On Fri, 2024-11-15 at 00:46 +0000, Anton Protopopov wrote:
[...]
> @@ -22537,6 +22543,76 @@ struct btf *bpf_get_btf_vmlinux(void)
> return btf_vmlinux;
> }
>
> +/*
> + * The add_fd_from_fd_array() is executed only if fd_array_cnt is given. In
> + * this case expect that every file descriptor in the array is either a map or
> + * a BTF, or a hole (0). Everything else is considered to be trash.
> + */
> +static int add_fd_from_fd_array(struct bpf_verifier_env *env, int fd)
> +{
> + struct bpf_map *map;
> + CLASS(fd, f)(fd);
> + int ret;
> +
> + map = __bpf_map_get(f);
> + if (IS_ERR(map)) {
> + if (!IS_ERR(__btf_get_by_fd(f)))
> + return 0;
> +
> + /* allow holes */
> + if (!fd)
> + return 0;
> +
> + verbose(env, "fd %d is not pointing to valid bpf_map or btf\n", fd);
> + return PTR_ERR(map);
> + }
> +
> + ret = add_used_map(env, map);
> + if (ret < 0)
> + return ret;
> + return 0;
> +}
Nit: keeping this function "flat" would allow easier extension, if necessary.
E.g.:
static int add_fd_from_fd_array(struct bpf_verifier_env *env, int fd)
{
struct bpf_map *map;
CLASS(fd, f)(fd);
int ret;
/* allow holes */
if (!fd) {
return 0;
}
map = __bpf_map_get(f);
if (!IS_ERR(map)) {
ret = add_used_map(env, map);
return ret < 0 ? ret : 0;
}
if (!IS_ERR(__btf_get_by_fd(f))) {
return 0;
}
verbose(env, "fd %d is not pointing to valid bpf_map or btf\n", fd);
return -EINVAL;
}
> +
> +static int env_init_fd_array(struct bpf_verifier_env *env, union bpf_attr *attr, bpfptr_t uattr)
> +{
> + int size = sizeof(int) * attr->fd_array_cnt;
> + int *copy;
> + int ret;
> + int i;
> +
> + if (attr->fd_array_cnt >= MAX_USED_MAPS)
> + return -E2BIG;
> +
> + env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
> +
> + /*
> + * The only difference between old (no fd_array_cnt is given) and new
> + * APIs is that in the latter case the fd_array is expected to be
> + * continuous and is scanned for map fds right away
> + */
> + if (!size)
> + return 0;
> +
> + copy = kzalloc(size, GFP_KERNEL);
> + if (!copy)
> + return -ENOMEM;
> +
> + if (copy_from_bpfptr_offset(copy, env->fd_array, 0, size)) {
> + ret = -EFAULT;
> + goto free_copy;
> + }
> +
> + for (i = 0; i < attr->fd_array_cnt; i++) {
> + ret = add_fd_from_fd_array(env, copy[i]);
> + if (ret)
> + goto free_copy;
> + }
> +
> +free_copy:
> + kfree(copy);
> + return ret;
> +}
> +
> int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
> {
> u64 start_time = ktime_get_ns();
[...]
