From 0d636dabc99276c37d9980ab6458e0f632278a71 Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 13:29:53 +0100
Subject: [PATCH 1/3] Check signature for history keeper in a different process

---
 lib/check-signature.js | 40 ++++++++++++++++++++++++++++++
 lib/commands/core.js   |  1 +
 lib/hk-util.js         | 55 +++++++++++++++++++++++++++++++-----------
 3 files changed, 82 insertions(+), 14 deletions(-)
 create mode 100644 lib/check-signature.js

diff --git a/lib/check-signature.js b/lib/check-signature.js
new file mode 100644
index 000000000..c81ffbb2d
--- /dev/null
+++ b/lib/check-signature.js
@@ -0,0 +1,40 @@
+const Nacl = require('tweetnacl/nacl-fast');
+
+// TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
+
+process.on('message', function (data) {
+    console.log(+new Date(), "Message received by subprocess");
+    if (!data || !data.key || !data.msg || !data.txid) {
+        process.send({
+            error:'E_INVAL'
+        });
+        return;
+    }
+    const txid = data.txid;
+
+    const signedMsg = Nacl.util.decodeBase64(data.msg);
+    var validateKey;
+    try {
+        validateKey = Nacl.util.decodeBase64(data.key);
+    } catch (e) {
+        process.send({
+            txid: txid,
+            error:'E_BADKEY'
+        });
+        return;
+    }
+    // validate the message
+    const validated = Nacl.sign.open(signedMsg, validateKey);
+    if (!validated) {
+        process.send({
+            txid: txid,
+            error:'FAILED'
+        });
+        return;
+    }
+    console.log(+new Date(), "Verification done in the subprocess");
+    process.send({
+        txid: txid,
+        success: true
+    });
+});
diff --git a/lib/commands/core.js b/lib/commands/core.js
index d7add69b4..bb5156749 100644
--- a/lib/commands/core.js
+++ b/lib/commands/core.js
@@ -3,6 +3,7 @@
 const Core = module.exports;
 const Util = require("../common-util");
 const escapeKeyCharacters = Util.escapeKeyCharacters;
+const { fork } = require('child_process');
 
 /*  Use Nacl for checking signatures of messages */
 const Nacl = require("tweetnacl/nacl-fast");
diff --git a/lib/hk-util.js b/lib/hk-util.js
index cb9e9b8ef..6f8c1811a 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -6,6 +6,7 @@ const nThen = require('nthen');
 const Util = require("./common-util");
 const MetaRPC = require("./commands/metadata");
 const Nacl = require('tweetnacl/nacl-fast');
+const { fork } = require('child_process');
 
 const now = function () { return (new Date()).getTime(); };
 const ONE_DAY = 1000 * 60 * 60 * 24; // one day in milliseconds
@@ -921,7 +922,14 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * adds timestamps to incoming messages
     * writes messages to the store
 */
+const check = fork('lib/check-signature.js');
+const onChecked = Util.mkEvent();
+check.on('message', function (res) {
+    onChecked.fire(res);
+});
+
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
+    console.log(+new Date(), "onChannelMessage");
     const Log = Env.Log;
 
     // TODO our usage of 'channel' here looks prone to errors
@@ -962,20 +970,37 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         let signedMsg = (isCp) ? msgStruct[4].replace(CHECKPOINT_PATTERN, '') : msgStruct[4];
         // convert the message from a base64 string into a Uint8Array
 
-        // FIXME this can fail and the client won't notice
-        signedMsg = Nacl.util.decodeBase64(signedMsg);
-
-        // FIXME this can blow up
-        // TODO check that that won't cause any problems other than not being able to append...
-        const validateKey = Nacl.util.decodeBase64(metadata.validateKey);
-        // validate the message
-        const validated = Nacl.sign.open(signedMsg, validateKey);
-        if (!validated) {
-            // don't go any further if the message fails validation
-            w.abort();
-            Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
-            return;
-        }
+        const txid = Util.uid();
+        const next = w();
+
+        // Listen for messages
+        const onCheck = function (res) {
+            if (!res) { return; }
+            if (res.txid !== txid) { return; }
+            // Wev'e received an answer, remove this handler
+            console.log(+new Date(), "Received verification response");
+            onChecked.unreg(onCheck);
+            if (res.error) {
+                // don't go any further if the message fails validation
+                if (res.error === 'FAILED') {
+                    // Signature doesn't match the public key
+                    Log.info("HK_SIGNED_MESSAGE_REJECTED", 'Channel '+channel.id);
+                }
+                w.abort();
+                return;
+            }
+            // Success, continue to next block
+            next();
+        };
+        onChecked.reg(onCheck);
+
+        console.log(+new Date(), "Send verification request");
+        // Send the request
+        check.send({
+            txid: txid,
+            msg: signedMsg,
+            key: metadata.validateKey
+        });
     }).nThen(function () {
         // do checkpoint stuff...
 
