security: Add common boot media write protection

Introduce boot media protection settings and use the existing
boot_device_wp_region() function to apply settings on all
platforms that supports it yet.

Also remove the Intel southbridge code, which is now obsolete.
Every platform locks the SPIBAR in a different stage.
For align up with the common mrc cache driver and lock after it has been
written to.

Tested on Supermicro X11SSH-TF. The whole address space is write-protected.

Change-Id: Iceb3ecf0bde5cec562bc62d1d5c79da35305d183
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32704
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/boot_device.h

@@ -62,4 +62,12 @@ int boot_device_wp_region(const struct region_device *rd,
  **/
 void boot_device_init(void);
 
+/*
+ * Restrict read/write access to the bootmedia using platform defined rules.
+ */
+#if CONFIG(BOOTMEDIA_LOCK_NONE)
+static inline void boot_device_security_lockdown(void) {}
+#else
+void boot_device_security_lockdown(void);
+#endif
 #endif /* _BOOT_DEVICE_H_ */

src/security/Kconfig

@@ -15,3 +15,4 @@ source "src/security/vboot/Kconfig"
 source "src/security/tpm/Kconfig"
 source "src/security/memory/Kconfig"
 source "src/security/intel/Kconfig"
+source "src/security/lockdown/Kconfig"

src/security/Makefile.inc

@@ -2,3 +2,4 @@ subdirs-y += vboot
 subdirs-y += tpm
 subdirs-y += memory
 subdirs-y += intel
+subdirs-y += lockdown

src/security/lockdown/Kconfig

@@ -0,0 +1,62 @@
+
+
+choice
+	prompt "Boot media protection mechanism"
+	default BOOTMEDIA_LOCK_NONE
+
+config BOOTMEDIA_LOCK_NONE
+	bool "Don't lock boot media sections"
+
+config BOOTMEDIA_LOCK_CONTROLLER
+	bool "Lock boot media using the controller"
+	help
+	  Select this if you want the controller to lock specific regions.
+	  This only works on some platforms, please check the code or boot log.
+	  On Intel platforms for e.g. this will make use of the SPIBAR PRRs.
+
+config BOOTMEDIA_LOCK_CHIP
+	bool "Lock boot media using the chip"
+	help
+	  Select this if you want the chip to lock specific regions.
+	  This only works on some chips, please check the code or boot log.
+
+endchoice
+
+choice
+	prompt "Boot media protected regions"
+	depends on !BOOTMEDIA_LOCK_NONE
+	default BOOTMEDIA_LOCK_WHOLE_RO
+
+config BOOTMEDIA_LOCK_WHOLE_RO
+	bool "Write-protect the whole boot medium"
+	help
+	  Select this if you want to write-protect the whole firmware boot
+	  medium.
+
+	  The locking will take place during the chipset lockdown.
+	  Chipset lockdown is platform specific und might be done unconditionally,
+	  when INTEL_CHIPSET_LOCKDOWN is set or has to be triggered later
+	  (e.g. by the payload or the OS).
+
+	  NOTE: If you trigger the chipset lockdown unconditionally,
+	  you won't be able to write to the whole flash chip using the
+	  internal controller any more.
+
+config BOOTMEDIA_LOCK_WHOLE_NO_ACCESS
+	depends on BOOTMEDIA_LOCK_CONTROLLER
+	bool "Read- and write-protect the whole boot medium"
+	help
+	  Select this if you want to protect the firmware boot medium against
+	  all further accesses. On platforms that memory map a part of the
+	  boot medium the corresponding region is still readable.
+
+	  The locking will take place during the chipset lockdown.
+	  Chipset lockdown is platform specific und might be done unconditionally,
+	  when INTEL_CHIPSET_LOCKDOWN is set or has to be triggered later
+	  (e.g. by the payload or the OS).
+
+	  NOTE: If you trigger the chipset lockdown unconditionally,
+	  you won't be able to write to the whole flash chip using the
+	  internal controller any more.
+
+endchoice

src/security/lockdown/Makefile.inc

@@ -0,0 +1,6 @@
+## SPDX-License-Identifier: GPL-2.0-or-later
+## This file is part of the coreboot project.
+
+ifneq ($(CONFIG_BOOTMEDIA_LOCK_NONE),y)
+ramstage-y += lockdown.c
+endif

