From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, dhowells@redhat.com,
linux-api@vger.kernel.org, luto@kernel.org,
Matthew Garrett <mjg59@srcf.ucam.org>,
Matthew Garrett <mjg59@google.com>,
Dave Young <dyoung@redhat.com>,
kexec@lists.infradead.org
Subject: [PATCH V31 04/25] kexec_load: Disable at runtime if the kernel is locked down
Date: Tue, 26 Mar 2019 11:27:20 -0700 [thread overview]
Message-ID: <20190326182742.16950-5-matthewgarrett@google.com> (raw)
In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com>
From: Matthew Garrett <mjg59@srcf.ucam.org>
The kexec_load() syscall permits the loading and execution of arbitrary
code in ring 0, which is something that lock-down is meant to prevent. It
makes sense to disable kexec_load() in this situation.
This does not affect kexec_file_load() syscall which can check for a
signature on the image to be booted.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Dave Young <dyoung@redhat.com>
cc: kexec@lists.infradead.org
---
kernel/kexec.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 68559808fdfa..57047acc9a36 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -207,6 +207,14 @@ static inline int kexec_load_check(unsigned long nr_segments,
if (result < 0)
return result;
+ /*
+ * kexec can be used to circumvent module loading restrictions, so
+ * prevent loading in that case
+ */
+ if (kernel_is_locked_down("kexec of unsigned images",
+ LOCKDOWN_INTEGRITY))
+ return -EPERM;
+
/*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
--
2.21.0.392.gf8f6787159e-goog
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <matthewgarrett-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: jmorris-gx6/JNMH7DfYtjvyW6yDsg@public.gmane.org
Cc: Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Matthew Garrett <mjg59-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: [PATCH V31 04/25] kexec_load: Disable at runtime if the kernel is locked down
Date: Tue, 26 Mar 2019 11:27:20 -0700 [thread overview]
Message-ID: <20190326182742.16950-5-matthewgarrett@google.com> (raw)
In-Reply-To: <20190326182742.16950-1-matthewgarrett-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
From: Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>
The kexec_load() syscall permits the loading and execution of arbitrary
code in ring 0, which is something that lock-down is meant to prevent. It
makes sense to disable kexec_load() in this situation.
This does not affect kexec_file_load() syscall which can check for a
signature on the image to be booted.
Signed-off-by: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Matthew Garrett <mjg59-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Acked-by: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
cc: kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
---
kernel/kexec.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 68559808fdfa..57047acc9a36 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -207,6 +207,14 @@ static inline int kexec_load_check(unsigned long nr_segments,
if (result < 0)
return result;
+ /*
+ * kexec can be used to circumvent module loading restrictions, so
+ * prevent loading in that case
+ */
+ if (kernel_is_locked_down("kexec of unsigned images",
+ LOCKDOWN_INTEGRITY))
+ return -EPERM;
+
/*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
--
2.21.0.392.gf8f6787159e-goog
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: Matthew Garrett <mjg59@srcf.ucam.org>,
linux-api@vger.kernel.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org, Matthew Garrett <mjg59@google.com>,
dhowells@redhat.com, linux-security-module@vger.kernel.org,
luto@kernel.org, Dave Young <dyoung@redhat.com>
Subject: [PATCH V31 04/25] kexec_load: Disable at runtime if the kernel is locked down
Date: Tue, 26 Mar 2019 11:27:20 -0700 [thread overview]
Message-ID: <20190326182742.16950-5-matthewgarrett@google.com> (raw)
In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com>
From: Matthew Garrett <mjg59@srcf.ucam.org>
The kexec_load() syscall permits the loading and execution of arbitrary
code in ring 0, which is something that lock-down is meant to prevent. It
makes sense to disable kexec_load() in this situation.
This does not affect kexec_file_load() syscall which can check for a
signature on the image to be booted.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Dave Young <dyoung@redhat.com>
cc: kexec@lists.infradead.org
---
kernel/kexec.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 68559808fdfa..57047acc9a36 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -207,6 +207,14 @@ static inline int kexec_load_check(unsigned long nr_segments,
if (result < 0)
return result;
+ /*
+ * kexec can be used to circumvent module loading restrictions, so
+ * prevent loading in that case
+ */
+ if (kernel_is_locked_down("kexec of unsigned images",
+ LOCKDOWN_INTEGRITY))
+ return -EPERM;
+
/*
* Verify we have a legal set of flags
* This leaves us room for future extensions.
--
2.21.0.392.gf8f6787159e-goog
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2019-03-26 18:30 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-26 18:27 [PATCH V31 00/25] Add support for kernel lockdown Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 01/25] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 02/25] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 03/25] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett [this message]
2019-03-26 18:27 ` [PATCH V31 04/25] kexec_load: Disable at runtime if " Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 05/25] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 06/25] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett
2019-06-21 6:34 ` Dave Young
2019-06-21 6:34 ` Dave Young
2019-06-21 6:34 ` Dave Young
2019-06-21 20:13 ` Matthew Garrett
2019-06-21 20:13 ` Matthew Garrett
2019-06-21 20:14 ` Matthew Garrett
2019-06-21 20:14 ` Matthew Garrett
2019-06-21 20:14 ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 07/25] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett
2019-06-21 6:43 ` Dave Young
2019-06-21 6:43 ` Dave Young
2019-06-21 20:18 ` Matthew Garrett
2019-06-21 20:18 ` Matthew Garrett
2019-06-21 20:18 ` Matthew Garrett
2019-06-24 1:52 ` Dave Young
2019-06-24 1:52 ` Dave Young
2019-06-24 21:06 ` Matthew Garrett
2019-06-24 21:06 ` Matthew Garrett
2019-06-24 21:27 ` Mimi Zohar
2019-06-24 21:27 ` Mimi Zohar
2019-06-25 0:02 ` Matthew Garrett
2019-06-25 0:02 ` Matthew Garrett
2019-06-25 1:46 ` Mimi Zohar
2019-06-25 1:46 ` Mimi Zohar
2019-06-25 2:51 ` Dave Young
2019-06-25 2:51 ` Dave Young
2019-03-26 18:27 ` [PATCH V31 08/25] hibernate: Disable when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 09/25] uswsusp: " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 10/25] PCI: Lock down BAR access " Matthew Garrett
2019-03-26 20:55 ` Andy Lutomirski
2019-03-26 21:19 ` Alex Williamson
2019-03-26 18:27 ` [PATCH V31 11/25] x86: Lock down IO port " Matthew Garrett
2019-03-26 20:56 ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 12/25] x86/msr: Restrict MSR " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 13/25] ACPI: Limit access to custom_method " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 14/25] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 15/25] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-03-26 18:27 ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 16/25] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 17/25] Lock down TIOCSSERIAL Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 18/25] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 19/25] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-03-27 15:57 ` Steven Rostedt
2019-03-27 16:55 ` Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 20/25] Lock down /proc/kcore Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 21/25] Lock down kprobes when in confidentiality mode Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 22/25] bpf: Restrict bpf when kernel lockdown is " Matthew Garrett
2019-03-26 19:21 ` Andy Lutomirski
2019-03-26 18:27 ` [PATCH V31 23/25] Lock down perf when " Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 24/25] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-03-26 18:27 ` [PATCH V31 25/25] debugfs: Disable open() when kernel is locked down Matthew Garrett
2019-03-26 19:20 ` Andy Lutomirski
2019-03-26 19:21 ` Matthew Garrett
2019-03-27 0:30 ` Greg KH
2019-03-27 4:29 ` Andy Lutomirski
2019-03-27 5:06 ` Greg KH
2019-03-27 5:29 ` Andy Lutomirski
2019-03-27 5:33 ` Greg KH
2019-03-27 16:53 ` James Morris
2019-03-27 17:39 ` Andy Lutomirski
2019-03-27 17:42 ` Matthew Garrett
2019-03-27 18:29 ` Greg KH
2019-03-27 18:31 ` Greg KH
2019-03-27 0:31 ` Greg KH
2019-03-27 2:06 ` Matthew Garrett
2019-03-27 2:35 ` Greg KH
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