@@ -1002,7 +1027,9 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
         msgStruct.push(now());
 
         // storeMessage
+        console.log(+new Date(), "Storing message");
         storeMessage(Env, channel, JSON.stringify(msgStruct), isCp, getHash(msgStruct[4], Log));
+        console.log(+new Date(), "Message stored");
     });
 };
 

From fb0eb1b20cfbd229c0fbd82c831dce7bd50366d5 Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 14:18:41 +0100
Subject: [PATCH 2/3] Use more subprocesses

---
 lib/check-signature.js |  5 +++++
 lib/hk-util.js         | 33 ++++++++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/lib/check-signature.js b/lib/check-signature.js
index c81ffbb2d..8f3d5edad 100644
--- a/lib/check-signature.js
+++ b/lib/check-signature.js
@@ -1,8 +1,13 @@
 const Nacl = require('tweetnacl/nacl-fast');
 
+// XXX npm "os" and "child_process"
+
 // TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
 
+console.log('New child process', process.pid);
+
 process.on('message', function (data) {
+    console.log('In process', process.pid)
     console.log(+new Date(), "Message received by subprocess");
     if (!data || !data.key || !data.msg || !data.txid) {
         process.send({
diff --git a/lib/hk-util.js b/lib/hk-util.js
index 6f8c1811a..889d5d0b0 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -7,6 +7,7 @@ const Util = require("./common-util");
 const MetaRPC = require("./commands/metadata");
 const Nacl = require('tweetnacl/nacl-fast');
 const { fork } = require('child_process');
+const numCPUs = require('os').cpus().length;
 
 const now = function () { return (new Date()).getTime(); };
 const ONE_DAY = 1000 * 60 * 60 * 24; // one day in milliseconds
@@ -922,11 +923,32 @@ HK.onDirectMessage = function (Env, Server, seq, userId, json) {
     * adds timestamps to incoming messages
     * writes messages to the store
 */
-const check = fork('lib/check-signature.js');
+
+
 const onChecked = Util.mkEvent();
-check.on('message', function (res) {
-    onChecked.fire(res);
-});
+// Create our workers
+const workers = [];
+for (let i = 0; i < numCPUs; i++) {
+    workers.push(fork('lib/check-signature.js'));
+}
+var initWorker = function (worker) {
+    worker.on('message', function (res) {
+        onChecked.fire(res);
+    });
+    // Spawn a new process in one ends
+    worker.on('exit', function () {
+        // XXX make sure it's dead?
+        var idx = workers.indexOf(worker);
+        if (idx !== -1) {
+            workers.splice(idx, 1);
+        }
+        // Spawn a new one
+        var w = fork('lib/check-signature.js');
+        workers.push(w);
+        initWorker(w);
+    });
+};
+workers.forEach(initWorker);
 
 HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
     console.log(+new Date(), "onChannelMessage");
@@ -996,7 +1018,8 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         console.log(+new Date(), "Send verification request");
         // Send the request
-        check.send({
+        const random = Math.floor(Math.random() * 4);
+        workers[random].send({
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey

From 923616aef05114c7b24cfdeaf01b25566617eddf Mon Sep 17 00:00:00 2001
From: yflory <yann.flory@xwiki.com>
Date: Tue, 17 Mar 2020 15:10:23 +0100
Subject: [PATCH 3/3] Use each process in order instead of using a random one

---
 lib/hk-util.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/hk-util.js b/lib/hk-util.js
index 889d5d0b0..a9b9f0eb1 100644
--- a/lib/hk-util.js
+++ b/lib/hk-util.js
@@ -931,6 +931,7 @@ const workers = [];
 for (let i = 0; i < numCPUs; i++) {
     workers.push(fork('lib/check-signature.js'));
 }
+var nextWorker = 0;
 var initWorker = function (worker) {
     worker.on('message', function (res) {
         onChecked.fire(res);
@@ -1018,12 +1019,12 @@ HK.onChannelMessage = function (Env, Server, channel, msgStruct) {
 
         console.log(+new Date(), "Send verification request");
         // Send the request
-        const random = Math.floor(Math.random() * 4);
-        workers[random].send({
+        workers[nextWorker].send({
             txid: txid,
             msg: signedMsg,
             key: metadata.validateKey
         });
+        if (++nextWorker > numCPUs) { nextWorker = 0; }
     }).nThen(function () {
         // do checkpoint stuff...