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2022-01-06efi/libstub: measure loaded initrd info into the TPMIlias Apalodimas1-14/+58
In an effort to ensure the initrd observed and used by the OS is the same one that was meant to be loaded, which is difficult to guarantee otherwise, let's measure the initrd if the EFI stub and specifically the newly introduced LOAD_FILE2 protocol was used. Modify the initrd loading sequence so that the contents of the initrd are measured into PCR9. Note that the patch is currently using EV_EVENT_TAG to create the eventlog entry instead of EV_IPL. According to the TCP PC Client specification this is used for PCRs defined for OS and application usage. Co-developed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Link: https://lore.kernel.org/r/20211119114745.1560453-5-ilias.apalodimas@linaro.org [ardb: add braces to initializer of tagged_event_data] Link: https://github.com/ClangBuiltLinux/linux/issues/1547 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2021-11-21efi/libstub: consolidate initrd handling across architecturesArd Biesheuvel1-4/+9
Before adding TPM measurement of the initrd contents, refactor the initrd handling slightly to be more self-contained and consistent. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Link: https://lore.kernel.org/r/20211119114745.1560453-4-ilias.apalodimas@linaro.org Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2021-08-19isystem: ship and use stdarg.hAlexey Dobriyan1-1/+1
Ship minimal stdarg.h (1 type, 4 macros) as <linux/stdarg.h>. stdarg.h is the only userspace header commonly used in the kernel. GPL 2 version of <stdarg.h> can be extracted from http://archive.debian.org/debian/pool/main/g/gcc-4.2/gcc-4.2_4.2.4.orig.tar.gz Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-07-16efi/libstub: Fix the efi_load_initrd function descriptionAtish Patra1-2/+2
The soft_limit and hard_limit in the function efi_load_initrd describes the preferred and max address of initrd loading location respectively. However, the description wrongly describes it as the size of the allocated memory. Fix the function description. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-10-12Merge branch 'efi/urgent' into efi/core, to pick up fixesIngo Molnar1-2/+10
These fixes missed the v5.9 merge window, pick them up for early v5.10 merge. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-09-17efi/x86: Add a quirk to support command line arguments on Dell EFI firmwareArvind Sankar1-1/+100
At least some versions of Dell EFI firmware pass the entire EFI_LOAD_OPTION descriptor, rather than just the OptionalData part, to the loaded image. This was verified with firmware revision 2.15.0 on a Dell Precision T3620 by Jacobo Pantoja. To handle this, add a quirk to check if the options look like a valid EFI_LOAD_OPTION descriptor, and if so, use the OptionalData part as the command line. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Reported-by: Jacobo Pantoja <jacobopantoja@gmail.com> Link: https://lore.kernel.org/linux-efi/20200907170021.GA2284449@rani.riverdale.lan/ Link: https://lore.kernel.org/r/20200914213535.933454-2-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-08-20efi/libstub: Handle unterminated cmdlineArvind Sankar1-2/+4
Make the command line parsing more robust, by handling the case it is not NUL-terminated. Use strnlen instead of strlen, and make sure that the temporary copy is NUL-terminated before parsing. Cc: <stable@vger.kernel.org> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200813185811.554051-4-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-08-20efi/libstub: Handle NULL cmdlineArvind Sankar1-1/+5
Treat a NULL cmdline the same as empty. Although this is unlikely to happen in practice, the x86 kernel entry does check for NULL cmdline and handles it, so do it here as well. Cc: <stable@vger.kernel.org> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200729193300.598448-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-08-20efi/libstub: Stop parsing arguments at "--"Arvind Sankar1-0/+2
Arguments after "--" are arguments for init, not for the kernel. Cc: <stable@vger.kernel.org> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200725155916.1376773-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-07-17Merge tag 'arm64-fixes' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into master Pull arm64 fixes from Will Deacon: "A batch of arm64 fixes. Although the diffstat is a bit larger than we'd usually have at this stage, a decent amount of it is the addition of comments describing our syscall tracing behaviour, and also a sweep across all the modular arm64 PMU drivers to make them rebust against unloading and unbinding. There are a couple of minor things kicking around at the moment (CPU errata and module PLTs for very large modules), but I'm not expecting any significant changes now for us in 5.8. - Fix kernel text addresses for relocatable images booting using EFI and with KASLR disabled so that they match the vmlinux ELF binary. - Fix unloading and unbinding of PMU driver modules. - Fix generic mmiowb() when writeX() is called from preemptible context (reported by the riscv folks). - Fix ptrace hardware single-step interactions with signal handlers, system calls and reverse debugging. - Fix reporting of 64-bit x0 register for 32-bit tasks via 'perf_regs'. - Add comments describing syscall entry/exit tracing ABI" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: drivers/perf: Prevent forced unbinding of PMU drivers asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible() arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter() arm64: syscall: Expand the comment about ptrace and syscall(-1) arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return arm64: ptrace: Override SPSR.SS when single-stepping is enabled arm64: ptrace: Consistently use pseudo-singlestep exceptions drivers/perf: Fix kernel panic when rmmod PMU modules during perf sampling efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
2020-07-13efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLRWill Deacon1-1/+1
Since commit 82046702e288 ("efi/libstub/arm64: Replace 'preferred' offset with alignment check"), loading a relocatable arm64 kernel at a physical address which is not 2MB aligned and subsequently booting with EFI will leave the Image in-place, relying on the kernel to relocate itself early during boot. In conjunction with commit dd4bc6076587 ("arm64: warn on incorrect placement of the kernel by the bootloader"), which enables CONFIG_RELOCATABLE by default, this effectively means that entering an arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using QEMU) will result in silent relocation at runtime. Unfortunately, this has a subtle but confusing affect for developers trying to inspect the PC value during a crash and comparing it to the symbol addresses in vmlinux using tools such as 'nm' or 'addr2line'; all text addresses will be displaced by a sub-2MB offset, resulting in the wrong symbol being identified in many cases. Passing "nokaslr" on the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help, since the EFI stub only copies the kernel Image to a 2MB boundary if it is not relocatable. Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB unless KASLR is in use. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: David Brazdil <dbrazdil@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
2020-06-16efi/libstub: Descriptions for stub helper functionsHeinrich Schuchardt1-11/+67
Provide missing descriptions for EFI stub helper functions. Adjust formatting of existing descriptions to kernel style. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200615234231.21059-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-22efi/libstub: Use pool allocation for the command lineArd Biesheuvel1-3/+3
Now that we removed the memory limit for the allocation of the command line, there is no longer a need to use the page based allocator so switch to a pool allocation instead. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-22efi/libstub: Don't parse overlong command linesArvind Sankar1-5/+23
Check if the command line passed in is larger than COMMAND_LINE_SIZE, and truncate it to the last full argument if so. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200521002921.69650-1-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-20efi/libstub: Use snprintf with %ls to convert the command lineArvind Sankar1-60/+6
Now we can use snprintf to do the UTF-16 to UTF-8 translation for the command line. Drop the special "zero" trick to handle an empty command line. This was unnecessary even before this since with options_chars == 0, efi_utf16_to_utf8 would not have accessed options at all. snprintf won't access it either with a precision of 0. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-25-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-20efi/libstub: Get the exact UTF-8 lengthArvind Sankar1-12/+32
efi_convert_cmdline currently overestimates the length of the equivalent UTF-8 encoding. snprintf can now be used to do the conversion to UTF-8, however, it does not have a way to specify the size of the UTF-16 string, only the size of the resulting UTF-8 string. So in order to use it, we need to precalculate the exact UTF-8 size. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-24-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-20efi/libstub: Add UTF-8 decoding to efi_putsArvind Sankar1-5/+62
In order to be able to use the UTF-16 support added to vsprintf in the previous commit, enhance efi_puts to decode UTF-8 into UTF-16. Invalid UTF-8 encodings are passed through unchanged. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-22-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-20efi/gop: Add an option to list out the available GOP modesArvind Sankar1-0/+35
Add video=efifb:list option to list the modes that are available. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-20-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-20efi/libstub: Implement printk-style loggingArvind Sankar1-2/+27
Use the efi_printk function in efi_info/efi_err, and add efi_debug. This allows formatted output at different log levels. Add the notion of a loglevel instead of just quiet/not-quiet, and parse the efi=debug kernel parameter in addition to quiet. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200520170223.GA3333632@rani.riverdale.lan/ Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-19efi/printf: Turn vsprintf into vsnprintfArvind Sankar1-1/+5
Implement vsnprintf instead of vsprintf to avoid the possibility of a buffer overflow. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-17-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-19efi/libstub: Add a basic printf implementationArvind Sankar1-0/+17
Copy vsprintf from arch/x86/boot/printf.c to get a simple printf implementation. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-5-nivedita@alum.mit.edu [ardb: add some missing braces in if...else clauses] Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-19efi/libstub: Buffer output of efi_putsArvind Sankar1-6/+13
Use a buffer to convert the string to UTF-16. This will reduce the number of firmware calls required to print the string from one per character to one per string in most cases. Cast the input char to unsigned char before converting to efi_char16_t to avoid sign-extension in case there are any non-ASCII characters in the input. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-4-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-19efi/libstub: Rename efi_[char16_]printk to efi_[char16_]putsArvind Sankar1-9/+9
These functions do not support formatting, unlike printk. Rename them to puts to make that clear. Move the implementations of these two functions next to each other. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-3-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-05efi/libstub: Make efi_printk() input argument const char*Ard Biesheuvel1-12/+7
To help the compiler figure out that efi_printk() will not modify the string it is given, make the input argument type const char*. While at it, simplify the implementation as well. Suggested-by: Joe Perches <joe@perches.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-05-01efi/libstub: Unify initrd loading across architecturesArvind Sankar1-3/+43
Factor out the initrd loading into a common function that can be called both from the generic efi-stub.c and the x86-specific x86-stub.c. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200430182843.2510180-10-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-04-24efi/libstub: Drop __pure getters for EFI stub optionsArd Biesheuvel1-25/+6
The practice of using __pure getter functions to access global variables in the EFI stub dates back to the time when we had to carefully prevent GOT entries from being emitted, because we could not rely on the toolchain to do this for us. Today, we use the hidden visibility pragma for all EFI stub source files, which now all live in the same subdirectory, and we apply a sanity check on the objects, so we can get rid of these getter functions and simply refer to global data objects directly. So switch over the remaining boolean variables carrying options set on the kernel command line. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-04-24efi/libstub: Drop __pure getter for efi_system_tableArd Biesheuvel1-3/+3
The practice of using __pure getter functions to access global variables in the EFI stub dates back to the time when we had to carefully prevent GOT entries from being emitted, because we could not rely on the toolchain to do this for us. Today, we use the hidden visibility pragma for all EFI stub source files, which now all live in the same subdirectory, and we apply a sanity check on the objects, so we can get rid of these getter functions and simply refer to global data objects directly. Start with efi_system_table(), and convert it into a global variable. While at it, make it a pointer-to-const, because we can. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-04-24efi: Kill __efistub_globalArvind Sankar1-8/+7
Now that both arm and x86 are using the linker script to place the EFI stub's global variables in the correct section, remove __efistub_global. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20200416151227.3360778-4-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-04-23efi/gop: Allow specifying mode number on command lineArvind Sankar1-0/+3
Add the ability to choose a video mode for the selected gop by using a command-line argument of the form video=efifb:mode=<n> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200320020028.1936003-12-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub/x86: Make loaded_image protocol handling mixed mode safeArd Biesheuvel1-2/+2
Add the definitions and use the special wrapper so that the loaded_image UEFI protocol can be safely used from mixed mode. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Take noinitrd cmdline argument into account for devpath initrdArd Biesheuvel1-0/+7
One of the advantages of using what basically amounts to a callback interface into the bootloader for loading the initrd is that it provides a natural place for the bootloader or firmware to measure the initrd contents while they are being passed to the kernel. Unfortunately, this is not a guarantee that the initrd will in fact be loaded and its /init invoked by the kernel, since the command line may contain the 'noinitrd' option, in which case the initrd is ignored, but this will not be reflected in the PCR that covers the initrd measurement. This could be addressed by measuring the command line as well, and including that PCR in the attestation policy, but this locks down the command line completely, which may be too restrictive. So let's take the noinitrd argument into account in the stub, too. This forces any PCR that covers the initrd to assume a different value when noinitrd is passed, allowing an attestation policy to disregard the command line if there is no need to take its measurement into account for other reasons. As Peter points out, this would still require the agent that takes the measurements to measure a separator event into the PCR in question at ExitBootServices() time, to prevent replay attacks using the known measurement from the TPM log. Cc: Peter Jones <pjones@redhat.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Add support for loading the initrd from a device pathArd Biesheuvel1-0/+86
There are currently two ways to specify the initrd to be passed to the Linux kernel when booting via the EFI stub: - it can be passed as a initrd= command line option when doing a pure PE boot (as opposed to the EFI handover protocol that exists for x86) - otherwise, the bootloader or firmware can load the initrd into memory, and pass the address and size via the bootparams struct (x86) or device tree (ARM) In the first case, we are limited to loading from the same file system that the kernel was loaded from, and it is also problematic in a trusted boot context, given that we cannot easily protect the command line from tampering without either adding complicated white/blacklisting of boot arguments or locking down the command line altogether. In the second case, we force the bootloader to duplicate knowledge about the boot protocol which is already encoded in the stub, and which may be subject to change over time, e.g., bootparams struct definitions, memory allocation/alignment requirements for the placement of the initrd etc etc. In the ARM case, it also requires the bootloader to modify the hardware description provided by the firmware, as it is passed in the same file. On systems where the initrd is measured after loading, it creates a time window where the initrd contents might be manipulated in memory before handing over to the kernel. Address these concerns by adding support for loading the initrd into memory by invoking the EFI LoadFile2 protocol installed on a vendor GUIDed device path that specifically designates a Linux initrd. This addresses the above concerns, by putting the EFI stub in charge of placement in memory and of passing the base and size to the kernel proper (via whatever means it desires) while still leaving it up to the firmware or bootloader to obtain the file contents, potentially from other file systems than the one the kernel itself was loaded from. On platforms that implement measured boot, it permits the firmware to take the measurement right before the kernel actually consumes the contents. Acked-by: Laszlo Ersek <lersek@redhat.com> Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Clean up command line parsing routineArd Biesheuvel1-53/+26
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: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Move file I/O support code into separate fileArd Biesheuvel1-288/+6
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: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Move get_dram_base() into arm-stub.cArd Biesheuvel1-35/+0
get_dram_base() is only called from arm-stub.c so move it into the same source file as its caller. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub/x86: Permit cmdline data to be allocated above 4 GBArd Biesheuvel1-7/+2
We now support cmdline data that is located in memory that is not 32-bit addressable, so relax the allocation limit on systems where this feature is enabled. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Use consistent type names for file I/O protocolsArd Biesheuvel1-8/+8
Align the naming of efi_file_io_interface_t and efi_file_handle_t with the UEFI spec, and call them efi_simple_file_system_protocol_t and efi_file_protocol_t, respectively, using the same convention we use for all other type definitions that originate in the UEFI spec. While at it, move the definitions to efistub.h, so they are only seen by code that needs them. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Simplify efi_high_alloc() and rename to efi_allocate_pages()Ard Biesheuvel1-3/+2
The implementation of efi_high_alloc() uses a complicated way of traversing the memory map to find an available region that is located as close as possible to the provided upper limit, and calls AllocatePages subsequently to create the allocation at that exact address. This is precisely what the EFI_ALLOCATE_MAX_ADDRESS allocation type argument to AllocatePages() does, and considering that EFI_ALLOC_ALIGN only exceeds EFI_PAGE_SIZE on arm64, let's use AllocatePages() directly and implement the alignment using code that the compiler can remove if it does not exceed EFI_PAGE_SIZE. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Move memory map handling and allocation routines to mem.cArd Biesheuvel1-313/+0
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: Ard Biesheuvel <ardb@kernel.org>
2020-01-10efi: Allow disabling PCI busmastering on bridges during bootMatthew Garrett1-0/+15
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: Matthew Garrett <mjg59@google.com> Signed-off-by: Matthew Garrett <mjg59@google.com> Signed-off-by: Ard 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.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-01-10efi/x86: Allow translating 64-bit arguments for mixed mode callsArvind Sankar1-4/+1
Introduce the ability to define macros to perform argument translation for the calls that need it, and define them for the boot services that we currently use. When calling 32-bit firmware methods in mixed mode, all output parameters that are 32-bit according to the firmware, but 64-bit in the kernel (ie OUT UINTN * or OUT VOID **) must be initialized in the kernel, or the upper 32 bits may contain garbage. Define macros that zero out the upper 32 bits of the output before invoking the firmware method. When a 32-bit EFI call takes 64-bit arguments, the mixed-mode call must push the two 32-bit halves as separate arguments onto the stack. This can be achieved by splitting the argument into its two halves when calling the assembler thunk. Define a macro to do this for the free_pages boot service. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Matthew Garrett <mjg59@google.com> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20200103113953.9571-17-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Tidy up types and names of global cmdline variablesArd Biesheuvel1-18/+18
Drop leading underscores and use bool not int for true/false variables set on the command line. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-25-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Rename efi_call_early/_runtime macros to be more intuitiveArd Biesheuvel1-37/+33
The macros efi_call_early and efi_call_runtime are used to call EFI boot services and runtime services, respectively. However, the naming is confusing, given that the early vs runtime distinction may suggest that these are used for calling the same set of services either early or late (== at runtime), while in reality, the sets of services they can be used with are completely disjoint, and efi_call_runtime is also only usable in 'early' code. So do a global sweep to replace all occurrences with efi_bs_call or efi_rt_call, respectively, where BS and RT match the idiom used by the UEFI spec to refer to boot time or runtime services. While at it, use 'func' as the macro parameter name for the function pointers, which is less likely to collide and cause weird build errors. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-24-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Drop 'table' argument from efi_table_attr() macroArd Biesheuvel1-7/+4
None of the definitions of the efi_table_attr() still refer to their 'table' argument so let's get rid of it entirely. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-23-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Drop protocol argument from efi_call_proto() macroArd Biesheuvel1-4/+2
After refactoring the mixed mode support code, efi_call_proto() no longer uses its protocol argument in any of its implementation, so let's remove it altogether. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-22-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub/x86: Work around page freeing issue in mixed modeArd Biesheuvel1-1/+4
Mixed mode translates calls from the 64-bit kernel into the 32-bit firmware by wrapping them in a call to a thunking routine that pushes a 32-bit word onto the stack for each argument passed to the function, regardless of the argument type. This works surprisingly well for most services and protocols, with the exception of ones that take explicit 64-bit arguments. efi_free() invokes the FreePages() EFI boot service, which takes a efi_physical_addr_t as its address argument, and this is one of those 64-bit types. This means that the 32-bit firmware will interpret the (addr, size) pair as a single 64-bit quantity, and since it is guaranteed to have the high word set (as size > 0), it will always fail due to the fact that EFI memory allocations are always < 4 GB on 32-bit firmware. So let's fix this by giving the thunking code a little hand, and pass two values for the address, and a third one for the size. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-21-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Remove 'sys_table_arg' from all function prototypesArd Biesheuvel1-41/+33
We have a helper efi_system_table() that gives us the address of the EFI system table in memory, so there is no longer point in passing it around from each function to the next. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-20-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Drop sys_table_arg from printk routinesArd Biesheuvel1-17/+17
As a first step towards getting rid of the need to pass around a function parameter 'sys_table_arg' pointing to the EFI system table, remove the references to it in the printing code, which is represents the majority of the use cases. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-19-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Unify the efi_char16_printk implementationsArd Biesheuvel1-0/+9
Use a single implementation for efi_char16_printk() across all architectures. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-17-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-25efi/libstub: Avoid protocol wrapper for file I/O routinesArd Biesheuvel1-10/+7
The EFI file I/O routines built on top of the file I/O firmware services are incompatible with mixed mode, so there is no need to obfuscate them by using protocol wrappers whose only purpose is to hide the mixed mode handling. So let's switch to plain indirect calls instead. This also means we can drop the mixed_mode aliases from the various types involved. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Borislav Petkov <bp@alien8.de> Cc: James Morse <james.morse@arm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-15-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
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