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d32de9130f
Currently, on arm64, we abort on any failure from efi_get_random_bytes() other than EFI_NOT_FOUND when it comes to setting the physical seed for KASLR, but ignore such failures when obtaining the seed for virtual KASLR or for early seeding of the kernel's entropy pool via the config table. This is inconsistent, and may lead to unexpected boot failures. So let's permit any failure for the physical seed, and simply report the error code if it does not equal EFI_NOT_FOUND. Cc: <stable@vger.kernel.org> # v5.8+ Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
121 lines
3.4 KiB
C
121 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org>
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*
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* This file implements the EFI boot stub for the arm64 kernel.
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* Adapted from ARM version by Mark Salter <msalter@redhat.com>
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*/
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#include <linux/efi.h>
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#include <asm/efi.h>
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#include <asm/memory.h>
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#include <asm/sections.h>
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#include <asm/sysreg.h>
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#include "efistub.h"
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efi_status_t check_platform_features(void)
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{
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u64 tg;
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/* UEFI mandates support for 4 KB granularity, no need to check */
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if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
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return EFI_SUCCESS;
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tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_TGRAN_SHIFT) & 0xf;
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if (tg != ID_AA64MMFR0_TGRAN_SUPPORTED) {
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if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
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efi_err("This 64 KB granular kernel is not supported by your CPU\n");
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else
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efi_err("This 16 KB granular kernel is not supported by your CPU\n");
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return EFI_UNSUPPORTED;
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}
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return EFI_SUCCESS;
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}
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/*
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* Although relocatable kernels can fix up the misalignment with respect to
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* MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of
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* sync with those recorded in the vmlinux when kaslr is disabled but the
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* image required relocation anyway. Therefore retain 2M alignment unless
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* KASLR is in use.
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*/
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static u64 min_kimg_align(void)
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{
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return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
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}
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efi_status_t handle_kernel_image(unsigned long *image_addr,
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unsigned long *image_size,
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unsigned long *reserve_addr,
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unsigned long *reserve_size,
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unsigned long dram_base,
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efi_loaded_image_t *image)
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{
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efi_status_t status;
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unsigned long kernel_size, kernel_memsize = 0;
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u32 phys_seed = 0;
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if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
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if (!efi_nokaslr) {
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status = efi_get_random_bytes(sizeof(phys_seed),
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(u8 *)&phys_seed);
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if (status == EFI_NOT_FOUND) {
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efi_info("EFI_RNG_PROTOCOL unavailable, KASLR will be disabled\n");
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efi_nokaslr = true;
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} else if (status != EFI_SUCCESS) {
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efi_err("efi_get_random_bytes() failed (0x%lx), KASLR will be disabled\n",
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status);
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efi_nokaslr = true;
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}
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} else {
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efi_info("KASLR disabled on kernel command line\n");
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}
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}
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if (image->image_base != _text)
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efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n");
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kernel_size = _edata - _text;
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kernel_memsize = kernel_size + (_end - _edata);
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*reserve_size = kernel_memsize + TEXT_OFFSET % min_kimg_align();
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if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) {
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/*
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* If KASLR is enabled, and we have some randomness available,
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* locate the kernel at a randomized offset in physical memory.
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*/
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status = efi_random_alloc(*reserve_size, min_kimg_align(),
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reserve_addr, phys_seed);
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} else {
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status = EFI_OUT_OF_RESOURCES;
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}
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if (status != EFI_SUCCESS) {
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if (IS_ALIGNED((u64)_text - TEXT_OFFSET, min_kimg_align())) {
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/*
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* Just execute from wherever we were loaded by the
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* UEFI PE/COFF loader if the alignment is suitable.
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*/
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*image_addr = (u64)_text;
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*reserve_size = 0;
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return EFI_SUCCESS;
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}
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status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,
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ULONG_MAX, min_kimg_align());
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if (status != EFI_SUCCESS) {
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efi_err("Failed to relocate kernel\n");
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*reserve_size = 0;
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return status;
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}
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}
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*image_addr = *reserve_addr + TEXT_OFFSET % min_kimg_align();
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memcpy((void *)*image_addr, _text, kernel_size);
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return EFI_SUCCESS;
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}
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