From 962ea4f047b3b4b4360446be4289c4e4deb29551 Mon Sep 17 00:00:00 2001 From: "Justin M. Forbes" Date: Wed, 14 Dec 2016 12:50:48 -0600 Subject: Linux v4.9-7150-gcdb98c2 --- efi-lockdown.patch | 2159 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2159 insertions(+) create mode 100644 efi-lockdown.patch (limited to 'efi-lockdown.patch') diff --git a/efi-lockdown.patch b/efi-lockdown.patch new file mode 100644 index 000000000..b848ee1a6 --- /dev/null +++ b/efi-lockdown.patch @@ -0,0 +1,2159 @@ +From d1d5053106cd1f8b2ae52fb6ffb2962f76053bf0 Mon Sep 17 00:00:00 2001 +From: Ard Biesheuvel +Date: Wed, 23 Nov 2016 10:42:44 +0000 +Subject: [PATCH 01/32] efi: use typed function pointers for runtime services + table + +Instead of using void pointers, and casting them to correctly typed +function pointers upon use, declare the runtime services pointers +as function pointers using their respective prototypes, for which +typedefs are already available. + +Signed-off-by: Ard Biesheuvel +Signed-off-by: David Howells +--- + include/linux/efi.h | 36 ++++++++++++++++++------------------ + 1 file changed, 18 insertions(+), 18 deletions(-) + +diff --git a/include/linux/efi.h b/include/linux/efi.h +index a07a476..93a82de 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -508,24 +508,6 @@ typedef struct { + u64 query_variable_info; + } efi_runtime_services_64_t; + +-typedef struct { +- efi_table_hdr_t hdr; +- void *get_time; +- void *set_time; +- void *get_wakeup_time; +- void *set_wakeup_time; +- void *set_virtual_address_map; +- void *convert_pointer; +- void *get_variable; +- void *get_next_variable; +- void *set_variable; +- void *get_next_high_mono_count; +- void *reset_system; +- void *update_capsule; +- void *query_capsule_caps; +- void *query_variable_info; +-} efi_runtime_services_t; +- + typedef efi_status_t efi_get_time_t (efi_time_t *tm, efi_time_cap_t *tc); + typedef efi_status_t efi_set_time_t (efi_time_t *tm); + typedef efi_status_t efi_get_wakeup_time_t (efi_bool_t *enabled, efi_bool_t *pending, +@@ -560,6 +542,24 @@ typedef efi_status_t efi_query_variable_store_t(u32 attributes, + unsigned long size, + bool nonblocking); + ++typedef struct { ++ efi_table_hdr_t hdr; ++ efi_get_time_t *get_time; ++ efi_set_time_t *set_time; ++ efi_get_wakeup_time_t *get_wakeup_time; ++ efi_set_wakeup_time_t *set_wakeup_time; ++ efi_set_virtual_address_map_t *set_virtual_address_map; ++ void *convert_pointer; ++ efi_get_variable_t *get_variable; ++ efi_get_next_variable_t *get_next_variable; ++ efi_set_variable_t *set_variable; ++ efi_get_next_high_mono_count_t *get_next_high_mono_count; ++ efi_reset_system_t *reset_system; ++ efi_update_capsule_t *update_capsule; ++ efi_query_capsule_caps_t *query_capsule_caps; ++ efi_query_variable_info_t *query_variable_info; ++} efi_runtime_services_t; ++ + void efi_native_runtime_setup(void); + + /* +-- +2.9.3 + +From 150ebd38630a3ac558b8ab839a7c7e5fd41cc5a8 Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Mon, 21 Nov 2016 23:36:31 +0000 +Subject: [PATCH 02/32] x86/efi: Allow invocation of arbitrary runtime services + +Provide the ability to perform mixed-mode runtime service calls for x86 in +the same way that commit 0a637ee61247bd4bed9b2a07568ef7a1cfc76187 +("x86/efi: Allow invocation of arbitrary boot services") provides the +ability to invoke arbitrary boot services. + +Suggested-by: Lukas Wunner +Signed-off-by: David Howells +--- + arch/x86/boot/compressed/eboot.c | 1 + + arch/x86/boot/compressed/head_32.S | 6 +++--- + arch/x86/boot/compressed/head_64.S | 8 ++++---- + arch/x86/include/asm/efi.h | 5 +++++ + 4 files changed, 13 insertions(+), 7 deletions(-) + +diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c +index ff01c8f..c8c32eb 100644 +--- a/arch/x86/boot/compressed/eboot.c ++++ b/arch/x86/boot/compressed/eboot.c +@@ -32,6 +32,7 @@ static void setup_boot_services##bits(struct efi_config *c) \ + \ + table = (typeof(table))sys_table; \ + \ ++ c->runtime_services = table->runtime; \ + c->boot_services = table->boottime; \ + c->text_output = table->con_out; \ + } +diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S +index fd0b6a2..d85b962 100644 +--- a/arch/x86/boot/compressed/head_32.S ++++ b/arch/x86/boot/compressed/head_32.S +@@ -82,7 +82,7 @@ ENTRY(efi_pe_entry) + + /* Relocate efi_config->call() */ + leal efi32_config(%esi), %eax +- add %esi, 32(%eax) ++ add %esi, 40(%eax) + pushl %eax + + call make_boot_params +@@ -108,7 +108,7 @@ ENTRY(efi32_stub_entry) + + /* Relocate efi_config->call() */ + leal efi32_config(%esi), %eax +- add %esi, 32(%eax) ++ add %esi, 40(%eax) + pushl %eax + 2: + call efi_main +@@ -264,7 +264,7 @@ relocated: + #ifdef CONFIG_EFI_STUB + .data + efi32_config: +- .fill 4,8,0 ++ .fill 5,8,0 + .long efi_call_phys + .long 0 + .byte 0 +diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S +index efdfba2..beab832 100644 +--- a/arch/x86/boot/compressed/head_64.S ++++ b/arch/x86/boot/compressed/head_64.S +@@ -265,7 +265,7 @@ ENTRY(efi_pe_entry) + /* + * Relocate efi_config->call(). + */ +- addq %rbp, efi64_config+32(%rip) ++ addq %rbp, efi64_config+40(%rip) + + movq %rax, %rdi + call make_boot_params +@@ -285,7 +285,7 @@ handover_entry: + * Relocate efi_config->call(). + */ + movq efi_config(%rip), %rax +- addq %rbp, 32(%rax) ++ addq %rbp, 40(%rax) + 2: + movq efi_config(%rip), %rdi + call efi_main +@@ -457,14 +457,14 @@ efi_config: + #ifdef CONFIG_EFI_MIXED + .global efi32_config + efi32_config: +- .fill 4,8,0 ++ .fill 5,8,0 + .quad efi64_thunk + .byte 0 + #endif + + .global efi64_config + efi64_config: +- .fill 4,8,0 ++ .fill 5,8,0 + .quad efi_call + .byte 1 + #endif /* CONFIG_EFI_STUB */ +diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h +index e99675b..2f77bce 100644 +--- a/arch/x86/include/asm/efi.h ++++ b/arch/x86/include/asm/efi.h +@@ -191,6 +191,7 @@ static inline efi_status_t efi_thunk_set_virtual_address_map( + struct efi_config { + u64 image_handle; + u64 table; ++ u64 runtime_services; + u64 boot_services; + u64 text_output; + efi_status_t (*call)(unsigned long, ...); +@@ -226,6 +227,10 @@ static inline bool efi_is_64bit(void) + #define __efi_call_early(f, ...) \ + __efi_early()->call((unsigned long)f, __VA_ARGS__); + ++#define efi_call_runtime(f, ...) \ ++ __efi_early()->call(efi_table_attr(efi_runtime_services, f, \ ++ __efi_early()->runtime_services), __VA_ARGS__) ++ + extern bool efi_reboot_required(void); + + #else +-- +2.9.3 + +From 1342301133b5619b79f3288acf7e39450f8ba34f Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Tue, 22 Nov 2016 00:20:00 +0000 +Subject: [PATCH 03/32] arm/efi: Allow invocation of arbitrary runtime services + +efi_call_runtime() is provided for x86 to be able abstract mixed mode +support. Provide this for ARM also so that common code work in mixed mode +also. + +Suggested-by: Lukas Wunner +Signed-off-by: David Howells +--- + arch/arm/include/asm/efi.h | 1 + + arch/arm64/include/asm/efi.h | 1 + + 2 files changed, 2 insertions(+) + +diff --git a/arch/arm/include/asm/efi.h b/arch/arm/include/asm/efi.h +index 0b06f53..e4e6a9d6 100644 +--- a/arch/arm/include/asm/efi.h ++++ b/arch/arm/include/asm/efi.h +@@ -55,6 +55,7 @@ void efi_virtmap_unload(void); + + #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) + #define __efi_call_early(f, ...) f(__VA_ARGS__) ++#define efi_call_runtime(f, ...) sys_table_arg->runtime->f(__VA_ARGS__) + #define efi_is_64bit() (false) + + #define efi_call_proto(protocol, f, instance, ...) \ +diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h +index 771b3f0..d74ae22 100644 +--- a/arch/arm64/include/asm/efi.h ++++ b/arch/arm64/include/asm/efi.h +@@ -49,6 +49,7 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md); + + #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__) + #define __efi_call_early(f, ...) f(__VA_ARGS__) ++#define efi_call_runtime(f, ...) sys_table_arg->runtime->f(__VA_ARGS__) + #define efi_is_64bit() (true) + + #define efi_call_proto(protocol, f, instance, ...) \ +-- +2.9.3 + +From 2e25c5beef2a97abbb660e707bced77c0eb0ace9 Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Tue, 22 Nov 2016 00:10:55 +0000 +Subject: [PATCH 04/32] efi: Add SHIM and image security database GUID + definitions + +Add the definitions for shim and image security database, both of which +are used widely in various Linux distros. + +Signed-off-by: Josh Boyer +Signed-off-by: David Howells +Reviewed-by: Ard Biesheuvel +--- + include/linux/efi.h | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/include/linux/efi.h b/include/linux/efi.h +index 93a82de..c790455 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -610,6 +610,9 @@ void efi_native_runtime_setup(void); + #define EFI_CONSOLE_OUT_DEVICE_GUID EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4, 0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d) + #define APPLE_PROPERTIES_PROTOCOL_GUID EFI_GUID(0x91bd12fe, 0xf6c3, 0x44fb, 0xa5, 0xb7, 0x51, 0x22, 0xab, 0x30, 0x3a, 0xe0) + ++#define EFI_IMAGE_SECURITY_DATABASE_GUID EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f) ++#define EFI_SHIM_LOCK_GUID EFI_GUID(0x605dab50, 0xe046, 0x4300, 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23) ++ + /* + * This GUID is used to pass to the kernel proper the struct screen_info + * structure that was populated by the stub based on the GOP protocol instance +-- +2.9.3 + +From 820d2f84670080c406bad4c8469e80e1e5f8a191 Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Mon, 21 Nov 2016 23:55:55 +0000 +Subject: [PATCH 05/32] efi: Get the secure boot status + +Get the firmware's secure-boot status in the kernel boot wrapper and stash +it somewhere that the main kernel image can find. + +The efi_get_secureboot() function is extracted from the arm stub and (a) +generalised so that it can be called from x86 and (b) made to use +efi_call_runtime() so that it can be run in mixed-mode. + +Suggested-by: Lukas Wunner +Signed-off-by: David Howells +--- + Documentation/x86/zero-page.txt | 2 + + arch/x86/boot/compressed/eboot.c | 2 + + arch/x86/boot/compressed/head_32.S | 1 + + arch/x86/boot/compressed/head_64.S | 1 + + arch/x86/include/asm/bootparam_utils.h | 5 ++- + arch/x86/include/uapi/asm/bootparam.h | 3 +- + arch/x86/kernel/asm-offsets.c | 1 + + drivers/firmware/efi/libstub/Makefile | 2 +- + drivers/firmware/efi/libstub/arm-stub.c | 58 ++------------------------- + drivers/firmware/efi/libstub/secureboot.c | 66 +++++++++++++++++++++++++++++++ + include/linux/efi.h | 8 ++++ + 11 files changed, 90 insertions(+), 59 deletions(-) + create mode 100644 drivers/firmware/efi/libstub/secureboot.c + +diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt +index 95a4d34..b8527c6 100644 +--- a/Documentation/x86/zero-page.txt ++++ b/Documentation/x86/zero-page.txt +@@ -31,6 +31,8 @@ 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 Secure boot is enabled in the firmware + 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 c8c32eb..5b151c2 100644 +--- a/arch/x86/boot/compressed/eboot.c ++++ b/arch/x86/boot/compressed/eboot.c +@@ -1158,6 +1158,8 @@ struct boot_params *efi_main(struct efi_config *c, + else + setup_boot_services32(efi_early); + ++ boot_params->secure_boot = efi_get_secureboot(sys_table); ++ + setup_graphics(boot_params); + + setup_efi_pci(boot_params); +diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S +index d85b962..c635f7e 100644 +--- a/arch/x86/boot/compressed/head_32.S ++++ b/arch/x86/boot/compressed/head_32.S +@@ -61,6 +61,7 @@ + + __HEAD + ENTRY(startup_32) ++ movb $0, BP_secure_boot(%esi) + #ifdef CONFIG_EFI_STUB + jmp preferred_addr + +diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S +index beab832..ccd2c74 100644 +--- a/arch/x86/boot/compressed/head_64.S ++++ b/arch/x86/boot/compressed/head_64.S +@@ -244,6 +244,7 @@ ENTRY(startup_64) + * that maps our entire kernel(text+data+bss+brk), zero page + * and command line. + */ ++ movb $0, BP_secure_boot(%rsi) + #ifdef CONFIG_EFI_STUB + /* + * The entry point for the PE/COFF executable is efi_pe_entry, so +diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h +index 4a8cb8d..7e16d53 100644 +--- a/arch/x86/include/asm/bootparam_utils.h ++++ b/arch/x86/include/asm/bootparam_utils.h +@@ -38,9 +38,10 @@ static void