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2020-03-08Merge branch 'efi/urgent' into efi/core, to pick up fixesIngo Molnar2-11/+25
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-08efi: Add a sanity check to efivar_store_raw()Vladis Dronov1-0/+3
Add a sanity check to efivar_store_raw() the same way efivar_{attr,size,data}_read() and efivar_show_raw() have it. Signed-off-by: Vladis Dronov <vdronov@redhat.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200305084041.24053-3-vdronov@redhat.com Link: https://lore.kernel.org/r/20200308080859.21568-25-ardb@kernel.org
2020-03-08efi: Fix a race and a buffer overflow while reading efivars via sysfsVladis Dronov1-9/+20
There is a race and a buffer overflow corrupting a kernel memory while reading an EFI variable with a size more than 1024 bytes via the older sysfs method. This happens because accessing struct efi_variable in efivar_{attr,size,data}_read() and friends is not protected from a concurrent access leading to a kernel memory corruption and, at best, to a crash. The race scenario is the following: CPU0: CPU1: efivar_attr_read() var->DataSize = 1024; efivar_entry_get(... &var->DataSize) down_interruptible(&efivars_lock) efivar_attr_read() // same EFI var var->DataSize = 1024; efivar_entry_get(... &var->DataSize) down_interruptible(&efivars_lock) virt_efi_get_variable() // returns EFI_BUFFER_TOO_SMALL but // var->DataSize is set to a real // var size more than 1024 bytes up(&efivars_lock) virt_efi_get_variable() // called with var->DataSize set // to a real var size, returns // successfully and overwrites // a 1024-bytes kernel buffer up(&efivars_lock) This can be reproduced by concurrent reading of an EFI variable which size is more than 1024 bytes: ts# for cpu in $(seq 0 $(nproc --ignore=1)); do ( taskset -c $cpu \ cat /sys/firmware/efi/vars/KEKDefault*/size & ) ; done Fix this by using a local variable for a var's data buffer size so it does not get overwritten. Fixes: e14ab23dde12b80d ("efivars: efivar_entry API") Reported-by: Bob Sanders <bob.sanders@hpe.com> and the LTP testsuite Signed-off-by: Vladis Dronov <vdronov@redhat.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200305084041.24053-2-vdronov@redhat.com Link: https://lore.kernel.org/r/20200308080859.21568-24-ardb@kernel.org
2020-03-08Merge tag 'efi-next' of ↵Ingo Molnar4-0/+210
git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/core More EFI updates for v5.7 - Incorporate a stable branch with the EFI pieces of Hans's work on loading device firmware from EFI boot service memory regions Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-03-04efi/arm: Start using fw_devlink_get_flags()Saravana Kannan1-1/+1
The fw_devlink_get_flags() provides the right flags to use when creating mandatory device links derived from information provided by the firmware. So, use that. Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Saravana Kannan <saravanak@google.com> Link: https://lore.kernel.org/r/20200222014038.180923-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-03efi: Add embedded peripheral firmware supportHans de Goede3-0/+153
Just like with PCI options ROMs, which we save in the setup_efi_pci* functions from arch/x86/boot/compressed/eboot.c, the EFI code / ROM itself sometimes may contain data which is useful/necessary for peripheral drivers to have access to. Specifically the EFI code may contain an embedded copy of firmware which needs to be (re)loaded into the peripheral. Normally such firmware would be part of linux-firmware, but in some cases this is not feasible, for 2 reasons: 1) The firmware is customized for a specific use-case of the chipset / use with a specific hardware model, so we cannot have a single firmware file for the chipset. E.g. touchscreen controller firmwares are compiled specifically for the hardware model they are used with, as they are calibrated for a specific model digitizer. 2) Despite repeated attempts we have failed to get permission to redistribute the firmware. This is especially a problem with customized firmwares, these get created by the chip vendor for a specific ODM and the copyright may partially belong with the ODM, so the chip vendor cannot give a blanket permission to distribute these. This commit adds support for finding peripheral firmware embedded in the EFI code and makes the found firmware available through the new efi_get_embedded_fw() function. Support for loading these firmwares through the standard firmware loading mechanism is added in a follow-up commit in this patch-series. Note we check the EFI_BOOT_SERVICES_CODE for embedded firmware near the end of start_kernel(), just before calling rest_init(), this is on purpose because the typical EFI_BOOT_SERVICES_CODE memory-segment is too large for early_memremap(), so the check must be done after mm_init(). This relies on EFI_BOOT_SERVICES_CODE not being free-ed until efi_free_boot_services() is called, which means that this will only work on x86 for now. Reported-by: Dave Olsthoorn <dave@bewaar.me> Suggested-by: Peter Jones <pjones@redhat.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20200115163554.101315-3-hdegoede@redhat.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-03-03efi: Export boot-services code and data as debugfs-blobsHans de Goede1-0/+57
