[PATCH v2 2/3] efi_loader: add UEFI GPT measurement
Ilias Apalodimas
ilias.apalodimas at linaro.org
Fri Oct 1 11:08:51 CEST 2021
On Fri, Oct 01, 2021 at 04:37:40PM +0900, Masahisa Kojima wrote:
> On Tue, 28 Sept 2021 at 05:21, Ilias Apalodimas
> <ilias.apalodimas at linaro.org> wrote:
> >
> > On Tue, Sep 21, 2021 at 04:19:30PM +0900, Masahisa Kojima wrote:
> > > This commit adds the UEFI GPT disk partition topology
> > > measurement required in TCG PC Client PFP Spec.
> > >
> > > Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> > > ---
> > >
> > > (no changes since v1)
> > >
> > > include/blk.h | 3 +
> > > include/efi_loader.h | 2 +-
> > > include/efi_tcg2.h | 12 +++
> > > lib/efi_loader/efi_boottime.c | 2 +-
> > > lib/efi_loader/efi_tcg2.c | 175 +++++++++++++++++++++++++++++++++-
> > > 5 files changed, 191 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/include/blk.h b/include/blk.h
> > > index 19bab081c2..f0cc7ca1a2 100644
> > > --- a/include/blk.h
> > > +++ b/include/blk.h
> > > @@ -45,6 +45,9 @@ enum if_type {
> > > #define BLK_PRD_SIZE 20
> > > #define BLK_REV_SIZE 8
> > >
> > > +#define PART_FORMAT_PCAT 0x1
> >
> > This isn't used anywhere
>
> UEFI spec says:
> ---
> Partition Format:
> 0x01 – PC-AT compatible legacy MBR
> 0x02 – GUID Partition Table
> ---
> I think it is better to define both value even if one of them is not used.
>
Fair enough
> >
> > > @@ -230,6 +230,18 @@ struct smbios_handoff_table_pointers2 {
> > > struct efi_configuration_table table_entry[];
> > > } __packed;
> > >
> > > +/**
> > > + * struct tdUEFI_GPT_DATA - event log structure of industry standard tables
> > > + * @uefi_partition_header: gpt partition header
> > > + * @number_of_partitions: the number of partition
> > > + * @partitions: partition entries
> > > + */
> > > +struct efi_gpt_data {
> > > + gpt_header uefi_partition_header;
> > > + u64 number_of_partitions;
> > > + gpt_entry partitions[];
> > > +} __packed;
> > > +
> > > struct efi_tcg2_protocol {
> > > efi_status_t (EFIAPI * get_capability)(struct efi_tcg2_protocol *this,
> > > struct efi_tcg2_boot_service_capability *capability);
> > > diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> > > index 701e2212c8..bf5661e1ee 100644
> > > --- a/lib/efi_loader/efi_boottime.c
> > > +++ b/lib/efi_loader/efi_boottime.c
> > > @@ -3003,7 +3003,7 @@ efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
> > >
> > > if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) {
> > > if (image_obj->image_type == IMAGE_SUBSYSTEM_EFI_APPLICATION) {
> > > - ret = efi_tcg2_measure_efi_app_invocation();
> > > + ret = efi_tcg2_measure_efi_app_invocation(image_obj);
> > > if (ret != EFI_SUCCESS) {
> > > log_warning("tcg2 measurement fails(0x%lx)\n",
> > > ret);
> > > diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
> > > index 4f68f6dfd5..ea2c1ead03 100644
> > > --- a/lib/efi_loader/efi_tcg2.c
> > > +++ b/lib/efi_loader/efi_tcg2.c
> > > @@ -1525,12 +1525,181 @@ static void *find_smbios_table(void)
> > > return NULL;
> > > }
> > >
> > > +/**
> > > + * search_gpt_dp_node() - search gpt device path node
> > > + *
> > > + * @device_path: device path
> > > + *
> > > + * Return: pointer to the gpt device path node
> > > + */
> > > +static struct
> > > +efi_device_path *search_gpt_dp_node(struct efi_device_path *device_path)
> > > +{
> > > + struct efi_device_path *dp = device_path;
> > > +
> > > + while (dp) {
> > > + if (dp->type == DEVICE_PATH_TYPE_MEDIA_DEVICE &&
> > > + dp->sub_type == DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH) {
> > > + struct efi_device_path_hard_drive_path *hd_dp =
> > > + (struct efi_device_path_hard_drive_path *)dp;
> > > +
> > > + if (hd_dp->partmap_type == PART_FORMAT_GPT &&
> >
> > On dp_part_node() partmap_type is set to 2 for EFI partition types. Why do
> > we interpret it as 'GPT' here?
