Cherry-pick/backport [65cc894ac5c24495|65cc894ac5]: fix off-by-one po…

…ssible buffer overrun when looking for encodings; found by coverity

Use GetModuleHandle() in stead of LoadLibrary() for ntdll, which is already loaded by Cygwin.

unix/tclUnixInit.c

@@ -14,11 +14,11 @@
 #ifdef HAVE_LANGINFO
 #   include <langinfo.h>
 #   ifdef __APPLE__
-#       if defined(HAVE_WEAK_IMPORT) && MAC_OS_X_VERSION_MIN_REQUIRED < 1030
+#	if defined(HAVE_WEAK_IMPORT) && MAC_OS_X_VERSION_MIN_REQUIRED < 1030
 	    /* Support for weakly importing nl_langinfo on Darwin. */
-#           define WEAK_IMPORT_NL_LANGINFO
+#	    define WEAK_IMPORT_NL_LANGINFO
 	    extern char *nl_langinfo(nl_item) WEAK_IMPORT_ATTRIBUTE;
-#       endif
+#	endif
 #    endif
 #endif
 #include <sys/resource.h>
@@ -34,7 +34,7 @@
 
 #ifdef __CYGWIN__
 DLLIMPORT extern __stdcall unsigned char GetVersionExW(void *);
-DLLIMPORT extern __stdcall void *LoadLibraryW(const void *);
+DLLIMPORT extern __stdcall void *GetModuleHandleW(const void *);
 DLLIMPORT extern __stdcall void FreeLibrary(void *);
 DLLIMPORT extern __stdcall void *GetProcAddress(void *, const char *);
 DLLIMPORT extern __stdcall void GetSystemInfo(void *);
@@ -45,12 +45,12 @@ static const char *const platforms[NUMPLATFORMS] = {
 };
 
 #define NUMPROCESSORS 11
-static const char *const  processors[NUMPROCESSORS] = {
+static const char *const processors[NUMPROCESSORS] = {
     "intel", "mips", "alpha", "ppc", "shx", "arm", "ia64", "alpha64", "msil",
     "amd64", "ia32_on_win64"
 };
 
-typedef struct _SYSTEM_INFO {
+typedef struct {
   union {
     DWORD  dwOemId;
     struct {
@@ -69,7 +69,7 @@ typedef struct _SYSTEM_INFO {
   int      wProcessorRevision;
 } SYSTEM_INFO;
 
-typedef struct _OSVERSIONINFOW {
+typedef struct {
   DWORD dwOSVersionInfoSize;
   DWORD dwMajorVersion;
   DWORD dwMinorVersion;
@@ -666,7 +666,7 @@ SearchKnownEncodings(
     int left = 0;
     int right = sizeof(localeTable)/sizeof(LocaleTable);
 
-    while (left <= right) {
+    while (left < right) {
 	int test = (left + right)/2;
 	int code = strcmp(localeTable[test].lang, encoding);
 
@@ -832,7 +832,7 @@ TclpSetVariables(
      */
 
     CFLocaleRef localeRef;
-    
+
     if (&CFLocaleCopyCurrent != NULL && &CFLocaleGetIdentifier != NULL &&
 	    (localeRef = CFLocaleCopyCurrent())) {
 	CFStringRef locale = CFLocaleGetIdentifier(localeRef);
@@ -929,16 +929,13 @@ TclpSetVariables(
 #ifdef __CYGWIN__
 	unameOK = 1;
     if (!osInfoInitialized) {
-	HANDLE handle = LoadLibraryW(L"NTDLL");
+	HANDLE handle = GetModuleHandleW(L"NTDLL");
 	int(__stdcall *getversion)(void *) =
 		(int(__stdcall *)(void *))GetProcAddress(handle, "RtlGetVersion");
 	osInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFOW);
 	if (!getversion || getversion(&osInfo)) {
 	    GetVersionExW(&osInfo);
 	}
-	if (handle) {
-	    FreeLibrary(handle);
-	}
 	osInfoInitialized = 1;
     }
 
@@ -1130,7 +1127,7 @@ TclpGetCStackParams(
 	stackGrowsDown = StackGrowsDown(NULL);
     }
 #endif
-    
+
     /*
      * The first time through in a thread: record the "outermost" stack
      * frame and inquire with the OS about the stack size.
@@ -1159,7 +1156,7 @@ TclpGetCStackParams(
 	if (!stackSize) {
 	    /*
 	     * Stack failure: if we didn't already blow up, we are within the
-	     * safety area. Recheck with the OS in case the stack was grown. 
+	     * safety area. Recheck with the OS in case the stack was grown.
 	     */
 	    result = GetStackSize(&stackSize);
 	    if (result != TCL_OK) {