey[olm_pk_sign_public_key_length() + 1];
+
+olm_pk_signing_key_from_seed(
+    signing,
+    pubkey, sizeof(pubkey),
+    seed, sizeof(seed)
+);
+
+printf("pubkey: %s\n", pubkey);
+
+char *message = strdup("We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.");
+
+std::uint8_t *sig_buffer = (std::uint8_t *) malloc(olm_pk_signature_length() + 1);
+
+olm_pk_sign(
+    signing,
+    (const uint8_t *)message, strlen(message),
+    sig_buffer, olm_pk_signature_length()
+);
+
+printf("sig: %s\n", sig_buffer);
+
+void * utility_buffer = malloc(::olm_utility_size());
+::OlmUtility * utility = ::olm_utility(utility_buffer);
+
+size_t result;
+
+result = ::olm_ed25519_verify(
+    utility,
+    pubkey, olm_pk_sign_public_key_length(),
+    message, strlen(message),
+    sig_buffer, olm_pk_signature_length()
+);
+
+assert_equals((size_t)0, result);
+
+sig_buffer[5] = 'm';
+
+result = ::olm_ed25519_verify(
+    utility,
+    pubkey, olm_pk_sign_public_key_length(),
+    message, strlen(message),
+    sig_buffer, olm_pk_signature_length()
+);
+
+assert_equals((size_t)-1, result);
+
+free(message);
+free(sig_buffer);
+
+olm_clear_pk_signing(signing);
+
+}
 }