From nobody Wed Sep 17 10:33:01 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4686C4332F for ; Wed, 21 Dec 2022 12:50:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232500AbiLUMu3 (ORCPT ); Wed, 21 Dec 2022 07:50:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231818AbiLUMuU (ORCPT ); Wed, 21 Dec 2022 07:50:20 -0500 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2A8422BF5 for ; Wed, 21 Dec 2022 04:50:18 -0800 (PST) Received: by mail-ej1-x62e.google.com with SMTP id fc4so36461562ejc.12 for ; Wed, 21 Dec 2022 04:50:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=0uo7tfZaiqOin2cp8QemVMZCCRCz92hxCxC8vhk5Wl8=; b=R2RT15ASWFQQ+HJe+0sCo+uF2kmwezaj3G470IQ3VwrN9sGIz7hH7YtE7+LcKHt6Cj oJw2V0LJVsPN/SBndPAGkCuI6O+DXEN9nMef2mvpzYidC5dI2ivk5DxCDGzkMzM1FMVl QVCsZJW6B1pti7LEpdEOt0AR1rG8O44Pgjaag= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=0uo7tfZaiqOin2cp8QemVMZCCRCz92hxCxC8vhk5Wl8=; b=S1grZ1xWhcS/UqvylDTUuTb1lq8v5bmUSVYG8YCjKAi7nP4nVOTFVqvdMssEu+NFe2 aTIElr5Y9BrujuTz0vQeglIkdrjzq+VxZ43ne1rPGMdlYE7BeYXPoJnALkxXrHZtK7jq ms1YAMRS3ZUTnXBjNxsN3yBKFUq1EYhqcm5rxDoMXlBUfJ3+YFhJ/yB3Kr2FAK16kxfG 2RiJDlw72AnnnCXneCLm8B0Fxpr4eHrIVcBEp8gHbNlCpyLAJ0xZHMgIQ3szxH0MvFr6 iLpQFMwYcPLDnzCL2u51vRmt+7EjwmKlAYex/XOFj5KZpMCZ1QUf5hZLz3krkzMGaZuB D1/A== X-Gm-Message-State: AFqh2kr6mmd8F2kDHwgwh92spL50nvm6WabqXXknmvG1rQ7FsN6nWn23 +NQ/RNiVMw+UPPhTzYZQ4tFb9A== X-Google-Smtp-Source: AMrXdXsP7f6lqej8FU5+HkqvdNOpkaOSpgva0UJJ4q1TLYkqxkisLNkbycJ2AA6LvfmifmlzW3CSdA== X-Received: by 2002:a17:907:d10:b0:82d:e258:fa55 with SMTP id gn16-20020a1709070d1000b0082de258fa55mr1453100ejc.36.1671627018527; Wed, 21 Dec 2022 04:50:18 -0800 (PST) Received: from alco.roam.corp.google.com ([2620:0:1059:10:4b82:b1f8:cb4f:fbbd]) by smtp.gmail.com with ESMTPSA id w7-20020a170906b18700b007c0b28b85c5sm7039250ejy.138.2022.12.21.04.50.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Dec 2022 04:50:17 -0800 (PST) From: Ricardo Ribalda Date: Wed, 21 Dec 2022 13:50:02 +0100 Subject: [PATCH v4 2/3] kexec: Factor out kexec_load_permitted MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20221114-disable-kexec-reset-v4-2-ab809c8d988c@chromium.org> References: <20221114-disable-kexec-reset-v4-0-ab809c8d988c@chromium.org> In-Reply-To: <20221114-disable-kexec-reset-v4-0-ab809c8d988c@chromium.org> To: Jonathan Corbet , Philipp Rudo , Eric Biederman , "Guilherme G. Piccoli" Cc: kexec@lists.infradead.org, Ricardo Ribalda , Ross Zwisler , Steven Rostedt , "Joel Fernandes (Google)" , Sergey Senozhatsky , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org X-Mailer: b4 0.11.0-dev-696ae X-Developer-Signature: v=1; a=openpgp-sha256; l=2724; i=ribalda@chromium.org; h=from:subject:message-id; bh=rm7FZlNI1K3HcWDQ5vaPpIW63r8rInBklo9MHxPCtFE=; b=owEBbQKS/ZANAwAKAdE30T7POsSIAcsmYgBjowECkFe21vSuqwF6tn2p8L+BKJ7tkuaiu4yiHveG nMtEFu+JAjMEAAEKAB0WIQREDzjr+/4oCDLSsx7RN9E+zzrEiAUCY6MBAgAKCRDRN9E+zzrEiO7dD/ 0XCbh5Qt8a1g8a4Ymj0sdar9KtUlQmWiFta0b5GfuPwcKQF19M9Med6ybxz+sbYW42P4SmN9A2XNec hNqPXR722Yi+HMUx4Qd/B+ioG5bVXLpahjFybWh0OzFejOEsoFCdP+ZIGKqe7i6jIfWWayud7NCbIL 