linux-stable.git/drivers/firmware/efi, branch v5.4

efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN

2019-10-31T08:40:21+00:00

The driver exposes EFI runtime services to user-space through an IOCTL
interface, calling the EFI services function pointers directly without
using the efivar API.

Disallow access to the /dev/efi_test character device when the kernel is
locked down to prevent arbitrary user-space to call EFI runtime services.

Also require CAP_SYS_ADMIN to open the chardev to prevent unprivileged
users to call the EFI runtime services, instead of just relying on the
chardev file mode bits for this.

The main user of this driver is the fwts [0] tool that already checks if
the effective user ID is 0 and fails otherwise. So this change shouldn't
cause any regression to this tool.

[0]: https://wiki.ubuntu.com/FirmwareTestSuite/Reference/uefivarinfo

Signed-off-by: Javier Martinez Canillas 
Signed-off-by: Ard Biesheuvel 
Acked-by: Laszlo Ersek 
Acked-by: Matthew Garrett 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-7-ardb@kernel.org
Signed-off-by: Ingo Molnar

x86, efi: Never relocate kernel below lowest acceptable address

2019-10-31T08:40:19+00:00

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.

[ ardb: introduce efi_low_alloc_above() to reduce the scope of the change ]

Signed-off-by: Kairui Song 
Signed-off-by: Ard Biesheuvel 
Acked-by: Jarkko Sakkinen 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-6-ardb@kernel.org
Signed-off-by: Ingo Molnar

efi: libstub/arm: Account for firmware reserved memory at the base of RAM

2019-10-31T08:40:19+00:00

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.

Tested-by: Guillaume Gardet 
Signed-off-by: Ard Biesheuvel 
Acked-by: Chester Lin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org
Signed-off-by: Ingo Molnar

efi/random: Treat EFI_RNG_PROTOCOL output as bootloader randomness

2019-10-31T08:40:18+00:00

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.

[ ardb: update commit log ]

Tested-by: Bhupesh Sharma 
Signed-off-by: Dominik Brodowski 
Signed-off-by: Ard Biesheuvel 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-4-ardb@kernel.org
Signed-off-by: Ingo Molnar

efi/tpm: Return -EINVAL when determining tpm final events log size fails

2019-10-31T08:40:17+00:00

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.

Suggested-by: Dan Carpenter 
Signed-off-by: Jerry Snitselaar 
Signed-off-by: Ard Biesheuvel 
Reviewed-by: Jarkko Sakkinen 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Fixes: e658c82be556 ("efi/tpm: Only set 'efi_tpm_final_log_size' after ...")
Link: https://lkml.kernel.org/r/20191029173755.27149-3-ardb@kernel.org
Signed-off-by: Ingo Molnar

efi: Make CONFIG_EFI_RCI2_TABLE selectable on x86 only

2019-10-31T08:40:16+00:00

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.

Suggested-by: Geert Uytterhoeven 
Reported-by: Geert Uytterhoeven 
Tested-by: Geert Uytterhoeven 
Signed-off-by: Narendra K 
Signed-off-by: Ard Biesheuvel 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-2-ardb@kernel.org
Signed-off-by: Ingo Molnar

efi/tpm: Fix sanity check of unsigned tbl_size being less than zero

2019-10-08T11:01:09+00:00

Currently the check for tbl_size being less than zero is always false
because tbl_size is unsigned. Fix this by making it a signed int.

Addresses-Coverity: ("Unsigned compared against 0")
Signed-off-by: Colin Ian King 
Cc: Ard Biesheuvel 
Cc: Jerry Snitselaar 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: kernel-janitors@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Fixes: e658c82be556 ("efi/tpm: Only set 'efi_tpm_final_log_size' after successful event log parsing")
Link: https://lkml.kernel.org/r/20191008100153.8499-1-colin.king@canonical.com
Signed-off-by: Ingo Molnar

efi: Make unexported efi_rci2_sysfs_init() static

2019-10-07T13:24:36+00:00

The efi_rci2_sysfs_init() is not used outside of rci2-table.c so
make it static to silence the following Sparse warning:

  drivers/firmware/efi/rci2-table.c:79:12: warning: symbol 'efi_rci2_sysfs_init' was not declared. Should it be static?

Signed-off-by: Ben Dooks 
Signed-off-by: Ard Biesheuvel 
Cc: Dave Young 
Cc: Jarkko Sakkinen 
Cc: Jerry Snitselaar 
Cc: Linus Torvalds 
Cc: Lukas Wunner 
Cc: Lyude Paul 
Cc: Matthew Garrett 
Cc: Octavian Purdila 
Cc: Peter Jones 
Cc: Peter Zijlstra 
Cc: Scott Talbert 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Link: https://lkml.kernel.org/r/20191002165904.8819-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar

efi/tpm: Only set 'efi_tpm_final_log_size' after successful event log parsing

2019-10-07T13:24:36+00:00

If __calc_tpm2_event_size() fails to parse an event it will return 0,
resulting tpm2_calc_event_log_size() returning -1. Currently there is
no check of this return value, and 'efi_tpm_final_log_size' can end up
being set to this negative value resulting in a crash like this one:

  BUG: unable to handle page fault for address: ffffbc8fc00866ad
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page

  RIP: 0010:memcpy_erms+0x6/0x10
  Call Trace:
   tpm_read_log_efi()
   tpm_bios_log_setup()
   tpm_chip_register()
   tpm_tis_core_init.cold.9+0x28c/0x466
   tpm_tis_plat_probe()
   platform_drv_probe()
   ...

Also __calc_tpm2_event_size() returns a size of 0 when it fails
to parse an event, so update function documentation to reflect this.

The root cause of the issue that caused the failure of event parsing
in this case is resolved by Peter Jone's patchset dealing with large
event logs where crossing over a page boundary causes the page with
the event count to be unmapped.

Signed-off-by: Jerry Snitselaar 
Signed-off-by: Ard Biesheuvel 
Cc: Ben Dooks 
Cc: Dave Young 
Cc: Jarkko Sakkinen 
Cc: Linus Torvalds 
Cc: Lukas Wunner 
Cc: Lyude Paul 
Cc: Matthew Garrett 
Cc: Octavian Purdila 
Cc: Peter Jones 
Cc: Peter Zijlstra 
Cc: Scott Talbert 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: c46f3405692de ("tpm: Reserve the TPM final events table")
Link: https://lkml.kernel.org/r/20191002165904.8819-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar

efi/tpm: Don't traverse an event log with no events

2019-10-07T13:24:35+00:00

When there are no entries to put into the final event log, some machines
will return the template they would have populated anyway.  In this case
the nr_events field is 0, but the rest of the log is just garbage.

This patch stops us from trying to iterate the table with
__calc_tpm2_event_size() when the number of events in the table is 0.

Tested-by: Lyude Paul 
Signed-off-by: Peter Jones 
Signed-off-by: Jarkko Sakkinen 
Signed-off-by: Ard Biesheuvel 
Reviewed-by: Jarkko Sakkinen 
Acked-by: Matthew Garrett 
Acked-by: Ard Biesheuvel 
Cc: Ben Dooks 
Cc: Dave Young 
Cc: Jerry Snitselaar 
Cc: Linus Torvalds 
Cc: Lukas Wunner 
Cc: Octavian Purdila 
Cc: Peter Zijlstra 
Cc: Scott Talbert 
Cc: Thomas Gleixner 
Cc: linux-efi@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: c46f3405692d ("tpm: Reserve the TPM final events table")
Link: https://lkml.kernel.org/r/20191002165904.8819-5-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar