[GIT PULL 0/5] EFI fixes for v5.4

[GIT PULL 0/5] EFI fixes for v5.4

[Ard Biesheuvel]

The following changes since commit 7d194c2100ad2a6dded545887d02754948ca5241:

  Linux 5.4-rc4 (2019-10-20 15:56:22 -0400)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git efi-urgent

for you to fetch changes up to 0d0013109c849cccb16560df213b5d6115a2d206:

  x86, efi: never relocate kernel below lowest acceptable address (2019-10-23 09:00:10 +0200)

----------------------------------------------------------------
Some more fixes for the EFI subsystem:
- Prevent boot problems on HyperV due to incorrect placement of the kernel
- Classify UEFI randomness as bootloader randomness
- Fix EFI boot for the Raspberry Pi2 running U-boot
- Some more odd fixes.

----------------------------------------------------------------
Ard Biesheuvel (1):
      efi: libstub/arm: account for firmware reserved memory at the base of RAM

Dominik Brodowski (1):
      efi/random: treat EFI_RNG_PROTOCOL output as bootloader randomness

Jerry Snitselaar (1):
      efi/tpm: return -EINVAL when determining tpm final events log size fails

Kairui Song (1):
      x86, efi: never relocate kernel below lowest acceptable address

Narendra K (1):
      efi: Make CONFIG_EFI_RCI2_TABLE selectable on x86 only

 arch/x86/boot/compressed/eboot.c               |  4 +++-
 drivers/firmware/efi/Kconfig                   |  1 +
 drivers/firmware/efi/efi.c                     |  2 +-
 drivers/firmware/efi/libstub/Makefile          |  1 +
 drivers/firmware/efi/libstub/arm32-stub.c      | 16 +++++++++++++---
 drivers/firmware/efi/libstub/efi-stub-helper.c | 24 ++++++++++--------------
 drivers/firmware/efi/tpm.c                     |  1 +
 include/linux/efi.h                            | 18 ++++++++++++++++--
 8 files changed, 46 insertions(+), 21 deletions(-)

[PATCH 1/5] efi: Make CONFIG_EFI_RCI2_TABLE selectable on x86 only

[Ard Biesheuvel]

From: Narendra K <Narendra.K@dell.com>

For the EFI_RCI2_TABLE kconfig option, 'make oldconfig' asks the user
for input on platforms where the option may not be applicable. This patch
modifies the kconfig option to ask the user for input only when CONFIG_X86
or CONFIG_COMPILE_TEST is set to y.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Narendra K <Narendra.K@dell.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 178ee8106828..b248870a9806 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -182,6 +182,7 @@ config RESET_ATTACK_MITIGATION
 
 config EFI_RCI2_TABLE
 	bool "EFI Runtime Configuration Interface Table Version 2 Support"
+	depends on X86 || COMPILE_TEST
 	help
 	  Displays the content of the Runtime Configuration Interface
 	  Table version 2 on Dell EMC PowerEdge systems as a binary
-- 
2.17.1

[PATCH 2/5] efi/tpm: return -EINVAL when determining tpm final events log size fails

[Ard Biesheuvel]

From: Jerry Snitselaar <jsnitsel@redhat.com>

Currently nothing checks the return value of efi_tpm_eventlog_init,
but in case that changes in the future make sure an error is
returned when it fails to determine the tpm final events log
size.

Fixes: e658c82be556 ("efi/tpm: Only set 'efi_tpm_final_log_size' after ...")
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/tpm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
index ebd7977653a8..31f9f0e369b9 100644
--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -88,6 +88,7 @@ int __init efi_tpm_eventlog_init(void)
 
 	if (tbl_size < 0) {
 		pr_err(FW_BUG "Failed to parse event in TPM Final Events Log\n");
+		ret = -EINVAL;
 		goto out_calc;
 	}
 
-- 
2.17.1

[PATCH 3/5] efi/random: treat EFI_RNG_PROTOCOL output as bootloader randomness

[Ard Biesheuvel]

From: Dominik Brodowski <linux@dominikbrodowski.net>

Commit 428826f5358c ("fdt: add support for rng-seed") introduced
add_bootloader_randomness(), permitting randomness provided by the
bootloader or firmware to be credited as entropy. However, the fact
that the UEFI support code was already wired into the RNG subsystem
via a call to add_device_randomness() was overlooked, and so it was
not converted at the same time.

Note that this UEFI (v2.4 or newer) feature is currently only
implemented for EFI stub booting on ARM, and further note that
CONFIG_RANDOM_TRUST_BOOTLOADER must be enabled, and this should be
done only if there indeed is sufficient trust in the bootloader
_and_ its source of randomness.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
[ardb: update commit log]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/efi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 69f00f7453a3..e98bbf8e56d9 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -554,7 +554,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz,
 					      sizeof(*seed) + size);
 			if (seed != NULL) {
 				pr_notice("seeding entropy pool\n");
-				add_device_randomness(seed->bits, seed->size);
+				add_bootloader_randomness(seed->bits, seed->size);
 				early_memunmap(seed, sizeof(*seed) + size);
 			} else {
 				pr_err("Could not map UEFI random seed!\n");
-- 
2.17.1

[PATCH 4/5] efi: libstub/arm: account for firmware reserved memory at the base of RAM

[Ard Biesheuvel]

The EFI stubloader for ARM starts out by allocating a 32 MB window
at the base of RAM, in order to ensure that the decompressor (which
blindly copies the uncompressed kernel into that window) does not
overwrite other allocations that are made while running in the context
of the EFI firmware.

In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is
causing boot failures because this initial allocation conflicts with
a page of reserved memory at the base of RAM that contains the SMP spin
tables and other pieces of firmware data and which was put there by
the bootloader under the assumption that the TEXT_OFFSET window right
below the kernel is only used partially during early boot, and will be
left alone once the memory reservations are processed and taken into
account.

So let's permit reserved memory regions to exist in the region starting
at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is
the window below the kernel that is not touched by the early boot code.

Acked-by: Chester Lin <clin@suse.com>
Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/efi/libstub/Makefile     |  1 +
 drivers/firmware/efi/libstub/arm32-stub.c | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 0460c7581220..ee0661ddb25b 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -52,6 +52,7 @@ lib-$(CONFIG_EFI_ARMSTUB)	+= arm-stub.o fdt.o string.o random.o \
 
 lib-$(CONFIG_ARM)		+= arm32-stub.o
 lib-$(CONFIG_ARM64)		+= arm64-stub.o
+CFLAGS_arm32-stub.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
 CFLAGS_arm64-stub.o		:= -DTEXT_OFFSET=$(TEXT_OFFSET)
 
 #
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
index e8f7aefb6813..ffa242ad0a82 100644
--- a/drivers/firmware/efi/libstub/arm32-stub.c
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -195,6 +195,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 				 unsigned long dram_base,
 				 efi_loaded_image_t *image)
 {
+	unsigned long kernel_base;
 	efi_status_t status;
 
 	/*
@@ -204,9 +205,18 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 	 * loaded. These assumptions are made by the decompressor,
 	 * before any memory map is available.
 	 */
-	dram_base = round_up(dram_base, SZ_128M);
+	kernel_base = round_up(dram_base, SZ_128M);
 
-	status = reserve_kernel_base(sys_table, dram_base, reserve_addr,
+	/*
+	 * Note that some platforms (notably, the Raspberry Pi 2) put
+	 * spin-tables and other pieces of firmware at the base of RAM,
+	 * abusing the fact that the window of TEXT_OFFSET bytes at the
+	 * base of the kernel image is only partially used at the moment.
+	 * (Up to 5 pages are used for the swapper page tables)
+	 */
+	kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE;
+
+	status = reserve_kernel_base(sys_table, kernel_base, reserve_addr,
 				     reserve_size);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n");
@@ -220,7 +230,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 	*image_size = image->image_size;
 	status = efi_relocate_kernel(sys_table, image_addr, *image_size,
 				     *image_size,
-				     dram_base + MAX_UNCOMP_KERNEL_SIZE, 0);
+				     kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Failed to relocate kernel.\n");
 		efi_free(sys_table, *reserve_size, *reserve_addr);
-- 
2.17.1

[PATCH 5/5] x86, efi: never relocate kernel below lowest acceptable address

[Ard Biesheuvel]

From: Kairui Song <kasong@redhat.com>

Currently, kernel fails to boot on some HyperV VMs when using EFI.
And it's a potential issue on all x86 platforms.

It's caused by broken kernel relocation on EFI systems, when below three
conditions are met:

1. Kernel image is not loaded to the default address (LOAD_PHYSICAL_ADDR)
   by the loader.
2. There isn't enough room to contain the kernel, starting from the
   default load address (eg. something else occupied part the region).
3. In the memmap provided by EFI firmware, there is a memory region
   starts below LOAD_PHYSICAL_ADDR, and suitable for containing the
   kernel.

EFI stub will perform a kernel relocation when condition 1 is met. But
due to condition 2, EFI stub can't relocate kernel to the preferred
address, so it fallback to ask EFI firmware to alloc lowest usable memory
region, got the low region mentioned in condition 3, and relocated
kernel there.

It's incorrect to relocate the kernel below LOAD_PHYSICAL_ADDR. This
is the lowest acceptable kernel relocation address.

The first thing goes wrong is in arch/x86/boot/compressed/head_64.S.
Kernel decompression will force use LOAD_PHYSICAL_ADDR as the output
address if kernel is located below it. Then the relocation before
decompression, which move kernel to the end of the decompression buffer,
will overwrite other memory region, as there is no enough memory there.

