Merge #21043: net: Avoid UBSan warning in ProcessMessage(...)

3ddbf22ed179a2db733af4b521bec5d2b13ebf4b util: Disallow negative mocktime (MarcoFalke)
f5f2f9716885e7548809e77f46b493c896a019bf net: Avoid UBSan warning in ProcessMessage(...) (practicalswift)

Pull request description:

  Avoid UBSan warning in `ProcessMessage(...)`.

  Context: https://github.com/bitcoin/bitcoin/pull/20380#issuecomment-770427182 (thanks Crypt-iQ!)

ACKs for top commit:
  MarcoFalke:
    re-ACK 3ddbf22ed179a2db733af4b521bec5d2b13ebf4b only change is adding patch written by me
  ajtowns:
    ACK 3ddbf22ed179a2db733af4b521bec5d2b13ebf4b -- code review only

Tree-SHA512: e8d7af0457ca86872b75a4e406c0a93aafd841c2962e244e147e748cc7ca118c56be0fdafe53765f4b291410030b2c3cc8f76f733b37a955d34fc885ab6037b9

3 files changed, 18 insertions, 9 deletions

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index a246c8fa1c..6ee9846c52 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -2489,6 +2489,9 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         bool fRelay = true;
 
         vRecv >> nVersion >> nServiceInt >> nTime >> addrMe;
+        if (nTime < 0) {
+            nTime = 0;
+        }
         nServices = ServiceFlags(nServiceInt);
         if (!pfrom.IsInboundConn())
         {
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index b75a7b8d26..38a0bddddb 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -365,13 +365,13 @@ static RPCHelpMan signmessagewithprivkey()
 static RPCHelpMan setmocktime()
 {
     return RPCHelpMan{"setmocktime",
-                "\nSet the local time to given timestamp (-regtest only)\n",
-                {
-                    {"timestamp", RPCArg::Type::NUM, RPCArg::Optional::NO, UNIX_EPOCH_TIME + "\n"
-            "   Pass 0 to go back to using the system time."},
-                },
-                RPCResult{RPCResult::Type::NONE, "", ""},
-                RPCExamples{""},
+        "\nSet the local time to given timestamp (-regtest only)\n",
+        {
+            {"timestamp", RPCArg::Type::NUM, RPCArg::Optional::NO, UNIX_EPOCH_TIME + "\n"
+             "Pass 0 to go back to using the system time."},
+        },
+        RPCResult{RPCResult::Type::NONE, "", ""},
+        RPCExamples{""},
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
     if (!Params().IsMockableChain()) {
@@ -386,7 +386,10 @@ static RPCHelpMan setmocktime()
     LOCK(cs_main);
 
     RPCTypeCheck(request.params, {UniValue::VNUM});
-    int64_t time = request.params[0].get_int64();
+    const int64_t time{request.params[0].get_int64()};
+    if (time < 0) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Mocktime can not be negative: %s.", time));
+    }
     SetMockTime(time);
     if (request.context.Has<NodeContext>()) {
         for (const auto& chain_client : request.context.Get<NodeContext>().chain_clients) {
diff --git a/src/util/time.cpp b/src/util/time.cpp
index e96972fe12..d130e4e4d4 100644
--- a/src/util/time.cpp
+++ b/src/util/time.cpp
@@ -9,6 +9,8 @@
 
 #include <util/time.h>
 
+#include <util/check.h>
+
 #include <atomic>
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <ctime>
@@ -18,7 +20,7 @@
 
 void UninterruptibleSleep(const std::chrono::microseconds& n) { std::this_thread::sleep_for(n); }
 
-static std::atomic<int64_t> nMockTime(0); //!< For unit testing
+static std::atomic<int64_t> nMockTime(0); //!< For testing
 
 int64_t GetTime()
 {
@@ -46,6 +48,7 @@ template std::chrono::microseconds GetTime();
 
 void SetMockTime(int64_t nMockTimeIn)
 {
+    Assert(nMockTimeIn >= 0);
     nMockTime.store(nMockTimeIn, std::memory_order_relaxed);
 }