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Dan Rosenberg 455cd5ab30 kptr_restrict for hiding kernel pointers from unprivileged users 
Add the %pK printk format specifier and the /proc/sys/kernel/kptr_restrict
sysctl.

The %pK format specifier is designed to hide exposed kernel pointers,
specifically via /proc interfaces.  Exposing these pointers provides an
easy target for kernel write vulnerabilities, since they reveal the
locations of writable structures containing easily triggerable function
pointers.  The behavior of %pK depends on the kptr_restrict sysctl.

If kptr_restrict is set to 0, no deviation from the standard %p behavior
occurs.  If kptr_restrict is set to 1, the default, if the current user
(intended to be a reader via seq_printf(), etc.) does not have CAP_SYSLOG
(currently in the LSM tree), kernel pointers using %pK are printed as 0's.
 If kptr_restrict is set to 2, kernel pointers using %pK are printed as
0's regardless of privileges.  Replacing with 0's was chosen over the
default "(null)", which cannot be parsed by userland %p, which expects
"(nil)".

[akpm@linux-foundation.org: check for IRQ context when !kptr_restrict, save an indent level, s/WARN/WARN_ONCE/]
[akpm@linux-foundation.org: coding-style fixup]
[randy.dunlap@oracle.com: fix kernel/sysctl.c warning]
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: James Morris <jmorris@namei.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Thomas Graf <tgraf@infradead.org>
Cc: Eugene Teo <eugeneteo@kernel.org>
Cc: Kees Cook <kees.cook@canonical.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Eric Paris <eparis@parisplace.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-13 08:03:08 -08:00
..
ABI leds: add output inversion option to backlight trigger 2011-01-13 08:03:06 -08:00
accounting taskstats: pad taskstats netlink response for aligment issues on ia64 2010-12-22 19:43:34 -08:00
acpi ACPI: introduce module parameter acpi.aml_debug_output 2010-08-14 23:02:14 -04:00
aoe Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
arm Merge branch 'omap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 2011-01-06 19:13:58 -08:00
auxdisplay
blackfin Blackfin: document SPI CS limitations with CPHA=0 2010-08-06 12:55:52 -04:00
block Documentation: remove anticipatory scheduler info 2010-11-11 12:09:59 +01:00
blockdev Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
cdrom Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
cgroups cgroup: add clone_children control file 2010-10-27 18:03:09 -07:00
connector Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
console doc: fix console doc typo 2010-02-24 13:51:32 +01:00
cpu-freq [CPUFREQ] Processor Clocking Control interface driver 2010-01-13 10:55:16 -05:00
cpuidle
cris
crypto
development-process Documentation/development-process: more staging info 2010-11-18 15:00:47 -08:00
device-mapper Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
DocBook Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2011-01-07 14:45:47 -08:00
driver-model driver core: prune docs about device_interface 2010-11-10 16:57:11 -08:00
dvb [media] Documentation/lmedm04: Fix firmware extract information 2010-12-29 08:16:30 -02:00
early-userspace
fault-injection lkdtm: add debugfs access and loosen KPROBE ties 2010-03-06 11:26:32 -08:00
fb Merge branch 'fbdev/udlfb' 2011-01-06 18:10:09 +09:00
filesystems NTFS: writev() fix and maintenance/contact details update 2011-01-12 08:35:53 -08:00
firmware_class firmware: Update hotplug script 2010-08-05 13:53:34 -07:00
frv
hwmon hwmon: Support for Dallas Semiconductor DS620 2011-01-09 09:10:10 -08:00
i2c i2c: Add generic I2C multiplexer using GPIO API 2011-01-10 22:11:23 +01:00
i2o
ia64 Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
ide
infiniband Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
input Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rydberg/input-mt into next 2010-12-27 17:33:20 -08:00
ioctl [media] bt819: the ioctls in the header are internal to the kernel 2010-12-29 08:17:19 -02:00
isdn Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-08-04 15:31:02 -07:00
ja_JP Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
kbuild Merge branch 'next-devicetree' of git://git.secretlab.ca/git/linux-2.6 2011-01-10 08:57:03 -08:00
kdump
ko_KR Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
kvm KVM: Document that KVM_GET_SUPPORTED_CPUID may return emulated values 2010-10-24 10:52:48 +02:00
