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Sergey Senozhatsky 1238334082 zsmalloc: calling zs_map_object() from irq is a bug
[ Upstream commit 1aedcafbf3 ]

Use BUG_ON(in_interrupt()) in zs_map_object().  This is not a new
BUG_ON(), it's always been there, but was recently changed to
VM_BUG_ON().  There are several problems there.  First, we use use
per-CPU mappings both in zsmalloc and in zram, and interrupt may easily
corrupt those buffers.  Second, and more importantly, we believe it's
possible to start leaking sensitive information.  Consider the following
case:

-> process P
	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page A
-> IRQ

	swap out
	 zram
	  per-cpu mapping CPU1
	   compress page B
	    write page from per-cpu mapping CPU1 to zsmalloc pool
	iret

-> process P
	    write page from per-cpu mapping CPU1 to zsmalloc pool  [*]
	return

* so we store overwritten data that actually belongs to another
  page (task) and potentially contains sensitive data. And when
  process P will page fault it's going to read (swap in) that
  other task's data.

Link: http://lkml.kernel.org/r/20170929045140.4055-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2017-12-14 09:53:10 +01:00
arch sparc64/mm: set fields in deferred pages 2017-12-14 09:53:10 +01:00
block block: wake up all tasks blocked in get_request() 2017-12-14 09:53:10 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto X.509: fix comparisons of ->pkey_algo 2017-12-14 09:52:53 +01:00
Documentation dt-bindings: usb: fix reg-property port-number range 2017-12-14 09:53:09 +01:00
drivers nfp: fix flower offload metadata flag usage 2017-12-14 09:53:09 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs xfs: fix forgotten rcu read unlock when skipping inode reclaim 2017-12-14 09:53:09 +01:00
include lib/genalloc.c: make the avail variable an atomic_long_t 2017-12-14 09:53:08 +01:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel pipe: match pipe_max_size data type with procfs 2017-12-14 09:53:08 +01:00
lib dynamic-debug-howto: fix optional/omitted ending line number to be LARGE instead of 0 2017-12-14 09:53:08 +01:00
mm zsmalloc: calling zs_map_object() from irq is a bug 2017-12-14 09:53:10 +01:00
net sunrpc: Fix rpc_task_begin trace point 2017-12-14 09:53:09 +01:00
samples License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
scripts coccinelle: fix parallel build with CHECK=scripts/coccicheck 2017-12-14 09:53:06 +01:00
security apparmor: fix leak of null profile name if profile allocation fails 2017-12-14 09:53:06 +01:00
sound ALSA: usb-audio: Add check return value for usb_string() 2017-12-14 09:52:55 +01:00
tools x86/mpx/selftests: Fix up weird arrays 2017-12-14 09:53:06 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: vgic-its: Check result of allocation before use 2017-12-14 09:53:01 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.5 2017-12-10 13:40:45 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.