src/security/lockdown/lockdown.c

@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* This file is part of the coreboot project. */
+
+#include <boot_device.h>
+#include <commonlib/region.h>
+#include <console/console.h>
+#include <bootstate.h>
+
+/*
+ * Enables read- /write protection of the bootmedia.
+ */
+void boot_device_security_lockdown(void)
+{
+	const struct region_device *rdev;
+	enum bootdev_prot_type lock_type;
+
+	printk(BIOS_DEBUG, "BM-LOCKDOWN: Enabling boot media protection scheme ");
+
+	if (CONFIG(BOOTMEDIA_LOCK_CONTROLLER)) {
+		if (CONFIG(BOOTMEDIA_LOCK_WHOLE_RO)) {
+			printk(BIOS_DEBUG, "'readonly'");
+			lock_type = CTRLR_WP;
+		} else if (CONFIG(BOOTMEDIA_LOCK_WHOLE_NO_ACCESS)) {
+			printk(BIOS_DEBUG, "'no access'");
+			lock_type = CTRLR_RWP;
+		}
+		printk(BIOS_DEBUG, "using CTRL...\n");
+	} else {
+		if (CONFIG(BOOTMEDIA_LOCK_WHOLE_RO)) {
+			printk(BIOS_DEBUG, "'readonly'");
+			lock_type = MEDIA_WP;
+		}
+		printk(BIOS_DEBUG, "using flash chip...\n");
+	}
+
+	rdev = boot_device_ro();
+
+	if (boot_device_wp_region(rdev, lock_type) >= 0)
+		printk(BIOS_INFO, "BM-LOCKDOWN: Enabled bootmedia protection\n");
+	else
+		printk(BIOS_ERR, "BM-LOCKDOWN: Failed to enable bootmedia protection\n");
+}
+
+static void lock(void *unused)
+{
+	boot_device_security_lockdown();
+}
+
+/*
+ * Keep in sync with mrc_cache.c
+ */
+
+#if CONFIG(MRC_WRITE_NV_LATE)
+BOOT_STATE_INIT_ENTRY(BS_OS_RESUME_CHECK, BS_ON_EXIT, lock, NULL);
+#else
+BOOT_STATE_INIT_ENTRY(BS_DEV_RESOURCES, BS_ON_ENTRY, lock, NULL);
+#endif

src/southbridge/intel/common/Kconfig

@@ -97,42 +97,3 @@ config INTEL_CHIPSET_LOCKDOWN
 config SOUTHBRIDGE_INTEL_COMMON_WATCHDOG
 	bool
 	depends on SOUTHBRIDGE_INTEL_COMMON_PMBASE
-
-if SOUTHBRIDGE_INTEL_COMMON_FINALIZE
-
-choice
-	prompt "Flash locking during chipset lockdown"
-	default LOCK_SPI_FLASH_NONE
-
-config LOCK_SPI_FLASH_NONE
-	bool "Don't lock flash sections"
-
-config LOCK_SPI_FLASH_RO
-	bool "Write-protect all flash sections"
-	help
-	  Select this if you want to write-protect the whole firmware flash
-	  chip. The locking will take place during the chipset lockdown, which
-	  is either triggered by coreboot (when INTEL_CHIPSET_LOCKDOWN is set)
-	  or has to be triggered later (e.g. by the payload or the OS).
-
-	        NOTE: If you trigger the chipset lockdown unconditionally,
-	        you won't be able to write to the flash chip using the
-	        internal programmer any more.
-
-config LOCK_SPI_FLASH_NO_ACCESS
-	bool "Write-protect all flash sections and read-protect non-BIOS sections"
-	help
-	  Select this if you want to protect the firmware flash against all
-	  further accesses (with the exception of the memory mapped BIOS re-
-	  gion which is always readable). The locking will take place during
-	  the chipset lockdown, which is either triggered by coreboot (when
-	  INTEL_CHIPSET_LOCKDOWN is set) or has to be triggered later (e.g.
-	  by the payload or the OS).
-
-	        NOTE: If you trigger the chipset lockdown unconditionally,
-	        you won't be able to write to the flash chip using the
-	        internal programmer any more.
-
-endchoice
-
-endif

src/southbridge/intel/common/finalize.c

@@ -15,16 +15,6 @@ void intel_pch_finalize_smm(void)
 {
 	const pci_devfn_t lpc_dev = PCI_DEV(0, 0x1f, 0);
 
-	if (CONFIG(LOCK_SPI_FLASH_RO) ||
-	    CONFIG(LOCK_SPI_FLASH_NO_ACCESS)) {
-		int i;
-		u32 lockmask = 1UL << 31;
-		if (CONFIG(LOCK_SPI_FLASH_NO_ACCESS))
-			lockmask |= 1 << 15;
-		for (i = 0; i < 20; i += 4)
-			RCBA32(0x3874 + i) = RCBA32(0x3854 + i) | lockmask;
-	}
-
 	/* Lock SPIBAR */
 	RCBA32_OR(0x3804, (1 << 15));