From b837b334db5dd6232725fd2350928ff4fbd3feee Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@protonmail.com>
Date: Mon, 30 Sep 2019 12:27:27 +0200
Subject: [PATCH 1/2] net: Fail instead of truncate command name in
 CMessageHeader

Replace the memset/strncpy dance in `CMessageHeader::CMessageHeader`
with explicit code that copies then name and asserts the length.

This removes a warning in g++ 9.1.1 and IMO makes the code more readable
by not relying on strncpy padding and silent truncation behavior.
---
 src/protocol.cpp | 9 +++++++--
 src/protocol.h   | 4 ++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/protocol.cpp b/src/protocol.cpp
index e49e5523ac..bd3ed25a8a 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -85,8 +85,13 @@ CMessageHeader::CMessageHeader(const MessageStartChars& pchMessageStartIn)
 CMessageHeader::CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn)
 {
     memcpy(pchMessageStart, pchMessageStartIn, MESSAGE_START_SIZE);
-    memset(pchCommand, 0, sizeof(pchCommand));
-    strncpy(pchCommand, pszCommand, COMMAND_SIZE);
+
+    // Copy the command name, zero-padding to COMMAND_SIZE bytes
+    size_t i = 0;
+    for (; i < COMMAND_SIZE && pszCommand[i] != 0; ++i) pchCommand[i] = pszCommand[i];
+    assert(pszCommand[i] == 0); // Assert that the command name passed in is not longer than COMMAND_SIZE
+    for (; i < COMMAND_SIZE; ++i) pchCommand[i] = 0;
+
     nMessageSize = nMessageSizeIn;
     memset(pchChecksum, 0, CHECKSUM_SIZE);
 }
diff --git a/src/protocol.h b/src/protocol.h
index db07efb9f9..6639ae2aac 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -37,6 +37,10 @@ public:
     typedef unsigned char MessageStartChars[MESSAGE_START_SIZE];
 
     explicit CMessageHeader(const MessageStartChars& pchMessageStartIn);
+
+    /** Construct a P2P message header from message-start characters, a command and the size of the message.
+     * @note Passing in a `pszCommand` longer than COMMAND_SIZE will result in a run-time assertion error.
+     */
     CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn);
 
     std::string GetCommand() const;

From ff9c671b11d40e5d0623eff3dd12e48cbaafb34e Mon Sep 17 00:00:00 2001
From: Russell Yanofsky <russ@yanofsky.org>
Date: Tue, 1 Oct 2019 14:00:46 +0200
Subject: [PATCH 2/2] refactor: Work around GCC 9 `-Wredundant-move` warning

Use std::move workaround for unique_ptr, for when the C++ compiler lacks
a fix for this issue:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579
Do this in a way that avoids a GCC 9 `-Wredundant-move` warning.
---
 src/interfaces/chain.cpp | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index 643bb58d56..5a3420349f 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -236,11 +236,10 @@ public:
     explicit ChainImpl(NodeContext& node) : m_node(node) {}
     std::unique_ptr<Chain::Lock> lock(bool try_lock) override
     {
-        auto result = MakeUnique<LockImpl>(::cs_main, "cs_main", __FILE__, __LINE__, try_lock);
-        if (try_lock && result && !*result) return {};
-        // std::move necessary on some compilers due to conversion from
-        // LockImpl to Lock pointer
-        return std::move(result);
+        auto lock = MakeUnique<LockImpl>(::cs_main, "cs_main", __FILE__, __LINE__, try_lock);
+        if (try_lock && lock && !*lock) return {};
+        std::unique_ptr<Chain::Lock> result = std::move(lock); // Temporary to avoid CWG 1579
+        return result;
     }
     bool findBlock(const uint256& hash, CBlock* block, int64_t* time, int64_t* time_max) override
     {