cfg parser: Fix underflow with an empty mpath

(cherry picked from commit 9e07f3f)
OpenSIPS · Jul 3, 2017 · eaafc9b · eaafc9b
1 parent 8c35fc4
commit eaafc9b
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/cfg.y b/cfg.y
@@ -1082,7 +1082,7 @@ assign_stm: DEBUG EQUAL snumber
 		| TOS EQUAL error { yyerror("number expected"); }
 		| MPATH EQUAL STRING { mpath=$3; strcpy(mpath_buf, $3);
 								mpath_len=strlen($3);
-								if(mpath_buf[mpath_len-1]!='/') {
+								if(mpath_len==0 || mpath_buf[mpath_len-1]!='/') {
 									mpath_buf[mpath_len]='/';
 									mpath_len++;
 									mpath_buf[mpath_len]='\0';