Quoting Matthew Garrett (mjg@xxxxxxxxxx):
> The firmware has a set of flags that indicate whether secure boot is enabled
> and enforcing. Use them to indicate whether the kernel should lock itself
> down.
>
> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
(purely for the non-firmware bits) seems good, thanks.
Acked-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxx>
> ---
> Documentation/x86/zero-page.txt | 2 ++
> arch/x86/boot/compressed/eboot.c | 32 ++++++++++++++++++++++++++++++++
> arch/x86/include/asm/bootparam.h | 3 ++-
> arch/x86/kernel/setup.c | 3 +++
> include/linux/cred.h | 2 ++
> 5 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
> index cf5437d..7f9ed48 100644
> --- a/Documentation/x86/zero-page.txt
> +++ b/Documentation/x86/zero-page.txt
> @@ -27,6 +27,8 @@ Offset Proto Name Meaning
> 1E9/001 ALL eddbuf_entries Number of entries in eddbuf (below)
> 1EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer
> (below)
> +1EB/001 ALL kbd_status Numlock is enabled
> +1EC/001 ALL secure_boot Kernel should enable secure boot lockdowns
> 290/040 ALL edd_mbr_sig_buffer EDD MBR signatures
> 2D0/A00 ALL e820_map E820 memory map table
> (array of struct e820entry)
> diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
> index b3e0227..3789356 100644
> --- a/arch/x86/boot/compressed/eboot.c
> +++ b/arch/x86/boot/compressed/eboot.c
> @@ -724,6 +724,36 @@ fail:
> return status;
> }
>
> +static int get_secure_boot(efi_system_table_t *_table)
> +{
> + u8 sb, setup;
> + unsigned long datasize = sizeof(sb);
> + efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
> + efi_status_t status;
> +
> + status = efi_call_phys5(sys_table->runtime->get_variable,
> + L"SecureBoot", &var_guid, NULL, &datasize, &sb);
> +
> + if (status != EFI_SUCCESS)
> + return 0;
> +
> + if (sb == 0)
> + return 0;
> +
> +
> + status = efi_call_phys5(sys_table->runtime->get_variable,
> + L"SetupMode", &var_guid, NULL, &datasize,
> + &setup);
> +
> + if (status != EFI_SUCCESS)
> + return 0;
> +
> + if (setup == 1)
> + return 0;
> +
> + return 1;
> +}
> +
> /*
> * Because the x86 boot code expects to be passed a boot_params we
> * need to create one ourselves (usually the bootloader would create
> @@ -1018,6 +1048,8 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,
> if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
> goto fail;
>
> + boot_params->secure_boot = get_secure_boot(sys_table);
> +
> setup_graphics(boot_params);
>
> status = efi_call_phys3(sys_table->boottime->allocate_pool,
> diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
> index 2ad874c..c7338e0 100644
> --- a/arch/x86/include/asm/bootparam.h
> +++ b/arch/x86/include/asm/bootparam.h
> @@ -114,7 +114,8 @@ struct boot_params {
> __u8 eddbuf_entries; /* 0x1e9 */
> __u8 edd_mbr_sig_buf_entries; /* 0x1ea */
> __u8 kbd_status; /* 0x1eb */
> - __u8 _pad6[5]; /* 0x1ec */
> + __u8 secure_boot; /* 0x1ec */
> + __u8 _pad6[4]; /* 0x1ed */
> struct setup_header hdr; /* setup header */ /* 0x1f1 */
> __u8 _pad7[0x290-0x1f1-sizeof(struct setup_header)];
> __u32 edd_mbr_sig_buffer[EDD_MBR_SIG_MAX]; /* 0x290 */
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index f4b9b80..239bf2a 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -947,6 +947,9 @@ void __init setup_arch(char **cmdline_p)
>
> io_delay_init();
>
> + if (boot_params.secure_boot)
> + secureboot_enable();
> +
> /*
> * Parse the ACPI tables for possible boot-time SMP configuration.
> */
> diff --git a/include/linux/cred.h b/include/linux/cred.h
> index ebbed2c..a24faf1 100644
> --- a/include/linux/cred.h
> +++ b/include/linux/cred.h
> @@ -170,6 +170,8 @@ extern int set_security_override_from_ctx(struct cred *, const char *);
> extern int set_create_files_as(struct cred *, struct inode *);
> extern void __init cred_init(void);
>
> +extern void secureboot_enable(void);
> +
> /*
> * check for validity of credentials
> */
> --
> 1.7.11.4
>
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