Sometimes it is useful to be able to dump the efi boot-services code and data. This commit adds these as debugfs-blobs to /sys/kernel/debug/efi, but only if efi=debug is passed on the kernel-commandline as this requires not freeing those memory-regions, which costs 20+ MB of RAM. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20200115163554.101315-2-hdegoede@redhat.com Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-29efi: Mark all EFI runtime services as unsupported on non-EFI bootArd Biesheuvel1-3/+3
Recent changes to the way we deal with EFI runtime services that are marked as unsupported by the firmware resulted in a regression for non-EFI boot. The problem is that all EFI runtime services are marked as available by default, and any non-NULL checks on the EFI service function pointers (which will be non-NULL even for runtime services that are unsupported on an EFI boot) were replaced with checks against the mask stored in efi.runtime_supported_mask. When doing a non-EFI boot, this check against the mask will return a false positive, given the fact that all runtime services are marked as enabled by default. Since we dropped the non-NULL check of the runtime service function pointer in favor of the mask check, we will now unconditionally dereference the function pointer, even if it is NULL, and go boom. So let's ensure that the mask reflects reality on a non-EFI boot, which is that all EFI runtime services are unsupported. Reported-by: David Hildenbrand <david@redhat.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20200228121408.9075-7-ardb@kernel.org
2020-02-29efi: Don't shadow 'i' in efi_config_parse_tables()Heinrich Schuchardt1-1/+0
Shadowing variables is generally frowned upon. Let's simply reuse the existing loop counter 'i' instead of shadowing it. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Hildenbrand <david@redhat.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Link: https://lore.kernel.org/r/20200223221324.156086-1-xypron.glpk@gmx.de Link: https://lore.kernel.org/r/20200228121408.9075-4-ardb@kernel.org
2020-02-29efi/x86: Add RNG seed EFI table to unencrypted mapping checkTom Lendacky1-8/+10
When booting with SME active, EFI tables must be mapped unencrypted since they were built by UEFI in unencrypted memory. Update the list of tables to be checked during early_memremap() processing to account for the EFI RNG seed table. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Hildenbrand <david@redhat.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/b64385fc13e5d7ad4b459216524f138e7879234f.1582662842.git.thomas.lendacky@amd.com Link: https://lore.kernel.org/r/20200228121408.9075-3-ardb@kernel.org
2020-02-26efi: READ_ONCE rng seed size before munmapJason A. Donenfeld1-2/+2
This function is consistent with using size instead of seed->size (except for one place that this patch fixes), but it reads seed->size without using READ_ONCE, which means the compiler might still do something unwanted. So, this commit simply adds the READ_ONCE wrapper. Fixes: 636259880a7e ("efi: Add support for seeding the RNG from a UEFI ...") Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200217123354.21140-1-Jason@zx2c4.com Link: https://lore.kernel.org/r/20200221084849.26878-5-ardb@kernel.org
2020-02-25x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame ↵Arvind Sankar1-1/+2
sections While discussing a patch to discard .eh_frame from the compressed vmlinux using the linker script, Fangrui Song pointed out [1] that these sections shouldn't exist in the first place because arch/x86/Makefile uses -fno-asynchronous-unwind-tables. It turns out this is because the Makefiles used to build the compressed kernel redefine KBUILD_CFLAGS, dropping this flag. Add the flag to the Makefile for the compressed kernel, as well as the EFI stub Makefile to fix this. Also add the flag to boot/Makefile and realmode/rm/Makefile so that the kernel's boot code (boot/setup.elf) and realmode trampoline (realmode/rm/realmode.elf) won't be compiled with .eh_frame sections, since their linker scripts also just discard them. [1] https://lore.kernel.org/lkml/20200222185806.ywnqhfqmy67akfsa@google.com/ Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Link: https://lkml.kernel.org/r/20200224232129.597160-2-nivedita@alum.mit.edu
2020-02-23efi: Use EFI ResetSystem only when availableArd Biesheuvel1-2/+2
Do not attempt to call EFI ResetSystem if the runtime supported mask tells us it is no longer functional at OS runtime. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Register EFI rtc platform device only when availableArd Biesheuvel1-0/+3
Drop the separate driver that registers the EFI rtc on all EFI systems that have runtime services available, and instead, move the registration into the core EFI code, and make it conditional on whether the actual time related services are available. Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Use more granular check for availability for variable servicesArd Biesheuvel3-22/+10
The UEFI spec rev 2.8 permits firmware implementations to support only a subset of EFI runtime services at OS runtime (i.e., after the call to ExitBootServices()), so let's take this into account in the drivers that rely specifically on the availability of the EFI variable services. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Add support for EFI_RT_PROPERTIES tableArd Biesheuvel1-0/+12
Take the newly introduced EFI_RT_PROPERTIES_TABLE configuration table into account, which carries a mask of which EFI runtime services are still functional after ExitBootServices() has been called by the OS. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Store mask of supported runtime services in struct efiArd Biesheuvel1-10/+17
Revision 2.8 of the UEFI spec introduces provisions for firmware to advertise lack of support for certain runtime services at OS runtime. Let's store this mask in struct efi for easy access. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/arm: Rewrite FDT param discovery routinesArd Biesheuvel1-121/+89
The efi_get_fdt_params() routine uses the early OF device tree traversal helpers, that iterate over each node in the DT and invoke a caller provided callback that can inspect the node's contents and look for the required data. This requires a special param struct to be passed around, with pointers into param enumeration structs that contain (and duplicate) property names and offsets into yet another struct that carries the collected data. Since we know the data we look for is either under /hypervisor/uefi or under /chosen, it is much simpler to use the libfdt routines, and just try to grab a reference to either node directly, and read each property in sequence. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/arm: Move FDT specific definitions into fdtparams.cArd Biesheuvel2-18/+29
Push the FDT params specific types and definition into fdtparams.c, and instead, pass a reference to the memory map data structure and populate it directly, and return the system table address as the return value. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/arm: Move FDT param discovery code out of efi.cArd Biesheuvel3-135/+143
On ARM systems, we discover the UEFI system table address and memory map address from the /chosen node in the device tree, or in the Xen case, from a similar node under /hypervisor. Before making some functional changes to that code, move it into its own file that only gets built if CONFIG_EFI_PARAMS_FROM_FDT=y. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/x86: Implement mixed mode boot without the handover protocolArd Biesheuvel1-13/+16
Add support for booting 64-bit x86 kernels from 32-bit firmware running on 64-bit capable CPUs without requiring the bootloader to implement the EFI handover protocol or allocate the setup block, etc etc, all of which can be done by the stub itself, using code that already exists. Instead, create an ordinary EFI application entrypoint but implemented in 32-bit code [so that it can be invoked by 32-bit firmware], and stash the address of this 32-bit entrypoint in the .compat section where the bootloader can find it. Note that we use the setup block embedded in the binary to go through startup_32(), but it gets reallocated and copied in efi_pe_entry(), using the same code that runs when the x86 kernel is booted in EFI mode from native firmware. This requires the loaded image protocol to be installed on the kernel image's EFI handle, and point to the kernel image itself and not to its loader. This, in turn, requires the bootloader to use the LoadImage() boot service to load the 64-bit image from 32-bit firmware, which is in fact supported by firmware based on EDK2. (Only StartImage() will fail, and instead, the newly added entrypoint needs to be invoked) Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub/x86: Use Exit() boot service to exit the stub on errorsArd Biesheuvel2-8/+17
Currently, we either return with an error [from efi_pe_entry()] or enter a deadloop [in efi_main()] if any fatal errors occur during execution of the EFI stub. Let's switch to calling the Exit() EFI boot service instead in both cases, so that we a) can get rid of the deadloop, and simply return to the boot manager if any errors occur during execution of the stub, including during the call to ExitBootServices(), b) can also return cleanly from efi_pe_entry() or efi_main() in mixed mode, once we introduce support for LoadImage/StartImage based mixed mode in the next patch. Note that on systems running downstream GRUBs [which do not use LoadImage or StartImage to boot the kernel, and instead, pass their own image handle as the loaded image handle], calling Exit() will exit from GRUB rather than from the kernel, but this is a tolerable side effect. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub/x86: Make loaded_image protocol handling mixed mode safeArd Biesheuvel3-18/+35