sanitize_boot_params(struct boot_params *boot_params) + memset(&boot_params->ext_ramdisk_image, 0, + (char *)&boot_params->efi_info - + (char *)&boot_params->ext_ramdisk_image); +- memset(&boot_params->kbd_status, 0, ++ boot_params->kbd_status = 0; ++ memset(&boot_params->_pad5, 0, + (char *)&boot_params->hdr - +- (char *)&boot_params->kbd_status); ++ (char *)&boot_params->_pad5); + memset(&boot_params->_pad7[0], 0, + (char *)&boot_params->edd_mbr_sig_buffer[0] - + (char *)&boot_params->_pad7[0]); +diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h +index b10bf31..5138dac 100644 +--- a/arch/x86/include/uapi/asm/bootparam.h ++++ b/arch/x86/include/uapi/asm/bootparam.h +@@ -135,7 +135,8 @@ 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/asm-offsets.c b/arch/x86/kernel/asm-offsets.c +index c62e015..de827d6 100644 +--- a/arch/x86/kernel/asm-offsets.c ++++ b/arch/x86/kernel/asm-offsets.c +@@ -81,6 +81,7 @@ void common(void) { + + BLANK(); + OFFSET(BP_scratch, boot_params, scratch); ++ OFFSET(BP_secure_boot, boot_params, secure_boot); + OFFSET(BP_loadflags, boot_params, hdr.loadflags); + OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch); + OFFSET(BP_version, boot_params, hdr.version); +diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile +index 6621b13..9af9668 100644 +--- a/drivers/firmware/efi/libstub/Makefile ++++ b/drivers/firmware/efi/libstub/Makefile +@@ -28,7 +28,7 @@ OBJECT_FILES_NON_STANDARD := y + # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. + KCOV_INSTRUMENT := n + +-lib-y := efi-stub-helper.o gop.o ++lib-y := efi-stub-helper.o gop.o secureboot.o + + # include the stub's generic dependencies from lib/ when building for ARM/arm64 + arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c +diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c +index b4f7d78..06d5034 100644 +--- a/drivers/firmware/efi/libstub/arm-stub.c ++++ b/drivers/firmware/efi/libstub/arm-stub.c +@@ -20,52 +20,6 @@ + + bool __nokaslr; + +-static int efi_get_secureboot(efi_system_table_t *sys_table_arg) +-{ +- static efi_char16_t const sb_var_name[] = { +- 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 }; +- static efi_char16_t const sm_var_name[] = { +- 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 }; +- +- efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID; +- efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable; +- u8 val; +- unsigned long size = sizeof(val); +- efi_status_t status; +- +- status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid, +- NULL, &size, &val); +- +- if (status != EFI_SUCCESS) +- goto out_efi_err; +- +- if (val == 0) +- return 0; +- +- status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid, +- NULL, &size, &val); +- +- if (status != EFI_SUCCESS) +- goto out_efi_err; +- +- if (val == 1) +- return 0; +- +- return 1; +- +-out_efi_err: +- switch (status) { +- case EFI_NOT_FOUND: +- return 0; +- case EFI_DEVICE_ERROR: +- return -EIO; +- case EFI_SECURITY_VIOLATION: +- return -EACCES; +- default: +- return -EINVAL; +- } +-} +- + efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg, + void *__image, void **__fh) + { +@@ -226,7 +180,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, + efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID; + unsigned long reserve_addr = 0; + unsigned long reserve_size = 0; +- int secure_boot = 0; ++ enum efi_secureboot_mode secure_boot = efi_secureboot_mode_unknown; + struct screen_info *si; + + /* Check if we were booted by the EFI firmware */ +@@ -296,19 +250,13 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, + pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n"); + + secure_boot = efi_get_secureboot(sys_table); +- if (secure_boot > 0) +- pr_efi(sys_table, "UEFI Secure Boot is enabled.\n"); +- +- if (secure_boot < 0) { +- pr_efi_err(sys_table, +- "could not determine UEFI Secure Boot status.\n"); +- } + + /* + * Unauthenticated device tree data is a security hazard, so + * ignore 'dtb=' unless UEFI Secure Boot is disabled. + */ +- if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) { ++ if (secure_boot != efi_secureboot_mode_disabled && ++ strstr(cmdline_ptr, "dtb=")) { + pr_efi(sys_table, "Ignoring DTB from command line.