On Wed, Jul 2, 2025 at 3:42 PM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
>
> Allow specifying __arg_untrusted for void */char */int */long *
> parameters. Treat such parameters as
> PTR_TO_MEM|MEM_RDONLY|PTR_UNTRUSTED of size zero.
> Intended usage is as follows:
>
> int memcmp(char *a __arg_untrusted, char *b __arg_untrusted, size_t n) {
> bpf_for(i, 0, n) {
> if (a[i] - b[i]) // load at any offset is allowed
> return a[i] - b[i];
> }
> return 0;
> }
...
> +bool btf_type_is_primitive(const struct btf_type *t)
> +{
> + return (btf_type_is_int(t) && btf_type_int_is_regular(t)) ||
> + btf_is_any_enum(t);
> +}
Should array of primitive types be allowed as well ?
Since in C
int memcmp(char a[] __arg_untrusted, char b[] __arg_untrusted, size_t n) {
bpf_for(i, 0, n) {
if (a[i] - b[i]) // load at any offset is allowed
return a[i] - b[i];
will work just like 'char *'.
