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a4866aa812
linux/drivers/char
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Kees Cook a4866aa812 mm: Tighten x86 /dev/mem with zeroing reads 
Under CONFIG_STRICT_DEVMEM, reading System RAM through /dev/mem is
disallowed. However, on x86, the first 1MB was always allowed for BIOS
and similar things, regardless of it actually being System RAM. It was
possible for heap to end up getting allocated in low 1MB RAM, and then
read by things like x86info or dd, which would trip hardened usercopy:

usercopy: kernel memory exposure attempt detected from ffff880000090000 (dma-kmalloc-256) (4096 bytes)

This changes the x86 exception for the low 1MB by reading back zeros for
System RAM areas instead of blindly allowing them. More work is needed to
extend this to mmap, but currently mmap doesn't go through usercopy, so
hardened usercopy won't Oops the kernel.

Reported-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Tested-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-04-12 11:40:23 -07:00
..
agp mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf 2017-02-24 17:46:54 -08:00
hw_random hwrng: geode - Revert managed API changes 2017-03-16 17:43:11 +08:00
ipmi sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
mwave Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pcmcia lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
tpm tpm: declare tpm2_get_pcr_allocation() as static 2017-02-20 13:23:18 +02:00
xilinx_hwicap char: xilinx_hwicap: Remove pointless local variables 2017-01-25 11:41:44 +01:00
xillybus char: xillybus: Fix spelling mistake and comment 2016-08-31 14:47:54 +02:00
apm-emulation.c apm-emulation: move APM_MINOR_DEV to include/linux/miscdevice.h 2017-01-10 21:46:41 +01:00
applicom.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
applicom.h
bfin-otp.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
bsr.c
ds1302.c ds1302: remove unneeded linux/miscdevice.h include 2017-01-10 21:46:41 +01:00
ds1620.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
dsp56k.c dsp56k: prevent a harmless underflow 2016-07-14 16:21:53 +09:00
dtlk.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
efirtc.c drivers/char: make efirtc.c driver explicitly non-modular 2015-09-20 19:32:35 -07:00
generic_nvram.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hangcheck-timer.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hpet.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
Kconfig TTY/Serial driver patches for 4.11-rc1 2017-02-22 12:17:25 -08:00
lp.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
Makefile RTC for 4.8 2016-08-05 09:48:22 -04:00
mbcs.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mbcs.h
mem.c mm: Tighten x86 /dev/mem with zeroing reads 2017-04-12 11:40:23 -07:00
misc.c char: make misc_deregister a void function 2015-08-05 10:35:49 -07:00
mmtimer.c mmtimer: add member name to the miscdevice declaration 2017-01-10 21:46:41 +01:00
mspec.c mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf 2017-02-24 17:46:54 -08:00
nsc_gpio.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
nvram.c char/nvram: set array of const as const 2016-02-08 14:57:30 -08:00
nwbutton.c drivers/char/nwbutton: Fix build breakage caused by include file reshuffling 2017-03-07 08:35:49 +01:00
nwbutton.h
nwflash.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
pc8736x_gpio.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
powernv-op-panel.c powerpc/powernv: Add driver for operator panel on FSP machines 2016-06-29 17:33:46 +10:00
ppdev.c ppdev: fix registering same device name 2017-03-16 17:32:21 +09:00
ps3flash.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
random.c random: move random_min_urandom_seed into CONFIG_SYSCTL ifdef block 2017-02-06 20:46:49 -05:00
raw.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
rtc.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
scx200_gpio.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
snsc_event.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
snsc.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
snsc.h
sonypi.c scripts/spelling.txt: add "initialiazation" pattern and fix typo instances 2017-02-27 18:43:47 -08:00
tb0219.c mips: separate extable.h, switch module.h to it 2016-10-05 18:36:18 -04:00
tile-srom.c tile-srom: allow the driver to be built as a module 2016-11-10 15:18:56 +01:00
tlclk.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
toshiba.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ttyprintk.c ttyprintk: Neaten and simplify printing 2016-09-13 17:30:17 +02:00
uv_mmtimer.c
virtio_console.c virtio-console: avoid DMA from stack 2017-03-02 01:35:06 +02:00