pool: stricter rules for custom user agent

integration/package.json

@@ -1,5 +1,7 @@
 {
   "name": "hnsd_integration_test",
+  "meta": "!! version must match hnsd version in Makefile.am !!",
+  "version": "1.0.0", 
   "scripts": {
     "test": "bmocha --reporter spec test/*.js",
     "test-file": "bmocha --reporter spec"

integration/test-util.js

@@ -64,11 +64,11 @@ class TestUtil {
       this.hnsd = spawn(
         path.join(__dirname, '..', 'hnsd'),
         this.hnsdArgs,
-        {stdio: 'ignore'}
+        {stdio: 'ignore'} // pro tip: switch to 'inherit' to see hnsd output
       );
 
-      this.hnsd.on('spawn', () => resolve());
-      this.hnsd.on('error', () => reject());
+      this.hnsd.on('spawn', () => resolve(this.hnsd));
+      this.hnsd.on('error', e => reject(e));
     });
   }
 

integration/test/config-test.js

@@ -0,0 +1,66 @@
+/* eslint-env mocha */
+/* eslint prefer-arrow-callback: "off" */
+/* eslint max-len: "off" */
+/* eslint no-return-assign: "off" */
+
+'use strict';
+
+const assert = require('bsert');
+const {version} = require('../package.json');
+
+const TestUtil = require('../test-util');
+const util = new TestUtil();
+
+describe('Configuration', function() {
+  this.timeout(5000);
+
+  before(async () => {
+    await util.open();
+  });
+
+  after(async () => {
+    await util.close();
+  });
+
+  describe('--agent', function () {
+    it('should have default user agent', async () => {
+      await util.generate(1);
+      await util.waitForSync();
+
+      const peer = util.node.pool.peers.head();
+      assert.strictEqual(peer.agent, `/hnsd:${version}/`);
+    });
+
+    it('should fail to start with too-long agent', async () => {
+      const agent = 'x'.repeat(255 - `/hnsd:${version}/`.length);
+      const hnsd = await util.restartHNSD(['-a', agent]);
+      await new Promise((resolve) => {
+        hnsd.once('exit', (code, signal) => {
+          assert.strictEqual(code, 3); // HSK_EFAILURE
+          resolve();
+        });
+      });
+    });
+
+    it('should fail to start with backslash-containing agent', async () => {
+      const agent = 'beacon/browser/verifies/dane';
+      const hnsd = await util.restartHNSD(['-a', agent]);
+      await new Promise((resolve) => {
+        hnsd.once('exit', (code, signal) => {
+          assert.strictEqual(code, 3); // HSK_EFAILURE
+          resolve();
+        });
+      });
+    });
+
+    it('should have custom user agent', async () => {
+      const agent = 'x'.repeat(255 - `/hnsd:${version}/`.length - 1);
+      await util.restartHNSD(['-a', agent]);
+      await util.generate(1);
+      await util.waitForSync();
+
+      const peer = util.node.pool.peers.head();
+      assert.strictEqual(peer.agent, `/hnsd:${version}/${agent}/`);
+    });
+  });
+});

src/pool.c

@@ -302,14 +302,19 @@ hsk_pool_set_agent(hsk_pool_t *pool, const char *user_agent) {
   if (!user_agent)
     return true;
 
+  if (strchr(user_agent, '/'))
+    return false;
+
   size_t len = strlen(pool->user_agent);
   len += strlen(user_agent);
+  len += 1; // terminal "/"
 
   // Agent size in p2p version message is 1 byte
-  if (len > 0xff)
+  if (len > HSK_MAX_AGENT)
     return false;
 
   pool->user_agent = strcat(pool->user_agent, user_agent);
+  pool->user_agent = strcat(pool->user_agent, "/");
 
   return true;
 }

src/pool.h

@@ -27,6 +27,7 @@
 #define HSK_STATE_READING 4
 #define HSK_STATE_HANDSHAKE 5
 #define HSK_STATE_DISCONNECTING 6
+#define HSK_MAX_AGENT 255
 
 /*
  * Types
@@ -59,6 +60,7 @@ typedef struct hsk_peer_s {
   hsk_brontide_t *brontide;
   uint64_t id;
   char host[HSK_MAX_HOST];
+  char agent[HSK_MAX_AGENT];
   hsk_addr_t addr;
   int state;
   uint8_t read_buffer[HSK_BUFFER_SIZE];