6CXuHhCyrTGg8tpp3wsxfnogoFnEi6Q252E+w1Jgmlyyd/u1tMQbVSJ5XRnOpVTOPWFLecrDwZLRkm vJrOhRDdEnRjGh8q0E12ff/RTZ9giik6eekXfuPzJP6cI9mynKpzBzk8lxlqJzv/c1AdGr1eBvidU7 SwH9z8VvgHgK6vuN/A2DcxIC2Nce4PgvCzE6HLf6N1SaFL1iLZgB1GfFvYRxKf3cstzH9PVF2aYtlm r+QOw7ZwzrUnuYCZ+oULXDrpN9BNvxXwiG8Z2XdLWWqApjvxbZg72DlSXqkoiXK1k67Lj60HEehYyc jW+mz5MmMhqWT9rPRTbOMYdx+ppB4Szq4LEWarobPro9UZ8hhekXyXhYqgdncIvlR707JCUDjuEfpa Y2/uGgzDL2NaIOghN2/Y6X29qA6cfq4aR5wEEKHh8YhUEJBL/lHtsVN//Na8/DHod2e95JHXdO1EFQ JCZkKRC/0AcMQmLyUH832g1pR/uqXtS1FKqQfFmUTzN8WRH+qZmdP3k0Psng== X-Developer-Key: i=ribalda@chromium.org; a=openpgp; fpr=9EC3BB66E2FC129A6F90B39556A0D81F9F782DA9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Both syscalls (kexec and kexec_file) do the same check, lets factor it out. Signed-off-by: Ricardo Ribalda --- include/linux/kexec.h | 3 ++- kernel/kexec.c | 2 +- kernel/kexec_core.c | 11 ++++++++++- kernel/kexec_file.c | 2 +- 4 files changed, 14 insertions(+), 4 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 41a686996aaa..182e0c11b87b 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -406,7 +406,8 @@ extern int kimage_crash_copy_vmcoreinfo(struct kimage *= image); =20 extern struct kimage *kexec_image; extern struct kimage *kexec_crash_image; -extern int kexec_load_disabled; + +bool kexec_load_permitted(void); =20 #ifndef kexec_flush_icache_page #define kexec_flush_icache_page(page) diff --git a/kernel/kexec.c b/kernel/kexec.c index cb8e6e6f983c..ce1bca874a8d 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -193,7 +193,7 @@ static inline int kexec_load_check(unsigned long nr_seg= ments, int result; =20 /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted()) return -EPERM; =20 /* Permit LSMs and IMA to fail the kexec */ diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index ca2743f9c634..a1efc70f4158 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -928,7 +928,7 @@ int kimage_load_segment(struct kimage *image, =20 struct kimage *kexec_image; struct kimage *kexec_crash_image; -int kexec_load_disabled; +static int kexec_load_disabled; #ifdef CONFIG_SYSCTL static struct ctl_table kexec_core_sysctls[] =3D { { @@ -952,6 +952,15 @@ static int __init kexec_core_sysctl_init(void) late_initcall(kexec_core_sysctl_init); #endif =20 +bool kexec_load_permitted(void) +{ + /* + * Only the superuser can use the kexec syscall and if it has not + * been disabled. + */ + return capable(CAP_SYS_BOOT) && !kexec_load_disabled; +} + /* * No panic_cpu check version of crash_kexec(). This function is called * only when panic_cpu holds the current CPU number; this is the only CPU diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 45637511e0de..29efa43ea951 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -330,7 +330,7 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, i= nitrd_fd, struct kimage **dest_image, *image; =20 /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted()) return -EPERM; =20 /* Make sure we have a legal set of flags */ --=20 2.39.0.314.g84b9a713c41-goog-b4-0.11.0-dev-696ae