From 36099367c88765bbf851e75002504116adadd824 Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@gmail.com>
Date: Fri, 31 May 2024 10:56:08 -0400
Subject: [PATCH] fix condition where the Log and ActivityLog would overflow
 the character buffer by no properly calculating the length of the va_args
 string (this should resolve buffer overflow terminations on GCC 13+);

---
 src/common/Log.cpp       | 9 ++++++---
 src/fne/ActivityLog.cpp  | 7 +++++--
 src/host/ActivityLog.cpp | 7 +++++--
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/common/Log.cpp b/src/common/Log.cpp
index ec9d21dc..3610865d 100644
--- a/src/common/Log.cpp
+++ b/src/common/Log.cpp
@@ -35,7 +35,7 @@
 
 #define EOL    "\r\n"
 
-const uint32_t LOG_BUFFER_LEN = 16384U;
+const uint32_t LOG_BUFFER_LEN = 4096U;
 
 // ---------------------------------------------------------------------------
 //  Global Variables
@@ -216,11 +216,14 @@ void Log(uint32_t level, const char *module, const char* fmt, ...)
         }
     }
 
-    va_list vl;
+    va_list vl, vl_len;
     va_start(vl, fmt);
+    va_copy(vl_len, vl);
 
-    ::vsnprintf(buffer + ::strlen(buffer), LOG_BUFFER_LEN - 1U, fmt, vl);
+    size_t len = ::vsnprintf(nullptr, 0U, fmt, vl_len);
+    ::vsnprintf(buffer + ::strlen(buffer), len + 1U, fmt, vl);
 
+    va_end(vl_len);
     va_end(vl);
 
     if (m_outStream && g_logDisplayLevel == 0U) {
diff --git a/src/fne/ActivityLog.cpp b/src/fne/ActivityLog.cpp
index a25d7e1f..1d923c5f 100644
--- a/src/fne/ActivityLog.cpp
+++ b/src/fne/ActivityLog.cpp
@@ -119,11 +119,14 @@ void ActivityLog(const char* msg, ...)
 
     char buffer[ACT_LOG_BUFFER_LEN];
 
-    va_list vl;
+    va_list vl, vl_len;
     va_start(vl, msg);
+    va_copy(vl_len, vl);
 
-    ::vsnprintf(buffer, ACT_LOG_BUFFER_LEN - 1U, msg, vl);
+    size_t len = ::vsnprintf(nullptr, 0U, msg, vl_len);
+    ::vsnprintf(buffer, len + 1U, msg, vl);
 
+    va_end(vl_len);
     va_end(vl);
 
     bool ret = ::ActivityLogOpen();
diff --git a/src/host/ActivityLog.cpp b/src/host/ActivityLog.cpp
index 2fc1899a..544202f1 100644
--- a/src/host/ActivityLog.cpp
+++ b/src/host/ActivityLog.cpp
@@ -138,11 +138,14 @@ void ActivityLog(const char *mode, const bool sourceRf, const char* msg, ...)
         ::sprintf(buffer, "A: %04d-%02d-%02d %02d:%02d:%02d.%03lu %s %s ", tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, now.tv_usec / 1000U, mode, (sourceRf) ? "RF" : "Net");
     }
 
-    va_list vl;
+    va_list vl, vl_len;
     va_start(vl, msg);
+    va_copy(vl_len, vl);
 
-    ::vsnprintf(buffer + ::strlen(buffer), ACT_LOG_BUFFER_LEN - 1U, msg, vl);
+    size_t len = ::vsnprintf(nullptr, 0U, msg, vl_len);
+    ::vsnprintf(buffer + ::strlen(buffer), len + 1U, msg, vl);
 
+    va_end(vl_len);
     va_end(vl);
 
     bool ret = ::ActivityLogOpen();