that are entirely function pointers (along with a couple designated
initializer fixes).
- For the structleak plugin, provide an option to perform zeroing
initialization of all otherwise uninitialized stack variables that are
passed by reference (Ard Biesheuvel).
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Merge tag 'gcc-plugins-v4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook:
"This finishes the porting work on randstruct, and introduces a new
option to structleak, both noted below:
- For the randstruct plugin, enable automatic randomization of
structures that are entirely function pointers (along with a couple
designated initializer fixes).
- For the structleak plugin, provide an option to perform zeroing
initialization of all otherwise uninitialized stack variables that
are passed by reference (Ard Biesheuvel)"
* tag 'gcc-plugins-v4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: structleak: add option to init all vars used as byref args
randstruct: Enable function pointer struct detection
drivers/net/wan/z85230.c: Use designated initializers
drm/amd/powerplay: rv: Use designated initializers
This implements refcount_t overflow protection on x86 without a noticeable
performance impact, though without the fuller checking of REFCOUNT_FULL.
This is done by duplicating the existing atomic_t refcount implementation
but with normally a single instruction added to detect if the refcount
has gone negative (e.g. wrapped past INT_MAX or below zero). When detected,
the handler saturates the refcount_t to INT_MIN / 2. With this overflow
protection, the erroneous reference release that would follow a wrap back
to zero is blocked from happening, avoiding the class of refcount-overflow
use-after-free vulnerabilities entirely.
Only the overflow case of refcounting can be perfectly protected, since
it can be detected and stopped before the reference is freed and left to
be abused by an attacker. There isn't a way to block early decrements,
and while REFCOUNT_FULL stops increment-from-zero cases (which would
be the state _after_ an early decrement and stops potential double-free
conditions), this fast implementation does not, since it would require
the more expensive cmpxchg loops. Since the overflow case is much more
common (e.g. missing a "put" during an error path), this protection
provides real-world protection. For example, the two public refcount
overflow use-after-free exploits published in 2016 would have been
rendered unexploitable:
http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/http://cyseclabs.com/page?n=02012016
This implementation does, however, notice an unchecked decrement to zero
(i.e. caller used refcount_dec() instead of refcount_dec_and_test() and it
resulted in a zero). Decrements under zero are noticed (since they will
have resulted in a negative value), though this only indicates that a
use-after-free may have already happened. Such notifications are likely
avoidable by an attacker that has already exploited a use-after-free
vulnerability, but it's better to have them reported than allow such
conditions to remain universally silent.
On first overflow detection, the refcount value is reset to INT_MIN / 2
(which serves as a saturation value) and a report and stack trace are
produced. When operations detect only negative value results (such as
changing an already saturated value), saturation still happens but no
notification is performed (since the value was already saturated).
On the matter of races, since the entire range beyond INT_MAX but before
0 is negative, every operation at INT_MIN / 2 will trap, leaving no
overflow-only race condition.
As for performance, this implementation adds a single "js" instruction
to the regular execution flow of a copy of the standard atomic_t refcount
operations. (The non-"and_test" refcount_dec() function, which is uncommon
in regular refcount design patterns, has an additional "jz" instruction
to detect reaching exactly zero.) Since this is a forward jump, it is by
default the non-predicted path, which will be reinforced by dynamic branch
prediction. The result is this protection having virtually no measurable
change in performance over standard atomic_t operations. The error path,
located in .text.unlikely, saves the refcount location and then uses UD0
to fire a refcount exception handler, which resets the refcount, handles
reporting, and returns to regular execution. This keeps the changes to
.text size minimal, avoiding return jumps and open-coded calls to the
error reporting routine.
Example assembly comparison:
refcount_inc() before:
.text:
ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp)
refcount_inc() after:
.text:
ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp)
ffffffff8154614d: 0f 88 80 d5 17 00 js ffffffff816c36d3
...
.text.unlikely:
ffffffff816c36d3: 48 8d 4d f4 lea -0xc(%rbp),%rcx
ffffffff816c36d7: 0f ff (bad)
These are the cycle counts comparing a loop of refcount_inc() from 1
to INT_MAX and back down to 0 (via refcount_dec_and_test()), between
unprotected refcount_t (atomic_t), fully protected REFCOUNT_FULL
(refcount_t-full), and this overflow-protected refcount (refcount_t-fast):
2147483646 refcount_inc()s and 2147483647 refcount_dec_and_test()s:
cycles protections
atomic_t 82249267387 none
refcount_t-fast 82211446892 overflow, untested dec-to-zero
refcount_t-full 144814735193 overflow, untested dec-to-zero, inc-from-zero
This code is a modified version of the x86 PAX_REFCOUNT atomic_t
overflow defense from the last public patch of PaX/grsecurity, based
on my understanding of the code. Changes or omissions from the original
code are mine and don't reflect the original grsecurity/PaX code. Thanks
to PaX Team for various suggestions for improvement for repurposing this
code to be a refcount-only protection.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170815161924.GA133115@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the Linux kernel, struct type variables are rarely passed by-value,
and so functions that initialize such variables typically take an input
reference to the variable rather than returning a value that can
subsequently be used in an assignment.
If the initalization function is not part of the same compilation unit,
the lack of an assignment operation defeats any analysis the compiler
can perform as to whether the variable may be used before having been
initialized. This means we may end up passing on such variables
uninitialized, resulting in potential information leaks.
