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[2620:137:e000::1:20]) by mx.google.com with ESMTP id gw17-20020a17090b0a5100b002637fd817d0si12733417pjb.3.2023.07.13.06.50.18; Thu, 13 Jul 2023 06:50:30 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@rivosinc-com.20221208.gappssmtp.com header.s=20221208 header.b=Q65VG0hl; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233992AbjGMNfL (ORCPT + 99 others); Thu, 13 Jul 2023 09:35:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233081AbjGMNfJ (ORCPT ); Thu, 13 Jul 2023 09:35:09 -0400 Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29023E4D for ; Thu, 13 Jul 2023 06:35:08 -0700 (PDT) Received: by mail-ej1-x62a.google.com with SMTP id a640c23a62f3a-98e39784a85so426944366b.1 for ; Thu, 13 Jul 2023 06:35:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20221208.gappssmtp.com; s=20221208; t=1689255306; x=1691847306; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=totAZSGL3sMvt7aEqkeHA/bfBbkIFO3TpIoyWFj1SaE=; b=Q65VG0hlMy4fTnNfEj7Co5ymFjOQholWjsJx7pchjVWrMJ+/+sOVZ2uMUtNd06d4PK T7RinXrSx9pLCql06yAnz0BO0AFGMZK/+cyvZmRxw61HquaaT2Xl10qRueSs46MXAuoU L8xwxvUVkAGYpZ2qi3SId5jI4FA5+TyuIqKHxSp2ir+y2jEVl861wEE+Zm6VhgTR7PbF enmvvgWm4XGV7dv7bCeoqjBT3ljED05x1vo2juD9nvejvqthHE88bMIAzvpJIy5Xm8lT 0c57uQg/TY06OK6zFlN5p2VtOSAprR2rkC3B60UcYQwTTgW7B/vA4drueUTy4Dmwfvd5 x2OA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689255306; x=1691847306; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=totAZSGL3sMvt7aEqkeHA/bfBbkIFO3TpIoyWFj1SaE=; b=G7d4+EfapSjbiZL2KAPEawe6fMeiIY8+diReh5xgmqRQ2ev6P+3cHCnHPm3N+pavfZ 11y17LsZKXoAobKiQn/m07ZJFtdG2RM20GPnkiWImggj7J4ICgxltv8L/QvCMKJXg8Wx rURjhDWYqOGOSJF4FGrorWf16hD2l2saj2z0OJqh+HITQ74f8de85l902dv2FwBudsX2 yEuI0SyL3gCoQhSrkB0evf8XX7OJgKQPndQs/OKIQvFNzEODMTE5kGH9yP9C4pIJkhVE W548iTzApXlRgN9aPUodwynTRiR9GRpXUfTWJhySrK5iCNPOz3fIDqq+Cm2JU68jqlGJ 9wrQ== X-Gm-Message-State: ABy/qLY1n/srEaUqIZ9UfzkGnE5f6fduvU1O+xkvKIqQJXrqjK1lz/// //QYzQreUUek67Abcwr8Mnubbg== X-Received: by 2002:a17:906:7a55:b0:98e:370c:be69 with SMTP id i21-20020a1709067a5500b0098e370cbe69mr2398008ejo.6.1689255306576; Thu, 13 Jul 2023 06:35:06 -0700 (PDT) Received: from alex-rivos.ba.rivosinc.com ([93.23.19.53]) by smtp.gmail.com with ESMTPSA id x14-20020a170906804e00b0099364d9f0e9sm3991397ejw.102.2023.07.13.06.35.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Jul 2023 06:35:06 -0700 (PDT) From: Alexandre Ghiti To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Ard Biesheuvel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandre Ghiti Subject: [PATCH v4 1/5] riscv: Introduce virtual kernel mapping KASLR Date: Thu, 13 Jul 2023 15:33:57 +0200 Message-Id: <20230713133401.116506-2-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230713133401.116506-1-alexghiti@rivosinc.com> References: <20230713133401.116506-1-alexghiti@rivosinc.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1771313541442177613 X-GMAIL-MSGID: 1771313541442177613 KASLR implementation relies on a relocatable kernel so that we can move the kernel mapping. The seed needed to virtually move the kernel is taken from the device tree, so we rely on the bootloader to provide a correct seed. Zkr could be used unconditionnally instead if implemented, but that's for another patch. Signed-off-by: Alexandre Ghiti --- arch/riscv/Kconfig | 19 +++++++++++++++ arch/riscv/include/asm/page.h | 3 +++ arch/riscv/kernel/pi/Makefile | 2 +- arch/riscv/kernel/pi/cmdline_early.c | 13 ++++++++++ arch/riscv/kernel/pi/fdt_early.c | 30 +++++++++++++++++++++++ arch/riscv/mm/init.c | 36 +++++++++++++++++++++++++++- 6 files changed, 101 insertions(+), 2 deletions(-) create mode 100644 arch/riscv/kernel/pi/fdt_early.c diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 4c07b9189c86..6a606d5b74c6 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -719,6 +719,25 @@ config RELOCATABLE If unsure, say N. +config RANDOMIZE_BASE + bool "Randomize the address of the kernel image" + select RELOCATABLE + depends on MMU && 64BIT && !XIP_KERNEL + help + Randomizes the virtual address at which the kernel image is + loaded, as a security feature that deters exploit attempts + relying on knowledge of the location of kernel internals. + + It is the bootloader's job to provide entropy, by passing a + random u64 value in /chosen/kaslr-seed at kernel entry. + + When booting via the UEFI stub, it will invoke the firmware's + EFI_RNG_PROTOCOL implementation (if available) to supply entropy + to the kernel proper. In addition, it will randomise the physical + location of the kernel Image as well. + + If unsure, say N. + endmenu # "Kernel features" menu "Boot options" diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h index b55ba20903ec..5488ecc337b6 100644 --- a/arch/riscv/include/asm/page.h +++ b/arch/riscv/include/asm/page.h @@ -106,6 +106,7 @@ typedef struct page *pgtable_t; struct kernel_mapping { unsigned long page_offset; unsigned long virt_addr; + unsigned long virt_offset; uintptr_t phys_addr; uintptr_t size; /* Offset between linear mapping virtual address and kernel load address */ @@ -185,6 +186,8 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x); #define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x)) +unsigned long kaslr_offset(void); + #endif /* __ASSEMBLY__ */ #define virt_addr_valid(vaddr) ({ \ diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile index 7b593d44c712..07915dc9279e 100644 --- a/arch/riscv/kernel/pi/Makefile +++ b/arch/riscv/kernel/pi/Makefile @@ -35,5 +35,5 @@ $(obj)/string.o: $(srctree)/lib/string.c FORCE $(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE $(call if_changed_rule,cc_o_c) -obj-y := cmdline_early.pi.o string.pi.o ctype.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o +obj-y := cmdline_early.pi.o fdt_early.pi.o string.pi.o ctype.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o extra-y := $(patsubst %.pi.o,%.o,$(obj-y)) diff --git a/arch/riscv/kernel/pi/cmdline_early.c b/arch/riscv/kernel/pi/cmdline_early.c index 05652d13c746..68e786c84c94 100644 --- a/arch/riscv/kernel/pi/cmdline_early.c +++ b/arch/riscv/kernel/pi/cmdline_early.c @@ -14,6 +14,7 @@ static char early_cmdline[COMMAND_LINE_SIZE]; * LLVM complain because the function is actually unused in this file). */ u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa); +bool set_nokaslr_from_cmdline(uintptr_t dtb_pa); static char *get_early_cmdline(uintptr_t dtb_pa) { @@ -60,3 +61,15 @@ u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa) return match_noXlvl(cmdline); } + +static bool match_nokaslr(char *cmdline) +{ + return strstr(cmdline, "nokaslr"); +} + +bool set_nokaslr_from_cmdline(uintptr_t dtb_pa) +{ + char *cmdline = get_early_cmdline(dtb_pa); + + return match_nokaslr(cmdline); +} diff --git a/arch/riscv/kernel/pi/fdt_early.c b/arch/riscv/kernel/pi/fdt_early.c new file mode 100644 index 000000000000..899610e042ab --- /dev/null +++ b/arch/riscv/kernel/pi/fdt_early.