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[80.71.134.83]) by smtp.gmail.com with ESMTPSA id f24-20020a056402005800b0046cbcc86bdesm7382008edu.7.2022.12.21.11.46.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Dec 2022 11:46:11 -0800 (PST) From: Ricardo Ribalda Date: Wed, 21 Dec 2022 20:45:58 +0100 Subject: [PATCH v5 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-v5-2-1bd37caf3c75@chromium.org> References: <20221114-disable-kexec-reset-v5-0-1bd37caf3c75@chromium.org> In-Reply-To: <20221114-disable-kexec-reset-v5-0-1bd37caf3c75@chromium.org> To: "Guilherme G. Piccoli" , Eric Biederman , Jonathan Corbet , Philipp Rudo Cc: Ross Zwisler , Sergey Senozhatsky , Steven Rostedt , kexec@lists.infradead.org, Ricardo Ribalda , "Joel Fernandes (Google)" , 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/ZANAwAKAdE30T7POsSIAcsmYgBjo2J+j6VSiwnd2NWq7ZYy+eTh20kxBVZ9N+tQgsO4 igsMiaWJAjMEAAEKAB0WIQREDzjr+/4oCDLSsx7RN9E+zzrEiAUCY6NifgAKCRDRN9E+zzrEiGD7EA CYxHLKOPM0+bvFezijOnO/4euoKLtab/2RYTcKlJRXfaLDSfpGPq/yiF2XmosQXz9H1wOwxZjPq0UV S+/PlFVreAJhuOn9yogBEAdK9wkQu4xJUtE84othkWC84aYXOHQK6PSZCScw6dWYV3JV2v3JOrNqB3 hRcsbyMxlyPsXIdpxlwA6ZHmdLVsivB1zoYcJl7CwUGPNcC+/OLyyVORgUI55LdUAVqeHxyaVfuGav gY8xZzttKJEAlpzfB5cz7yyqK1Zd5FPdV/1BDsxLEG2G1ej1IFkaoUZItbfAPHq+w/q+zJfpv76m3L 7bw4bH8WT321wqTso6Ixppe2rUErDpNDtDWSUJJDIlRZJeWmr0opiVPxaG+i51uWHfO3d7YKV6JJ16 ACej0FAbBCJgZgAGSWby008b6GoyJWcMoN4a6xfP6hEDqjsmSYDJ+GQNBuWg3U0t/PlFDJbQZS2Y2c C3QCGfQ+o+6QYZ5RTV0pv90pQZunYJ3VJlaxVD16OSM+HRroJGo1zhLgJeMbDr+00+BNw9BRUnEtQk KQ7E20venuQA+qKYRD+AB1egECzOpXL1bpBMNjmE8254qy60xBRjk3iM1dqnApJPFBI9qSKY4V39ZC kH4XZdG16Fnrhi2q3Mr4lD8J1Q5WMmGdya5RTg4lw0296MOpLuJqkhRD3+Gw== 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