So extend the existing structleak GCC plugin so it will [optionally]
apply to all struct type variables that have their address taken at any
point, rather than only to variables of struct types that have a __user
annotation.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
This enables the automatic structure selection logic in the randstruct
GCC plugin. The selection logic randomizes all structures that contain
only function pointers, unless marked with __no_randomize_layout.
Signed-off-by: Kees Cook <keescook@chromium.org>
This adds support for compiling with a rough equivalent to the glibc
_FORTIFY_SOURCE=1 feature, providing compile-time and runtime buffer
overflow checks for string.h functions when the compiler determines the
size of the source or destination buffer at compile-time. Unlike glibc,
it covers buffer reads in addition to writes.
GNU C __builtin_*_chk intrinsics are avoided because they would force a
much more complex implementation. They aren't designed to detect read
overflows and offer no real benefit when using an implementation based
on inline checks. Inline checks don't add up to much code size and
allow full use of the regular string intrinsics while avoiding the need
for a bunch of _chk functions and per-arch assembly to avoid wrapper
overhead.
This detects various overflows at compile-time in various drivers and
some non-x86 core kernel code. There will likely be issues caught in
regular use at runtime too.
Future improvements left out of initial implementation for simplicity,
as it's all quite optional and can be done incrementally:
* Some of the fortified string functions (strncpy, strcat), don't yet
place a limit on reads from the source based on __builtin_object_size of
the source buffer.
* Extending coverage to more string functions like strlcat.
* It should be possible to optionally use __builtin_object_size(x, 1) for
some functions (C strings) to detect intra-object overflows (like
glibc's _FORTIFY_SOURCE=2), but for now this takes the conservative
approach to avoid likely compatibility issues.
* The compile-time checks should be made available via a separate config
option which can be enabled by default (or always enabled) once enough
time has passed to get the issues it catches fixed.
Kees said:
"This is great to have. While it was out-of-tree code, it would have
blocked at least CVE-2016-3858 from being exploitable (improper size
argument to strlcpy()). I've sent a number of fixes for
out-of-bounds-reads that this detected upstream already"
[arnd@arndb.de: x86: fix fortified memcpy]
Link: http://lkml.kernel.org/r/20170627150047.660360-1-arnd@arndb.de
[keescook@chromium.org: avoid panic() in favor of BUG()]
Link: http://lkml.kernel.org/r/20170626235122.GA25261@beast
[keescook@chromium.org: move from -mm, add ARCH_HAS_FORTIFY_SOURCE, tweak Kconfig help]
Link: http://lkml.kernel.org/r/20170526095404.20439-1-danielmicay@gmail.com
Link: http://lkml.kernel.org/r/1497903987-21002-8-git-send-email-keescook@chromium.org
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split
HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR.
LOCKUP_DETECTOR implies the general boot, sysctl, and programming
interfaces for the lockup detectors.
An architecture that wants to use a hard lockup detector must define
HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH.
Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the
minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and
does not implement the LOCKUP_DETECTOR interfaces.
sparc is unusual in that it has started to implement some of the
interfaces, but not fully yet. It should probably be converted to a full
HAVE_HARDLOCKUP_DETECTOR_ARCH.
[npiggin@gmail.com: fix]
Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com
Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Tested-by: Babu Moger <babu.moger@oracle.com> [sparc]
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Thin archives migration by Nicholas Piggin.
THIN_ARCHIVES has been available for a while as an optional feature
only for PowerPC architecture, but we do not need two different
intermediate-artifact schemes.
Using thin archives instead of conventional incremental linking has
various advantages:
- save disk space for builds
- speed-up building a little
- fix some link issues (for example, allyesconfig on ARM) due to
more flexibility for the final linking
- work better with dead code elimination we are planning
As discussed before, this migration has been done unconditionally
so that any problems caused by this will show up with "git bisect".
With testing with 0-day and linux-next, some architectures actually
showed up problems, but they were trivial and all fixed now.
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Merge tag 'kbuild-thinar-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild thin archives updates from Masahiro Yamada:
"Thin archives migration by Nicholas Piggin.
THIN_ARCHIVES has been available for a while as an optional feature
only for PowerPC architecture, but we do not need two different
intermediate-artifact schemes.
Using thin archives instead of conventional incremental linking has
various advantages:
- save disk space for builds
- speed-up building a little
- fix some link issues (for example, allyesconfig on ARM) due to more
flexibility for the final linking
- work better with dead code elimination we are planning
As discussed before, this migration has been done unconditionally so
that any problems caused by this will show up with "git bisect".
With testing with 0-day and linux-next, some architectures actually
showed up problems, but they were trivial and all fixed now"
* tag 'kbuild-thinar-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
tile: remove unneeded extra-y in Makefile
kbuild: thin archives make default for all archs
x86/um: thin archives build fix
tile: thin archives fix linking
ia64: thin archives fix linking
sh: thin archives fix linking
kbuild: handle libs-y archives separately from built-in.o archives
kbuild: thin archives use P option to ar
kbuild: thin archives final link close --whole-archives option
ia64: remove unneeded extra-y in Makefile.gate
tile: fix dependency and .*.cmd inclusion for incremental build
sparc64: Use indirect calls in hamming weight stubs
- typo fix in Kconfig (Jean Delvare)
- randstruct infrastructure
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Merge tag 'gcc-plugins-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull GCC plugin updates from Kees Cook:
"The big part is the randstruct plugin infrastructure.
