From: Javier Martinez Canillas <javierm@redhat.com>
To: Thiebaud Weksteen <tweek@google.com>
Cc: linux-efi@vger.kernel.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Matt Fleming <matt@codeblueprint.co.uk>,
linux-kernel@vger.kernel.org, Matthew Garrett <mjg59@google.com>,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
tpmdd-devel@lists.sourceforge.net,
jarkko.sakkinen@linux.intel.com, Peter Jones <pjones@redhat.com>
Subject: Re: [tpmdd-devel] [PATCH v2 2/3] efi: call get_event_log before ExitBootServices
Date: Mon, 18 Sep 2017 14:49:00 +0200 [thread overview]
Message-ID: <e29971dc-c266-95a6-86fa-0459490ef754@redhat.com> (raw)
In-Reply-To: <CA+zpnLfewoD7H1hZzCnVKi09a6+DvfGY8ZhFTYuKKFTBgSgoOA@mail.gmail.com>
On 09/18/2017 02:11 PM, Thiebaud Weksteen wrote:
> On Thu, Sep 14, 2017 at 12:24 PM, Javier Martinez Canillas
> <javierm@redhat.com> wrote:
>> On 09/11/2017 12:00 PM, Thiebaud Weksteen via tpmdd-devel wrote:
[snip]
>>> +
>>> + if (status != EFI_SUCCESS) {
>>> + efi_printk(sys_table_arg,
>>> + "Unable to allocate memory for event log\n");
>>> + return;
>>> + }
>>
>> If this fails or any previous error that will prevent the event log table + logs
>> to be allocated, shouldn't tpm_read_log_efi() be notified somehow? Since AFAICT
>> it will still try to access them even if the EFI allocate_pool did not succeed.
>>
>
> The implicit part that covers this case is in
> drivers/firmware/efi/efi.c. The match_config_table function will go
> through all the installed configuration tables and only fill up the
> associated member of the efi structure if it exists. In this case,
> .tpm_log will remains at EFI_INVALID_TABLE_ADDR unless
> efi_call_early(install_configuration_table, ...) is called. So no
> further processing is to be expected should the allocation failed.
>
I see, missed that. Thanks a lot for the explanation.
>>> + */
>>> +int __init efi_tpm_eventlog_init(void)
>>> +{
>>> + struct linux_efi_tpm_eventlog *tbl;
>>> + unsigned int tbl_size;
>>> +
>>
>> The functions efi_retrieve_tpm2_eventlog_1_2() and tpm_read_log_efi() are using
>> log_tbl as variable name, so I would use it here too for consistency.
>>
>
> Done.
>
>>> + if (efi.tpm_log == EFI_INVALID_TABLE_ADDR)
>>> + return 0;
>>> +
>>> + tbl = early_memremap(efi.tpm_log, sizeof(*tbl));
>>> + if (!tbl) {
>>> + pr_err("Failed to map TPM Event Log table @ 0x%lx\n",
>>> + efi.tpm_log);
>>> + return -ENOMEM;
>>> + }
>>> +
>>
>> Same question than before, if this fails then the table + logs memory won't be
>> reserved but tpm_read_log_efi() will still try to access it. I'm not sure what
>> is the correct way to notify though, maybe setting efi.tpm_log to 0 and then in
>> tpm_read_log_efi() check efi.tpm_log for 0 or EFI_INVALID_TABLE_ADDR instead?
>>
>
> That's right. To keep it simple, it might be easier to just set
> tpm_log to EFI_INVALID_TABLE_ADDR if that happens. Added in the next
> version of the patch set.
>
Right. I wasn't sure if you wanted to distinguish between the two cases, but that
is simpler indeed.
Best regards,
--
Javier Martinez Canillas
Software Engineer - Desktop Hardware Enablement
Red Hat
next prev parent reply other threads:[~2017-09-18 12:49 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 10:00 [PATCH v2 0/3] Call GetEventLog before ExitBootServices Thiebaud Weksteen
2017-09-11 10:00 ` [PATCH v2 1/3] tpm: move tpm_eventlog.h outside of drivers folder Thiebaud Weksteen
2017-09-11 10:00 ` [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Thiebaud Weksteen
[not found] ` <20170911100022.7251-3-tweek-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-09-13 14:49 ` kbuild test robot
[not found] ` <201709132252.uZyTCtDz%fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-09-13 16:28 ` Thiebaud Weksteen via tpmdd-devel
2017-09-14 10:24 ` [tpmdd-devel] " Javier Martinez Canillas
[not found] ` <1f25ebdc-ab90-517f-b580-991a7cb5e25a-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-09-18 12:11 ` Thiebaud Weksteen
2017-09-18 12:49 ` Javier Martinez Canillas [this message]
2017-09-14 18:43 ` Jarkko Sakkinen
[not found] ` <20170914184126.eevnstwq3i6fiq4j-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-09-14 18:48 ` Matthew Garrett
2017-09-14 19:02 ` Jarkko Sakkinen
[not found] ` <20170914190247.rrbdzdexjjywxipf-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-09-15 4:06 ` Jarkko Sakkinen
2017-09-18 12:28 ` Thiebaud Weksteen
[not found] ` <CA+zpnLfs=DhW6kgbLV63_XzmKS7VnGGE0ecbFBZ0bu4wx3Jf+w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-09-18 17:56 ` Jarkko Sakkinen
2017-09-11 10:00 ` [PATCH v2 3/3] tpm: parse TPM event logs based on EFI table Thiebaud Weksteen
[not found] ` <20170911100022.7251-4-tweek-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-09-11 16:47 ` Jason Gunthorpe
2017-09-12 8:48 ` Thiebaud Weksteen
[not found] ` <20170912084851.z3ednbeojawnyxk2-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-09-18 12:38 ` Thiebaud Weksteen
2017-09-18 16:28 ` Jason Gunthorpe
2017-09-13 16:27 ` kbuild test robot
[not found] ` <201709140034.ESdZA8H8%fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-09-13 16:43 ` Thiebaud Weksteen
2017-09-14 18:47 ` Jarkko Sakkinen
[not found] ` <20170914184732.uiypaz4yft777oc7-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-09-18 12:33 ` Thiebaud Weksteen
[not found] ` <20170911100022.7251-1-tweek-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-09-13 18:59 ` [PATCH v2 0/3] Call GetEventLog before ExitBootServices Jarkko Sakkinen
2017-11-03 15:27 ` Jarkko Sakkinen
2017-09-14 10:21 ` [tpmdd-devel] " Javier Martinez Canillas
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