laptops thinkpad-acpi: untangle ACPI/vendor backlight selection 2010-08-16 11:54:50 -04:00
leds Documentation: led drivers lp5521 and lp5523 2010-11-12 07:55:32 -08:00
lguest Merge branch 'v2.6.36-rc8' into for-2.6.37/barrier 2010-10-19 09:13:04 +02:00
m68k
make kbuild: introduce HDR_ARCH_LIST for headers_install_all 2010-12-14 22:16:19 +01:00
mips
misc-devices Documentation: short descriptions for bh1770glc and apds990x drivers 2010-10-26 16:52:14 -07:00
mmc mmc: add erase, secure erase, trim and secure trim operations 2010-08-12 08:43:30 -07:00
mn10300
mtd Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
namespaces
netlabel Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
networking dccp: make upper bound for seq_window consistent on 32/64 bit 2011-01-07 12:22:44 +01:00
parisc
PCI Documentation: pci.txt: fix typo 2010-07-11 22:17:45 +02:00
pcmcia pcmcia: use autoconfiguration feature for ioports and iomem 2010-09-29 17:20:24 +02:00
power PM: Fix references to basic-pm-debugging.txt in drivers-testing.txt 2010-12-24 15:02:41 +01:00
powerpc Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2011-01-11 16:31:41 -08:00
pps
prctl
RCU rcu: update documentation/comments for Lai's adoption patch 2010-11-29 22:01:59 -08:00
s390 Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
scheduler sched: Remove USER_SCHED from documentation 2010-04-02 20:12:01 +02:00
scsi [SCSI] megaraid_sas: Documentation update 2010-12-22 23:26:53 -06:00
serial RS485 documentation: add 16C950 UART description 2010-11-30 17:26:04 -08:00
sh sh: clkfwk: Kill off unused clk_set_rate_ex(). 2010-11-15 18:25:12 +09:00
sound Merge branch 'topic/hda' into for-linus 2010-10-25 10:40:05 +02:00
sparc
spi arm/pxa2xx: reorgazine SSP and SPI header files 2010-12-01 12:18:33 +01:00
sysctl kptr_restrict for hiding kernel pointers from unprivileged users 2011-01-13 08:03:08 -08:00
telephony Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
thermal
timers Documentation/timers/hpet_example.c: add supporting info for hpet_example 2010-10-26 16:52:11 -07:00
trace tools, perf: Documentation for the power events API 2011-01-05 21:25:29 +01:00
uml Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
usb USB: use the runtime-PM autosuspend implementation 2010-11-16 14:03:41 -08:00
video4linux [media] cardlist: Update lists for em28xx and saa7134 2010-12-29 08:17:17 -02:00
vm slub: Fix build breakage in Documentation/vm 2010-11-06 09:04:33 +02:00
w1 Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
watchdog watchdog: docs: add an entry for imx2_wdt 2010-07-01 16:02:55 +00:00
wimax
x86 x86: Add CE4100 platform support 2010-11-12 00:45:41 +01:00
zh_CN Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
.gitignore add random binaries to .gitignore 2010-04-08 11:34:34 +02:00
00-INDEX mmc: add erase, secure erase, trim and secure trim operations 2010-08-12 08:43:30 -07:00
apparmor.txt AppArmor: update Maintainer and Documentation 2010-08-02 15:35:15 +10:00
applying-patches.txt
atomic_ops.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt documentation: fix almost duplicate filenames (IO/io-mapping.txt) 2010-07-20 17:49:30 +00:00
cachetlb.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
Changes Documentation update broken web addresses 2010-07-11 21:55:42 +02:00
circular-buffers.txt Document Linux's circular buffering capabilities 2010-03-24 16:31:22 -07:00
coccinelle.txt scripts/coccinelle: update for compatability with Coccinelle 0.2.4 2010-12-03 12:27:01 +01:00
CodingStyle
cpu-hotplug.txt documentation: fix erroneous email address. 2010-08-11 23:04:10 +09:30
cpu-load.txt
cputopology.txt topology/sysfs: Provide book id and siblings attributes 2010-09-09 20:41:25 +02:00
credentials.txt CRED: Fix __task_cred()'s lockdep check and banner comment 2010-07-29 15:16:18 -07:00
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2010-10-28 09:35:11 -07:00
DMA-API-HOWTO.txt Documentation: DMA-API-HOWTO.txt: rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN 2010-08-14 11:56:46 -07:00
DMA-API.txt dma-mapping: remove dma_is_consistent API 2010-08-11 08:59:21 -07:00
DMA-attributes.txt
DMA-ISA-LPC.txt
dmaengine.txt
dontdiff Documentation/dontdiff: add further autogenerated files to ignore list 2011-01-06 09:59:37 -08:00
dynamic-debug-howto.txt Dynamic Debug: Introduce ddebug_query= boot parameter 2010-10-22 10:16:42 -07:00