This is the first of two expected pull requests for randstruct since
there are dependencies in other trees that would be easier to merge
once those have landed. Notably, the IPC allocation refactoring in
-mm, and many trivial merge conflicts across several trees when
applying the __randomize_layout annotation.
As a result, it seemed like I should send this now since it is
relatively self-contained, and once the rest of the trees have landed,
send the annotation patches. I'm expecting the final phase of
randstruct (automatic struct selection) will land for v4.14, but if
its other tree dependencies actually make it for v4.13, I can send
that merge request too.
Summary:
- typo fix in Kconfig (Jean Delvare)
- randstruct infrastructure"
* tag 'gcc-plugins-v4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
ARM: Prepare for randomized task_struct
randstruct: Whitelist NIU struct page overloading
randstruct: Whitelist big_key path struct overloading
randstruct: Whitelist UNIXCB cast
randstruct: Whitelist struct security_hook_heads cast
gcc-plugins: Add the randstruct plugin
Fix English in description of GCC_PLUGIN_STRUCTLEAK
compiler: Add __designated_init annotation
gcc-plugins: Detail c-common.h location for GCC 4.6
Make thin archives build the default, but keep the config option
to allow exemptions if any breakage can't be quickly solved.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Many subsystems will not use refcount_t unless there is a way to build the
kernel so that there is no regression in speed compared to atomic_t. This
adds CONFIG_REFCOUNT_FULL to enable the full refcount_t implementation
which has the validation but is slightly slower. When not enabled,
refcount_t uses the basic unchecked atomic_t routines, which results in
no code changes compared to just using atomic_t directly.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170621200026.GA115679@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This randstruct plugin is modified from Brad Spengler/PaX Team's code
in the last public patch of grsecurity/PaX based on my understanding
of the code. Changes or omissions from the original code are mine and
don't reflect the original grsecurity/PaX code.
The randstruct GCC plugin randomizes the layout of selected structures
at compile time, as a probabilistic defense against attacks that need to
know the layout of structures within the kernel. This is most useful for
"in-house" kernel builds where neither the randomization seed nor other
build artifacts are made available to an attacker. While less useful for
distribution kernels (where the randomization seed must be exposed for
third party kernel module builds), it still has some value there since now
all kernel builds would need to be tracked by an attacker.
In more performance sensitive scenarios, GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
can be selected to make a best effort to restrict randomization to
cacheline-sized groups of elements, and will not randomize bitfields. This
comes at the cost of reduced randomization.
Two annotations are defined,__randomize_layout and __no_randomize_layout,
which respectively tell the plugin to either randomize or not to
randomize instances of the struct in question. Follow-on patches enable
the auto-detection logic for selecting structures for randomization
that contain only function pointers. It is disabled here to assist with
bisection.
Since any randomized structs must be initialized using designated
initializers, __randomize_layout includes the __designated_init annotation
even when the plugin is disabled so that all builds will require
the needed initialization. (With the plugin enabled, annotations for
automatically chosen structures are marked as well.)
The main differences between this implemenation and grsecurity are:
- disable automatic struct selection (to be enabled in follow-up patch)
- add designated_init attribute at runtime and for manual marking
- clarify debugging output to differentiate bad cast warnings
- add whitelisting infrastructure
- support gcc 7's DECL_ALIGN and DECL_MODE changes (Laura Abbott)
- raise minimum required GCC version to 4.7
Earlier versions of this patch series were ported by Michael Leibowitz.
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull RCU updates from Ingo Molnar:
"The main changes are:
- Debloat RCU headers
- Parallelize SRCU callback handling (plus overlapping patches)
- Improve the performance of Tree SRCU on a CPU-hotplug stress test
- Documentation updates
- Miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits)
rcu: Open-code the rcu_cblist_n_lazy_cbs() function
rcu: Open-code the rcu_cblist_n_cbs() function
rcu: Open-code the rcu_cblist_empty() function
rcu: Separately compile large rcu_segcblist functions
srcu: Debloat the <linux/rcu_segcblist.h> header
srcu: Adjust default auto-expediting holdoff
srcu: Specify auto-expedite holdoff time
srcu: Expedite first synchronize_srcu() when idle
srcu: Expedited grace periods with reduced memory contention
srcu: Make rcutorture writer stalls print SRCU GP state
srcu: Exact tracking of srcu_data structures containing callbacks
srcu: Make SRCU be built by default
srcu: Fix Kconfig botch when SRCU not selected
rcu: Make non-preemptive schedule be Tasks RCU quiescent state
srcu: Expedite srcu_schedule_cbs_snp() callback invocation
srcu: Parallelize callback handling
kvm: Move srcu_struct fields to end of struct kvm
rcu: Fix typo in PER_RCU_NODE_PERIOD header comment
rcu: Use true/false in assignment to bool
rcu: Use bool value directly
...
Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and
reuse crashkernel parameter for fadump", v4.
Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.
This patchset removes dependency with CONFIG_KEXEC for crashkernel
parameter and vmcoreinfo related code as it can be reused without kexec
support. Also, crashkernel parameter is reused instead of
fadump_reserve_mem to reserve memory for fadump.
The first patch moves crashkernel parameter parsing and vmcoreinfo
related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE. The
second patch reuses the definitions of append_elf_note() & final_note()
functions under CONFIG_CRASH_CORE in IA64 arch code. The third patch
removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump)
in powerpc. The next patch reuses crashkernel parameter for reserving
memory for fadump, instead of the fadump_reserve_mem parameter. This
has the advantage of using all syntaxes crashkernel parameter supports,
for fadump as well. The last patch updates fadump kernel documentation
about use of crashkernel parameter.
