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  1. 11 11月, 2022 1 次提交
    • A
      arm64: efi: Force the use of SetVirtualAddressMap() on Altra machines · 550b33cf
      由 Ard Biesheuvel 提交于 
      Ampere Altra machines are reported to misbehave when the SetTime() EFI
runtime service is called after ExitBootServices() but before calling
SetVirtualAddressMap(). Given that the latter is horrid, pointless and
explicitly documented as optional by the EFI spec, we no longer invoke
it at boot if the configured size of the VA space guarantees that the
EFI runtime memory regions can remain mapped 1:1 like they are at boot
time.

On Ampere Altra machines, this results in SetTime() calls issued by the
rtc-efi driver triggering synchronous exceptions during boot.  We can
now recover from those without bringing down the system entirely, due to
commit 23715a26 ("arm64: efi: Recover from synchronous
exceptions occurring in firmware"). However, it would be better to avoid
the issue entirely, given that the firmware appears to remain in a funny
state after this.

So attempt to identify these machines based on the 'family' field in the
type #1 SMBIOS record, and call SetVirtualAddressMap() unconditionally
in that case.
Tested-by: NAlexandru Elisei <alexandru.elisei@gmail.com>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      550b33cf
  3. 04 10月, 2022 1 次提交
    • A
      kmsan: disable instrumentation of unsupported common kernel code · 79dbd006
      由 Alexander Potapenko 提交于 
      EFI stub cannot be linked with KMSAN runtime, so we disable
instrumentation for it.

Instrumenting kcov, stackdepot or lockdep leads to infinite recursion
caused by instrumentation hooks calling instrumented code again.

Link: https://lkml.kernel.org/r/20220915150417.722975-13-glider@google.comSigned-off-by: NAlexander Potapenko <glider@google.com>
Reviewed-by: NMarco Elver <elver@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      79dbd006
  5. 27 9月, 2022 2 次提交
    • A
      efi/loongarch: libstub: remove dependency on flattened DT · 40cd01a9
      由 Ard Biesheuvel 提交于 
      LoongArch does not use FDT or DT natively [yet], and the only reason it
currently uses it is so that it can reuse the existing EFI stub code.

Overloading the DT with data passed between the EFI stub and the core
kernel has been a source of problems: there is the overlap between
information provided by EFI which DT can also provide (initrd base/size,
command line, memory descriptions), requiring us to reason about which
is which and what to prioritize. It has also resulted in ABI leaks,
i.e., internal ABI being promoted to external ABI inadvertently because
the bootloader can set the EFI stub's DT properties as well (e.g.,
"kaslr-seed"). This has become especially problematic with boot
environments that want to pretend that EFI boot is being done (to access
ACPI and SMBIOS tables, for instance) but have no ability to execute the
EFI stub, and so the environment that the EFI stub creates is emulated
[poorly, in some cases].

Another downside of treating DT like this is that the DT binary that the
kernel receives is different from the one created by the firmware, which
is undesirable in the context of secure and measured boot.

Given that LoongArch support in Linux is brand new, we can avoid these
pitfalls, and treat the DT strictly as a hardware description, and use a
separate handover method between the EFI stub and the kernel. Now that
initrd loading and passing the EFI memory map have been refactored into
pure EFI routines that use EFI configuration tables, the only thing we
need to pass directly is the kernel command line (even if we could pass
this via a config table as well, it is used extremely early, so passing
it directly is preferred in this case.)
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Acked-by: NHuacai Chen <chenhuacai@loongson.cn>
      40cd01a9
    • S
      treewide: Filter out CC_FLAGS_CFI · f143ff39
      由 Sami Tolvanen 提交于 
      In preparation for removing CC_FLAGS_CFI from CC_FLAGS_LTO, explicitly
filter out CC_FLAGS_CFI in all the makefiles where we currently filter
out CC_FLAGS_LTO.
Signed-off-by: NSami Tolvanen <samitolvanen@google.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Tested-by: NKees Cook <keescook@chromium.org>
Tested-by: NNathan Chancellor <nathan@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-2-samitolvanen@google.com
      f143ff39
  7. 20 9月, 2022 1 次提交
    • A
      efi/libstub: implement generic EFI zboot · a0509109
      由 Ard Biesheuvel 提交于 
      Implement a minimal EFI app that decompresses the real kernel image and
launches it using the firmware's LoadImage and StartImage boot services.
This removes the need for any arch-specific hacks.

Note that on systems that have UEFI secure boot policies enabled,
LoadImage/StartImage require images to be signed, or their hashes known
a priori, in order to be permitted to boot.

There are various possible strategies to work around this requirement,
but they all rely either on overriding internal PI/DXE protocols (which
are not part of the EFI spec) or omitting the firmware provided
LoadImage() and StartImage() boot services, which is also undesirable,
given that they encapsulate platform specific policies related to secure
boot and measured boot, but also related to memory permissions (whether
or not and which types of heap allocations have both write and execute
permissions.)

The only generic and truly portable way around this is to simply sign
both the inner and the outer image with the same key/cert pair, so this
is what is implemented here.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      a0509109
  9. 19 9月, 2022 1 次提交
  11. 17 9月, 2022 1 次提交
    • A
      efi/libstub: use EFI provided memcpy/memset routines · c82ceb44
      由 Ard Biesheuvel 提交于 
      The stub is used in different execution environments, but on arm64,
RISC-V and LoongArch, we still use the core kernel's implementation of
memcpy and memset, as they are just a branch instruction away, and can
generally be reused even from code such as the EFI stub that runs in a
completely different address space.

KAsan complicates this slightly, resulting in the need for some hacks to
expose the uninstrumented, __ prefixed versions as the normal ones, as
the latter are instrumented to include the KAsan checks, which only work
in the core kernel.

Unfortunately, #define'ing memcpy to __memcpy when building C code does
not guarantee that no explicit memcpy() calls will be emitted. And with
the upcoming zboot support, which consists of a separate binary which
therefore needs its own implementation of memcpy/memset anyway, it's
better to provide one explicitly instead of linking to the existing one.

Given that EFI exposes implementations of memmove() and memset() via the
boot services table, let's wire those up in the appropriate way, and
drop the references to the core kernel ones.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      c82ceb44
  13. 06 9月, 2022 1 次提交
    • H
      efi/loongarch: Add efistub booting support · ead384d9
      由 Huacai Chen 提交于 
      This patch adds efistub booting support, which is the standard UEFI boot
protocol for LoongArch to use.

We use generic efistub, which means we can pass boot information (i.e.,
system table, memory map, kernel command line, initrd) via a light FDT
and drop a lot of non-standard code.

We use a flat mapping to map the efi runtime in the kernel's address
space. In efi, VA = PA; in kernel, VA = PA + PAGE_OFFSET. As a result,
flat mapping is not identity mapping, SetVirtualAddressMap() is still
needed for the efi runtime.
Tested-by: NXi Ruoyao <xry111@xry111.site>
Signed-off-by: NHuacai Chen <chenhuacai@loongson.cn>
[ardb: change fpic to fpie as suggested by Xi Ruoyao]
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      ead384d9
  15. 25 8月, 2022 1 次提交
    • A
      efi: libstub: Disable struct randomization · 1a388792
      由 Ard Biesheuvel 提交于 
      The EFI stub is a wrapper around the core kernel that makes it look like
a EFI compatible PE/COFF application to the EFI firmware. EFI
applications run on top of the EFI runtime, which is heavily based on
so-called protocols, which are struct types consisting [mostly] of
function pointer members that are instantiated and recorded in a
protocol database.

These structs look like the ideal randomization candidates to the
randstruct plugin (as they only carry function pointers), but of course,
these protocols are contracts between the firmware that exposes them,
and the EFI applications (including our stubbed kernel) that invoke
them. This means that struct randomization for EFI protocols is not a
great idea, and given that the stub shares very little data with the
core kernel that is represented as a randomizable struct, we're better
off just disabling it completely here.

Cc: <stable@vger.kernel.org> # v4.14+
Reported-by: NDaniel Marth <daniel.marth@inso.tuwien.ac.at>
Tested-by: NDaniel Marth <daniel.marth@inso.tuwien.ac.at>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Acked-by: NKees Cook <keescook@chromium.org>
      1a388792
  17. 26 3月, 2021 1 次提交
  19. 15 1月, 2021 1 次提交
  21. 03 10月, 2020 1 次提交
  23. 07 9月, 2020 1 次提交
  25. 01 9月, 2020 1 次提交
  27. 14 8月, 2020 1 次提交
  29. 09 7月, 2020 1 次提交
  31. 07 7月, 2020 2 次提交
  33. 15 6月, 2020 1 次提交
  35. 19 5月, 2020 2 次提交
  37. 15 5月, 2020 1 次提交
  39. 05 5月, 2020 1 次提交
    • A
      efi/libstub/x86: Work around LLVM ELF quirk build regression · f77767ed
      由 Ard Biesheuvel 提交于 
      When building the x86 EFI stub with Clang, the libstub Makefile rules
that manipulate the ELF object files may throw an error like:

    STUBCPY drivers/firmware/efi/libstub/efi-stub-helper.stub.o
  strip: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10
  objcopy: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10

This is the result of a LLVM feature [0] where symbol references are
stored in a LLVM specific .llvm_addrsig section in a non-transparent way,
causing generic ELF tools such as strip or objcopy to choke on them.

So force the compiler not to emit these sections, by passing the
appropriate command line option.

[0] https://sourceware.org/bugzilla/show_bug.cgi?id=23817

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Reported-by: NArnd Bergmann <arnd@arndb.de>
Suggested-by: NFangrui Song <maskray@google.com>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      f77767ed
  41. 24 4月, 2020 4 次提交
  43. 23 4月, 2020 1 次提交
  45. 25 2月, 2020 1 次提交
  47. 24 2月, 2020 6 次提交
    • A
      efi/libstub: Clean up command line parsing routine · 91d150c0
      由 Ard Biesheuvel 提交于 
      We currently parse the command non-destructively, to avoid having to
allocate memory for a copy before passing it to the standard parsing
routines that are used by the core kernel, and which modify the input
to delineate the parsed tokens with NUL characters.

Instead, we call strstr() and strncmp() to go over the input multiple
times, and match prefixes rather than tokens, which implies that we
would match, e.g., 'nokaslrfoo' in the stub and disable KASLR, while
the kernel would disregard the option and run with KASLR enabled.

In order to avoid having to reason about whether and how this behavior
may be abused, let's clean up the parsing routines, and rebuild them
on top of the existing helpers.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      91d150c0
    • A
      efi/libstub: Move file I/O support code into separate file · 5193a33d
      由 Ard Biesheuvel 提交于 
      Split off the file I/O support code into a separate source file so
it ends up in a separate object file in the static library, allowing
the linker to omit it if the routines are not used.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      5193a33d
    • A
      efi/libstub: Move efi_random_alloc() into separate source file · 0ed02bda
      由 Ard Biesheuvel 提交于 
      efi_random_alloc() is only used on arm64, but as it shares a source
file with efi_random_get_seed(), the latter will pull in the former
on other architectures as well.

Let's take advantage of the fact that libstub is a static library,
and so the linker will only incorporate objects that are needed to
satisfy dependencies in other objects. This means we can move the
random alloc code to a separate source file that gets built
unconditionally, but only used when needed.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      0ed02bda
    • A
      efi/libstub/x86: Incorporate eboot.c into libstub · c2d0b470
      由 Ard Biesheuvel 提交于 
      Most of the EFI stub source files of all architectures reside under
drivers/firmware/efi/libstub, where they share a Makefile with special
CFLAGS and an include file with declarations that are only relevant
for stub code.

Currently, we carry a lot of stub specific stuff in linux/efi.h only
because eboot.c in arch/x86 needs them as well. So let's move eboot.c
into libstub/, and move the contents of eboot.h that we still care
about into efistub.h
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      c2d0b470
    • A
      efi/libstub: Move memory map handling and allocation routines to mem.c · f57db62c
      由 Ard Biesheuvel 提交于 
      Create a new source file mem.c to keep the routines involved in memory
allocation and deallocation and manipulation of the EFI memory map.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      f57db62c
    • A
      efi/libstub: Use hidden visibility for all source files · 6f05106e
      由 Ard Biesheuvel 提交于 
      Instead of setting the visibility pragma for a small set of symbol
declarations that could result in absolute references that we cannot
support in the stub, declare hidden visibility for all code in the
EFI stub, which is more robust and future proof.

To ensure that the #pragma is taken into account before any other
includes are processed, put it in a header file of its own and
include it via the compiler command line using the -include option.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      6f05106e
  49. 23 2月, 2020 1 次提交
    • A
      efi/libstub/arm64: Use 1:1 mapping of RT services if property table exists · b92165d2
      由 Ard Biesheuvel 提交于 
      The UEFI spec defines (and deprecates) a misguided and shortlived
memory protection feature that is based on splitting memory regions
covering PE/COFF executables into separate code and data regions,
without annotating them as belonging to the same executable image.
When the OS assigns the virtual addresses of these regions, it may
move them around arbitrarily, without taking into account that the
PE/COFF code sections may contain relative references into the data
sections, which means the relative placement of these segments has
to be preserved or the executable image will be corrupted.

The original workaround on arm64 was to ensure that adjacent regions
of the same type were mapped adjacently in the virtual mapping, but
this requires sorting of the memory map, which we would prefer to
avoid.

Considering that the native physical mapping of the PE/COFF images
does not suffer from this issue, let's preserve it at runtime, and
install it as the virtual mapping as well.
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
      b92165d2
  51. 11 1月, 2020 1 次提交
    • M
      efi: Allow disabling PCI busmastering on bridges during boot · 4444f854
      由 Matthew Garrett 提交于 
      Add an option to disable the busmaster bit in the control register on
all PCI bridges before calling ExitBootServices() and passing control
to the runtime kernel. System firmware may configure the IOMMU to prevent
malicious PCI devices from being able to attack the OS via DMA. However,
since firmware can't guarantee that the OS is IOMMU-aware, it will tear
down IOMMU configuration when ExitBootServices() is called. This leaves
a window between where a hostile device could still cause damage before
Linux configures the IOMMU again.

If CONFIG_EFI_DISABLE_PCI_DMA is enabled or "efi=disable_early_pci_dma"
is passed on the command line, the EFI stub will clear the busmaster bit
on all PCI bridges before ExitBootServices() is called. This will
prevent any malicious PCI devices from being able to perform DMA until
the kernel reenables busmastering after configuring the IOMMU.

This option may cause failures with some poorly behaved hardware and
should not be enabled without testing. The kernel commandline options
"efi=disable_early_pci_dma" or "efi=no_disable_early_pci_dma" may be
used to override the default. Note that PCI devices downstream from PCI
bridges are disconnected from their drivers first, using the UEFI
driver model API, so that DMA can be disabled safely at the bridge
level.

[ardb: disconnect PCI I/O handles first, as suggested by Arvind]
Co-developed-by: NMatthew Garrett <mjg59@google.com>
Signed-off-by: NMatthew Garrett <mjg59@google.com>
Signed-off-by: NArd Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Matthew Garrett <matthewgarrett@google.com>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20200103113953.9571-18-ardb@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      4444f854
  53. 16 11月, 2019 1 次提交
  55. 07 11月, 2019 1 次提交
  57. 31 10月, 2019 1 次提交
    • A
      efi: libstub/arm: Account for firmware reserved memory at the base of RAM · 41cd96fa
      由 Ard Biesheuvel 提交于 
      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: NGuillaume Gardet <Guillaume.Gardet@arm.com>
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NChester Lin <clin@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
      41cd96fa