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/arm: Drop unnecessary references to efi.systabArd Biesheuvel2-37/+14
Instead of populating efi.systab very early during efi_init() with a mapping that is released again before the function exits, use a local variable here. Now that we use efi.runtime to access the runtime services table, this removes the only reference efi.systab, so there is no need to populate it anymore, or discover its virtually remapped address. So drop the references entirely. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Add 'runtime' pointer to struct efiArd Biesheuvel2-2/+3
Instead of going through the EFI system table each time, just copy the runtime services table pointer into struct efi directly. This is the last use of the system table pointer in struct efi, allowing us to drop it in a future patch, along with a fair amount of quirky handling of the translated address. Note that usually, the runtime services pointer changes value during the call to SetVirtualAddressMap(), so grab the updated value as soon as that call returns. (Mixed mode uses a 1:1 mapping, and kexec boot enters with the updated address in the system table, so in those cases, we don't need to do anything here) Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/x86: Make fw_vendor, config_table and runtime sysfs nodes x86 specificArd Biesheuvel2-37/+6
There is some code that exposes physical addresses of certain parts of the EFI firmware implementation via sysfs nodes. These nodes are only used on x86, and are of dubious value to begin with, so let's move their handling into the x86 arch code. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Clean up config_parse_tables()Ard Biesheuvel2-27/+25
config_parse_tables() is a jumble of pointer arithmetic, due to the fact that on x86, we may be dealing with firmware whose native word size differs from the kernel's. This is not a concern on other architectures, and doesn't quite justify the state of the code, so let's clean it up by adding a non-x86 code path, constifying statically allocated tables and replacing preprocessor conditionals with IS_ENABLED() checks. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Make efi_config_init() x86 onlyArd Biesheuvel1-31/+0
The efi_config_init() routine is no longer shared with ia64 so let's move it into the x86 arch code before making further x86 specific changes to it. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Merge EFI system table revision and vendor checksArd Biesheuvel2-27/+66
We have three different versions of the code that checks the EFI system table revision and copies the firmware vendor string, and they are mostly equivalent, with the exception of the use of early_memremap_ro vs. __va() and the lowest major revision to warn about. Let's move this into common code and factor out the commonalities. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Make memreserve table handling local to efi.cArd Biesheuvel1-6/+6
There is no need for struct efi to carry the address of the memreserve table and share it with the world. So move it out and make it __initdata as well. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Move mem_attr_table out of struct efiArd Biesheuvel2-8/+8
The memory attributes table is only used at init time by the core EFI code, so there is no need to carry its address in struct efi that is shared with the world. So move it out, and make it __ro_after_init as well, considering that the value is set during early boot. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Make rng_seed table handling local to efi.cArd Biesheuvel1-11/+10
Move the rng_seed table address from struct efi into a static global variable in efi.c, which is the only place we ever refer to it anyway. This reduces the footprint of struct efi, which is a r/w data structure that is shared with the world. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Move UGA and PROP table handling to x86 codeArd Biesheuvel1-24/+1
The UGA table is x86 specific (its handling was introduced when the EFI support code was modified to accommodate IA32), so there is no need to handle it in generic code. The EFI properties table is not strictly x86 specific, but it was deprecated almost immediately after having been introduced, due to implementation difficulties. Only x86 takes it into account today, and this is not going to change, so make this table x86 only as well. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/ia64: Move HCDP and MPS table handling into IA64 arch codeArd Biesheuvel1-8/+6
