linux-kernel - Re: [PATCH v3 RESEND] efi: Do not import certificates from UEFI Secure Boot for T2 Macs

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Message-ID: <2913e2998892833d4bc7d866b99dcd9bd234e82e.camel@linux.ibm.com>
Date:   Tue, 12 Apr 2022 11:13:52 -0400
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Aditya Garg <gargaditya08@...e.com>
Cc:     "jarkko@...nel.org" <jarkko@...nel.org>,
        "dmitry.kasatkin@...il.com" <dmitry.kasatkin@...il.com>,
        "jmorris@...ei.org" <jmorris@...ei.org>,
        "serge@...lyn.com" <serge@...lyn.com>,
        "ast@...nel.org" <ast@...nel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        "andrii@...nel.org" <andrii@...nel.org>,
        "kafai@...com" <kafai@...com>,
        "songliubraving@...com" <songliubraving@...com>,
        "yhs@...com" <yhs@...com>,
        "john.fastabend@...il.com" <john.fastabend@...il.com>,
        "kpsingh@...nel.org" <kpsingh@...nel.org>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        "keyrings@...r.kernel.org" <keyrings@...r.kernel.org>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        Orlando Chamberlain <redecorating@...tonmail.com>,
        "admin@...eit.net" <admin@...eit.net>
Subject: Re: [PATCH v3 RESEND] efi: Do not import certificates from UEFI
 Secure Boot for T2 Macs

On Tue, 2022-04-12 at 14:13 +0000, Aditya Garg wrote:
> >> @@ -138,6 +181,11 @@ static int __init load_uefi_certs(void)
> >>      unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
> >>      efi_status_t status;
> >>      int rc = 0;
> >> +    const struct dmi_system_id *dmi_id;
> >> +
> >> +    dmi_id = dmi_first_match(uefi_skip_cert);
> >> +    if (dmi_id)
> >> +            return 0;
> > 
> > uefi_check_ignore_db(), get_cert_list(), uefi_check_ignore_db(), and
> > /load_moklist_certs() are all defined all static and are gated here by
> > this dmi_first_match(). There's probably no need for any of the other
> > calls to dmi_first_match().
> I couldn’t get you here. Could you elaborate?

dmi_first_match() is called here at the beginning of load_uefi_certs().
Only if it succeeds would uefi_check_ignore_db(), get_cert_list(),
uefi_check_ignore_db(), or
load_moklist_certs() be called.  Is there a need for adding a call to
dmi_first_match() in any of these other functions?

thanks,

Mimi

> > 
> > Like in all the other cases, there should be some sort of message. At
> > minimum, there should be a pr_info().
> > 
> >> 
> >>      if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
> >>              return false;
> >