This patch (of 5):
Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.
But currently, code related to vmcoreinfo and parsing of crashkernel
parameter is built under CONFIG_KEXEC_CORE. This patch introduces
CONFIG_CRASH_CORE and moves the above mentioned code under this config,
allowing code reuse without dependency on CONFIG_KEXEC. There is no
functional change with this patch.
Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull livepatch updates from Jiri Kosina:
- a per-task consistency model is being added for architectures that
support reliable stack dumping (extending this, currently rather
trivial set, is currently in the works).
This extends the nature of the types of patches that can be applied
by live patching infrastructure. The code stems from the design
proposal made [1] back in November 2014. It's a hybrid of SUSE's
kGraft and RH's kpatch, combining advantages of both: it uses
kGraft's per-task consistency and syscall barrier switching combined
with kpatch's stack trace switching. There are also a number of
fallback options which make it quite flexible.
Most of the heavy lifting done by Josh Poimboeuf with help from
Miroslav Benes and Petr Mladek
[1] https://lkml.kernel.org/r/20141107140458.GA21774@suse.cz
- module load time patch optimization from Zhou Chengming
- a few assorted small fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: add missing printk newlines
livepatch: Cancel transition a safe way for immediate patches
livepatch: Reduce the time of finding module symbols
livepatch: make klp_mutex proper part of API
livepatch: allow removal of a disabled patch
livepatch: add /proc/<pid>/patch_state
livepatch: change to a per-task consistency model
livepatch: store function sizes
livepatch: use kstrtobool() in enabled_store()
livepatch: move patching functions into patch.c
livepatch: remove unnecessary object loaded check
livepatch: separate enabled and patched states
livepatch/s390: add TIF_PATCH_PENDING thread flag
livepatch/s390: reorganize TIF thread flag bits
livepatch/powerpc: add TIF_PATCH_PENDING thread flag
livepatch/x86: add TIF_PATCH_PENDING thread flag
livepatch: create temporary klp_update_patch_state() stub
x86/entry: define _TIF_ALLWORK_MASK flags explicitly
stacktrace/x86: add function for detecting reliable stack traces
The definition of smp_mb__after_unlock_lock() is currently smp_mb()
for CONFIG_PPC and a no-op otherwise. It would be better to instead
provide an architecture-selectable Kconfig option, and select the
strength of smp_mb__after_unlock_lock() based on that option. This
commit therefore creates ARCH_WEAK_RELEASE_ACQUIRE, has PPC select it,
and bases the definition of smp_mb__after_unlock_lock() on this new
ARCH_WEAK_RELEASE_ACQUIRE Kconfig option.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Boqun Feng <boqun.feng@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: <linuxppc-dev@lists.ozlabs.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
mmap() uses a base address, from which it starts to look for a free space
for allocation.
The base address is stored in mm->mmap_base, which is calculated during
exec(). The address depends on task's size, set rlimit for stack, ASLR
randomization. The base depends on the task size and the number of random
bits which are different for 64-bit and 32bit applications.
Due to the fact, that the base address is fixed, its mmap() from a compat
(32bit) syscall issued by a 64bit task will return a address which is based
on the 64bit base address and does not fit into the 32bit address space
(4GB). The returned pointer is truncated to 32bit, which results in an
invalid address.
To solve store a seperate compat address base plus a compat legacy address
base in mm_struct. These bases are calculated at exec() time and can be
used later to address the 32bit compat mmap() issued by 64 bit
applications.
As a consequence of this change 32-bit applications issuing a 64-bit
syscall (after doing a long jump) will get a 64-bit mapping now. Before
this change 32-bit applications always got a 32bit mapping.
[ tglx: Massaged changelog and added a comment ]
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: 0x7f454c46@gmail.com
Cc: linux-mm@kvack.org
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20170306141721.9188-4-dsafonov@virtuozzo.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For live patching and possibly other use cases, a stack trace is only
useful if it can be assured that it's completely reliable. Add a new
save_stack_trace_tsk_reliable() function to achieve that.
Note that if the target task isn't the current task, and the target task
is allowed to run, then it could be writing the stack while the unwinder
is reading it, resulting in possible corruption. So the caller of
save_stack_trace_tsk_reliable() must ensure that the task is either
'current' or inactive.
save_stack_trace_tsk_reliable() relies on the x86 unwinder's detection
of pt_regs on the stack. If the pt_regs are not user-mode registers
from a syscall, then they indicate an in-kernel interrupt or exception
(e.g. preemption or a page fault), in which case the stack is considered
unreliable due to the nature of frame pointers.
It also relies on the x86 unwinder's detection of other issues, such as:
- corrupted stack data
- stack grows the wrong way
- stack walk doesn't reach the bottom
- user didn't provide a large enough entries array
Such issues are reported by checking unwind_error() and !unwind_done().
Also add CONFIG_HAVE_RELIABLE_STACKTRACE so arch-independent code can
determine at build time whether the function is implemented.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Ingo Molnar <mingo@kernel.org> # for the x86 changes
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Fix typos and add the following to the scripts/spelling.txt:
an user||a user
an userspace||a userspace
I also added "userspace" to the list since it is a common word in Linux.
I found some instances for "an userfaultfd", but I did not add it to the
list. I felt it is endless to find words that start with "user" such as
"userland" etc., so must draw a line somewhere.
Link: http://lkml.kernel.org/r/1481573103-11329-4-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current transparent hugepage code only supports PMDs. This patch
adds support for transparent use of PUDs with DAX. It does not include
support for anonymous pages. x86 support code also added.
Most of this patch simply parallels the work that was done for huge
PMDs. The only major difference is how the new ->pud_entry method in
mm_walk works. The ->pmd_entry method replaces the ->pte_entry method,
whereas the ->pud_entry method works along with either ->pmd_entry or
->pte_entry. The pagewalk code takes care of locking the PUD before
calling ->pud_walk, so handlers do not need to worry whether the PUD is
stable.
[dave.jiang@intel.com: fix SMP x86 32bit build for native_pud_clear()]
Link: http://lkml.kernel.org/r/148719066814.31111.3239231168815337012.stgit@djiang5-desk3.ch.intel.com
[dave.jiang@intel.com: native_pud_clear missing on i386 build]
Link: http://lkml.kernel.org/r/148640375195.69754.3315433724330910314.stgit@djiang5-desk3.ch.intel.com
Link: http://lkml.kernel.org/r/148545059381.17912.8602162635537598445.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking updates from David Miller:
"Highlights:
1) Support TX_RING in AF_PACKET TPACKET_V3 mode, from Sowmini
Varadhan.
2) Simplify classifier state on sk_buff in order to shrink it a bit.
From Willem de Bruijn.
3) Introduce SIPHASH and it's usage for secure sequence numbers and
syncookies. From Jason A. Donenfeld.
4) Reduce CPU usage for ICMP replies we are going to limit or
suppress, from Jesper Dangaard Brouer.
5) Introduce Shared Memory Communications socket layer, from Ursula
Braun.
6) Add RACK loss detection and allow it to actually trigger fast
recovery instead of just assisting after other algorithms have
triggered it. From Yuchung Cheng.
7) Add xmit_more and BQL support to mvneta driver, from Simon Guinot.
8) skb_cow_data avoidance in esp4 and esp6, from Steffen Klassert.
9) Export MPLS packet stats via netlink, from Robert Shearman.
10) Significantly improve inet port bind conflict handling, especially
when an application is restarted and changes it's setting of
reuseport. From Josef Bacik.
11) Implement TX batching in vhost_net, from Jason Wang.
12) Extend the dummy device so that VF (virtual function) features,
such as configuration, can be more easily tested. From Phil
Sutter.
13) Avoid two atomic ops per page on x86 in bnx2x driver, from Eric
Dumazet.
14) Add new bpf MAP, implementing a longest prefix match trie. From
Daniel Mack.
15) Packet sample offloading support in mlxsw driver, from Yotam Gigi.
16) Add new aquantia driver, from David VomLehn.
17) Add bpf tracepoints, from Daniel Borkmann.
18) Add support for port mirroring to b53 and bcm_sf2 drivers, from
Florian Fainelli.
19) Remove custom busy polling in many drivers, it is done in the core
networking since 4.5 times. From Eric Dumazet.
20) Support XDP adjust_head in virtio_net, from John Fastabend.
21) Fix several major holes in neighbour entry confirmation, from
Julian Anastasov.
22) Add XDP support to bnxt_en driver, from Michael Chan.
23) VXLAN offloads for enic driver, from Govindarajulu Varadarajan.
24) Add IPVTAP driver (IP-VLAN based tap driver) from Sainath Grandhi.
25) Support GRO in IPSEC protocols, from Steffen Klassert"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1764 commits)
Revert "ath10k: Search SMBIOS for OEM board file extension"
net: socket: fix recvmmsg not returning error from sock_error
bnxt_en: use eth_hw_addr_random()
bpf: fix unlocking of jited image when module ronx not set
arch: add ARCH_HAS_SET_MEMORY config
net: napi_watchdog() can use napi_schedule_irqoff()
tcp: Revert "tcp: tcp_probe: use spin_lock_bh()"
net/hsr: use eth_hw_addr_random()
net: mvpp2: enable building on 64-bit platforms
net: mvpp2: switch to build_skb() in the RX path
net: mvpp2: simplify MVPP2_PRS_RI_* definitions
net: mvpp2: fix indentation of MVPP2_EXT_GLOBAL_CTRL_DEFAULT
net: mvpp2: remove unused register definitions
net: mvpp2: simplify mvpp2_bm_bufs_add()
net: mvpp2: drop useless fields in mvpp2_bm_pool and related code
net: mvpp2: remove unused 'tx_skb' field of 'struct mvpp2_tx_queue'
net: mvpp2: release reference to txq_cpu[] entry after unmapping
net: mvpp2: handle too large value in mvpp2_rx_time_coal_set()
net: mvpp2: handle too large value handling in mvpp2_rx_pkts_coal_set()
net: mvpp2: remove useless arguments in mvpp2_rx_{pkts, time}_coal_set
...
- infrastructure updates (gcc-common.h)
- introduce structleak plugin for forced initialization of some structures
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Merge tag 'gcc-plugins-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc-plugins updates from Kees Cook:
"This includes infrastructure updates and the structleak plugin, which
performs forced initialization of certain structures to avoid possible
information exposures to userspace.
Summary:
- infrastructure updates (gcc-common.h)
- introduce structleak plugin for forced initialization of some
structures"
* tag 'gcc-plugins-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Add structleak for more stack initialization
gcc-plugins: consolidate on PASS_INFO macro
gcc-plugins: add PASS_INFO and build_const_char_string()
Currently, there's no good way to test for the presence of
set_memory_ro/rw/x/nx() helpers implemented by archs such as
x86, arm, arm64 and s390.
There's DEBUG_SET_MODULE_RONX and DEBUG_RODATA, however both
don't really reflect that: set_memory_*() are also available
even when DEBUG_SET_MODULE_RONX is turned off, and DEBUG_RODATA
is set by parisc, but doesn't implement above functions. Thus,
add ARCH_HAS_SET_MEMORY that is selected by mentioned archs,
where generic code can test against this.
This also allows later on to move DEBUG_SET_MODULE_RONX out of
the arch specific Kconfig to define it only once depending on
ARCH_HAS_SET_MEMORY.
Suggested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Both of these options are poorly named. The features they provide are
necessary for system security and should not be considered debug only.
Change the names to CONFIG_STRICT_KERNEL_RWX and
CONFIG_STRICT_MODULE_RWX to better describe what these options do.
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
There are multiple architectures that support CONFIG_DEBUG_RODATA and
CONFIG_SET_MODULE_RONX. These options also now have the ability to be
turned off at runtime. Move these to an architecture independent
location and make these options def_bool y for almost all of those
arches.
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Relax ordering(RO) is one feature of 82599 NIC, to enable this feature can
enhance the performance for some cpu architecure, such as SPARC and so on.
Currently it only supports one special cpu architecture(SPARC) in 82599
driver to enable RO feature, this is not very common for other cpu architecture
which really needs RO feature.
This patch add one common config CONFIG_ARCH_WANT_RELAX_ORDER to set RO feature,
and should define CONFIG_ARCH_WANT_RELAX_ORDER in sparc Kconfig firstly.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Reviewed-by: Alexander Duyck <alexander.duyck@gmail.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This plugin detects any structures that contain __user attributes and
makes sure it is being fully initialized so that a specific class of
information exposure is eliminated. (This plugin was originally designed
to block the exposure of siginfo in CVE-2013-2141.)
Ported from grsecurity/PaX. This version adds a verbose option to the
plugin and the Kconfig.
Signed-off-by: Kees Cook <keescook@chromium.org>
Patch series "ima: carry the measurement list across kexec", v8.
The TPM PCRs are only reset on a hard reboot. In order to validate a
TPM's quote after a soft reboot (eg. kexec -e), the IMA measurement
list of the running kernel must be saved and then restored on the
subsequent boot, possibly of a different architecture.
The existing securityfs binary_runtime_measurements file conveniently
provides a serialized format of the IMA measurement list. This patch
set serializes the measurement list in this format and restores it.
Up to now, the binary_runtime_measurements was defined as architecture
native format. The assumption being that userspace could and would
handle any architecture conversions. With the ability of carrying the
measurement list across kexec, possibly from one architecture to a
different one, the per boot architecture information is lost and with it
the ability of recalculating the template digest hash. To resolve this
problem, without breaking the existing ABI, this patch set introduces
the boot command line option "ima_canonical_fmt", which is arbitrarily
defined as little endian.
The need for this boot command line option will be limited to the
existing version 1 format of the binary_runtime_measurements.
Subsequent formats will be defined as canonical format (eg. TPM 2.0
support for larger digests).
A simplified method of Thiago Bauermann's "kexec buffer handover" patch
series for carrying the IMA measurement list across kexec is included in
this patch set. The simplified method requires all file measurements be
taken prior to executing the kexec load, as subsequent measurements will
not be carried across the kexec and restored.
This patch (of 10):
The IMA kexec buffer allows the currently running kernel to pass the
measurement list via a kexec segment to the kernel that will be kexec'd.
The second kernel can check whether the previous kernel sent the buffer
and retrieve it.
This is the architecture-specific part which enables IMA to receive the
measurement list passed by the previous kernel. It will be used in the
next patch.
The change in machine_kexec_64.c is to factor out the logic of removing
an FDT memory reservation so that it can be used by remove_ima_buffer.
Link: http://lkml.kernel.org/r/1480554346-29071-2-git-send-email-zohar@linux.vnet.ibm.com
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andreas Steffen <andreas.steffen@strongswan.org>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Josh Sklar <sklar@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Add the gcc plugins Makefile to MAINTAINERS to route things correctly
- Hide cyc_complexity behind !CONFIG_TEST for the future unhiding of
plugins generally.
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Merge tag 'gcc-plugins-v4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins updates from Kees Cook:
"Minor changes to the gcc plugins:
- add the gcc plugins Makefile to MAINTAINERS to route things
correctly
- hide cyc_complexity behind !CONFIG_TEST for the future unhiding of
plugins generally"
* tag 'gcc-plugins-v4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Adjust Kconfig to avoid cyc_complexity
MAINTAINERS: add GCC plugins Makefile
Pull scheduler updates from Ingo Molnar:
"The main scheduler changes in this cycle were:
- support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a
notion of 'better cores', which the scheduler will prefer to
schedule single threaded workloads on. (Tim Chen, Srinivas
Pandruvada)
- enhance the handling of asymmetric capacity CPUs further (Morten
Rasmussen)
- improve/fix load handling when moving tasks between task groups
(Vincent Guittot)
- simplify and clean up the cputime code (Stanislaw Gruszka)
- improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent
Guittot)
- make struct kthread kmalloc()ed and related fixes (Oleg Nesterov)
- add uaccess atomicity debugging (when using access_ok() in the
wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra)
- implement various fixes, cleanups and other enhancements (Daniel
Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
sched/core: Use load_avg for selecting idlest group
sched/core: Fix find_idlest_group() for fork
kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker()
kthread: Don't use to_live_kthread() in kthread_[un]park()
kthread: Don't use to_live_kthread() in kthread_stop()
Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function"
kthread: Make struct kthread kmalloc'ed
x86/uaccess, sched/preempt: Verify access_ok() context
sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable
sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO
x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h>
cpufreq/intel_pstate: Use CPPC to get max performance
acpi/bus: Set _OSC for diverse core support
acpi/bus: Enable HWP CPPC objects
x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU
x86/sysctl: Add sysctl for ITMT scheduling feature
x86: Enable Intel Turbo Boost Max Technology 3.0
x86/topology: Define x86's arch_update_cpu_topology
sched: Extend scheduler's asym packing
sched/fair: Clean up the tunable parameter definitions
...
Signed-off-by: Eric Saint Etienne <eric.saint.etienne@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Only s390 and powerpc have hardware facilities allowing to measure
cputimes scaled by frequency. On all other architectures
utimescaled/stimescaled are equal to utime/stime (however they are
accounted separately).
Remove {u,s}timescaled accounting on all architectures except
powerpc and s390, where those values are explicitly accounted
in the proper places.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161031162143.GB12646@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In preparation for removing "depends on !COMPILE_TEST" from GCC_PLUGINS,
the GCC_PLUGIN_CYC_COMPLEXITY plugin needs to gain the restriction,
since it is mainly an example, and produces (intended) voluminous stderr
reporting, which is generally undesirable for allyesconfig-style build
tests. This additionally puts the plugin behind EXPERT and improves the
help text.
Signed-off-by: Kees Cook <keescook@chromium.org>
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
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Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"
* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
Pull kbuild updates from Michal Marek:
- EXPORT_SYMBOL for asm source by Al Viro.
This does bring a regression, because genksyms no longer generates
checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
working on a patch to fix this.
Plus, we are talking about functions like strcpy(), which rarely
change prototypes.
- Fixes for PPC fallout of the above by Stephen Rothwell and Nick
Piggin
- fixdep speedup by Alexey Dobriyan.
- preparatory work by Nick Piggin to allow architectures to build with
-ffunction-sections, -fdata-sections and --gc-sections
- CONFIG_THIN_ARCHIVES support by Stephen Rothwell
- fix for filenames with colons in the initramfs source by me.
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
initramfs: Escape colons in depfile
ppc: there is no clear_pages to export
powerpc/64: whitelist unresolved modversions CRCs
kbuild: -ffunction-sections fix for archs with conflicting sections
kbuild: add arch specific post-link Makefile
kbuild: allow archs to select link dead code/data elimination
kbuild: allow architectures to use thin archives instead of ld -r
kbuild: Regenerate genksyms lexer
kbuild: genksyms fix for typeof handling
fixdep: faster CONFIG_ search
ia64: move exports to definitions
sparc32: debride memcpy.S a bit
[sparc] unify 32bit and 64bit string.h
sparc: move exports to definitions
ppc: move exports to definitions
arm: move exports to definitions
s390: move exports to definitions
m68k: move exports to definitions
alpha: move exports to actual definitions
x86: move exports to actual definitions
...
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).
To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).
Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.
Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
Enabling -ffunction-sections modified the generic linker script to
pull .text.* sections into regular TEXT_TEXT section, conflicting
with some architectures. Revert that change and require archs that
enable the option to ensure they have no conflicting section names,
and do the appropriate merging.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: b67067f117 ("kbuild: allow archs to select link dead code/data elimination")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to
select to build with -ffunction-sections, -fdata-sections, and link
with --gc-sections. It requires some work (documented) to ensure all
unreferenced entrypoints are live, and requires toolchain and build
verification, so it is made a per-arch option for now.
On a random powerpc64le build, this yelds a significant size saving,
it boots and runs fine, but there is a lot I haven't tested as yet, so
these savings may be reduced if there are bugs in the link.
text data bss dec filename
11169741 1180744 1923176 14273661 vmlinux
10445269 1004127 1919707 13369103 vmlinux.dce
~700K text, ~170K data, 6% removed from kernel image size.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
ld -r is an incremental link used to create built-in.o files in build
subdirectories. It produces relocatable object files containing all
its input files, and these are are then pulled together and relocated
in the final link. Aside from the bloat, this constrains the final
link relocations, which has bitten large powerpc builds with
unresolvable relocations in the final link.
Alan Modra has recommended the kernel use thin archives for linking.
This is an alternative and means that the linker has more information
available to it when it links the kernel.
This patch enables a config option architectures can select, which
causes all built-in.o files to be built as thin archives. built-in.o
files in subdirectories do not get symbol table or index attached,
which improves speed and size. The final link pass creates a
built-in.o archive in the root output directory which includes the
symbol table and index. The linker then uses takes this file to link.
The --whole-archive linker option is required, because the linker now
has visibility to every individual object file, and it will otherwise
just completely avoid including those without external references
(consider a file with EXPORT_SYMBOL or initcall or hardware exceptions
as its only entry points). The traditional built works "by luck" as
built-in.o files are large enough that they're going to get external
references. However this optimisation is unpredictable for the kernel
(due to above external references), ineffective at culling unused, and
costly because the .o files have to be searched for references.
