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Dave Hansen 359b8ff328 x86/pkeys: Override pkey when moving away from PROT_EXEC
commit 0a0b152083 upstream.

I got a bug report that the following code (roughly) was
causing a SIGSEGV:

	mprotect(ptr, size, PROT_EXEC);
	mprotect(ptr, size, PROT_NONE);
	mprotect(ptr, size, PROT_READ);
	*ptr = 100;

The problem is hit when the mprotect(PROT_EXEC)
is implicitly assigned a protection key to the VMA, and made
that key ACCESS_DENY|WRITE_DENY.  The PROT_NONE mprotect()
failed to remove the protection key, and the PROT_NONE->
PROT_READ left the PTE usable, but the pkey still in place
and left the memory inaccessible.

To fix this, we ensure that we always "override" the pkee
at mprotect() if the VMA does not have execute-only
permissions, but the VMA has the execute-only pkey.

We had a check for PROT_READ/WRITE, but it did not work
for PROT_NONE.  This entirely removes the PROT_* checks,
which ensures that PROT_NONE now works.

Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 62b5f7d013 ("mm/core, x86/mm/pkeys: Add execute-only protection keys support")
Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-22 18:53:59 +02:00
arch x86/pkeys: Override pkey when moving away from PROT_EXEC 2018-05-22 18:53:59 +02:00
block bfq-iosched: ensure to clear bic/bfqq pointers when preparing request 2018-05-01 12:58:19 -07:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: af_alg - fix possible uninit-value in alg_bind() 2018-05-16 10:10:23 +02:00
Documentation arm64: Add work around for Arm Cortex-A55 Erratum 1024718 2018-05-16 10:10:25 +02:00
drivers s390/qdio: don't release memory in qdio_setup_irq() 2018-05-22 18:53:59 +02:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs proc: do not access cmdline nor environ from file-backed areas 2018-05-19 10:20:27 +02:00
include tracing/x86/xen: Remove zero data size trace events trace_xen_mmu_flush_tlb{_all} 2018-05-22 18:53:57 +02:00
init kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-24 09:36:23 +02:00
kernel perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[] 2018-05-16 10:10:31 +02:00
lib radix tree: fix multi-order iteration race 2018-05-22 18:53:58 +02:00
mm mm: don't allow deferred pages with NEED_PER_CPU_KM 2018-05-22 18:53:58 +02:00
net netfilter: nf_socket: Fix out of bounds access in nf_sk_lookup_slow_v{4,6} 2018-05-22 18:53:58 +02:00
samples samples/bpf: Partially fixes the bpf.o build 2018-04-26 11:02:12 +02:00
scripts kconfig: Fix expr_free() E_NOT leak 2018-04-26 11:02:08 +02:00
security commoncap: Handle memory allocation failure. 2018-04-29 11:33:16 +02:00
sound ALSA: control: fix a redundant-copy issue 2018-05-22 18:53:56 +02:00
tools test_firmware: fix setting old custom fw path back on exit, second try 2018-05-09 09:51:54 +02:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: VGIC/ITS: protect kvm_read_guest() calls with SRCU lock 2018-05-22 18:53:57 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
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 dt-bindings: Document mti,mips-cpc binding 2018-03-15 10:54:35 +01:00
Makefile Linux 4.14.42 2018-05-19 10:20:27 +02:00
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.