From 1ecc8a3eef4271931dc11edef6fb4d849657f7c7 Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Sat, 4 Jan 2020 17:15:06 -0500
Subject: [PATCH] Enforce seperate license keys for connected replicas

Former-commit-id: bc005cb50b1010a2bc9170e261cd93dba849c35f
---
 src/replication.cpp | 46 +++++++++++++++++++++++++++++++++++++++++++++
 src/server.h        | 22 ++++++++++++----------
 2 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/src/replication.cpp b/src/replication.cpp
index 730746081..44fa91452 100644
--- a/src/replication.cpp
+++ b/src/replication.cpp
@@ -985,6 +985,19 @@ LError:
     return;
 }
 
+void processReplconfLicense(client *c, robj *arg)
+{
+    if (cserver.license_key != nullptr)
+    {
+        if (strcmp(cserver.license_key, szFromObj(arg)) == 0) {
+            addReplyError(c, "Each replica must have a unique license key");
+            c->flags |= CLIENT_CLOSE_AFTER_REPLY;
+            return;
+        }
+    }
+    addReply(c, shared.ok);
+}
+
 /* REPLCONF <option> <value> <option> <value> ...
  * This command is used by a replica in order to configure the replication
  * process before starting it with the SYNC command.
@@ -1067,6 +1080,9 @@ void replconfCommand(client *c) {
             /* REPLCONF uuid is used to set and send the UUID of each host */
             processReplconfUuid(c, c->argv[j+1]);
             return; // the process function replies to the client for both error and success
+        } else if (!strcasecmp(szFromObj(c->argv[j]),"license")) {
+            processReplconfLicense(c, c->argv[j+1]);
+            return;
         } else {
             addReplyErrorFormat(c,"Unrecognized REPLCONF option: %s",
                 (char*)ptrFromObj(c->argv[j]));
@@ -2072,6 +2088,36 @@ void syncWithMaster(aeEventLoop *el, int fd, void *privdata, int mask) {
             }
         }
         sdsfree(err);
+        mi->repl_state = REPL_STATE_SEND_KEY;
+        // fallthrough
+    }
+
+    /* Send LICENSE Key */
+    if (mi->repl_state == REPL_STATE_SEND_KEY)
+    {
+        if (cserver.license_key == nullptr)
+        {
+            mi->repl_state = REPL_STATE_SEND_PORT;
+        }
+        else
+        {
+            err = sendSynchronousCommand(mi, SYNC_CMD_WRITE,fd,"REPLCONF","license",cserver.license_key,NULL);
+            if (err) goto write_error;
+            mi->repl_state = REPL_STATE_KEY_ACK;
+            return;
+        }
+    }
+
+    /* LICENSE Key Ack */
+    if (mi->repl_state == REPL_STATE_KEY_ACK)
+    {
+        err = sendSynchronousCommand(mi, SYNC_CMD_READ,fd,NULL);
+        if (err[0] == '-') {
+            serverLog(LL_WARNING, "Recieved error from client: %s", err);
+            sdsfree(err);
+            goto error;
+        }
+        sdsfree(err);
         mi->repl_state = REPL_STATE_SEND_PORT;
         // fallthrough
     }
diff --git a/src/server.h b/src/server.h
index 8bf1d344c..35edac232 100644
--- a/src/server.h
+++ b/src/server.h
@@ -554,17 +554,19 @@ public:
 #define REPL_STATE_RECEIVE_AUTH 5 /* Wait for AUTH reply */
 #define REPL_STATE_SEND_UUID 6 /* send our UUID */
 #define REPL_STATE_RECEIVE_UUID 7 /* they should ack with their UUID */
-#define REPL_STATE_SEND_PORT 8 /* Send REPLCONF listening-port */
-#define REPL_STATE_RECEIVE_PORT 9 /* Wait for REPLCONF reply */
-#define REPL_STATE_SEND_IP 10 /* Send REPLCONF ip-address */
-#define REPL_STATE_RECEIVE_IP 11 /* Wait for REPLCONF reply */
-#define REPL_STATE_SEND_CAPA 12 /* Send REPLCONF capa */
-#define REPL_STATE_RECEIVE_CAPA 13 /* Wait for REPLCONF reply */
-#define REPL_STATE_SEND_PSYNC 14 /* Send PSYNC */
-#define REPL_STATE_RECEIVE_PSYNC 15 /* Wait for PSYNC reply */
+#define REPL_STATE_SEND_KEY 8
+#define REPL_STATE_KEY_ACK 9
+#define REPL_STATE_SEND_PORT 10 /* Send REPLCONF listening-port */
+#define REPL_STATE_RECEIVE_PORT 11 /* Wait for REPLCONF reply */
+#define REPL_STATE_SEND_IP 12 /* Send REPLCONF ip-address */
+#define REPL_STATE_RECEIVE_IP 13 /* Wait for REPLCONF reply */
+#define REPL_STATE_SEND_CAPA 14 /* Send REPLCONF capa */
+#define REPL_STATE_RECEIVE_CAPA 15 /* Wait for REPLCONF reply */
+#define REPL_STATE_SEND_PSYNC 16 /* Send PSYNC */
+#define REPL_STATE_RECEIVE_PSYNC 17 /* Wait for PSYNC reply */
 /* --- End of handshake states --- */
-#define REPL_STATE_TRANSFER 16 /* Receiving .rdb from master */
-#define REPL_STATE_CONNECTED 17 /* Connected to master */
+#define REPL_STATE_TRANSFER 18 /* Receiving .rdb from master */
+#define REPL_STATE_CONNECTED 19 /* Connected to master */
 
 /* State of slaves from the POV of the master. Used in client->replstate.
  * In SEND_BULK and ONLINE state the replica receives new updates