From 82c54b1b546cdd6ed6ae37f139e14b31cf731bb1 Mon Sep 17 00:00:00 2001
From: Alibek Omarov <a1ba.omarov@gmail.com>
Date: Sun, 19 Apr 2020 13:02:36 +0300
Subject: [PATCH] engine: disallow zero-width strings for getenv()

---
 engine/common/filesystem.c        | 6 ++++--
 engine/common/host.c              | 8 +++++---
 engine/common/identification.c    | 4 ++--
 engine/common/launcher.c          | 2 +-
 engine/platform/posix/sys_posix.c | 2 +-
 5 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/engine/common/filesystem.c b/engine/common/filesystem.c
index 333f8688..0977aa23 100644
--- a/engine/common/filesystem.c
+++ b/engine/common/filesystem.c
@@ -1383,9 +1383,11 @@ void FS_Rescan( void )
 		FS_AddPak_Fullpath( va( "%sextras_%s.pak", SDL_GetBasePath(), GI->gamefolder ), NULL, extrasFlags );
 	}
 #else
-	if( ( str = getenv( "XASH3D_EXTRAS_PAK1" ) ) )
+	str = getenv( "XASH3D_EXTRAS_PAK1" );
+	if( COM_CheckString( str ) )
 		FS_AddPak_Fullpath( str, NULL, extrasFlags );
-	if( ( str = getenv( "XASH3D_EXTRAS_PAK2" ) ) )
+	str = getenv( "XASH3D_EXTRAS_PAK2" );
+	if( COM_CheckString( str ) )
 		FS_AddPak_Fullpath( str, NULL, extrasFlags );
 #endif
 
diff --git a/engine/common/host.c b/engine/common/host.c
index ac1a18f7..079cc5c0 100644
--- a/engine/common/host.c
+++ b/engine/common/host.c
@@ -899,7 +899,9 @@ void Host_InitCommon( int argc, char **argv, const char *progname, qboolean bCha
 
 	Platform_Init();
 
-	if( ( baseDir = getenv( "XASH3D_BASEDIR" ) ) )
+	baseDir = getenv( "XASH3D_BASEDIR" );
+
+	if( COM_CheckString( baseDir ) )
 	{
 		Q_strncpy( host.rootdir, baseDir, sizeof(host.rootdir) );
 	}
@@ -932,9 +934,9 @@ void Host_InitCommon( int argc, char **argv, const char *progname, qboolean bCha
 	host.rodir[0] = 0;
 	if( !Sys_GetParmFromCmdLine( "-rodir", host.rodir ))
 	{
-		char *roDir;
+		char *roDir = getenv( "XASH3D_RODIR" );
 
-		if(( roDir = getenv( "XASH3D_RODIR" )))
+		if( COM_CheckString( roDir ))
 			Q_strncpy( host.rodir, roDir, sizeof( host.rodir ));
 	}
 
diff --git a/engine/common/identification.c b/engine/common/identification.c
index 833d03bc..432b401a 100644
--- a/engine/common/identification.c
+++ b/engine/common/identification.c
@@ -640,7 +640,7 @@ void ID_Init( void )
 #else
 	{
 		const char *home = getenv( "HOME" );
-		if( home )
+		if( COM_CheckString( home ) )
 		{
 			FILE *cfg = fopen( va( "%s/.config/.xash_id", home ), "r" );
 			if( !cfg )
@@ -690,7 +690,7 @@ void ID_Init( void )
 #else
 	{
 		const char *home = getenv( "HOME" );
-		if( home )
+		if( COM_CheckString( home ) )
 		{
 			FILE *cfg = fopen( va( "%s/.config/.xash_id", home ), "w" );
 			if( !cfg )
diff --git a/engine/common/launcher.c b/engine/common/launcher.c
index a2d0001c..2100839f 100644
--- a/engine/common/launcher.c
+++ b/engine/common/launcher.c
@@ -68,7 +68,7 @@ int main( int argc, char** argv )
 	char gamedir_buf[32] = "";
 	const char *gamedir = getenv( "XASH3D_GAMEDIR" );
 
-	if( !gamedir )
+	if( !COM_CheckString( gamedir ) )
 	{
 		gamedir = "valve";
 	}
diff --git a/engine/platform/posix/sys_posix.c b/engine/platform/posix/sys_posix.c
index 8ae7879c..dd448726 100644
--- a/engine/platform/posix/sys_posix.c
+++ b/engine/platform/posix/sys_posix.c
@@ -33,7 +33,7 @@ static qboolean Sys_FindExecutable( const char *baseName, char *buf, size_t size
 		return false;
 
 	envPath = getenv( "PATH" );
-	if( !envPath )
+	if( !COM_CheckString( envPath ) )
 		return false;
 
 	baseNameLength = Q_strlen( baseName );