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[80.71.134.83]) by smtp.gmail.com with ESMTPSA id ku13-20020a170907788d00b00837ac146a53sm1175492ejc.23.2022.12.20.14.06.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Dec 2022 14:06:06 -0800 (PST) From: Ricardo Ribalda Date: Tue, 20 Dec 2022 23:05:44 +0100 Subject: [PATCH v3 2/3] kexec: Factor out kexec_load_permitted MIME-Version: 1.0 Message-Id: <20221114-disable-kexec-reset-v3-2-4ef4e929adf6@chromium.org> References: <20221114-disable-kexec-reset-v3-0-4ef4e929adf6@chromium.org> In-Reply-To: <20221114-disable-kexec-reset-v3-0-4ef4e929adf6@chromium.org> To: Philipp Rudo , Eric Biederman , Jonathan Corbet , "Guilherme G. Piccoli" Cc: linux-doc@vger.kernel.org, Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org, "Joel Fernandes (Google)" , Ricardo Ribalda , Ross Zwisler , kexec@lists.infradead.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/ZANAwAKAdE30T7POsSIAcsmYgBjojHJBckCkaRQr+TYZrF3kjpd1KCko1R5cEm6gufq +jL/ctqJAjMEAAEKAB0WIQREDzjr+/4oCDLSsx7RN9E+zzrEiAUCY6IxyQAKCRDRN9E+zzrEiMSUD/ 9f/BnyydzLUgxCB/+6MPK5x85yrh4BQzpJFvUHfpUcS4bvaQxOKcu42CXvd7TlWapp3anOCskcmg42 XTOJ6jxFo2Zdjd+HB+gQc8AzBwAsTS7lk5/GG5HkOXdqE7oRGXSpyVzd7daWjm0ZAD/e40xju8QvwS yCZM5hT9nhnEwG9RFkNm3p/5yeJngpYqubIHxexqLNz8P6HyUUGskiE6epSpx0A8l1gK5CjJdcJ2QD TAcAv3+NxhErfOIe28YkMiuiHBibNKLw7kolvHnOoLqgUsbGkAgsTJsXayRaN+aQ+UeCiaEIny4inY IsXan5vCvqjJi6Y59k4ojkdtblxbbHoC6438DfPpfOdJfhPPYkBBsc7GQuMU02H38ig942i8nSLHP3 1h96Q+D3M2QiXyOMsdHuMMrM6xgWpICODgLT0avXHXY9zlK+998nN1iWUJEFzcgDuzD9goVzcGPHTa eriwadLeYeSXIrrpHzkNDincaSpNoxHP1jXLEkQzcvsOX5HNXAWiDBgHVwtGjtRWaMjtuOkmQDZNkB h9hbV7C4XbZLQ8WWhkHcSTxK6sNEhY3V2xWDcGfPKhoMQXZNuRAPy81AEeNwO5djhddq/ldkmJio7C 6cCvL9mR9mST3ODQ0BZSE1QACA5mrPVAR0W95BJ5eAUXM/3nnQs4+askGnFw== X-Developer-Key: i=ribalda@chromium.org; a=openpgp; fpr=9EC3BB66E2FC129A6F90B39556A0D81F9F782DA9 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS 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: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1752772555515890179?= X-GMAIL-MSGID: =?utf-8?q?1752772555515890179?= 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); extern struct kimage *kexec_image; extern struct kimage *kexec_crash_image; -extern int kexec_load_disabled; + +bool kexec_load_permitted(void); #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_segments, int result; /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted()) return -EPERM; /* 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, 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[] = { { @@ -952,6 +952,15 @@ static int __init kexec_core_sysctl_init(void) late_initcall(kexec_core_sysctl_init); #endif +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, initrd_fd, struct kimage **dest_image, *image; /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted()) return -EPERM; /* Make sure we have a legal set of flags */