Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933504Ab3CRVfx (ORCPT ); Mon, 18 Mar 2013 17:35:53 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:35934 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933346Ab3CRVcz (ORCPT ); Mon, 18 Mar 2013 17:32:55 -0400 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, Matthew Garrett , Josh Boyer Subject: [PATCH 04/12] efi: Enable secure boot lockdown automatically when enabled in firmware Date: Mon, 18 Mar 2013 17:32:25 -0400 Message-Id: <1363642353-30749-4-git-send-email-matthew.garrett@nebula.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> References: <1363642353-30749-1-git-send-email-matthew.garrett@nebula.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2001:470:1f07:1371:e0f4:3a1:9c35:d688 X-SA-Exim-Mail-From: matthew.garrett@nebula.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4876 Lines: 143 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. We also indicate the machine is in secure boot mode by adding the EFI_SECURE_BOOT bit for use with efi_enabled. Signed-off-by: Matthew Garrett Signed-off-by: Josh Boyer --- Documentation/x86/zero-page.txt | 3 ++- arch/x86/boot/compressed/eboot.c | 32 ++++++++++++++++++++++++++++++++ arch/x86/include/uapi/asm/bootparam.h | 3 ++- arch/x86/kernel/setup.c | 5 +++++ include/linux/cred.h | 2 ++ include/linux/efi.h | 1 + 6 files changed, 44 insertions(+), 2 deletions(-) diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt index 199f453..16f2464 100644 --- a/Documentation/x86/zero-page.txt +++ b/Documentation/x86/zero-page.txt @@ -29,7 +29,8 @@ Offset Proto Name Meaning 1E8/001 ALL e820_entries Number of entries in e820_map (below) 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 1EF/001 ALL sentinel Used to detect broken bootloaders 290/040 ALL edd_mbr_sig_buffer EDD MBR signatures 2D0/A00 ALL e820_map E820 memory map table diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index c205035..96d859d 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -861,6 +861,36 @@ 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 @@ -1155,6 +1185,8 @@ 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); setup_efi_pci(boot_params); diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h index c15ddaf..85d7685 100644 --- a/arch/x86/include/uapi/asm/bootparam.h +++ b/arch/x86/include/uapi/asm/bootparam.h @@ -131,7 +131,8 @@ struct boot_params { __u8 eddbuf_entries; /* 0x1e9 */ __u8 edd_mbr_sig_buf_entries; /* 0x1ea */ __u8 kbd_status; /* 0x1eb */ - __u8 _pad5[3]; /* 0x1ec */ + __u8 secure_boot; /* 0x1ec */ + __u8 _pad5[2]; /* 0x1ed */ /* * The sentinel is set to a nonzero value (0xff) in header.S. * diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 90d8cc9..5ef9285 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1104,6 +1104,11 @@ void __init setup_arch(char **cmdline_p) io_delay_init(); + if (boot_params.secure_boot) { + set_bit(EFI_SECURE_BOOT, &x86_efi_facility); + 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 04421e8..9e69542 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -156,6 +156,8 @@ 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 */ diff --git a/include/linux/efi.h b/include/linux/efi.h index 9bf2f1f..1bf382b 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -627,6 +627,7 @@ extern int __init efi_setup_pcdp_console(char *); #define EFI_RUNTIME_SERVICES 3 /* Can we use runtime services? */ #define EFI_MEMMAP 4 /* Can we use EFI memory map? */ #define EFI_64BIT 5 /* Is the firmware 64-bit? */ +#define EFI_SECURE_BOOT 6 /* Are we in Secure Boot mode? */ #ifdef CONFIG_EFI # ifdef CONFIG_X86 -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/