Kees Cook 7984754b99 kexec: add sysctl to disable kexec_load ... For general-purpose (i.e. distro) kernel builds it makes sense to build with CONFIG_KEXEC to allow end users to choose what kind of things they want to do with kexec. However, in the face of trying to lock down a system with such a kernel, there needs to be a way to disable kexec_load (much like module loading can be disabled). Without this, it is too easy for the root user to modify kernel memory even when CONFIG_STRICT_DEVMEM and modules_disabled are set. With this change, it is still possible to load an image for use later, then disable kexec_load so the image (or lack of image) can't be altered. The intention is for using this in environments where "perfect" enforcement is hard. Without a verified boot, along with verified modules, and along with verified kexec, this is trying to give a system a better chance to defend itself (or at least grow the window of discoverability) against attack in the face of a privilege escalation. In my mind, I consider several boot scenarios: 1) Verified boot of read-only verified root fs loading fd-based verification of kexec images. 2) Secure boot of writable root fs loading signed kexec images. 3) Regular boot loading kexec (e.g. kcrash) image early and locking it. 4) Regular boot with no control of kexec image at all. 1 and 2 don't exist yet, but will soon once the verified kexec series has landed. 4 is the state of things now. The gap between 2 and 4 is too large, so this change creates scenario 3, a middle-ground above 4 when 2 and 1 are not possible for a system. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2014-01-23 16:37:03 -08:00
..
ABI	f2fs updates for v3.14	2014-01-23 09:21:09 -08:00
accounting
acpi	GPIO tree bulk changes for v3.14	2014-01-21 10:09:12 -08:00
aoe	aoe: remove do-nothing NAME="%k" term from example udev rules	2013-09-11 15:59:28 -07:00
arm	gpio: samsung: Update documentation	2014-01-07 19:00:59 +01:00
arm64	arm64: Use 42-bit address space with 64K pages	2013-11-05 17:23:52 +00:00
auxdisplay
backlight	backlight: lp855x_bl: support new LP8555 device	2013-11-13 12:09:14 +09:00
blackfin
block	null_blk: set use_per_node_hctx param to false	2013-12-21 09:30:33 -07:00
blockdev	Documentation/blockdev/ramdisk.txt: updates	2014-01-23 16:37:01 -08:00
bus-devices
cdrom
cgroups	doc: cgroups: Fix typo in doc/cgroups	2013-12-31 07:33:38 -05:00
connector	connector - documentation: simplify netlink message length assignment	2013-10-02 16:03:51 -04:00
console
cpu-freq	cpufreq: Implement light weight ->target_index() routine	2013-10-25 22:42:24 +02:00
cpuidle	cpuidle: remove cpuidle_unregister_governor()	2013-10-30 01:21:24 +01:00
cris
crypto
development-process
device-mapper	dm cache: add policy name to status output	2014-01-16 13:44:11 -05:00
devicetree	dt-bindings: add hym8563 binding	2014-01-23 16:36:59 -08:00
DocBook	Merge branch 'master' into for-next	2013-12-19 15:08:32 +01:00
driver-model	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-01-22 21:21:55 -08:00
dvb
early-userspace	Documentation: remove reference to 2.7 kernel in early-userspace	2013-08-20 12:47:28 +02:00
EDID
extcon	extcon: fix switch class porting guide (Documentation)	2014-01-07 11:54:28 +09:00
fault-injection
fb	Documentation/fb/viafb.modes fix a typo	2013-08-20 12:41:11 +02:00
filesystems	Documentation/filesystems/00-INDEX: updates	2014-01-23 16:37:01 -08:00
firmware_class
fmc	doc: Fix typo "is is" in Documentations	2013-08-27 10:50:52 +02:00
frv
gpio	gpiolib: return -ENOENT if no GPIO mapping exists	2013-12-12 19:33:59 +01:00
hid
hwmon	Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging	2013-11-15 16:35:10 -08:00
i2c	Documentation: i2c: Remove obsolete example	2014-01-09 23:02:46 +01:00
i2o
ia64
ide
infiniband
input	Input: clarify gamepad API ABS values	2013-10-15 23:42:07 -07:00
ioctl	ALSA: add DICE driver	2013-10-17 21:18:32 +02:00
isdn
ja_JP	Documentation: ja_JP: Update broken link to tpp	2013-12-10 23:09:08 -08:00
kbuild	Documentation/kbuild/kconfig.txt: 'make listnewconfig' replaces: yes "" | make oldconfig	2013-10-08 23:51:50 +02:00
kdump
