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author | Justin M. Forbes <jforbes@redhat.com> | 2016-12-14 12:50:48 -0600 |
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committer | Justin M. Forbes <jforbes@redhat.com> | 2016-12-14 12:50:48 -0600 |
commit | 962ea4f047b3b4b4360446be4289c4e4deb29551 (patch) | |
tree | 0a13142b9219114c8902cac2b45fe9c7abc96897 /efi-lockdown.patch | |
parent | b31b0fb7f4d47143f49fdbc50e7c0da678c0540b (diff) | |
download | kernel-962ea4f047b3b4b4360446be4289c4e4deb29551.tar.gz kernel-962ea4f047b3b4b4360446be4289c4e4deb29551.tar.xz kernel-962ea4f047b3b4b4360446be4289c4e4deb29551.zip |
Linux v4.9-7150-gcdb98c2
Diffstat (limited to 'efi-lockdown.patch')
-rw-r--r-- | efi-lockdown.patch | 2159 |
1 files changed, 2159 insertions, 0 deletions
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 <ard.biesheuvel@linaro.org> +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 <ard.biesheuvel@linaro.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <dhowells@redhat.com> +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 <lukas@wunner.de> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <dhowells@redhat.com> +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 <lukas@wunner.de> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <dhowells@redhat.com> +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 <jwboyer@fedoraproject.org> +Signed-off-by: David Howells <dhowells@redhat.com> +Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> +--- + 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 <dhowells@redhat.com> +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 <lukas@wunner.de> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <roy.franz@linaro.org ++ * Copyright (C) 2013 Red Hat, Inc. ++ * Mark Salter <msalter@redhat.com> ++ * ++ * This file is part of the Linux kernel, and is made available under the ++ * terms of the GNU General Public License version 2. ++ * ++ */ ++ ++#include <linux/efi.h> ++#include <asm/efi.h> ++ ++/* 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 <jwboyer@fedoraproject.org> +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 <jwboyer@fedoraproject.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <jwboyer@fedoraproject.org> +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 <jwboyer@fedoraproject.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <dhowells@redhat.com> +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 <James.Bottomley@HansenPartnership.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + 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 <dhowells@redhat.com> +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 <dhowells@redhat.com> +--- + 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 <linux/security.h> ++#include <linux/export.h> ++ ++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 <dhowells@redhat.com> +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 <dhowells@redhat.com> +--- + 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 <linux/crash_dump.h> + #include <linux/tboot.h> + #include <linux/jiffies.h> ++#include <linux/security.h> + + #include <video/edid.h> + +@@ -1159,7 +1160,12 @@ void __init setup_arch(char **cmdline_p) + break; + case efi_secureboot_mode_enabled: + set_bit(EFI_SECURE_BOOT, &efi.flags); +- pr_info("Secure boot enabled\n"); ++ if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT_LOCK_DOWN)) { ++ lock_kernel_down(); ++ pr_info("Secure boot enabled and kernel locked down\n"); ++ } else { ++ pr_info("Secure boot enabled\n"); ++ } + break; + default: + pr_info("Secure boot could not be determined\n"); +-- +2.9.3 + +From 03ff1bcf82c3acc3df8e8fd1badbbc9f6a27a2e6 Mon Sep 17 00:00:00 2001 +From: David Howells <dhowells@redhat.com> +Date: Wed, 23 Nov 2016 13:22:22 +0000 +Subject: [PATCH 11/32] Enforce module signatures if the kernel is locked down + +If the kernel is locked down, require that all modules have valid +signatures that we can verify. + +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/module.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/kernel/module.c b/kernel/module.c +index f57dd63..2a021c3 100644 +--- a/kernel/module.c ++++ b/kernel/module.c +@@ -2744,7 +2744,7 @@ static int module_sig_check(struct load_info *info, int flags) + } + + /* Not having a signature is only an error if we're strict. */ +- if (err == -ENOKEY && !sig_enforce) ++ if (err == -ENOKEY && !sig_enforce && !kernel_is_locked_down()) + err = 0; + + return err; +-- +2.9.3 + +From 328104a3a9859084a25240ea031572e0d20ceaf4 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:16 +0000 +Subject: [PATCH 12/32] Restrict /dev/mem and /dev/kmem when the kernel is + locked down + +Allowing users to write to address space makes it possible for the kernel to +be subverted, avoiding module loading restrictions. Prevent this when the +kernel has been locked down. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/char/mem.c | 6 ++++++ + 1 file changed, 6 insertions(+) + +diff --git a/drivers/char/mem.c b/drivers/char/mem.c +index 5bb1985..6441d21 100644 +--- a/drivers/char/mem.c ++++ b/drivers/char/mem.c +@@ -163,6 +163,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, + if (p != *ppos) + return -EFBIG; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (!valid_phys_addr_range(p, count)) + return -EFAULT; + +@@ -515,6 +518,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf, + if (!pfn_valid(PFN_DOWN(p))) + return -EIO; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (p < (unsigned long) high_memory) { + unsigned long to_write = min_t(unsigned long, count, + (unsigned long)high_memory - p); +-- +2.9.3 + +From 2cfe484bdc7e42b42be4887f2b4d23ac9de79593 Mon Sep 17 00:00:00 2001 +From: Kyle McMartin <kyle@redhat.com> +Date: Mon, 21 Nov 2016 23:55:56 +0000 +Subject: [PATCH 13/32] Add a sysrq option to exit secure boot mode + +Make sysrq+x exit secure boot mode on x86_64, thereby allowing the running +kernel image to be modified. This lifts the lockdown. + +Signed-off-by: David Howells <dhowells@redhat.com> +--- + arch/x86/Kconfig | 10 ++++++++++ + arch/x86/kernel/setup.c | 31 +++++++++++++++++++++++++++++++ + drivers/input/misc/uinput.c | 1 + + drivers/tty/sysrq.c | 19 +++++++++++++------ + include/linux/input.h | 5 +++++ + include/linux/sysrq.h | 8 +++++++- + kernel/debug/kdb/kdb_main.c | 2 +- + 7 files changed, 68 insertions(+), 8 deletions(-) + +diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig +index 5b19997..c2b481b 100644 +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -1798,6 +1798,16 @@ config EFI_SECURE_BOOT_LOCK_DOWN + image. Say Y here to automatically lock down the kernel when a + system boots with UEFI Secure Boot enabled. + ++config EFI_ALLOW_SECURE_BOOT_EXIT ++ def_bool n ++ depends on EFI_SECURE_BOOT_LOCK_DOWN && MAGIC_SYSRQ ++ select ALLOW_LOCKDOWN_LIFT ++ prompt "Allow secure boot mode to be exited with SysRq+x on a keyboard" ++ ---help--- ++ Allow secure boot mode to be exited and the kernel lockdown lifted by ++ typing SysRq+x on a keyboard attached to the system (not permitted ++ through procfs). ++ + 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 facaeb9..de24041 100644 +--- a/arch/x86/kernel/setup.c ++++ b/arch/x86/kernel/setup.c +@@ -71,6 +71,11 @@ + #include <linux/jiffies.h> + #include <linux/security.h> + ++#include <linux/fips.h> ++#include <linux/cred.h> ++#include <linux/sysrq.h> ++#include <linux/init_task.h> ++ + #include <video/edid.h> + + #include <asm/mtrr.h> +@@ -1304,6 +1309,32 @@ void __init i386_reserve_resources(void) + + #endif /* CONFIG_X86_32 */ + ++#ifdef CONFIG_EFI_ALLOW_SECURE_BOOT_EXIT ++ ++static void sysrq_handle_secure_boot(int key) ++{ ++ if (!efi_enabled(EFI_SECURE_BOOT)) ++ return; ++ ++ pr_info("Secure boot disabled\n"); ++ lift_kernel_lockdown(); ++} ++static struct sysrq_key_op secure_boot_sysrq_op = { ++ .handler = sysrq_handle_secure_boot, ++ .help_msg = "unSB(x)", ++ .action_msg = "Disabling Secure Boot restrictions", ++ .enable_mask = SYSRQ_DISABLE_USERSPACE, ++}; ++static int __init secure_boot_sysrq(void) ++{ ++ if (efi_enabled(EFI_SECURE_BOOT)) ++ register_sysrq_key('x', &secure_boot_sysrq_op); ++ return 0; ++} ++late_initcall(secure_boot_sysrq); ++#endif /*CONFIG_EFI_ALLOW_SECURE_BOOT_EXIT*/ ++ ++ + static struct notifier_block kernel_offset_notifier = { + .notifier_call = dump_kernel_offset + }; +diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c +index 92595b9..894ed3f 100644 +--- a/drivers/input/misc/uinput.c ++++ b/drivers/input/misc/uinput.c +@@ -379,6 +379,7 @@ static int uinput_allocate_device(struct uinput_device *udev) + if (!udev->dev) + return -ENOMEM; + ++ udev->dev->flags |= INPUTDEV_FLAGS_SYNTHETIC; + udev->dev->event = uinput_dev_event; + input_set_drvdata(udev->dev, udev); + +diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c +index 52bbd27..72f46a1 100644 +--- a/drivers/tty/sysrq.c ++++ b/drivers/tty/sysrq.c +@@ -479,6 +479,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = { + /* x: May be registered on mips for TLB dump */ + /* x: May be registered on ppc/powerpc for xmon */ + /* x: May be registered on sparc64 for global PMU dump */ ++ /* x: May be registered on x86_64 for disabling secure boot */ + NULL, /* x */ + /* y: May be registered on sparc64 for global register dump */ + NULL, /* y */ +@@ -522,7 +523,7 @@ static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) + sysrq_key_table[i] = op_p; + } + +-void __handle_sysrq(int key, bool check_mask) ++void __handle_sysrq(int key, unsigned int from) + { + struct sysrq_key_op *op_p; + int orig_log_level; +@@ -542,11 +543,15 @@ void __handle_sysrq(int key, bool check_mask) + + op_p = __sysrq_get_key_op(key); + if (op_p) { ++ /* Ban synthetic events from some sysrq functionality */ ++ if ((from == SYSRQ_FROM_PROC || from == SYSRQ_FROM_SYNTHETIC) && ++ op_p->enable_mask & SYSRQ_DISABLE_USERSPACE) ++ printk("This sysrq operation is disabled from userspace.