kernel/drivers/firmware/efi/libstub/secureboot.c, branch linux-6.9.y

efi: libstub: check Shim mode using MokSBStateRT

2022-09-22T08:15:44Z

We currently check the MokSBState variable to decide whether we should treat UEFI secure boot as being disabled, even if the firmware thinks otherwise. This is used by shim to indicate that it is not checking signatures on boot images. In the kernel, we use this to relax lockdown policies. However, in cases where shim is not even being used, we don't want this variable to interfere with lockdown, given that the variable may be non-volatile and therefore persist across a reboot. This means setting it once will persistently disable lockdown checks on a given system. So switch to the mirrored version of this variable, called MokSBStateRT, which is supposed to be volatile, and this is something we can check. Cc: # v4.19+ Signed-off-by: Ard Biesheuvel Reviewed-by: Ilias Apalodimas Reviewed-by: Peter Jones

efi: x86/xen: switch to efi_get_secureboot_mode helper

2020-11-17T14:09:32Z

Now that we have a static inline helper to discover the platform's secure boot mode that can be shared between the EFI stub and the kernel proper, switch to it, and drop some comments about keeping them in sync manually. Signed-off-by: Ard Biesheuvel

efi: generalize efi_get_secureboot

2020-11-04T22:05:40Z

Generalize the efi_get_secureboot() function so not only efistub but also other subsystems can use it. Note that the MokSbState handling is not factored out: the variable is boot time only, and so it cannot be parameterized as easily. Also, the IMA code will switch to this version in a future patch, and it does not incorporate the MokSbState exception in the first place. Note that the new efi_get_secureboot_mode() helper treats any failures to read SetupMode as setup mode being disabled. Co-developed-by: Chester Lin Signed-off-by: Chester Lin Acked-by: Mimi Zohar Signed-off-by: Ard Biesheuvel

efi/libstub: Move pr_efi/pr_efi_err into efi namespace

2020-05-01T07:40:02Z

Rename pr_efi to efi_info and pr_efi_err to efi_err to make it more obvious that they are part of the EFI stub and not generic printk infra. Suggested-by: Joe Perches Signed-off-by: Arvind Sankar Link: https://lore.kernel.org/r/20200430182843.2510180-4-nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel

efi/libstub: Rename efi_call_early/_runtime macros to be more intuitive

2019-12-25T09:49:25Z

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 Cc: Arvind Sankar Cc: Borislav Petkov Cc: James Morse Cc: Matt Fleming Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-24-ardb@kernel.org Signed-off-by: Ingo Molnar

efi/libstub: Remove 'sys_table_arg' from all function prototypes

2019-12-25T09:49:23Z

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 Cc: Arvind Sankar Cc: Borislav Petkov Cc: James Morse Cc: Matt Fleming Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-20-ardb@kernel.org Signed-off-by: Ingo Molnar

efi/libstub: Drop sys_table_arg from printk routines

2019-12-25T09:49:22Z

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 Cc: Arvind Sankar Cc: Borislav Petkov Cc: James Morse Cc: Matt Fleming Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224151025.32482-19-ardb@kernel.org Signed-off-by: Ingo Molnar

efi: Replace GPL license boilerplate with SPDX headers

2019-02-04T07:27:25Z

Replace all GPL license blurbs with an equivalent SPDX header (most files are GPLv2, some are GPLv2+). While at it, drop some outdated header changelogs as well. Signed-off-by: Ard Biesheuvel Cc: AKASHI Takahiro Cc: Alexander Graf Cc: Bjorn Andersson Cc: Borislav Petkov Cc: Heinrich Schuchardt Cc: Jeffrey Hugo Cc: Lee Jones Cc: Leif Lindholm Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Jones Cc: Peter Zijlstra Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190202094119.13230-7-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar

x86/xen/efi: Initialize UEFI secure boot state during dom0 boot

2018-05-14T06:57:46Z

Initialize UEFI secure boot state during dom0 boot. Otherwise the kernel may not even know that it runs on secure boot enabled platform. Note that part of drivers/firmware/efi/libstub/secureboot.c is duplicated by this patch, only in this case, it runs in the context of the kernel proper rather than UEFI boot context. The reason for the duplication is that maintaining the original code to run correctly on ARM/arm64 as well as on all the quirky x86 firmware we support is enough of a burden as it is, and adding the x86/Xen execution context to that mix just so we can reuse a single routine just isn't worth it. [ardb: explain rationale for code duplication] Signed-off-by: Daniel Kiper Signed-off-by: Ard Biesheuvel Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180504060003.19618-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar

efi: Use string literals for efi_char16_t variable initializers

2018-03-12T09:05:02Z

Now that we unambiguously build the entire kernel with -fshort-wchar, it is no longer necessary to open code efi_char16_t[] initializers as arrays of characters, and we can move to the L"xxx" notation instead. Signed-off-by: Ard Biesheuvel Cc: Arnd Bergmann Cc: Linus Torvalds Cc: Lukas Wunner Cc: Matt Fleming Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180312084500.10764-6-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar