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Filename Latest commit message Latest commit date
Thomas Gleixner 987e90450a x86/pti/32: Size initial_page_table correctly
commit f490e07c53d66045d9d739e134145ec9b38653d3 upstream.

Commit 945fd17ab6 ("x86/cpu_entry_area: Sync cpu_entry_area to
initial_page_table") introduced the sync for the initial page table for
32bit.

sync_initial_page_table() uses clone_pgd_range() which does the update for
the kernel page table. If PTI is enabled it also updates the user space
page table counterpart, which is assumed to be in the next page after the
target PGD.

At this point in time 32-bit did not have PTI support, so the user space
page table update was not taking place.

The support for PTI on 32-bit which was introduced later on, did not take
that into account and missed to add the user space counter part for the
initial page table.

As a consequence sync_initial_page_table() overwrites any data which is
located in the page behing initial_page_table causing random failures,
e.g. by corrupting doublefault_tss and wreckaging the doublefault handler
on 32bit.

Fix it by adding a "user" page table right after initial_page_table.

Fixes: 7757d607c6 ("x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-29 10:09:52 +01:00
arch x86/pti/32: Size initial_page_table correctly 2019-11-29 10:09:52 +01:00
block
certs
crypto
Documentation x86/speculation: Fix incorrect MDS/TAA mitigation status 2019-11-29 10:09:46 +01:00
drivers nbd: prevent memory leak 2019-11-29 10:09:47 +01:00
fs Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-11-24 12:36:39 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
init
ipc
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
lib
LICENSES
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-11-22 09:11:18 -08:00
net udp: drop skb extensions before marking skb stateless 2019-11-22 09:28:46 -08:00
samples
scripts
security
sound
tools x86/insn: Fix awk regexp warnings 2019-11-29 10:09:45 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
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COPYING
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MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4 2019-11-24 16:32:01 -08:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.