\n"); + /* + * Should we check for enabled operations (/proc/sysrq-trigger + * should not) and is the invoked operation enabled? + */ +- if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { ++ if (from == SYSRQ_FROM_KERNEL || sysrq_on_mask(op_p->enable_mask)) { + pr_cont("%s\n", op_p->action_msg); + console_loglevel = orig_log_level; + op_p->handler(key); +@@ -578,7 +583,7 @@ void __handle_sysrq(int key, bool check_mask) + void handle_sysrq(int key) + { + if (sysrq_on()) +- __handle_sysrq(key, true); ++ __handle_sysrq(key, SYSRQ_FROM_KERNEL); + } + EXPORT_SYMBOL(handle_sysrq); + +@@ -659,7 +664,7 @@ static void sysrq_do_reset(unsigned long _state) + static void sysrq_handle_reset_request(struct sysrq_state *state) + { + if (state->reset_requested) +- __handle_sysrq(sysrq_xlate[KEY_B], false); ++ __handle_sysrq(sysrq_xlate[KEY_B], SYSRQ_FROM_KERNEL); + + if (sysrq_reset_downtime_ms) + mod_timer(&state->keyreset_timer, +@@ -810,8 +815,10 @@ static bool sysrq_handle_keypress(struct sysrq_state *sysrq, + + default: + if (sysrq->active && value && value != 2) { ++ int from = sysrq->handle.dev->flags & INPUTDEV_FLAGS_SYNTHETIC ? ++ SYSRQ_FROM_SYNTHETIC : 0; + sysrq->need_reinject = false; +- __handle_sysrq(sysrq_xlate[code], true); ++ __handle_sysrq(sysrq_xlate[code], from); + } + break; + } +@@ -1095,7 +1102,7 @@ static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, + + if (get_user(c, buf)) + return -EFAULT; +- __handle_sysrq(c, false); ++ __handle_sysrq(c, SYSRQ_FROM_PROC); + } + + return count; +diff --git a/include/linux/input.h b/include/linux/input.h +index a65e3b2..8b03571 100644 +--- a/include/linux/input.h ++++ b/include/linux/input.h +@@ -42,6 +42,7 @@ struct input_value { + * @phys: physical path to the device in the system hierarchy + * @uniq: unique identification code for the device (if device has it) + * @id: id of the device (struct input_id) ++ * @flags: input device flags (SYNTHETIC, etc.) + * @propbit: bitmap of device properties and quirks + * @evbit: bitmap of types of events supported by the device (EV_KEY, + * EV_REL, etc.) +@@ -124,6 +125,8 @@ struct input_dev { + const char *uniq; + struct input_id id; + ++ unsigned int flags; ++ + unsigned long propbit[BITS_TO_LONGS(INPUT_PROP_CNT)]; + + unsigned long evbit[BITS_TO_LONGS(EV_CNT)]; +@@ -190,6 +193,8 @@ struct input_dev { + }; + #define to_input_dev(d) container_of(d, struct input_dev, dev) + ++#define INPUTDEV_FLAGS_SYNTHETIC 0x000000001 ++ + /* + * Verify that we are in sync with input_device_id mod_devicetable.h #defines + */ +diff --git a/include/linux/sysrq.h b/include/linux/sysrq.h +index 387fa7d..f7c52a9 100644 +--- a/include/linux/sysrq.h ++++ b/include/linux/sysrq.h +@@ -28,6 +28,8 @@ + #define SYSRQ_ENABLE_BOOT 0x0080 + #define SYSRQ_ENABLE_RTNICE 0x0100 + ++#define SYSRQ_DISABLE_USERSPACE 0x00010000 ++ + struct sysrq_key_op { + void (*handler)(int); + char *help_msg; +@@ -42,8 +44,12 @@ struct sysrq_key_op { + * are available -- else NULL's). + */ + ++#define SYSRQ_FROM_KERNEL 0x0001 ++#define SYSRQ_FROM_PROC 0x0002 ++#define SYSRQ_FROM_SYNTHETIC 0x0004 ++ + void handle_sysrq(int key); +-void __handle_sysrq(int key, bool check_mask); ++void __handle_sysrq(int key, unsigned int from); + int register_sysrq_key(int key, struct sysrq_key_op *op); + int unregister_sysrq_key(int key, struct sysrq_key_op *op); + struct sysrq_key_op *__sysrq_get_key_op(int key); +diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c +index 2a20c0d..d46d2e1 100644 +--- a/kernel/debug/kdb/kdb_main.c ++++ b/kernel/debug/kdb/kdb_main.c +@@ -1968,7 +1968,7 @@ static int kdb_sr(int argc, const char **argv) + return KDB_ARGCOUNT; + + kdb_trap_printk++; +- __handle_sysrq(*argv[1], check_mask); ++ __handle_sysrq(*argv[1], check_mask ? SYSRQ_FROM_KERNEL : 0); + kdb_trap_printk--; + + return 0; +-- +2.9.3 + +From a82fdfceffac8e9cdc0287d874a8ba1b9d875e70 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:15 +0000 +Subject: [PATCH 14/32] kexec: Disable at runtime if the kernel is locked down + +kexec permits the loading and execution of arbitrary code in ring 0, which +is something that lock-down is meant to prevent. It makes sense to disable +kexec in this situation. + +This does not affect kexec_file_load() which can check for a signature on the +image to be booted. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/kexec.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/kernel/kexec.c b/kernel/kexec.c +index 980936a..46de8e6 100644 +--- a/kernel/kexec.c ++++ b/kernel/kexec.c +@@ -194,6 +194,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, + return -EPERM; + + /* ++ * kexec can be used to circumvent module loading restrictions, so ++ * prevent loading in that case ++ */ ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ ++ /* + * Verify we have a legal set of flags + * This leaves us room for future extensions. + */ +-- +2.9.3 + +From 43d4cec4b9acbe2954afb355cc32dbd456ca77bd Mon Sep 17 00:00:00 2001 +From: Dave Young <dyoung@redhat.com> +Date: Tue, 22 Nov 2016 08:46:15 +0000 +Subject: [PATCH 15/32] Copy secure_boot flag in boot params across kexec + reboot + +Kexec reboot in case secure boot being enabled does not keep the secure +boot mode in new kernel, so later one can load unsigned kernel via legacy +kexec_load. In this state, the system is missing the protections provided +by secure boot. + +Adding a patch to fix this by retain the secure_boot flag in original +kernel. + +secure_boot flag in boot_params is set in EFI stub, but kexec bypasses the +stub. Fixing this issue by copying secure_boot flag across kexec reboot. + +Signed-off-by: Dave Young <dyoung@redhat.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + arch/x86/kernel/kexec-bzimage64.c | 1 + + 1 file changed, 1 insertion(+) + +diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c +index 3407b14..b843a4e 100644 +--- a/arch/x86/kernel/kexec-bzimage64.c ++++ b/arch/x86/kernel/kexec-bzimage64.c +@@ -179,6 +179,7 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr, + if (efi_enabled(EFI_OLD_MEMMAP)) + return 0; + ++ params->secure_boot = boot_params.secure_boot; + ei->efi_loader_signature = current_ei->efi_loader_signature; + ei->efi_systab = current_ei->efi_systab; + ei->efi_systab_hi = current_ei->efi_systab_hi; +-- +2.9.3 + +From 7f303a867209a3641d3da378d914967314b60254 Mon Sep 17 00:00:00 2001 +From: "Lee, Chun-Yi" <joeyli.kernel@gmail.com> +Date: Wed, 23 Nov 2016 13:49:19 +0000 +Subject: [PATCH 16/32] kexec_file: Disable at runtime if securelevel has been + set + +When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image +through kexec_file systemcall if securelevel has been set. + +This code was showed in Matthew's patch but not in git: +https://lkml.org/lkml/2015/3/13/778 + +Cc: Matthew Garrett <mjg59@srcf.ucam.org> +Signed-off-by: Lee, Chun-Yi <jlee@suse.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/kexec_file.c | 6 ++++++ + 1 file changed, 6 insertions(+) + +diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c +index 037c321..04f48f2 100644 +--- a/kernel/kexec_file.c ++++ b/kernel/kexec_file.c +@@ -264,6 +264,12 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, + if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + return -EPERM; + ++ /* Don't permit images to be loaded into trusted kernels if we're not ++ * going to verify the signature on them ++ */ ++ if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && kernel_is_locked_down()) ++ return -EPERM; ++ + /* Make sure we have a legal set of flags */ + if (flags != (flags & KEXEC_FILE_FLAGS)) + return -EINVAL; +-- +2.9.3 + +From 7b42e60e328109fc2a04434c3cfedeb53eae6426 Mon Sep 17 00:00:00 2001 +From: Josh Boyer <jwboyer@fedoraproject.org> +Date: Tue, 22 Nov 2016 08:46:15 +0000 +Subject: [PATCH 17/32] hibernate: Disable when the kernel is locked down + +There is currently no way to verify the resume image when returning +from hibernate. This might compromise the signed modules trust model, +so until we can work with signed hibernate images we disable it when the +kernel is locked down. + +Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/power/hibernate.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c +index b26dbc4..3732187 100644 +--- a/kernel/power/hibernate.c ++++ b/kernel/power/hibernate.c +@@ -67,7 +67,7 @@ static const struct platform_hibernation_ops *hibernation_ops; + + bool hibernation_available(void) + { +- return (nohibernate == 0); ++ return nohibernate == 0 && !kernel_is_locked_down(); + } + + /** +-- +2.9.3 + +From a2a550718c501375c22f5afdead9d25225abdcd3 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <mjg59@srcf.ucam.org> +Date: Wed, 23 Nov 2016 13:28:17 +0000 +Subject: [PATCH 18/32] uswsusp: Disable when the kernel is locked down + +uswsusp allows a user process to dump and then restore kernel state, which +makes it possible to modify the running kernel. Disable this if the kernel +is locked down. + +Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/power/user.c | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/kernel/power/user.c b/kernel/power/user.c +index 35310b6..c9ef5e1 100644 +--- a/kernel/power/user.c ++++ b/kernel/power/user.c +@@ -52,6 +52,9 @@ static int snapshot_open(struct inode *inode, struct file *filp) + if (!hibernation_available()) + return -EPERM; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + lock_system_sleep(); + + if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { +-- +2.9.3 + +From 81204660ab5d1914cb59fb246f103288ecf9a177 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:15 +0000 +Subject: [PATCH 19/32] PCI: Lock down BAR access when the kernel is locked + down + +Any hardware that can potentially generate DMA has to be locked down in +order to avoid it being possible for an attacker to modify kernel code, +allowing them to circumvent disabled module loading or module signing. +Default to paranoid - in future we can potentially relax this for +sufficiently IOMMU-isolated devices. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/pci/pci-sysfs.c | 9 +++++++++ + drivers/pci/proc.c | 8 +++++++- + drivers/pci/syscall.c | 2 +- + 3 files changed, 17 insertions(+), 2 deletions(-) + +diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c +index bcd10c7..02b9c9e 100644 +--- a/drivers/pci/pci-sysfs.c ++++ b/drivers/pci/pci-sysfs.c +@@ -716,6 +716,9 @@ static ssize_t pci_write_config(struct file *filp, struct kobject *kobj, + loff_t init_off = off; + u8 *data = (u8 *) buf; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (off > dev->cfg_size) + return 0; + if (off + count > dev->cfg_size) { +@@ -1007,6 +1010,9 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr, + resource_size_t start, end; + int i; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + for (i = 0; i < PCI_ROM_RESOURCE; i++) + if (res == &pdev->resource[i]) + break; +@@ -1106,6 +1112,9 @@ static ssize_t pci_write_resource_io(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t off, size_t count) + { ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + return pci_resource_io(filp, kobj, attr, buf, off, count, true); + } + +diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c +index 2408abe..eaccf9b 100644 +--- a/drivers/pci/proc.c ++++ b/drivers/pci/proc.c +@@ -116,6 +116,9 @@ static ssize_t proc_bus_pci_write(struct file *file, const char __user *buf, + int size = dev->cfg_size; + int cnt; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (pos >= size) + return 0; + if (nbytes >= size) +@@ -195,6 +198,9 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd, + #endif /* HAVE_PCI_MMAP */ + int ret = 0; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + switch (cmd) { + case PCIIOC_CONTROLLER: + ret = pci_domain_nr(dev->bus); +@@ -233,7 +239,7 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma) + struct pci_filp_private *fpriv = file->private_data; + int i, ret, write_combine; + +- if (!capable(CAP_SYS_RAWIO)) ++ if (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down()) + return -EPERM; + + /* Make sure the caller is mapping a real resource for this device */ +diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c +index b91c4da..81544dc 100644 +--- a/drivers/pci/syscall.c ++++ b/drivers/pci/syscall.c +@@ -92,7 +92,7 @@ SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn, + u32 dword; + int err = 0; + +- if (!capable(CAP_SYS_ADMIN)) ++ if (!capable(CAP_SYS_ADMIN) || kernel_is_locked_down()) + return -EPERM; + + dev = pci_get_bus_and_slot(bus, dfn); +-- +2.9.3 + +From 18f4177e0a147adccbbacb1fa95e340352228db3 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:16 +0000 +Subject: [PATCH 20/32] x86: Lock down IO port access when the kernel is locked + down + +IO port access would permit users to gain access to PCI configuration +registers, which in turn (on a lot of hardware) give access to MMIO +register space. This would potentially permit root to trigger arbitrary +DMA, so lock it down by default. + +This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and +KDDISABIO console ioctls. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + arch/x86/kernel/ioport.c | 4 ++-- + drivers/char/mem.c | 2 ++ + 2 files changed, 4 insertions(+), 2 deletions(-) + +diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c +index 589b319..f0789ab 100644 +--- a/arch/x86/kernel/ioport.c ++++ b/arch/x86/kernel/ioport.c +@@ -28,7 +28,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on) + + if ((from + num <= from) || (from + num > IO_BITMAP_BITS)) + return -EINVAL; +- if (turn_on && !capable(CAP_SYS_RAWIO)) ++ if (turn_on && (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down())) + return -EPERM; + + /* +@@ -108,7 +108,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level) + return -EINVAL; + /* Trying to gain more privileges? */ + if (level > old) { +- if (!capable(CAP_SYS_RAWIO)) ++ if (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down()) + return -EPERM; + } + regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | +diff --git a/drivers/char/mem.c b/drivers/char/mem.c +index 6441d21..f653c36 100644 +--- a/drivers/char/mem.c ++++ b/drivers/char/mem.c +@@ -743,6 +743,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) + + static int open_port(struct inode *inode, struct file *filp) + { ++ if (kernel_is_locked_down()) ++ return -EPERM; + return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; + } + +-- +2.9.3 + +From bdd2ae6c0c8ce5a4dadaa41019a6e065e9aa9128 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:17 +0000 +Subject: [PATCH 21/32] x86: Restrict MSR access when the kernel is locked down + +Writing to MSRs should not be allowed if the kernel is locked down, since +it could lead to execution of arbitrary code in kernel mode. Based on a +patch by Kees Cook. + +Cc: Kees Cook <keescook@chromium.org> +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + arch/x86/kernel/msr.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c +index 7f3550a..90cddc1 100644 +--- a/arch/x86/kernel/msr.c ++++ b/arch/x86/kernel/msr.c +@@ -83,6 +83,9 @@ static ssize_t msr_write(struct file *file, const char __user *buf, + int err = 0; + ssize_t bytes = 0; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (count % 8) + return -EINVAL; /* Invalid chunk size */ + +@@ -130,6 +133,10 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg) + err = -EBADF; + break; + } ++ if (kernel_is_locked_down()) { ++ err = -EPERM; ++ break; ++ } + if (copy_from_user(®s, uregs, sizeof regs)) { + err = -EFAULT; + break; +-- +2.9.3 + +From 50d0b2fd4e13f1da62d7bfabe7559cdaaceee06b Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:16 +0000 +Subject: [PATCH 22/32] asus-wmi: Restrict debugfs interface when the kernel is + locked down + +We have no way of validating what all of the Asus WMI methods do on a given +machine - and there's a risk that some will allow hardware state to be +manipulated in such a way that arbitrary code can be executed in the +kernel, circumventing module loading restrictions. Prevent that if the +kernel is locked down. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/platform/x86/asus-wmi.c | 9 +++++++++ + 1 file changed, 9 insertions(+) + +diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c +index ce6ca31..d860017 100644 +--- a/drivers/platform/x86/asus-wmi.c ++++ b/drivers/platform/x86/asus-wmi.c +@@ -1872,6 +1872,9 @@ static int show_dsts(struct seq_file *m, void *data) + int err; + u32 retval = -1; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval); + + if (err < 0) +@@ -1888,6 +1891,9 @@ static int show_devs(struct seq_file *m, void *data) + int err; + u32 retval = -1; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param, + &retval); + +@@ -1912,6 +1918,9 @@ static int show_call(struct seq_file *m, void *data) + union acpi_object *obj; + acpi_status status; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, + 1, asus->debug.method_id, + &input, &output); +-- +2.9.3 + +From 88156357adede0ba4060adb0934d08e75afb6e9d Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <matthew.garrett@nebula.com> +Date: Tue, 22 Nov 2016 08:46:16 +0000 +Subject: [PATCH 23/32] ACPI: Limit access to custom_method when the kernel is + locked down + +custom_method effectively allows arbitrary access to system memory, making +it possible for an attacker to circumvent restrictions on module loading. +Disable it if the kernel is locked down. + +Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/acpi/custom_method.c | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c +index c68e724..e4d721c 100644 +--- a/drivers/acpi/custom_method.c ++++ b/drivers/acpi/custom_method.c +@@ -29,6 +29,9 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, + struct acpi_table_header table; + acpi_status status; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + if (!(*ppos)) { + /* parse the table header to get the table length */ + if (count <= sizeof(struct acpi_table_header)) +-- +2.9.3 + +From 960205f64271826552eec6d7ba34144b1615c376 Mon Sep 17 00:00:00 2001 +From: Josh Boyer <jwboyer@redhat.com> +Date: Tue, 22 Nov 2016 08:46:16 +0000 +Subject: [PATCH 24/32] acpi: Ignore acpi_rsdp kernel param when the kernel has + been locked down + +This option allows userspace to pass the RSDP address to the kernel, which +makes it possible for a user to circumvent any restrictions imposed on +loading modules. Ignore the option when the kernel is locked down. + +Signed-off-by: Josh Boyer <jwboyer@redhat.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/acpi/osl.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c +index 416953a..79f3d03 100644 +--- a/drivers/acpi/osl.c ++++ b/drivers/acpi/osl.c +@@ -191,7 +191,7 @@ early_param("acpi_rsdp", setup_acpi_rsdp); + acpi_physical_address pa = 0; + + #ifdef CONFIG_KEXEC +- if (acpi_rsdp) ++ if (acpi_rsdp && !kernel_is_locked_down()) + return acpi_rsdp; + #endif + +-- +2.9.3 + +From 2f200d295a041b154f3938940c2d8aa1742f1379 Mon Sep 17 00:00:00 2001 +From: Linn Crosetto <linn@hpe.com> +Date: Wed, 23 Nov 2016 13:32:27 +0000 +Subject: [PATCH 25/32] acpi: Disable ACPI table override if the kernel is + locked down + +From the kernel documentation (initrd_table_override.txt): + + If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible + to override nearly any ACPI table provided by the BIOS with an + instrumented, modified one. + +When securelevel is set, the kernel should disallow any unauthenticated +changes to kernel space. ACPI tables contain code invoked by the kernel, +so do not allow ACPI tables to be overridden if the kernel is locked down. + +Signed-off-by: Linn Crosetto <linn@hpe.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/acpi/tables.c | 5 +++++ + 1 file changed, 5 insertions(+) + +diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c +index cdd56c4..c657c08 100644 +--- a/drivers/acpi/tables.c ++++ b/drivers/acpi/tables.c +@@ -545,6 +545,11 @@ void __init acpi_table_upgrade(void) + if (table_nr == 0) + return; + ++ if (kernel_is_locked_down()) { ++ pr_notice("kernel is locked down, ignoring table override\n"); ++ return; ++ } ++ + acpi_tables_addr = + memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS, + all_tables_size, PAGE_SIZE); +-- +2.9.3 + +From 6244dff831988f59797add76cee80c73961d5ac5 Mon Sep 17 00:00:00 2001 +From: Linn Crosetto <linn@hpe.com> +Date: Wed, 23 Nov 2016 13:39:41 +0000 +Subject: [PATCH 26/32] acpi: Disable APEI error injection if the kernel is + locked down + +ACPI provides an error injection mechanism, EINJ, for debugging and testing +the ACPI Platform Error Interface (APEI) and other RAS features. If +supported by the firmware, ACPI specification 5.0 and later provide for a +way to specify a physical memory address to which to inject the error. + +Injecting errors through EINJ can produce errors which to the platform are +indistinguishable from real hardware errors. This can have undesirable +side-effects, such as causing the platform to mark hardware as needing +replacement. + +While it does not provide a method to load unauthenticated privileged code, +the effect of these errors may persist across reboots and affect trust in +the underlying hardware, so disable error injection through EINJ if +the kernel is locked down. + +Signed-off-by: Linn Crosetto <linn@hpe.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/acpi/apei/einj.c | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c +index eebb7e3..e4f126a 100644 +--- a/drivers/acpi/apei/einj.c ++++ b/drivers/acpi/apei/einj.c +@@ -518,6 +518,9 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, + int rc; + u64 base_addr, size; + ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + /* If user manually set "flags", make sure it is legal */ + if (flags && (flags & + ~(SETWA_FLAGS_APICID|SETWA_FLAGS_MEM|SETWA_FLAGS_PCIE_SBDF))) +-- +2.9.3 + +From a17a541d1af379c3d6ff21924c212f9e2e38c1c8 Mon Sep 17 00:00:00 2001 +From: Matthew Garrett <mjg59@coreos.com> +Date: Wed, 23 Nov 2016 13:41:23 +0000 +Subject: [PATCH 27/32] Enable cold boot attack mitigation + +--- + arch/x86/boot/compressed/eboot.c | 28 ++++++++++++++++++++++++++++ + 1 file changed, 28 insertions(+) + +diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c +index 5b151c2..5093a76 100644 +--- a/arch/x86/boot/compressed/eboot.c ++++ b/arch/x86/boot/compressed/eboot.c +@@ -774,6 +774,31 @@ void setup_graphics(struct boot_params *boot_params) + } + } + ++#define MEMORY_ONLY_RESET_CONTROL_GUID \ ++ EFI_GUID (0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29) ++ ++static void enable_reset_attack_mitigation(void) ++{ ++ static const efi_guid_t var_guid = MEMORY_ONLY_RESET_CONTROL_GUID; ++ static const efi_char16_t MemoryOverwriteRequestControl_name[] = { ++ 'M', 'e', 'm', 'o', 'r', 'y', ++ 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't', 'e', ++ 'R', 'e', 'q', 'u', 'e', 's', 't', ++ 'C', 'o', 'n', 't', 'r', 'o', 'l', ++ 0 ++ }; ++ u8 val = 1; ++ ++ /* Ignore the return value here - there's not really a lot we can do */ ++ efi_call_runtime(set_variable, ++ (efi_char16_t *)MemoryOverwriteRequestControl_name, ++ (efi_guid_t *)&var_guid, ++ EFI_VARIABLE_NON_VOLATILE | ++ EFI_VARIABLE_BOOTSERVICE_ACCESS | ++ EFI_VARIABLE_RUNTIME_ACCESS, ++ sizeof(val), val); ++} ++ + /* + * Because the x86 boot code expects to be passed a boot_params we + * need to create one ourselves (usually the bootloader would create +@@ -1158,6 +1183,9 @@ struct boot_params *efi_main(struct efi_config *c, + else + setup_boot_services32(efi_early); + ++ /* Ask the firmware to clear memory if we don't have a clean shutdown */ ++ enable_reset_attack_mitigation(); ++ + boot_params->secure_boot = efi_get_secureboot(sys_table); + + setup_graphics(boot_params); +-- +2.9.3 + +From c9c34942d873f7a09b9c7211bda3063354ff5706 Mon Sep 17 00:00:00 2001 +From: "Lee, Chun-Yi" <jlee@suse.com> +Date: Wed, 23 Nov 2016 13:52:16 +0000 +Subject: [PATCH 28/32] bpf: Restrict kernel image access functions when the + kernel is locked down + +There are some bpf functions can be used to read kernel memory: +bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow +private keys in kernel memory (e.g. the hibernation image signing key) to +be read by an eBPF program. Prohibit those functions when the kernel is +locked down. + +Signed-off-by: Lee, Chun-Yi <jlee@suse.com> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + kernel/trace/bpf_trace.c | 11 +++++++++++ + 1 file changed, 11 insertions(+) + +diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c +index 5dcb992..474e001 100644 +--- a/kernel/trace/bpf_trace.c ++++ b/kernel/trace/bpf_trace.c +@@ -65,6 +65,11 @@ BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr) + { + int ret; + ++ if (kernel_is_locked_down()) { ++ memset(dst, 0, size); ++ return -EPERM; ++ } ++ + ret = probe_kernel_read(dst, unsafe_ptr, size); + if (unlikely(ret < 0)) + memset(dst, 0, size); +@@ -84,6 +89,9 @@ static const struct bpf_func_proto bpf_probe_read_proto = { + BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src, + u32, size) + { ++ if (kernel_is_locked_down()) ++ return -EPERM; ++ + /* + * Ensure we're in user context which is safe for the helper to + * run. This helper has no business in a kthread. +@@ -143,6 +151,9 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, + if (fmt[--fmt_size] != 0) + return -EINVAL; + ++ if (kernel_is_locked_down()) ++ return __trace_printk(1, fmt, 0, 0, 0); ++ + /* check format string for allowed specifiers */ + for (i = 0; i < fmt_size; i++) { + if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i])) +-- +2.9.3 + +From 04485aa7865dc340f38e32ad29793c625167acf3 Mon Sep 17 00:00:00 2001 +From: David Howells <dhowells@redhat.com> +Date: Tue, 22 Nov 2016 10:10:34 +0000 +Subject: [PATCH 29/32] scsi: Lock down the eata driver + +When the kernel is running in secure boot mode, we lock down the kernel to +prevent userspace from modifying the running kernel image. Whilst this +includes prohibiting access to things like /dev/mem, it must also prevent +access by means of configuring driver modules in such a way as to cause a +device to access or modify the kernel image. + +The eata driver takes a single string parameter that contains a slew of +settings, including hardware resource configuration. Prohibit use of the +parameter if the kernel is locked down. + +Suggested-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> +Signed-off-by: David Howells <dhowells@redhat.com> +cc: Dario Ballabio <ballabio_dario@emc.com> +cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com> +cc: "Martin K. Petersen" <martin.petersen@oracle.com> +cc: linux-scsi@vger.kernel.org +--- + drivers/scsi/eata.c | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) + +diff --git a/drivers/scsi/eata.c b/drivers/scsi/eata.c +index 227dd2c..5c036d1 100644 +--- a/drivers/scsi/eata.c ++++ b/drivers/scsi/eata.c +@@ -1552,8 +1552,13 @@ static int eata2x_detect(struct scsi_host_template *tpnt) + + tpnt->proc_name = "eata2x"; + +- if (strlen(boot_options)) ++ if (strlen(boot_options)) { ++ if (kernel_is_locked_down()) { ++ pr_err("Command line-specified device addresses, irqs and dma channels are not permitted when the kernel is locked down\n"); ++ return -EPERM; ++ } + option_setup(boot_options); ++ } + + #if defined(MODULE) + /* io_port could have been modified when loading as a module */ +-- +2.9.3 + +From b1e8f012b7b17e0146f8e63de51f6f45819c859e Mon Sep 17 00:00:00 2001 +From: David Howells <dhowells@redhat.com> +Date: Fri, 25 Nov 2016 14:37:45 +0000 +Subject: [PATCH 30/32] Prohibit PCMCIA CIS storage when the kernel is locked + down + +Prohibit replacement of the PCMCIA Card Information Structure when the +kernel is locked down. + +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/pcmcia/cistpl.c | 5 +++++ + 1 file changed, 5 insertions(+) + +diff --git a/drivers/pcmcia/cistpl.c b/drivers/pcmcia/cistpl.c +index 55ef7d1..193e4f7 100644 +--- a/drivers/pcmcia/cistpl.c ++++ b/drivers/pcmcia/cistpl.c +@@ -1578,6 +1578,11 @@ static ssize_t pccard_store_cis(struct file *filp, struct kobject *kobj, + struct pcmcia_socket *s; + int error; + ++ if (kernel_is_locked_down()) { ++ pr_err("Direct CIS storage isn't permitted when the kernel is locked down\n"); ++ return -EPERM; ++ } ++ + s = to_socket(container_of(kobj, struct device, kobj)); + + if (off) +-- +2.9.3 + +From 66d9c09b9427719e3c6a34132e9ca0724cb1e3a8 Mon Sep 17 00:00:00 2001 +From: David Howells <dhowells@redhat.com> +Date: Wed, 7 Dec 2016 10:28:39 +0000 +Subject: [PATCH 31/32] Lock down TIOCSSERIAL + +Lock down TIOCSSERIAL as that can be used to change the ioport and irq +settings on a serial port. This only appears to be an issue for the serial +drivers that use the core serial code. All other drivers seem to either +ignore attempts to change port/irq or give an error. + +Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Signed-off-by: David Howells <dhowells@redhat.com> +--- + drivers/tty/serial/serial_core.c | 6 ++++++ + 1 file changed, 6 insertions(+) + +diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c +index f2303f3..f2c07fa 100644 +--- a/drivers/tty/serial/serial_core.c ++++ b/drivers/tty/serial/serial_core.c +@@ -819,6 +819,12 @@ static int uart_set_info(struct tty_struct *tty, struct tty_port *port, + new_flags = new_info->flags; + old_custom_divisor = uport->custom_divisor; + ++ if ((change_port || change_irq) && kernel_is_locked_down()) { ++ pr_err("Using TIOCSSERIAL to change device addresses, irqs and dma channels is not permitted when the kernel is locked down\n"); ++ retval = -EPERM; ++ goto exit; ++ } ++ + if (!capable(CAP_SYS_ADMIN)) { + retval = -EPERM; + if (change_irq || change_port || +-- +2.9.3 |