Re: [PATCH v8 bpf-next 1/9] bpf: Add __bpf_dynptr_data* for in kernel use

Song Liu
2023-11-02T22:59:55Z

On Thu, Nov 2, 2023 at 1:16 PM Song Liu <song@kernel.org> wrote:
>
[...]
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index df697c74d519..92dc20d9b9ae 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1378,6 +1378,7 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr,
> struct bpf_dynptr_kern *sig_ptr,
> struct bpf_key *trusted_keyring)
> {
> + void *data, *sig;
> int ret;
>
> if (trusted_keyring->has_ref) {
> @@ -1394,10 +1395,14 @@ __bpf_kfunc int bpf_verify_pkcs7_signature(struct bpf_dynptr_kern *data_ptr,
> return ret;
> }
>
> - return verify_pkcs7_signature(data_ptr->data,
> - __bpf_dynptr_size(data_ptr),
> - sig_ptr->data,
> - __bpf_dynptr_size(sig_ptr),
> + data = __bpf_dynptr_data(data_ptr, __bpf_dynptr_size(data_ptr));
> + sig = __bpf_dynptr_data(sig_ptr, __bpf_dynptr_size(sig_ptr));
> +
> + if (!data || !sig)
> + return -EINVAL;

Sigh, I missed this failure:

https://github.com/kernel-patches/bpf/actions/runs/6737884115/job/18316480188

#110/1 kfunc_dynptr_param/dynptr_data_null
...
verify_success:FAIL:err unexpected err: actual -22 != expected -74

It is easy to fix, but I am not sure which is the right fix.

Basically, null dynptr bpf_verify_pkcs7_signature used to return
-EBADMSG. And it
is returning -EINVAL after this change. Do we need to keep the error code as
-EBADMSG?

Thanks,
Song

> +
> + return verify_pkcs7_signature(data, __bpf_dynptr_size(data_ptr),
> + sig, __bpf_dynptr_size(sig_ptr),
> trusted_keyring->key,
> VERIFYING_UNSPECIFIED_SIGNATURE, NULL,
> NULL);
> --
> 2.34.1
>
>