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-rw-r--r--debian/patches/features/all/lockdown/efi-lock-down-the-kernel-if-booted-in-secure-boot-mo.patch127
1 files changed, 127 insertions, 0 deletions
diff --git a/debian/patches/features/all/lockdown/efi-lock-down-the-kernel-if-booted-in-secure-boot-mo.patch b/debian/patches/features/all/lockdown/efi-lock-down-the-kernel-if-booted-in-secure-boot-mo.patch
new file mode 100644
index 000000000..627e37154
--- /dev/null
+++ b/debian/patches/features/all/lockdown/efi-lock-down-the-kernel-if-booted-in-secure-boot-mo.patch
@@ -0,0 +1,127 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Tue, 10 Sep 2019 11:54:28 +0100
+Subject: efi: Lock down the kernel if booted in secure boot mode
+
+Based on an earlier patch by David Howells, who wrote the following
+description:
+
+> 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: Ben Hutchings <ben@decadent.org.uk>
+---
+ arch/x86/kernel/setup.c | 4 ++--
+ drivers/firmware/efi/secureboot.c | 3 +++
+ include/linux/security.h | 6 ++++++
+ security/lockdown/Kconfig | 15 +++++++++++++++
+ security/lockdown/lockdown.c | 2 +-
+ 5 files changed, 27 insertions(+), 3 deletions(-)
+
+Index: debian-kernel/arch/x86/kernel/setup.c
+===================================================================
+--- debian-kernel.orig/arch/x86/kernel/setup.c
++++ debian-kernel/arch/x86/kernel/setup.c
+@@ -979,6 +979,8 @@ void __init setup_arch(char **cmdline_p)
+ if (efi_enabled(EFI_BOOT))
+ efi_init();
+
++ efi_set_secure_boot(boot_params.secure_boot);
++
+ dmi_setup();
+
+ /*
+@@ -1130,8 +1132,6 @@ void __init setup_arch(char **cmdline_p)
+ /* Allocate bigger log buffer */
+ setup_log_buf(1);
+
+- efi_set_secure_boot(boot_params.secure_boot);
+-
+ reserve_initrd();
+
+ acpi_table_upgrade();
+Index: debian-kernel/drivers/firmware/efi/secureboot.c
+===================================================================
+--- debian-kernel.orig/drivers/firmware/efi/secureboot.c
++++ debian-kernel/drivers/firmware/efi/secureboot.c
+@@ -15,6 +15,7 @@
+ #include <linux/efi.h>
+ #include <linux/kernel.h>
+ #include <linux/printk.h>
++#include <linux/security.h>
+
+ /*
+ * Decide what to do when UEFI secure boot mode is enabled.
+@@ -28,6 +29,10 @@ void __init efi_set_secure_boot(enum efi
+ break;
+ case efi_secureboot_mode_enabled:
+ set_bit(EFI_SECURE_BOOT, &efi.flags);
++#ifdef CONFIG_LOCK_DOWN_IN_EFI_SECURE_BOOT
++ lock_kernel_down("EFI Secure Boot",
++ LOCKDOWN_INTEGRITY_MAX);
++#endif
+ pr_info("Secure boot enabled\n");
+ break;
+ default:
+Index: debian-kernel/include/linux/security.h
+===================================================================
+--- debian-kernel.orig/include/linux/security.h
++++ debian-kernel/include/linux/security.h
+@@ -451,6 +451,7 @@ int security_inode_notifysecctx(struct i
+ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
+ int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+ int security_locked_down(enum lockdown_reason what);
++int lock_kernel_down(const char *where, enum lockdown_reason level);
+ #else /* CONFIG_SECURITY */
+
+ static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data)
+@@ -1291,6 +1292,11 @@ static inline int security_locked_down(e
+ {
+ return 0;
+ }
++static inline int
++lock_kernel_down(const char *where, enum lockdown_reason level)
++{
++ return -EOPNOTSUPP;
++}
+ #endif /* CONFIG_SECURITY */
+
+ #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
+Index: debian-kernel/security/lockdown/Kconfig
+===================================================================
+--- debian-kernel.orig/security/lockdown/Kconfig
++++ debian-kernel/security/lockdown/Kconfig
+@@ -45,3 +45,18 @@ config LOCK_DOWN_KERNEL_FORCE_CONFIDENTI
+ disabled.
+
+ endchoice
++
++config LOCK_DOWN_IN_EFI_SECURE_BOOT
++ bool "Lock down the kernel in EFI Secure Boot mode"
++ default n
++ depends on SECURITY_LOCKDOWN_LSM
++ depends on EFI
++ select SECURITY_LOCKDOWN_LSM_EARLY
++ help
++ UEFI Secure Boot provides a mechanism for ensuring that the firmware
++ will only load signed bootloaders and kernels. Secure boot mode may
++ be determined from EFI variables provided by the system firmware if
++ not indicated by the boot parameters.
++
++ Enabling this option results in kernel lockdown being
++ triggered in confidentiality mode if EFI Secure Boot is set.
+Index: debian-kernel/security/lockdown/lockdown.c
+===================================================================
+--- debian-kernel.orig/security/lockdown/lockdown.c
++++ debian-kernel/security/lockdown/lockdown.c
+@@ -23,7 +23,7 @@ static const enum lockdown_reason lockdo
+ /*
+ * Put the kernel into lock-down mode.
+ */
+-static int lock_kernel_down(const char *where, enum lockdown_reason level)
++int lock_kernel_down(const char *where, enum lockdown_reason level)
+ {
+ if (kernel_locked_down >= level)
+ return -EPERM;