The HCDP and MPS tables are Itanium specific EFI config tables, so move their handling to ia64 arch code. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi: Drop handling of 'boot_info' configuration tableArd Biesheuvel1-3/+0
Some plumbing exists to handle a UEFI configuration table of type BOOT_INFO but since we never match it to a GUID anywhere, we never actually register such a table, or access it, for that matter. So simply drop all mentions of it. Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64 Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Take noinitrd cmdline argument into account for devpath initrdArd Biesheuvel4-35/+52
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 Biesheuvel4-3/+125
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/dev-path-parser: Add struct definition for vendor type device path nodesArd Biesheuvel2-23/+23
In preparation of adding support for loading the initrd via a special device path, add the struct definition of a vendor GUIDed device path node to efi.h. Since we will be producing these data structures rather than just consumsing the ones instantiated by the firmware, refactor the various device path node definitions so we can take the size of each node using sizeof() rather than having to resort to opaque arithmetic in the static initializers. While at it, drop the #if IS_ENABLED() check for the declaration of efi_get_device_by_path(), which is unnecessary, and constify its first argument as well. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/capsule-loader: Drop superfluous assignmentHeinrich Schuchardt1-1/+1
In efi_capsule_write() the value 0 assigned to ret is never used. Identified with cppcheck. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200223205435.114915-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/esrt: Clean up efi_esrt_initHeinrich Schuchardt1-4/+2
Remove an unused variable in __init efi_esrt_init(). Simplify a logical constraint. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200223204557.114634-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Fix error message in handle_cmdline_files()Heinrich Schuchardt1-1/+1
The memory for files is allocated not reallocated. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200221191829.18149-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Describe RNG functionsHeinrich Schuchardt1-0/+24
Provide descriptions for the functions invoking the EFI_RNG_PROTOCOL. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Link: https://lore.kernel.org/r/20200221114716.4372-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Describe efi_relocate_kernel()Heinrich Schuchardt1-9/+20
Update the description of of efi_relocate_kernel() to match Sphinx style. Update parameter references in the description of other memory functions to use @param style. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20200220065317.9096-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Describe memory functionsHeinrich Schuchardt1-2/+34
Provide descriptions of: * efi_get_memory_map() * efi_low_alloc_above() * efi_free() Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20200218063038.3436-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Simplify efi_get_memory_map()Heinrich Schuchardt1-6/+7
Do not check the value of status twice. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200216184050.3100-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Add function description of efi_allocate_pages()Heinrich Schuchardt1-2/+14
Provide a Sphinx style function description for efi_allocate_pages(). Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Link: https://lore.kernel.org/r/20200216171340.6070-1-xypron.glpk@gmx.de Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Make the LoadFile EFI protocol accessibleArd Biesheuvel1-0/+14
Add the protocol definitions, GUIDs and mixed mode glue so that the EFI loadfile protocol can be used from the stub. This will be used in a future patch to load the initrd. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Expose LocateDevicePath boot serviceArd Biesheuvel1-1/+5
We will be adding support for loading the initrd from a GUIDed device path in a subsequent patch, so update the prototype of the LocateDevicePath() boot service to make it callable from our code. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-02-23efi/libstub: Clean up command line parsing routineArd Biesheuvel5-55/+96
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: Take soft and hard memory limits into account for initrd loadingArd Biesheuvel4-17/+20
On x86, the preferred load address of the initrd is still below 4 GB, even though in some cases, we can cope with an initrd that is loaded above that. To simplify the code, and to make it more straightforward to introduce other ways to load the initrd, pass the soft and hard memory limits at the same time, and let the code handling the initrd= command line option deal with this. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>