zeek/tools/bifcl/bif_arg.cc
Arne Welzel e7cce57f2b bifcl: Render runtime type checks for var_args bifs
Currently, Zeek disables any static type checking for var_arg bifs.
However, the generated preamble for var_args bifs assume that
typed positional arguments are correctly typed and blindly calls
the type converters on them. This easily triggers abort()s at runtime
currently when a script mistakenly uses the wrong types for var_arg
bifs. For example, calling publish_rr() with a port instead of a string
causes a hard-abort with Zeek 5.0.8.

    $ zeek -e 'Cluster::publish_rr(Cluster::Pool(), 80/tcp)'
    fatal error in <no location>: Val::CONVERTER (port/string) (80/tcp)
    Aborted (core dumped)

Extend bifcl so that for var_arg functions and the types that bifcl understands,
we render a runtime type check and explicit early return to avoid the abort().
For any/other types, the implementer of the bif continuous to be responsible
for type checking.

This isn't solving the var_args situation generally, but avoids some
ad-hoc fixes trickling in current bif implementations.

Some references:

https://github.com/zeek/zeek/issues/1523
https://github.com/zeek/zeek/issues/2425
https://github.com/zeek/zeek/issues/2935
https://github.com/zeek/zeek/pull/2950
2025-08-20 08:52:25 -07:00

99 lines
2.9 KiB
C++

#include <set>
#include <string>
using namespace std;
#include <string.h>
#include "bif_arg.h"
static struct
{
const char* type_enum;
const char* bif_type;
const char* zeek_type;
const char* c_type;
const char* c_type_smart;
const char* accessor;
const char* accessor_smart;
const char* cast_smart;
const char* constructor;
const char* ctor_smart;
} builtin_func_arg_type[] = {
#define DEFINE_BIF_TYPE(id, bif_type, zeek_type, c_type, c_type_smart, accessor, accessor_smart, \
cast_smart, constructor, ctor_smart) \
{#id, bif_type, zeek_type, c_type, c_type_smart, \
accessor, accessor_smart, cast_smart, constructor, ctor_smart},
#include "bif_type.def"
#undef DEFINE_BIF_TYPE
};
extern const char* arg_list_name;
BuiltinFuncArg::BuiltinFuncArg(const char* arg_name, int arg_type)
{
name = arg_name;
type = arg_type;
type_str = "";
attr_str = "";
}
BuiltinFuncArg::BuiltinFuncArg(const char* arg_name, const char* arg_type_str,
const char* arg_attr_str)
{
name = arg_name;
type = TYPE_OTHER;
type_str = arg_type_str;
attr_str = arg_attr_str;
for ( int i = 0; builtin_func_arg_type[i].bif_type[0] != '\0'; ++i )
if ( ! strcmp(builtin_func_arg_type[i].bif_type, arg_type_str) )
{
type = i;
type_str = "";
}
}
void BuiltinFuncArg::PrintZeek(FILE* fp)
{
fprintf(fp, "%s: %s%s %s", name, builtin_func_arg_type[type].zeek_type, type_str, attr_str);
}
void BuiltinFuncArg::PrintCDef(FILE* fp, int n, bool runtime_type_check)
{
// Generate a runtime type-check pre-amble for types we understand
if ( runtime_type_check && type != TYPE_OTHER && type != TYPE_ANY )
{
fprintf(fp, "\t\t{\n");
fprintf(fp, "\t\t// Runtime type check for %s argument\n", name);
fprintf(fp, "\t\tzeek::TypeTag __tag = (*%s)[%d]->GetType()->Tag();\n", arg_list_name, n);
fprintf(fp, "\t\tif ( __tag != %s )\n", builtin_func_arg_type[type].type_enum);
fprintf(fp, "\t\t\t{\n");
fprintf(fp,
"\t\t\tzeek::emit_builtin_error(zeek::util::fmt(\"expected type %s for %s, got "
"%%s\", zeek::type_name(__tag)));\n",
builtin_func_arg_type[type].zeek_type, name);
fprintf(fp, "\t\t\treturn nullptr;\n");
fprintf(fp, "\t\t\t}\n");
fprintf(fp, "\t\t}\n");
}
fprintf(fp, "\t%s %s = (%s) (", builtin_func_arg_type[type].c_type, name,
builtin_func_arg_type[type].c_type);
char buf[1024];
snprintf(buf, sizeof(buf), "(*%s)[%d].get()", arg_list_name, n);
// Print the accessor expression.
fprintf(fp, builtin_func_arg_type[type].accessor, buf);
fprintf(fp, ");\n");
}
void BuiltinFuncArg::PrintCArg(FILE* fp, int n)
{
fprintf(fp, "%s %s", builtin_func_arg_type[type].c_type_smart, name);
}
void BuiltinFuncArg::PrintValConstructor(FILE* fp)
{
fprintf(fp, builtin_func_arg_type[type].ctor_smart, name);
}