\n"); + } else { + status = handle_cmdline_files(sys_table, image, cmdline_ptr, +diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c +new file mode 100644 +index 0000000..70e2a36 +--- /dev/null ++++ b/drivers/firmware/efi/libstub/secureboot.c +@@ -0,0 +1,66 @@ ++/* ++ * Secure boot handling. ++ * ++ * Copyright (C) 2013,2014 Linaro Limited ++ * Roy Franz ++ * ++ * This file is part of the Linux kernel, and is made available under the ++ * terms of the GNU General Public License version 2. ++ * ++ */ ++ ++#include ++#include ++ ++/* BIOS variables */ ++static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID; ++static const efi_char16_t const efi_SecureBoot_name[] = { ++ 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 ++}; ++static const efi_char16_t const efi_SetupMode_name[] = { ++ 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 ++}; ++ ++#define get_efi_var(name, vendor, ...) \ ++ efi_call_runtime(get_variable, \ ++ (efi_char16_t *)(name), (efi_guid_t *)(vendor), \ ++ __VA_ARGS__); ++ ++/* ++ * Determine whether we're in secure boot mode. We return: ++ */ ++enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) ++{ ++ u8 secboot, setupmode; ++ unsigned long size; ++ efi_status_t status; ++ ++ size = sizeof(secboot); ++ status = get_efi_var(efi_SecureBoot_name, &efi_variable_guid, ++ NULL, &size, &secboot); ++ if (status != EFI_SUCCESS) ++ goto out_efi_err; ++ ++ size = sizeof(setupmode); ++ status = get_efi_var(efi_SetupMode_name, &efi_variable_guid, ++ NULL, &size, &setupmode); ++ if (status != EFI_SUCCESS) ++ goto out_efi_err; ++ ++ if (secboot == 0 || setupmode == 1) ++ goto secure_boot_disabled; ++ ++ pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n"); ++ return efi_secureboot_mode_enabled; ++ ++secure_boot_disabled: ++ return efi_secureboot_mode_disabled; ++ ++out_efi_err: ++ pr_efi_err(sys_table_arg, "Could not determine UEFI Secure Boot status.\n"); ++ if (status == EFI_NOT_FOUND) ++ goto secure_boot_disabled; ++ return efi_secureboot_mode_unknown; ++} +diff --git a/include/linux/efi.h b/include/linux/efi.h +index c790455..92e23f0 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -1477,6 +1477,14 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg, + bool efi_runtime_disabled(void); + extern void efi_call_virt_check_flags(unsigned long flags, const char *call); + ++enum efi_secureboot_mode { ++ efi_secureboot_mode_unset, ++ efi_secureboot_mode_unknown, ++ efi_secureboot_mode_disabled, ++ efi_secureboot_mode_enabled, ++}; ++enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table); ++ + /* + * Arch code can implement the following three template macros, avoiding + * reptition for the void/non-void return cases of {__,}efi_call_virt(): +-- +2.9.3 + +From baa6cdc01e6017c6bd798b1af89458359e13155e Mon Sep 17 00:00:00 2001 +From: Josh Boyer +Date: Mon, 21 Nov 2016 23:55:55 +0000 +Subject: [PATCH 06/32] efi: Disable secure boot if shim is in insecure mode + +A user can manually tell the shim boot loader to disable validation of +images it loads. When a user does this, it creates a UEFI variable called +MokSBState that does not have the runtime attribute set. Given that the +user explicitly disabled validation, we can honor that and not enable +secure boot mode if that variable is set. + +Signed-off-by: Josh Boyer +Signed-off-by: David Howells +--- + drivers/firmware/efi/libstub/secureboot.c | 24 +++++++++++++++++++++++- + 1 file changed, 23 insertions(+), 1 deletion(-) + +diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c +index 70e2a36..ba6ef71 100644 +--- a/drivers/firmware/efi/libstub/secureboot.c ++++ b/drivers/firmware/efi/libstub/secureboot.c +@@ -23,6 +23,12 @@ static const efi_char16_t const efi_SetupMode_name[] = { + 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 + }; + ++/* SHIM variables */ ++static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID; ++static efi_char16_t const shim_MokSBState_name[] = { ++ 'M', 'o', 'k', 'S', 'B', 'S', 't', 'a', 't', 'e', 0 ++}; ++ + #define get_efi_var(name, vendor, ...) \ + efi_call_runtime(get_variable, \ + (efi_char16_t *)(name), (efi_guid_t *)(vendor), \ +@@ -33,7 +39,8 @@ static const efi_char16_t const efi_SetupMode_name[] = { + */ + enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) + { +- u8 secboot, setupmode; ++ u32 attr; ++ u8 secboot, setupmode, moksbstate; + unsigned long size; + efi_status_t status; + +@@ -52,6 +59,21 @@ enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) + if (secboot == 0 || setupmode == 1) + goto secure_boot_disabled; + ++ /* See if a user has put shim into insecure mode. If so, and if the ++ * variable doesn't have the runtime attribute set, we might as well ++ * honor that. ++ */ ++ size = sizeof(moksbstate); ++ status = get_efi_var(shim_MokSBState_name, &shim_guid, ++ &attr, &size, &moksbstate); ++ ++ /* If it fails, we don't care why. Default to secure */ ++ if (status != EFI_SUCCESS) ++ goto secure_boot_enabled; ++ if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS) && moksbstate == 1) ++ goto secure_boot_disabled; ++ ++secure_boot_enabled: + pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n"); + return efi_secureboot_mode_enabled; + +-- +2.9.3 + +From 9079547f4808ea5c8cd844bf40d3895994bd175e Mon Sep 17 00:00:00 2001 +From: Josh Boyer +Date: Mon, 21 Nov 2016 23:55:55 +0000 +Subject: [PATCH 07/32] efi: Add EFI_SECURE_BOOT bit + +UEFI machines can be booted in Secure Boot mode. Add a EFI_SECURE_BOOT bit +that can be passed to efi_enabled() to find out whether secure boot is +enabled. + +This will be used by the SysRq+x handler, registered by the x86 arch, to find +out whether secure boot mode is enabled so that it can be disabled. + +Signed-off-by: Josh Boyer +Signed-off-by: David Howells +--- + arch/x86/kernel/setup.c | 15 +++++++++++++++ + include/linux/efi.h | 1 + + 2 files changed, 16 insertions(+) + +diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c +index 9c337b0..d8972ec 100644 +--- a/arch/x86/kernel/setup.c ++++ b/arch/x86/kernel/setup.c +@@ -1152,6 +1152,21 @@ void __init setup_arch(char **cmdline_p) + /* Allocate bigger log buffer */ + setup_log_buf(1); + ++ if (IS_ENABLED(CONFIG_EFI)) { ++ switch (boot_params.secure_boot) { ++ case efi_secureboot_mode_disabled: ++ pr_info("Secure boot disabled\n"); ++ break; ++ case efi_secureboot_mode_enabled: ++ set_bit(EFI_SECURE_BOOT, &efi.flags); ++ pr_info("Secure boot enabled\n"); ++ break; ++ default: ++ pr_info("Secure boot could not be determined\n"); ++ break; ++ } ++ } ++ + reserve_initrd(); + + acpi_table_upgrade(); +diff --git a/include/linux/efi.h b/include/linux/efi.h +index 92e23f0..135ca9c 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -1066,6 +1066,7 @@ extern int __init efi_setup_pcdp_console(char *); + #define EFI_ARCH_1 7 /* First arch-specific bit */ + #define EFI_DBG 8 /* Print additional debug info at runtime */ + #define EFI_NX_PE_DATA 9 /* Can runtime data regions be mapped non-executable? */ ++#define EFI_SECURE_BOOT 10 /* Are we in Secure Boot mode? */ + + #ifdef CONFIG_EFI + /* +-- +2.9.3 + +From eada0243f0b8fc21588a21c564187219dee03e3c Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Fri, 25 Nov 2016 11:52:05 +0000 +Subject: [PATCH 08/32] efi: Handle secure boot from UEFI-2.6 + +UEFI-2.6 adds a new variable, DeployedMode. If it exists, this must be 1 +if we're to engage lockdown mode. + +Reported-by: James Bottomley +Signed-off-by: David Howells +--- + drivers/firmware/efi/libstub/secureboot.c | 16 +++++++++++++++- + include/linux/efi.h | 4 ++++ + 2 files changed, 19 insertions(+), 1 deletion(-) + +diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c +index ba6ef71..333b159 100644 +--- a/drivers/firmware/efi/libstub/secureboot.c ++++ b/drivers/firmware/efi/libstub/secureboot.c +@@ -22,6 +22,9 @@ static const efi_char16_t const efi_SecureBoot_name[] = { + static const efi_char16_t const efi_SetupMode_name[] = { + 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 + }; ++static const efi_char16_t const efi_DeployedMode_name[] = { ++ 'D', 'e', 'p', 'l', 'o', 'y', 'e', 'd', 'M', 'o', 'd', 'e', 0 ++}; + + /* SHIM variables */ + static const efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID; +@@ -40,7 +43,7 @@ static efi_char16_t const shim_MokSBState_name[] = { + enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) + { + u32 attr; +- u8 secboot, setupmode, moksbstate; ++ u8 secboot, setupmode, deployedmode, moksbstate; + unsigned long size; + efi_status_t status; + +@@ -59,6 +62,17 @@ enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg) + if (secboot == 0 || setupmode == 1) + goto secure_boot_disabled; + ++ /* UEFI-2.6 requires DeployedMode to be 1. */ ++ if (sys_table_arg->hdr.revision >= EFI_2_60_SYSTEM_TABLE_REVISION) { ++ size = sizeof(deployedmode); ++ status = get_efi_var(efi_DeployedMode_name, &efi_variable_guid, ++ NULL, &size, &deployedmode); ++ if (status != EFI_SUCCESS) ++ goto out_efi_err; ++ if (deployedmode == 0) ++ goto secure_boot_disabled; ++ } ++ + /* See if a user has put shim into insecure mode. If so, and if the + * variable doesn't have the runtime attribute set, we might as well + * honor that. +diff --git a/include/linux/efi.h b/include/linux/efi.h +index 135ca9c..e1893f5 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -645,6 +645,10 @@ typedef struct { + + #define EFI_SYSTEM_TABLE_SIGNATURE ((u64)0x5453595320494249ULL) + ++#define EFI_2_60_SYSTEM_TABLE_REVISION ((2 << 16) | (60)) ++#define EFI_2_50_SYSTEM_TABLE_REVISION ((2 << 16) | (50)) ++#define EFI_2_40_SYSTEM_TABLE_REVISION ((2 << 16) | (40)) ++#define EFI_2_31_SYSTEM_TABLE_REVISION ((2 << 16) | (31)) + #define EFI_2_30_SYSTEM_TABLE_REVISION ((2 << 16) | (30)) + #define EFI_2_20_SYSTEM_TABLE_REVISION ((2 << 16) | (20)) + #define EFI_2_10_SYSTEM_TABLE_REVISION ((2 << 16) | (10)) +-- +2.9.3 + +From 3b0695eda22ad712a2b9be9bb70979d875a37816 Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Mon, 21 Nov 2016 23:36:17 +0000 +Subject: [PATCH 09/32] Add the ability to lock down access to the running + kernel image + +Provide a single call to allow kernel code to determine whether the system +should be locked down, thereby disallowing various accesses that might +allow the running kernel image to be changed including the loading of +modules that aren't validly signed with a key we recognise, fiddling with +MSR registers and disallowing hibernation, + +Signed-off-by: David Howells +--- + include/linux/kernel.h | 9 +++++++++ + include/linux/security.h | 11 +++++++++++ + security/Kconfig | 15 +++++++++++++++ + security/Makefile | 3 +++ + security/lock_down.c | 40 ++++++++++++++++++++++++++++++++++++++++ + 5 files changed, 78 insertions(+) + create mode 100644 security/lock_down.c + +diff --git a/include/linux/kernel.h b/include/linux/kernel.h +index bc6ed52..8ab309d 100644 +--- a/include/linux/kernel.h ++++ b/include/linux/kernel.h +@@ -268,6 +268,15 @@ extern int oops_may_print(void); + void do_exit(long error_code) __noreturn; + void complete_and_exit(struct completion *, long) __noreturn; + ++#ifdef CONFIG_LOCK_DOWN_KERNEL ++extern bool kernel_is_locked_down(void); ++#else ++static inline bool kernel_is_locked_down(void) ++{ ++ return false; ++} ++#endif ++ + /* Internal, do not use. */ + int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res); + int __must_check _kstrtol(const char *s, unsigned int base, long *res); +diff --git a/include/linux/security.h b/include/linux/security.h +index c2125e9..41a7325 100644 +--- a/include/linux/security.h ++++ b/include/linux/security.h +@@ -1685,5 +1685,16 @@ static inline void free_secdata(void *secdata) + { } + #endif /* CONFIG_SECURITY */ + ++#ifdef CONFIG_LOCK_DOWN_KERNEL ++extern void lock_kernel_down(void); ++#ifdef CONFIG_ALLOW_LOCKDOWN_LIFT ++extern void lift_kernel_lockdown(void); ++#endif ++#else ++static inline void lock_kernel_down(void) ++{ ++} ++#endif ++ + #endif /* ! __LINUX_SECURITY_H */ + +diff --git a/security/Kconfig b/security/Kconfig +index 118f454..fa1a678 100644 +--- a/security/Kconfig ++++ b/security/Kconfig +@@ -158,6 +158,21 @@ config HARDENED_USERCOPY_PAGESPAN + been removed. This config is intended to be used only while + trying to find such users. + ++config LOCK_DOWN_KERNEL ++ bool "Allow the kernel to be 'locked down'" ++ help ++ Allow the kernel to be locked down under certain circumstances, for ++ instance if UEFI secure boot is enabled. Locking down the kernel ++ turns off various features that might otherwise allow access to the ++ kernel image (eg. setting MSR registers). ++ ++config ALLOW_LOCKDOWN_LIFT ++ bool ++ help ++ Allow the lockdown on a kernel to be lifted, thereby restoring the ++ ability of userspace to access the kernel image (eg. by SysRq+x under ++ x86). ++ + source security/selinux/Kconfig + source security/smack/Kconfig + source security/tomoyo/Kconfig +diff --git a/security/Makefile b/security/Makefile +index f2d71cd..8c4a43e 100644 +--- a/security/Makefile ++++ b/security/Makefile +@@ -29,3 +29,6 @@ obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o + # Object integrity file lists + subdir-$(CONFIG_INTEGRITY) += integrity + obj-$(CONFIG_INTEGRITY) += integrity/ ++ ++# Allow the kernel to be locked down ++obj-$(CONFIG_LOCK_DOWN_KERNEL) += lock_down.o +diff --git a/security/lock_down.c b/security/lock_down.c +new file mode 100644 +index 0000000..5788c60 +--- /dev/null ++++ b/security/lock_down.c +@@ -0,0 +1,40 @@ ++/* Lock down the kernel ++ * ++ * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. ++ * Written by David Howells (dhowells@redhat.com) ++ * ++ * This program is free software; you can redistribute it and/or ++ * modify it under the terms of the GNU General Public Licence ++ * as published by the Free Software Foundation; either version ++ * 2 of the Licence, or (at your option) any later version. ++ */ ++ ++#include ++#include ++ ++static __read_mostly bool kernel_locked_down; ++ ++/* ++ * Put the kernel into lock-down mode. ++ */ ++void lock_kernel_down(void) ++{ ++ kernel_locked_down = true; ++} ++ ++/* ++ * Take the kernel out of lockdown mode. ++ */ ++void lift_kernel_lockdown(void) ++{ ++ kernel_locked_down = false; ++} ++ ++/** ++ * kernel_is_locked_down - Find out if the kernel is locked down ++ */ ++bool kernel_is_locked_down(void) ++{ ++ return kernel_locked_down; ++} ++EXPORT_SYMBOL(kernel_is_locked_down); +-- +2.9.3 + +From c1cc643f82e1c9efee123eb81befb58e41b87310 Mon Sep 17 00:00:00 2001 +From: David Howells +Date: Mon, 21 Nov 2016 23:55:55 +0000 +Subject: [PATCH 10/32] efi: Lock down the kernel if booted in secure boot mode + +UEFI Secure Boot provides a mechanism for ensuring that the firmware will +only load signed bootloaders and kernels. Certain use cases may also +require that all kernel modules also be signed. Add a configuration option +that to lock down the kernel - which includes requiring validly signed +modules - if the kernel is secure-booted. + +Signed-off-by: David Howells +--- + arch/x86/Kconfig | 12 ++++++++++++ + arch/x86/kernel/setup.c | 8 +++++++- + 2 files changed, 19 insertions(+), 1 deletion(-) + +diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig +index bada636..5b19997 100644 +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -1786,6 +1786,18 @@ config EFI_MIXED + + If unsure, say N. + ++config EFI_SECURE_BOOT_LOCK_DOWN ++ def_bool n ++ depends on EFI ++ prompt "Lock down the kernel when UEFI Secure Boot is enabled" ++ ---help--- ++ UEFI Secure Boot provides a mechanism for ensuring that the firmware ++ will only load signed bootloaders and kernels. Certain use cases may ++ also require that all kernel modules also be signed and that ++ userspace is prevented from directly changing the running kernel ++ image. Say Y here to automatically lock down the kernel when a ++ system boots with UEFI Secure Boot enabled. ++ + config SECCOMP + def_bool y + prompt "Enable seccomp to safely compute untrusted bytecode" +diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c +index d8972ec..facaeb9 100644 +--- a/arch/x86/kernel/setup.c ++++ b/arch/x86/kernel/setup.c +@@ -69,6 +69,7 @@ + #include + #include + #include ++#include + + #include