>
> UEFI spec says:
> partmap_type = 0x02 – GUID Partition Table
Ah yes my bad, it's setting that to '2' indeed based on the 'struct
blk_desc' info. This is correct
> > > + total_gpt_entry_size = gpt_h->num_partition_entries *
[...]
> > > + gpt_h->sizeof_partition_entry;
> > > + orig_gpt_e = calloc(1, total_gpt_entry_size + block_io->media->io_align);
> > > + entry = (void *)ALIGN((uintptr_t)orig_gpt_e, block_io->media->io_align);
> > > + if (!entry) {
> > > + ret = EFI_OUT_OF_RESOURCES;
> > > + goto out2;
> > > + }
> > > +
> > > + ret = block_io->read_blocks(block_io, block_io->media->media_id,
> > > + gpt_h->partition_entry_lba,
> > > + total_gpt_entry_size, entry);
> > > + if (ret != EFI_SUCCESS)
> > > + goto out2;
> > > +
> >
> > Can't you use efi_bl_read() here, instead of searching for the protocol?
> > If you can, moving that out of a static function would make more sense.
>
> With chat discussion with Ilias, we concluded not to do this modification.
Indeed efi_bl_read() cant be used here. Just a heads up to the rest of the
people in this thread, just replace the alignment calls with PTR_ALIGN()
and split the allocation/reading to a different fucntion. This should make
this code a lot more readable.
Thanks!
/Ilias
>
> Thanks,
> Masahisa Kojima
>
> >
> > > + /* count valid GPT entry */
> > > + gpt_e = entry;
> > > + for (i = 0; i < gpt_h->num_partition_entries; i++) {
> > > + if (guidcmp(&null_guid, &gpt_e->partition_type_guid))
> > > + num_of_valid_entry++;
> > > +
> > > + gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
> > > + }
> > > +
> > > + /* prepare event data for measurement */
> > > + event_size = sizeof(struct efi_gpt_data) +
> > > + (num_of_valid_entry * gpt_h->sizeof_partition_entry);
> > > + event = calloc(1, event_size);
> > > + if (!event) {
> > > + ret = EFI_OUT_OF_RESOURCES;
> > > + goto out2;
> > > + }
> > > + memcpy(event, gpt_h, sizeof(gpt_header));
> > > + put_unaligned_le64(num_of_valid_entry, &event->number_of_partitions);
> > > +
> > > + /* copy valid GPT entry */
> > > + gpt_e = entry;
> > > + num_of_valid_entry = 0;
> > > + for (i = 0; i < gpt_h->num_partition_entries; i++) {
> > > + if (guidcmp(&null_guid, &gpt_e->partition_type_guid)) {
> > > + memcpy((u8 *)event->partitions +
> > > + (num_of_valid_entry * gpt_h->sizeof_partition_entry),
> > > + gpt_e, gpt_h->sizeof_partition_entry);
> > > + num_of_valid_entry++;
> > > + }
> > > +
> > > + gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
> > > + }
> > > +
> > > + ret = tcg2_measure_event(dev, 5, EV_EFI_GPT_EVENT, event_size, (u8 *)event);
> > > + if (ret != EFI_SUCCESS)
> > > + goto out2;
> > > +
> > > +out2:
> > > + EFI_CALL(efi_close_protocol((efi_handle_t)block_io, &efi_block_io_guid,
> > > + NULL, NULL));
> > > + free(orig_gpt_h);
> > > + free(orig_gpt_e);
> > > + free(event);
> > > +out1:
> > > + efi_free_pool(device_path);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > /**
> > > * efi_tcg2_measure_efi_app_invocation() - measure efi app invocation
> > > *
> > > * Return: status code
> > > */
> > > -efi_status_t efi_tcg2_measure_efi_app_invocation(void)
> > > +efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *handle)
> > > {
> > > efi_status_t ret;
> > > u32 pcr_index;
> > > @@ -1569,6 +1738,10 @@ efi_status_t efi_tcg2_measure_efi_app_invocation(void)
> > > goto out;
> > > }
> > >
> > > + ret = tcg2_measure_gpt_data(dev, handle);
> > > + if (ret != EFI_SUCCESS)
> > > + goto out;
> > > +
> > > tcg2_efi_app_invoked = true;
> > > out:
> > > return ret;
> > > --
> > > 2.17.1
> > >
> >
> > Cheers
> > /Ilias
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