security fix: prevent command injection via callvote

code/game/g_cmds.c

@@ -1213,6 +1213,7 @@ Cmd_CallVote_f
 ==================
 */
 void Cmd_CallVote_f( gentity_t *ent ) {
+	char*	c;
 	int		i;
 	char	arg1[MAX_STRING_TOKENS];
 	char	arg2[MAX_STRING_TOKENS];
@@ -1239,9 +1240,16 @@ void Cmd_CallVote_f( gentity_t *ent ) {
 	trap_Argv( 1, arg1, sizeof( arg1 ) );
 	trap_Argv( 2, arg2, sizeof( arg2 ) );
 
-	if( strchr( arg1, ';' ) || strchr( arg2, ';' ) ) {
-		trap_SendServerCommand( ent-g_entities, "print \"Invalid vote string.\n\"" );
-		return;
+	// check for command separators in arg2
+	for( c = arg2; *c; ++c) {
+		switch(*c) {
+			case '\n':
+			case '\r':
+			case ';':
+				trap_SendServerCommand( ent-g_entities, "print \"Invalid vote string.\n\"" );
+				return;
+			break;
+		}
 	}
 
 	if ( !Q_stricmp( arg1, "map_restart" ) ) {

code/qcommon/cmd.c

@@ -433,6 +433,22 @@ char *Cmd_Cmd(void)
 	return cmd_cmd;
 }
 
+/*
+   Replace command separators with space to prevent interpretation
+   This is a hack to protect buggy qvms
+   https://bugzilla.icculus.org/show_bug.cgi?id=3593
+*/
+void Cmd_Args_Sanitize( void ) {
+	int i;
+	for ( i = 1 ; i < cmd_argc ; i++ ) {
+		char* c = cmd_argv[i];
+		while ((c = strpbrk(c, "\n\r;"))) {
+			*c = ' ';
+			++c;
+		}
+	}
+}
+
 /*
 ============
 Cmd_TokenizeString

code/qcommon/qcommon.h

@@ -434,6 +434,7 @@ char	*Cmd_Args (void);
 char	*Cmd_ArgsFrom( int arg );
 void	Cmd_ArgsBuffer( char *buffer, int bufferLength );
 char	*Cmd_Cmd (void);
+void	Cmd_Args_Sanitize( void );
 // The functions that execute commands get their parameters with these
 // functions. Cmd_Argv () will return an empty string, not a NULL
 // if arg > argc, so string operations are allways safe.

code/server/sv_client.c

@@ -1500,6 +1500,7 @@ void SV_ExecuteClientCommand( client_t *cl, const char *s, qboolean clientOK ) {
 	if (clientOK) {
 		// pass unknown strings to the game
 		if (!u->name && sv.state == SS_GAME) {
+			Cmd_Args_Sanitize();
 			VM_Call( gvm, GAME_CLIENT_COMMAND, cl - svs.clients );
 		}
 	}