Fix manage data value in SEP0010 challenge builder.

package.json

@@ -141,7 +141,7 @@
     "eventsource": "^1.0.7",
     "lodash": "^4.17.11",
     "randombytes": "^2.1.0",
-    "stellar-base": "^1.0.3",
+    "stellar-base": "^1.1.1",
     "toml": "^2.3.0",
     "tslib": "^1.10.0",
     "urijs": "^1.19.1",

src/utils.ts

@@ -42,6 +42,13 @@ export namespace Utils {
     const account = new Account(serverKeypair.publicKey(), "-1");
     const now = Math.floor(Date.now() / 1000);
 
+    // A Base64 digit represents 6 bits, to generate a random 64 bytes
+    // base64 string, we need 48 random bytes = (64 * 6)/8
+    //
+    // Each Base64 digit is in ASCII and each ASCII characters when
+    // turned into binary represents 8 bits = 1 bytes.
+    const value = randomBytes(48).toString("base64");
+
     const transaction = new TransactionBuilder(account, {
       fee: BASE_FEE,
       timebounds: {
@@ -52,7 +59,7 @@ export namespace Utils {
       .addOperation(
         Operation.manageData({
           name: `${anchorName} auth`,
-          value: randomBytes(64),
+          value,
           source: clientAccountID,
         }),
       )
@@ -132,6 +139,18 @@ export namespace Utils {
       );
     }
 
+    if (Buffer.from(operation.value.toString(), "base64").length !== 48) {
+      throw new InvalidSep10ChallengeError(
+        "The transaction's operation value should be a 64 bytes base64 random string",
+      );
+    }
+
+    if (operation.type !== "manageData") {
+      throw new InvalidSep10ChallengeError(
+        "The transaction's operation should be manageData",
+      );
+    }
+
     if (!verifyTxSignedBy(transaction, serverAccountId)) {
       throw new InvalidSep10ChallengeError(
         "The transaction is not signed by the server",

test/unit/utils_test.js

@@ -38,6 +38,7 @@ describe('Utils', function() {
       expect(operation.source).to.eql("GBDIT5GUJ7R5BXO3GJHFXJ6AZ5UQK6MNOIDMPQUSMXLIHTUNR2Q5CFNF");
       expect(operation.type).to.eql("manageData");
       expect(operation.value.length).to.eql(64);
+      expect(Buffer.from(operation.value.toString(), 'base64').length).to.eql(48);
     });
 
     it('uses the passed-in timeout', function() {
@@ -154,7 +155,7 @@ describe('Utils', function() {
             .addOperation(
               StellarSdk.Operation.manageData({
                 name: 'SDF auth',
-                value: randomBytes(64)
+                value: randomBytes(48).toString('base64')
               })
             )
             .setTimeout(30)
@@ -201,6 +202,34 @@ describe('Utils', function() {
       );
     });
 
+    it('throws an error if operation value is not a 64 bytes base64 string', function() {
+      let keypair = StellarSdk.Keypair.random();
+      const account = new StellarSdk.Account(keypair.publicKey(), "-1");
+      const transaction = new StellarSdk.TransactionBuilder(account, { fee: 100 })
+            .addOperation(
+              StellarSdk.Operation.manageData({
+                name: 'SDF auth',
+                value: randomBytes(64),
+                source: 'GBDIT5GUJ7R5BXO3GJHFXJ6AZ5UQK6MNOIDMPQUSMXLIHTUNR2Q5CFNF'
+              })
+            )
+            .setTimeout(30)
+            .build();
+
+      transaction.sign(keypair);
+      const challenge = transaction
+            .toEnvelope()
+            .toXDR("base64")
+            .toString();
+
+      expect(
+        () => StellarSdk.Utils.verifyChallengeTx(challenge, keypair.publicKey())
+      ).to.throw(
+        StellarSdk.InvalidSep10ChallengeError,
+        /The transaction\'s operation value should be a 64 bytes base64 random string/
+      );
+    });
+
     it('throws an error if transaction is not signed by the server', function() {
       let keypair = StellarSdk.Keypair.random();
 

yarn.lock

@@ -7855,10 +7855,10 @@ statuses@~1.4.0:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/statuses/-/statuses-1.4.0.tgz#bb73d446da2796106efcc1b601a253d6c46bd087"
 
-stellar-base@^1.0.3:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/stellar-base/-/stellar-base-1.0.3.tgz#8d3121ca1ce85321b0647c44e69e5877be8e16e1"
-  integrity sha512-1JP/OnjUfbXryrICQJOrxsGgw9VlsgdpGje67692uI9mN8xP+2EyTF1fDs2KllO1Xx/6AaIB+DaU9VGv2nBMgw==
+stellar-base@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/stellar-base/-/stellar-base-1.1.1.tgz#2a97b25584e3e92241a601903a96a776938848cf"
+  integrity sha512-E7L6bjM2OlY4wtf+G9ruG52/LXP/Bs7i5L4jbJJK+RFK/2jp6CNqK97i8/isKF/XpO46WW14EwqOUnXvVfBioQ==
   dependencies:
     base32.js "^0.1.0"
     bignumber.js "^4.0.0"