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include + +/* + * Declare the functions that are exported (but prefixed) here so that LLVM + * does not complain it lacks the 'static' keyword (which, if added, makes + * LLVM complain because the function is actually unused in this file). + */ +u64 get_kaslr_seed(uintptr_t dtb_pa); + +u64 get_kaslr_seed(uintptr_t dtb_pa) +{ + int node, len; + fdt64_t *prop; + u64 ret; + + node = fdt_path_offset((void *)dtb_pa, "/chosen"); + if (node < 0) + return 0; + + prop = fdt_getprop_w((void *)dtb_pa, node, "kaslr-seed", &len); + if (!prop || len != sizeof(u64)) + return 0; + + ret = fdt64_to_cpu(*prop); + *prop = 0; + return ret; +} diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 70fb31960b63..ff926531236e 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -1012,11 +1012,45 @@ static void __init pt_ops_set_late(void) #endif } +#ifdef CONFIG_RANDOMIZE_BASE +extern bool __init __pi_set_nokaslr_from_cmdline(uintptr_t dtb_pa); +extern u64 __init __pi_get_kaslr_seed(uintptr_t dtb_pa); + +static int __init print_nokaslr(char *p) +{ + pr_info("Disabled KASLR"); + return 0; +} +early_param("nokaslr", print_nokaslr); + +unsigned long kaslr_offset(void) +{ + return kernel_map.virt_offset; +} +#endif + asmlinkage void __init setup_vm(uintptr_t dtb_pa) { pmd_t __maybe_unused fix_bmap_spmd, fix_bmap_epmd; - kernel_map.virt_addr = KERNEL_LINK_ADDR; +#ifdef CONFIG_RANDOMIZE_BASE + if (!__pi_set_nokaslr_from_cmdline(dtb_pa)) { + u64 kaslr_seed = __pi_get_kaslr_seed(dtb_pa); + u32 kernel_size = (uintptr_t)(&_end) - (uintptr_t)(&_start); + u32 nr_pos; + + /* + * Compute the number of positions available: we are limited + * by the early page table that only has one PUD and we must + * be aligned on PMD_SIZE. + */ + nr_pos = (PUD_SIZE - kernel_size) / PMD_SIZE; + + kernel_map.virt_offset = (kaslr_seed % nr_pos) * PMD_SIZE; + } +#endif + + kernel_map.virt_addr = KERNEL_LINK_ADDR + kernel_map.virt_offset; kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL); #ifdef CONFIG_XIP_KERNEL From patchwork Thu Jul 13 13:33:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 119916 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:a6b2:0:b0:3e4:2afc:c1 with SMTP id c18csp1850214vqm; Thu, 13 Jul 2023 07:08:43 -0700 (PDT) X-Google-Smtp-Source: APBJJlGa995IbA9Tp0VqwqeYLULVn6k6UCcpmuVJEbANbgNaxfy+5ELy54F/jqzJU37+7/hwHwBJ X-Received: by 2002:a17:906:22db:b0:991:b613:9b65 with SMTP id q27-20020a17090622db00b00991b6139b65mr1270767eja.37.1689257323252; 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Signed-off-by: Zong Li Signed-off-by: Alexandre Ghiti --- arch/riscv/kernel/setup.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 971fe776e2f8..0fb5a26ca4cc 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -341,3 +342,27 @@ void free_initmem(void) free_initmem_default(POISON_FREE_INITMEM); } + +static int dump_kernel_offset(struct notifier_block *self, + unsigned long v, void *p) +{ + pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n", + kernel_map.virt_offset, + KERNEL_LINK_ADDR); + + return 0; +} + +static struct notifier_block kernel_offset_notifier = { + .notifier_call = dump_kernel_offset +}; + +static int __init register_kernel_offset_dumper(void) +{ + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + atomic_notifier_chain_register(&panic_notifier_list, + &kernel_offset_notifier); + + return 0; +} +device_initcall(register_kernel_offset_dumper); From patchwork Thu Jul 13 13:33:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 119924 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:a6b2:0:b0:3e4:2afc:c1 with SMTP id c18csp1855017vqm; Thu, 13 Jul 2023 07:15:14 -0700 (PDT) X-Google-Smtp-Source: APBJJlH5HnK5crhl4tNuQEwABjXEcwqAler2Aw88bmlhobsTYnrCmRV0duXwyKnxYXxyJ+LDlWgF X-Received: by 2002:a17:906:3f14:b0:992:be80:aaf9 with SMTP id c20-20020a1709063f1400b00992be80aaf9mr1863443ejj.51.1689257714284; Thu, 13 Jul 2023 07:15:14 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1689257714; cv=none; d=google.com; s=arc-20160816; b=bme6SYWuwe/czIn2Q76UyDDWIXjNc6fgZ9+2DpyJnPz6bCGYqDoW3PaVSu+uOERr+3 ulEMuyXk/tlD3wb0nHpnmtspES+e8oeXPAAb0bHdxtk2vsV8nM9CerfHeT+teqIetK9C T9qwKNFbOAAe86GXHEAShHTog6odhYtn8X5ybaWzv3B4J1KWgxbJcc336P7WHZt+cQHp m/pJXsrR0jDM7k8tNKAZ0JMcFZ4hGFKhlocM1IfOGOrIcSNlxRP7h7MXH7ow7RYHKeCG Ku6xkJqSvRYduq6n3dmELFHcphUTiOBnfJTJ7gOw/Z4LOFbvFBEnAOpdH1P6O5imvkxj UveQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=62WVSB6WsPMHDl8cD5P6BTPChBTRmrVLO8yDqyWQGGU=; fh=/mGwUkmUbEVqt40z7nY4T9eynHzFx+zHgFU4kksMLww=; b=VuK8L37tnVz0a/eqIxG1cFYb+HCoxCKmwrZ3TDcB0r9poUxjSdgBn1wPhtX54+HMiV TbiEk6IeF9vLjkjiZqYhxsk7LM0B6gz/w/ucFRfiUDN/or7orf+9nmOtmWUloicIjGnt nxPGVGQLD+GAgqkboO6Sgzqv5BNbOZ5Y5BUvYJHSXc+QQs82569S3+JPjYQzRY2MzhJR qfyOVVCCOkSzf9lFJkfz3qaRz3IHcuMZQiOYYkux2oBuHWHca09qqtZ6Z/hXGH3Dj7V4 t1ilVEy8PpuS4rUh1j2aADFf2ODLXY3pJjXVjPhSyuyXbkTkvd7GKMXtJ9SzE8Fp+pBv anfg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@rivosinc-com.20221208.gappssmtp.com header.s=20221208 header.b=YNHxUnRL; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. 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Signed-off-by: Alexandre Ghiti --- arch/arm64/include/asm/efi.h | 4 + arch/riscv/include/asm/efi.h | 1 + drivers/firmware/efi/libstub/Makefile | 3 +- drivers/firmware/efi/libstub/arm64-stub.c | 117 ++----------- drivers/firmware/efi/libstub/efi-stub-kaslr.c | 159 ++++++++++++++++++ drivers/firmware/efi/libstub/efistub.h | 18 ++ 6 files changed, 197 insertions(+), 105 deletions(-) create mode 100644 drivers/firmware/efi/libstub/efi-stub-kaslr.c diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h index 4cf2cb053bc8..83a4d69fd968 100644 --- a/arch/arm64/include/asm/efi.h +++ b/arch/arm64/include/asm/efi.h @@ -111,6 +111,7 @@ static inline unsigned long efi_get_kimg_min_align(void) */ return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN; } +#define efi_get_kimg_min_align efi_get_kimg_min_align #define EFI_ALLOC_ALIGN SZ_64K #define EFI_ALLOC_LIMIT ((1UL << 48) - 1) @@ -168,4 +169,7 @@ static inline void efi_capsule_flush_cache_range(void *addr, int size) efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f); +void efi_icache_sync(unsigned long start, unsigned long end); +#define efi_icache_sync efi_icache_sync + #endif /* _ASM_EFI_H */ diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h index 29e9a0d84b16..c3dafaab36a2 100644 --- a/arch/riscv/include/asm/efi.h +++ b/arch/riscv/include/asm/efi.h @@ -43,6 +43,7 @@ static inline unsigned long efi_get_kimg_min_align(void) */ return IS_ENABLED(CONFIG_64BIT) ? SZ_2M : SZ_4M; } +#define efi_get_kimg_min_align efi_get_kimg_min_align #define EFI_KIMG_PREFERRED_ADDRESS efi_get_kimg_min_align() diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 16d64a34d1e1..5927fab5c834 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -67,7 +67,8 @@ OBJECT_FILES_NON_STANDARD := y # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in. KCOV_INSTRUMENT := n -lib-y := efi-stub-helper.o gop.o secureboot.o tpm.o \ +lib-y := efi-stub-helper.o efi-stub-kaslr.o \ + gop.o secureboot.o tpm.o \ file.o mem.o random.o randomalloc.o pci.o \ skip_spaces.o lib-cmdline.o lib-ctype.o \ alignedmem.o relocate.o printk.o vsprintf.o diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 770b8ecb7398..452b7ccd330e 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -14,42 +14,6 @@ #include "efistub.h" -/* - * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail - * to provide space, and fail to zero it). Check for this condition by double - * checking that the first and the last byte of the image are covered by the - * same EFI memory map entry. - */ -static bool check_image_region(u64 base, u64 size) -{ - struct efi_boot_memmap *map; - efi_status_t status; - bool ret = false; - int map_offset; - - status = efi_get_memory_map(&map, false); - if (status != EFI_SUCCESS) - return false; - - for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { - efi_memory_desc_t *md = (void *)map->map + map_offset; - u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; - - /* - * Find the region that covers base, and return whether - * it covers base+size bytes. - */ - if (base >= md->phys_addr && base < end) { - ret = (base + size) <= end; - break; - } - } - - efi_bs_call(free_pool, map); - - return ret; -} - efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, @@ -59,31 +23,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, { efi_status_t status; unsigned long kernel_size, kernel_codesize, kernel_memsize; - u32 phys_seed = 0; - u64 min_kimg_align = efi_get_kimg_min_align(); - - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { - efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; - void *p; - - if (efi_nokaslr) { - efi_info("KASLR disabled on kernel command line\n"); - } else if (efi_bs_call(handle_protocol, image_handle, - &li_fixed_proto, &p) == EFI_SUCCESS) { - efi_info("Image placement fixed by loader\n"); - } else { - status = efi_get_random_bytes(sizeof(phys_seed), - (u8 *)&phys_seed); - if (status == EFI_NOT_FOUND) { - efi_info("EFI_RNG_PROTOCOL unavailable\n"); - efi_nokaslr = true; - } else if (status != EFI_SUCCESS) { - efi_err("efi_get_random_bytes() failed (0x%lx)\n", - status); - efi_nokaslr = true; - } - } - } if (image->image_base != _text) { efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n"); @@ -98,50 +37,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, kernel_codesize = __inittext_end - _text; kernel_memsize = kernel_size + (_end - _edata); *reserve_size = kernel_memsize; + *image_addr = (unsigned long)_text; - if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { - /* - * If KASLR is enabled, and we have some randomness available, - * locate the kernel at a randomized offset in physical memory. - */ - status = efi_random_alloc(*reserve_size, min_kimg_align, - reserve_addr, phys_seed, - EFI_LOADER_CODE); - if (status != EFI_SUCCESS) - efi_warn("efi_random_alloc() failed: 0x%lx\n", status); - } else { - status = EFI_OUT_OF_RESOURCES; - } - - if (status != EFI_SUCCESS) { - if (!check_image_region((u64)_text, kernel_memsize)) { - efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); - } else if (IS_ALIGNED((u64)_text, min_kimg_align) && - (u64)_end < EFI_ALLOC_LIMIT) { - /* - * Just execute from wherever we were loaded by the - * UEFI PE/COFF loader if the placement is suitable. - */ - *image_addr = (u64)_text; - *reserve_size = 0; - return EFI_SUCCESS; - } - - status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, - ULONG_MAX, min_kimg_align, - EFI_LOADER_CODE); - - if (status != EFI_SUCCESS) { - efi_err("Failed to relocate kernel\n"); - *reserve_size = 0; - return status; - } - } - - *image_addr = *reserve_addr; - memcpy((void *)*image_addr, _text, kernel_size); - caches_clean_inval_pou(*image_addr, *image_addr + kernel_codesize); - efi_remap_image(*image_addr, *reserve_size, kernel_codesize); + status = efi_kaslr_relocate_kernel(image_addr, + reserve_addr, reserve_size, + kernel_size, kernel_codesize, + kernel_memsize, + efi_kaslr_get_phys_seed(image_handle)); + if (status != EFI_SUCCESS) + return status; return EFI_SUCCESS; } @@ -159,3 +63,8 @@ unsigned long primary_entry_offset(void) */ return (char *)primary_entry - _text; } + +void efi_icache_sync(unsigned long start, unsigned long end) +{ + caches_clean_inval_pou(start, end); +} diff --git a/drivers/firmware/efi/libstub/efi-stub-kaslr.c b/drivers/firmware/efi/libstub/efi-stub-kaslr.c new file mode 100644 index 000000000000..be0c8ab0982a --- /dev/null +++ b/drivers/firmware/efi/libstub/efi-stub-kaslr.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Helper functions used by the EFI stub on multiple + * architectures to deal with physical address space randomization. + */ +#include + +#include "efistub.h" + +/** + * efi_kaslr_get_phys_seed() - Get random seed for physical kernel KASLR + * @image_handle: Handle to the image + * + * If KASLR is not disabled, obtain a random seed using EFI_RNG_PROTOCOL + * that will be used to move the kernel physical mapping. + * + * Return: the random seed + */ +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle) +{ + efi_status_t status; + u32 phys_seed; + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; + void *p; + + if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) + return 0; + + if (efi_nokaslr) { + efi_info("KASLR disabled on kernel command line\n"); + } else if (efi_bs_call(handle_protocol, image_handle, + &li_fixed_proto, &p) == EFI_SUCCESS) { + efi_info("Image placement fixed by loader\n"); + } else { + status = efi_get_random_bytes(sizeof(phys_seed), + (u8 *)&phys_seed); + if (status == EFI_SUCCESS) { + return phys_seed; + } else if (status == EFI_NOT_FOUND) { + efi_info("EFI_RNG_PROTOCOL unavailable\n"); + efi_nokaslr = true; + } else if (status != EFI_SUCCESS) { + efi_err("efi_get_random_bytes() failed (0x%lx)\n", + status); + efi_nokaslr = true; + } + } + + return 0; +} + +/* + * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail + * to provide space, and fail to zero it). Check for this condition by double + * checking that the first and the last byte of the image are covered by the + * same EFI memory map entry. + */ +static bool check_image_region(u64 base, u64 size) +{ + struct efi_boot_memmap *map; + efi_status_t status; + bool ret = false; + int map_offset; + + status = efi_get_memory_map(&map, false); + if (status != EFI_SUCCESS) + return false; + + for (map_offset = 0; map_offset < map->map_size; map_offset += map->desc_size) { + efi_memory_desc_t *md = (void *)map->map + map_offset; + u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE; + + /* + * Find the region that covers base, and return whether + * it covers base+size bytes. + */ + if (base >= md->phys_addr && base < end) { + ret = (base + size) <= end; + break; + } + } + + efi_bs_call(free_pool, map); + + return ret; +} + +/** + * efi_kaslr_relocate_kernel() - Relocate the kernel (random if KASLR enabled) + * @image_addr: Pointer to the current kernel location + * @reserve_addr: Pointer to the relocated kernel location + * @reserve_size: Size of the relocated kernel + * @kernel_size: Size of the text + data + * @kernel_codesize: Size of the text + * @kernel_memsize: Size of the text + data + bss + * @phys_seed: Random seed used for the relocation + * + * If KASLR is not enabled, this function relocates the kernel to a fixed + * address (or leave it as its current location). If KASLR is enabled, the + * kernel physical location is randomized using the seed in parameter. + * + * Return: status code, EFI_SUCCESS if relocation is successful + */ +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_codesize, + unsigned long kernel_memsize, + u32 phys_seed) +{ + efi_status_t status; + u64 min_kimg_align = efi_get_kimg_min_align(); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { + /* + * If KASLR is enabled, and we have some randomness available, + * locate the kernel at a randomized offset in physical memory. + */ + status = efi_random_alloc(*reserve_size, min_kimg_align, + reserve_addr, phys_seed, + EFI_LOADER_CODE); + if (status != EFI_SUCCESS) + efi_warn("efi_random_alloc() failed: 0x%lx\n", status); + } else { + status = EFI_OUT_OF_RESOURCES; + } + + if (status != EFI_SUCCESS) { + if (!check_image_region(*image_addr, kernel_memsize)) { + efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n"); + } else if (IS_ALIGNED(*image_addr, min_kimg_align) && + (u64)_end < EFI_ALLOC_LIMIT) { + /* + * Just execute from wherever we were loaded by the + * UEFI PE/COFF loader if the placement is suitable. + */ + *reserve_size = 0; + return EFI_SUCCESS; + } + + status = efi_allocate_pages_aligned(*reserve_size, reserve_addr, + ULONG_MAX, min_kimg_align, + EFI_LOADER_CODE); + + if (status != EFI_SUCCESS) { + efi_err("Failed to relocate kernel\n"); + *reserve_size = 0; + return status; + } + } + + memcpy((void *)*reserve_addr, (void *)*image_addr, kernel_size); + *image_addr = *reserve_addr; + efi_icache_sync(*image_addr, *image_addr + kernel_codesize); + efi_remap_image(*image_addr, *reserve_size, kernel_codesize); + + return status; +} diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 6aa38a1bf126..35337ea5056e 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -1132,6 +1132,24 @@ const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record, void efi_remap_image(unsigned long image_base, unsigned alloc_size, unsigned long code_size); +efi_status_t efi_kaslr_relocate_kernel(unsigned long *image_addr, + unsigned long *reserve_addr, + unsigned long *reserve_size, + unsigned long kernel_size, + unsigned long kernel_codesize, + unsigned long kernel_memsize, + u32 phys_seed); +u32 efi_kaslr_get_phys_seed(efi_handle_t image_handle); + +#ifndef efi_get_kimg_min_align +static inline unsigned long efi_get_kimg_min_align(void) { return 0; } +#define efi_get_kimg_min_align efi_get_kimg_min_align +#endif + +#ifndef efi_icache_sync +static inline void efi_icache_sync(unsigned long start, unsigned long end) {} +#define efi_icache_sync efi_icache_sync +#endif asmlinkage efi_status_t __efiapi efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab);