shithub: riscv

Info  •  Files  •  Log  •  Branches

gs: fix missing type check in ztype (thanks jsmoody)

to reproduce:

gs <<.
null [[][][][][][][][][][][][][][][]] .type
.

--- a/sys/src/cmd/gs/src/ztype.c

+++ b/sys/src/cmd/gs/src/ztype.c

@@ -77,14 +77,15 @@

 	/* Must be either a stack underflow or a t_[a]struct. */

 	check_op(2);

 	{			/* Get the type name from the structure. */

-	    const char *sname =

-		gs_struct_type_name_string(gs_object_type(imemory,

-							  op[-1].value.pstruct));

-	    int code = name_ref(imemory, (const byte *)sname, strlen(sname),

-				(ref *) (op - 1), 0);

-

-	    if (code < 0)

-		return code;

+	    if ((r_has_type(&op[-1], t_struct) || r_has_type(&op[-1], t_astruct))

+	    && op[-1].value.pstruct != 0x00) {

+		const char *sname =

+		    gs_struct_type_name_string(gs_object_type(imemory, op[-1].value.pstruct));

+		code = name_ref(imemory, (const byte *)sname, strlen(sname), (ref *) (op - 1), 0);

+		if (code < 0)

+		    return code;

+	    } else

+		return_error(e_stackunderflow);

 	}

 	r_set_attrs(op - 1, a_executable);

     } else {

@@ -350,6 +351,8 @@

 		    pop(2);

 		    return 0;

 		}

+	    case t__invalid:

+		return_error(e_stackunderflow);

 	    default:

 		return_op_typecheck(op - 2);

 	}

@@ -371,6 +374,8 @@

 			return_error(e_rangecheck);

 		    ival = (ulong) (long)fval;

 		} break;

+	    case t__invalid:

+		return_error(e_stackunderflow);

 	    default:

 		return_op_typecheck(op - 2);

 	}