To fix it, just don't let EFI stub relocate the kernel to any address
lower than lowest acceptable address.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
[ardb: introduce efi_low_alloc_above() to reduce the scope of the change]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/boot/compressed/eboot.c              |  4 +++-
 drivers/firmware/efi/libstub/arm32-stub.c     |  2 +-
 .../firmware/efi/libstub/efi-stub-helper.c    | 24 ++++++++-----------
 include/linux/efi.h                           | 18 ++++++++++++--
 4 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index d6662fdef300..82bc60c8acb2 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -13,6 +13,7 @@
 #include <asm/e820/types.h>
 #include <asm/setup.h>
 #include <asm/desc.h>
+#include <asm/boot.h>
 
 #include "../string.h"
 #include "eboot.h"
@@ -813,7 +814,8 @@ efi_main(struct efi_config *c, struct boot_params *boot_params)
 		status = efi_relocate_kernel(sys_table, &bzimage_addr,
 					     hdr->init_size, hdr->init_size,
 					     hdr->pref_address,
-					     hdr->kernel_alignment);
+					     hdr->kernel_alignment,
+					     LOAD_PHYSICAL_ADDR);
 		if (status != EFI_SUCCESS) {
 			efi_printk(sys_table, "efi_relocate_kernel() failed!\n");
 			goto fail;
diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c
index ffa242ad0a82..41213bf5fcf5 100644
--- a/drivers/firmware/efi/libstub/arm32-stub.c
+++ b/drivers/firmware/efi/libstub/arm32-stub.c
@@ -230,7 +230,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 	*image_size = image->image_size;
 	status = efi_relocate_kernel(sys_table, image_addr, *image_size,
 				     *image_size,
-				     kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0);
+				     kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0, 0);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Failed to relocate kernel.\n");
 		efi_free(sys_table, *reserve_size, *reserve_addr);
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3caae7f2cf56..35dbc2791c97 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -260,11 +260,11 @@ efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 }
 
 /*
- * Allocate at the lowest possible address.
+ * Allocate at the lowest possible address that is not below 'min'.
  */
-efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
-			   unsigned long size, unsigned long align,
-			   unsigned long *addr)
+efi_status_t efi_low_alloc_above(efi_system_table_t *sys_table_arg,
+				 unsigned long size, unsigned long align,
+				 unsigned long *addr, unsigned long min)
 {
 	unsigned long map_size, desc_size, buff_size;
 	efi_memory_desc_t *map;
@@ -311,13 +311,8 @@ efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 		start = desc->phys_addr;
 		end = start + desc->num_pages * EFI_PAGE_SIZE;
 
-		/*
-		 * Don't allocate at 0x0. It will confuse code that
-		 * checks pointers against NULL. Skip the first 8
-		 * bytes so we start at a nice even number.
-		 */
-		if (start == 0x0)
-			start += 8;
+		if (start < min)
+			start = min;
 
 		start = round_up(start, align);
 		if ((start + size) > end)
@@ -698,7 +693,8 @@ efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 				 unsigned long image_size,
 				 unsigned long alloc_size,
 				 unsigned long preferred_addr,
-				 unsigned long alignment)
+				 unsigned long alignment,
+				 unsigned long min_addr)
 {
 	unsigned long cur_image_addr;
 	unsigned long new_addr = 0;
@@ -731,8 +727,8 @@ efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 	 * possible.
 	 */
 	if (status != EFI_SUCCESS) {
-		status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
-				       &new_addr);
+		status = efi_low_alloc_above(sys_table_arg, alloc_size,
+					     alignment, &new_addr, min_addr);
 	}
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
diff --git a/include/linux/efi.h b/include/linux/efi.h
index bd3837022307..d87acf62958e 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1579,9 +1579,22 @@ char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
 				struct efi_boot_memmap *map);
 
+efi_status_t efi_low_alloc_above(efi_system_table_t *sys_table_arg,
+				 unsigned long size, unsigned long align,
+				 unsigned long *addr, unsigned long min);
+
+static inline
 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 			   unsigned long size, unsigned long align,
-			   unsigned long *addr);
+			   unsigned long *addr)
+{
+	/*
+	 * Don't allocate at 0x0. It will confuse code that
+	 * checks pointers against NULL. Skip the first 8
+	 * bytes so we start at a nice even number.
+	 */
+	return efi_low_alloc_above(sys_table_arg, size, align, addr, 0x8);
+}
 
 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 			    unsigned long size, unsigned long align,
@@ -1592,7 +1605,8 @@ efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 				 unsigned long image_size,
 				 unsigned long alloc_size,
 				 unsigned long preferred_addr,
-				 unsigned long alignment);
+				 unsigned long alignment,
+				 unsigned long min_addr);
 
 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 				  efi_loaded_image_t *image,
-- 
2.17.1