kmsg/s390	s390/zcrypt: add support for EP11 coprocessor cards	2013-12-18 17:37:15 +01:00
ko_KR	Documentation: HOWTO: Updates on subsystem trees, patchwork, -next (vs. -mm) in ko_KR	2014-01-08 15:32:51 -08:00
laptops	Documentation: Fix size parameter for snprintf	2014-01-02 10:47:33 +01:00
leds	Documentation: leds-lp5521,lp5523: update device attribute information	2013-08-26 17:22:13 -07:00
m68k
make
memory-devices
metag
mic	misc: mic: Fix endianness issues.	2013-11-27 11:03:38 -08:00
mips
misc-devices	Documentation/misc-devices/mei/mei-amt-version.c: remove unneeded call of mei_deinit()	2014-01-08 15:20:20 -08:00
mmc
mn10300
mtd	doc: Fix typo "is is" in Documentations	2013-08-27 10:50:52 +02:00
namespaces
netlabel
networking	ipv4: improve documentation of ip_no_pmtu_disc	2013-12-17 15:20:15 -05:00
nfc
parisc
PCI	Merge branch 'pci/msi' into next	2014-01-07 17:34:39 -07:00
pcmcia
power	More ACPI and power management updates for 3.13-rc1	2013-11-20 13:25:04 -08:00
powerpc	powerpc: Update the 00-Index in Documentation/powerpc	2013-08-27 14:44:27 +10:00
pps	USB: serial: invoke dcd_change ldisc's handler.	2013-09-26 09:45:40 -07:00
prctl
pti
ptp	ptp: add the PTP_SYS_OFFSET ioctl to the testptp program	2013-09-23 16:46:17 -04:00
rapidio
RCU	Merge branches 'doc.2013.12.03a', 'fixes.2013.12.12a', 'rcutorture.2013.12.03a' and 'sparse.2013.12.12a' into HEAD	2013-12-12 12:35:38 -08:00
s390	s390/s390dbf: add debug_level_enabled() function	2013-10-24 17:16:53 +02:00
scheduler	H8/300 has been dead for several years, the kernel for it has	2013-11-12 14:13:14 +09:00
scsi	[SCSI] Update documentation	2013-12-19 07:39:03 -08:00
security	ima: update IMA-templates.txt documentation	2014-01-03 07:42:59 -05:00
serial	serial: core: delete .set_wake() callback	2013-10-16 13:16:19 -07:00
sh
sound	ASoC: docs: Update the Overview document	2014-01-07 17:56:32 +00:00
spi	spi/documentation: Fix usage of __initdata	2013-08-20 12:52:28 +02:00
sysctl	kexec: add sysctl to disable kexec_load	2014-01-23 16:37:03 -08:00
target	target: Remove TF_CIT_TMPL macro	2013-10-16 13:35:02 -07:00
thermal	thermal: thermal_core: allow binding with limits on bind_params	2013-09-03 09:10:24 -04:00
timers	doc: add missing files to timers/00-INDEX	2013-10-27 21:55:50 +00:00
tpm
trace	Documentation/trace/postprocess/trace-vmscan-postprocess.pl: fix the traceevent regex	2014-01-23 16:36:52 -08:00
usb	doc: Fix typo in USB Gadget Documentation	2014-01-10 15:33:54 +01:00
vDSO
video4linux	[media] V4L: Add support for integer menu controls with standard menu items	2013-08-18 07:12:59 -03:00
virtual	Merge tag 'kvm-arm-for-3.14' of git://git.linaro.org/people/christoffer.dall/linux-kvm-arm into kvm-queue	2014-01-15 12:14:29 +01:00
vm	mm: documentation: remove hopelessly out-of-date locking doc	2014-01-23 16:36:50 -08:00
w1
watchdog
wimax
x86	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2014-01-22 21:21:55 -08:00
xtensa
zh_CN	Documentation: zh_CN: Update broken link to tpp	2013-12-10 23:09:08 -08:00
.gitignore
00-INDEX	doc: fix a typo in Documentation/00-INDEX	2013-08-27 10:53:07 +02:00
applying-patches.txt
assoc_array.txt	KEYS: Fix multiple key add into associative array	2013-12-02 11:24:18 +00:00
atomic_ops.txt
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt	Documentation: fix typo and update version in cachetlb.txt	2013-08-20 12:46:52 +02:00
Changes	remove obsolete references to powertweak	2013-11-27 20:34:32 -08:00
circular-buffers.txt	documentation: Update circular buffer for load-acquire/store-release	2013-12-03 10:08:57 -08:00
clk.txt	clk: add support for clock reparent on set_rate	2013-08-19 12:27:17 -07:00
coccinelle.txt
CodingStyle
cpu-hotplug.txt	Documentation/cpu-hotplug.txt: fix a typo in example code	2014-01-23 16:37:01 -08:00
cpu-load.txt
cputopology.txt	doc: Documentation/cputopology.txt fix typo	2013-09-04 12:59:47 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt	cuse: add fix minor number to /dev/cuse	2013-10-01 16:44:54 +02:00
digsig.txt
DMA-API-HOWTO.txt	DMA-API: provide a helper to set both DMA and coherent DMA masks	2013-09-17 15:32:37 +01:00
DMA-API.txt	DMA-API: provide a helper to set both DMA and coherent DMA masks	2013-09-17 15:32:37 +01:00
DMA-attributes.txt	doc: Documentation/DMA-attributes.txt fix typo	2013-10-14 15:50:53 +02:00
dma-buf-sharing.txt	dma-buf: Expose buffer size to userspace (v2)	2013-09-10 11:36:45 +05:30
DMA-ISA-LPC.txt
dmaengine.txt
dmatest.txt	dmatest: add a 'wait' parameter	2013-11-14 11:04:40 -08:00
dontdiff
dynamic-debug-howto.txt	dynamic-debug-howto.txt: update since new wildcard support	2014-01-23 16:36:55 -08:00
edac.txt
efi-stub.txt	doc: Fix trivial spelling mistake in efi-stub.txt	2013-12-19 15:09:14 +01:00
eisa.txt
email-clients.txt	doc: fix some typos	2013-12-02 14:48:28 +01:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt	gcov: compile specific gcov implementation based on gcc version	2013-11-13 12:09:34 +09:00
highuid.txt
HOWTO	Documentation: HOWTO: Update broken links to tpp	2013-12-10 23:09:08 -08:00
hw_random.txt
hwspinlock.txt	doc: documentation/hwspinlock.txt fix typo	2013-08-27 10:46:02 +02:00
init.txt
initrd.txt
Intel-IOMMU.txt
intel_txt.txt
io-mapping.txt	doc: fix some typos	2013-12-02 14:48:28 +01:00
io_ordering.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt	doc: fix a typo about irq affinity	2013-08-20 12:59:18 +02:00
IRQ-domain.txt	doc: fix some typos	2013-12-02 14:48:28 +01:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
kernel-parameters.txt	doc/kmemcheck: add kmemcheck to kernel-parameters	2014-01-23 16:36:53 -08:00
kernel-per-CPU-kthreads.txt	kthread: Add pointer to vmstat-avoidance patch	2013-09-25 06:49:46 -07:00
kmemcheck.txt	Documentation/kmemcheck: update kmemcheck documentation	2013-08-27 10:47:05 +02:00
kmemleak.txt
kobject.txt	kobject: remove kset from sysfs immediately in kset_unregister()	2013-12-07 21:20:11 -08:00
kprobes.txt
kref.txt
ldm.txt
local_ops.txt
lockdep-design.txt
lockstat.txt	lockstat: Report avg wait and hold times	2013-10-09 08:19:08 +02:00
lockup-watchdogs.txt
logo.gif
logo.txt
magic-number.txt
Makefile
ManagementStyle
md.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
media-framework.txt
memory-barriers.txt	locking/doc: Rename LOCK/UNLOCK to ACQUIRE/RELEASE	2014-01-12 10:37:13 +01:00
memory-hotplug.txt	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2013-09-06 09:36:28 -07:00
module-signing.txt	Add Documentation/module-signing.txt file	2013-12-13 15:59:11 +00:00
mono.txt
mutex-design.txt	locking/doc: Update references to kernel/mutex.c	2013-11-11 12:41:33 +01:00
nommu-mmap.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt	drivers: phy: add generic PHY framework	2013-09-27 17:35:41 -07:00
pi-futex.txt
pinctrl.txt	pinctrl: Fix some typos and grammar issues in the documentation	2014-01-15 13:59:50 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt	vsprintf: add %pad extension for dma_addr_t use	2014-01-23 16:36:56 -08:00
pwm.txt	Documentation/pwm: Fix trivial typos	2013-10-24 10:51:33 +02:00
ramoops.txt
rbtree.txt
remoteproc.txt
rfkill.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
robust-futex-ABI.txt	Documentation/robust-futex-API: Count properly to 4	2013-11-30 14:08:28 +01:00
robust-futexes.txt
rpmsg.txt
rt-mutex-design.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
rt-mutex.txt
rtc.txt
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt
static-keys.txt	doc: fix some typos in documentations	2013-12-02 14:45:19 +01:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches	Documentation/SubmittingPatches: Request summaries for commit references	2013-08-20 12:58:15 +02:00
svga.txt
sysfs-rules.txt
sysrq.txt	sysrq: Allow magic SysRq key functions to be disabled through Kconfig	2013-10-16 13:01:44 -07:00
this_cpu_ops.txt
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt	vfio: fix documentation	2013-09-05 16:36:21 -06:00
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt	VME: Rename vme_slot_get to avoid confusion with reference counting	2013-12-03 11:15:58 -08:00
volatile-considered-harmful.txt
workqueue.txt	workqueue: Correct/Drop references to gcwq in Documentation	2013-08-21 10:32:09 -04:00
ww-mutex-design.txt
xz.txt
zorro.txt	zorro/UAPI: Disintegrate include/linux/zorro*.h	2013-11-26 11:09:08 +01:00