From: Ricardo Ribalda <ribalda@chromium.org>
To: Philipp Rudo <prudo@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
Jonathan Corbet <corbet@lwn.net>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: linux-doc@vger.kernel.org,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Ricardo Ribalda <ribalda@chromium.org>,
Ross Zwisler <zwisler@kernel.org>,
kexec@lists.infradead.org
Subject: [PATCH v3 2/3] kexec: Factor out kexec_load_permitted
Date: Tue, 20 Dec 2022 23:05:44 +0100 [thread overview]
Message-ID: <20221114-disable-kexec-reset-v3-2-4ef4e929adf6@chromium.org> (raw)
In-Reply-To: <20221114-disable-kexec-reset-v3-0-4ef4e929adf6@chromium.org>
Both syscalls (kexec and kexec_file) do the same check, lets factor it
out.
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
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 */
--
2.39.0.314.g84b9a713c41-goog-b4-0.11.0-dev-696ae
next prev parent reply other threads:[~2022-12-20 22:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-20 22:05 [PATCH v3 0/3] kexec: Add new parameter to limit the access to kexec Ricardo Ribalda
2022-12-20 22:05 ` [PATCH v3 1/3] Documentation: sysctl: Correct kexec_load_disabled Ricardo Ribalda
2022-12-20 22:05 ` Ricardo Ribalda [this message]
2022-12-20 22:05 ` [PATCH v3 3/3] kexec: Introduce parameters load_limit_reboot and load_limit_panic Ricardo Ribalda
2022-12-21 0:22 ` Steven Rostedt
2022-12-21 1:22 ` Ricardo Ribalda
2022-12-21 2:52 ` Steven Rostedt
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