Superior alternatives for link-time culling should be used instead.
Build characteristics for inclink vs thinarc, on a small powerpc64le
pseries VM with a modest .config:
inclink thinarc
sizes
vmlinux 15 618 680 15 625 028
sum of all built-in.o 56 091 808 1 054 334
sum excluding root built-in.o 151 430
find -name built-in.o | xargs rm ; time make vmlinux
real 22.772s 21.143s
user 13.280s 13.430s
sys 4.310s 2.750s
- Final kernel pulled in only about 6K more, which shows how
ineffective the object file culling is.
- Build performance looks improved due to less pagecache activity.
On IO constrained systems it could be a bigger win.
- Build size saving is significant.
Side note, the toochain understands archives, so there's some tricks,
$ ar t built-in.o # list all files you linked with
$ size built-in.o # and their sizes
$ objdump -d built-in.o # disassembly (unrelocated) with filenames
Implementation by sfr, minor tweaks by npiggin.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
If CONFIG_VMAP_STACK=y is selected, kernel stacks are allocated with
__vmalloc_node_range().
Grsecurity has had a similar feature (called GRKERNSEC_KSTACKOVERFLOW=y)
for a long time.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14c07d4fd173a5b117f51e8b939f9f4323e39899.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull kbuild updates from Michal Marek:
- GCC plugin support by Emese Revfy from grsecurity, with a fixup from
Kees Cook. The plugins are meant to be used for static analysis of
the kernel code. Two plugins are provided already.
- reduction of the gcc commandline by Arnd Bergmann.
- IS_ENABLED / IS_REACHABLE macro enhancements by Masahiro Yamada
- bin2c fix by Michael Tautschnig
- setlocalversion fix by Wolfram Sang
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
gcc-plugins: disable under COMPILE_TEST
kbuild: Abort build on bad stack protector flag
scripts: Fix size mismatch of kexec_purgatory_size
kbuild: make samples depend on headers_install
Kbuild: don't add obj tree in additional includes
Kbuild: arch: look for generated headers in obtree
Kbuild: always prefix objtree in LINUXINCLUDE
Kbuild: avoid duplicate include path
Kbuild: don't add ../../ to include path
vmlinux.lds.h: replace config_enabled() with IS_ENABLED()
kconfig.h: allow to use IS_{ENABLE,REACHABLE} in macro expansion
kconfig.h: use already defined macros for IS_REACHABLE() define
export.h: use __is_defined() to check if __KSYM_* is defined
kconfig.h: use __is_defined() to check if MODULE is defined
kbuild: setlocalversion: print error to STDERR
Add sancov plugin
Add Cyclomatic complexity GCC plugin
GCC plugin infrastructure
Shared library support
Since adding the gcc plugin development headers is required for the
gcc plugin support, we should ease into this new kernel build dependency
more slowly. For now, disable the gcc plugins under COMPILE_TEST so that
all*config builds will skip it.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
This creates per-architecture function arch_within_stack_frames() that
should validate if a given object is contained by a kernel stack frame.
Initial implementation is on x86.
This is based on code from PaX.
Signed-off-by: Kees Cook <keescook@chromium.org>
We've had the thread info allocated together with the thread stack for
most architectures for a long time (since the thread_info was split off
from the task struct), but that is about to change.
But the patches that move the thread info to be off-stack (and a part of
the task struct instead) made it clear how confused the allocator and
freeing functions are.
Because the common case was that we share an allocation with the thread
stack and the thread_info, the two pointers were identical. That
identity then meant that we would have things like
ti = alloc_thread_info_node(tsk, node);
...
tsk->stack = ti;
which certainly _worked_ (since stack and thread_info have the same
value), but is rather confusing: why are we assigning a thread_info to
the stack? And if we move the thread_info away, the "confusing" code
just gets to be entirely bogus.
So remove all this confusion, and make it clear that we are doing the
stack allocation by renaming and clarifying the function names to be
about the stack. The fact that the thread_info then shares the
allocation is an implementation detail, and not really about the
allocation itself.
This is a pure renaming and type fix: we pass in the same pointer, it's
just that we clarify what the pointer means.
The ia64 code that actually only has one single allocation (for all of
task_struct, thread_info and kernel thread stack) now looks a bit odd,
but since "tsk->stack" is actually not even used there, that oddity
doesn't matter. It would be a separate thing to clean that up, I
intentionally left the ia64 changes as a pure brute-force renaming and
type change.
Acked-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Several modern devices, such as PC/104 cards, are expected to run on
modern systems via an ISA bus interface. Since ISA is a legacy interface
for most modern architectures, ISA support should remain disabled in
general. Support for ISA-style drivers should be enabled on a per driver
basis.
To allow ISA-style drivers on modern systems, this patch introduces the
ISA_BUS_API and ISA_BUS Kconfig options. The ISA bus driver will now
build conditionally on the ISA_BUS_API Kconfig option, which defaults to
the legacy ISA Kconfig option. The ISA_BUS Kconfig option allows the
ISA_BUS_API Kconfig option to be selected on architectures which do not
enable ISA (e.g. X86_64).
The ISA_BUS Kconfig option is currently only implemented for X86
architectures. Other architectures may have their own ISA_BUS Kconfig
options added as required.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