edac.txt EDAC: Fix typos in Documentation/edac.txt 2010-11-25 17:32:47 +01:00
eisa.txt doc: fix Defaultd -> Defaults typo in EISA doc 2010-02-05 12:22:39 +01:00
email-clients.txt Documentation/email-clients.txt: update gmail information 2010-03-12 15:52:35 -08:00
feature-removal-schedule.txt Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2011-01-07 16:58:04 -08:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt Documentation/gpio.txt: explain poll/select usage 2010-11-18 15:00:46 -08:00
highuid.txt
HOWTO Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
hw_random.txt
init.txt init/main.c: improve usability in case of init binary failure 2010-03-06 11:26:29 -08:00
initrd.txt
intel_txt.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi: add parameter to limit CPU usage in kipmid 2010-03-12 15:52:39 -08:00
IRQ-affinity.txt
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt docbook: warn on unused doc entries 2010-09-11 16:49:21 -07:00
kernel-docs.txt Documentation: update kernel-docs.txt 2011-01-06 09:59:38 -08:00
kernel-parameters.txt Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2011-01-11 16:31:41 -08:00
keys-request-key.txt
keys-trusted-encrypted.txt keys: add new trusted key-type 2010-11-29 08:55:25 +11:00
keys.txt
kmemcheck.txt
kmemleak.txt
kobject.txt kobject: documentation: Update to refer to kset-example.c. 2010-03-19 07:12:20 -07:00
kprobes.txt kprobes: Update document about irq disabled state in kprobe handler 2010-10-14 08:55:27 +02:00
kref.txt
ldm.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
leds-class.txt led-class: always implement blinking 2010-11-12 07:55:32 -08:00
leds-lp3944.txt
local_ops.txt
lockdep-design.txt
lockstat.txt
logo.gif
logo.txt
magic-number.txt
Makefile [media] Remove the old V4L1 v4lgrab.c file 2010-12-29 08:17:12 -02:00
ManagementStyle
mca.txt
md.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
memory-barriers.txt Document Linux's circular buffering capabilities 2010-03-24 16:31:22 -07:00
memory-hotplug.txt mm: add numa node symlink for memory section in sysfs 2009-12-15 08:53:17 -08:00
memory.txt
mono.txt
mutex-design.txt mutex: Fix annotations to include it in kernel-locking docbook 2010-09-03 08:19:51 +02:00
nmi_watchdog.txt
nommu-mmap.txt nommu: fix malloc performance by adding uninitialized flag 2009-12-15 08:53:24 -08:00
numastat.txt
oops-tracing.txt panic: Add taint flag TAINT_FIRMWARE_WORKAROUND ('I') 2010-05-19 08:37:43 +01:00
padata.txt Documentation/padata.txt: fix typos etc. 2010-08-11 08:59:18 -07:00
parport-lowlevel.txt
parport.txt
pi-futex.txt
pnp.txt doc: capitalization and other minor fixes in pnp doc 2010-02-05 12:22:44 +01:00
preempt-locking.txt
printk-formats.txt
prio_tree.txt
rbtree.txt Documentation: remove anticipatory scheduler info 2010-11-11 12:09:59 +01:00
rfkill.txt Document the rfkill sysfs ABI 2010-03-10 17:09:33 -05:00
robust-futex-ABI.txt
robust-futexes.txt
rt-mutex-design.txt variable name fix to Documentation/rt-mutex-design.txt 2010-06-05 17:39:09 +02:00
rt-mutex.txt
rtc.txt
SAK.txt
SecurityBugs
SELinux.txt
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
SM501.txt
Smack.txt Documentation/: it's -> its where appropriate 2010-04-23 02:09:52 +02:00
sparse.txt update email address 2010-07-19 10:56:54 +02:00
spinlocks.txt Documentation: rw_lock lessons learned 2009-12-14 09:46:56 -08:00
stable_api_nonsense.txt
stable_kernel_rules.txt Documentation: -stable rules: upstream commit ID requirement reworded 2010-04-22 15:24:56 -07:00
SubmitChecklist Documentation: update SubmitChecklist for O=objdir and kconfig testing 2010-05-24 07:31:20 -07:00
SubmittingDrivers Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
SubmittingPatches SubmittingPatches: add more about patch descriptions 2010-08-09 20:45:05 -07:00
svga.txt
sysfs-rules.txt Fix typos in comments 2010-03-16 11:47:56 +01:00
sysrq.txt documentation: update sysrq.txt magic sysrq keys 2010-10-26 17:32:41 -07:00
tomoyo.txt TOMOYO: Update version to 2.3.0 2010-08-02 15:35:10 +10:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
VGA-softcursor.txt
vgaarbiter.txt vgaarbiter: fix a typo in the vgaarbiter Documentation 2009-12-16 11:28:58 -08:00
video-output.txt
volatile-considered-harmful.txt Documentation/volatile-considered-harmful.txt: correct cpu_relax() documentation 2010-03-24 16:31:20 -07:00
workqueue.txt workqueue: add and use WQ_MEM_RECLAIM flag 2010-10-11 15:20:26 +02:00
zorro.txt