diff options
author | David Howells <dhowells@redhat.com> | 2017-02-06 11:22:43 +0000 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2017-02-07 10:42:10 +0100 |
commit | de8cb458625c164bb3f93c4e415e479afce8fa9d (patch) | |
tree | 6da87e0a45c5d1e39bc5f46413123358734d8eba /drivers/firmware/efi/libstub/arm-stub.c | |
parent | e58910cdc9f43cda2e52fcdf2fddbdc74e80b2f7 (diff) |
efi: Get and store 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.
For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec. This allows secure-boot mode to be passed on to a new
kernel.
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-5-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/libstub/arm-stub.c')
-rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 63 |
1 files changed, 6 insertions, 57 deletions
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 6fca48c9e054..d4056c6be1ec 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) { @@ -157,7 +111,7 @@ 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; struct screen_info *si; /* Check if we were booted by the EFI firmware */ @@ -227,19 +181,14 @@ 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. + * Unauthenticated device tree data is a security hazard, so ignore + * 'dtb=' unless UEFI Secure Boot is disabled. We assume that secure + * boot is enabled if we can't determine its state. */ - 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, |