Quoting Linus:
I do think that it would be a good idea to very expressly document
the fact that it's not that the user access itself is unsafe. I do
agree that things like "get_user()" want to be protected, but not
because of any direct bugs or problems with get_user() and friends,
but simply because get_user() is an excellent source of a pointer
that is obviously controlled from a potentially attacking user
space. So it's a prime candidate for then finding _subsequent_
accesses that can then be used to perturb the cache.
Unlike the __get_user() case get_user() includes the address limit check
near the pointer de-reference. With that locality the speculation can be
mitigated with pointer narrowing rather than a barrier, i.e.
array_index_nospec(). Where the narrowing is performed by:
cmp %limit, %ptr
sbb %mask, %mask
and %mask, %ptr
With respect to speculation the value of %ptr is either less than %limit
or NULL.
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: torvalds@linux-foundation.org
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727417469.33451.11804043010080838495.stgit@dwillia2-desk3.amr.corp.intel.com
Quoting Linus:
I do think that it would be a good idea to very expressly document
the fact that it's not that the user access itself is unsafe. I do
agree that things like "get_user()" want to be protected, but not
because of any direct bugs or problems with get_user() and friends,
but simply because get_user() is an excellent source of a pointer
that is obviously controlled from a potentially attacking user
space. So it's a prime candidate for then finding _subsequent_
accesses that can then be used to perturb the cache.
__uaccess_begin_nospec() covers __get_user() and copy_from_iter() where the
limit check is far away from the user pointer de-reference. In those cases
a barrier_nospec() prevents speculation with a potential pointer to
privileged memory. uaccess_try_nospec covers get_user_try.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727416953.33451.10508284228526170604.stgit@dwillia2-desk3.amr.corp.intel.com
For __get_user() paths, do not allow the kernel to speculate on the value
of a user controlled pointer. In addition to the 'stac' instruction for
Supervisor Mode Access Protection (SMAP), a barrier_nospec() causes the
access_ok() result to resolve in the pipeline before the CPU might take any
speculative action on the pointer value. Given the cost of 'stac' the
speculation barrier is placed after 'stac' to hopefully overlap the cost of
disabling SMAP with the cost of flushing the instruction pipeline.
Since __get_user is a major kernel interface that deals with user
controlled pointers, the __uaccess_begin_nospec() mechanism will prevent
speculative execution past an access_ok() permission check. While
speculative execution past access_ok() is not enough to lead to a kernel
memory leak, it is a necessary precondition.
To be clear, __uaccess_begin_nospec() is addressing a class of potential
problems near __get_user() usages.
Note, that while the barrier_nospec() in __uaccess_begin_nospec() is used
to protect __get_user(), pointer masking similar to array_index_nospec()
will be used for get_user() since it incorporates a bounds check near the
usage.
uaccess_try_nospec provides the same mechanism for get_user_try.
No functional changes.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727415922.33451.5796614273104346583.stgit@dwillia2-desk3.amr.corp.intel.com
Rename the open coded form of this instruction sequence from
rdtsc_ordered() into a generic barrier primitive, barrier_nospec().
One of the mitigations for Spectre variant1 vulnerabilities is to fence
speculative execution after successfully validating a bounds check. I.e.
force the result of a bounds check to resolve in the instruction pipeline
to ensure speculative execution honors that result before potentially
operating on out-of-bounds data.
No functional changes.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727415361.33451.9049453007262764675.stgit@dwillia2-desk3.amr.corp.intel.com
array_index_nospec() is proposed as a generic mechanism to mitigate
against Spectre-variant-1 attacks, i.e. an attack that bypasses boundary
checks via speculative execution. The array_index_nospec()
implementation is expected to be safe for current generation CPUs across
multiple architectures (ARM, x86).
Based on an original implementation by Linus Torvalds, tweaked to remove
speculative flows by Alexei Starovoitov, and tweaked again by Linus to
introduce an x86 assembly implementation for the mask generation.
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Co-developed-by: Alexei Starovoitov <ast@kernel.org>
Suggested-by: Cyril Novikov <cnovikov@lynx.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: kernel-hardening@lists.openwall.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: gregkh@linuxfoundation.org
Cc: torvalds@linux-foundation.org
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727414229.33451.18411580953862676575.stgit@dwillia2-desk3.amr.corp.intel.com
write_inode() could be called variety of reasons, in the case of syncfs(2)
there is no need to wait for flush getting completed in write_inode(),
->sync_fs is for guaranteeing flush completion for all inodes at that point.
Signed-off-by: Chengguang Xu <cgxu519@icloud.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- Implement frequency/CPU invariance and OPP selection for
SCHED_DEADLINE (Juri Lelli)
- Tweak the task migration logic for better multi-tasking
workload scalability (Mel Gorman)
- Misc cleanups, fixes and improvements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Make bandwidth enforcement scale-invariant
sched/cpufreq: Move arch_scale_{freq,cpu}_capacity() outside of #ifdef CONFIG_SMP
sched/cpufreq: Remove arch_scale_freq_capacity()'s 'sd' parameter
sched/cpufreq: Always consider all CPUs when deciding next freq
sched/cpufreq: Split utilization signals
sched/cpufreq: Change the worker kthread to SCHED_DEADLINE
sched/deadline: Move CPU frequency selection triggering points
sched/cpufreq: Use the DEADLINE utilization signal
sched/deadline: Implement "runtime overrun signal" support
sched/fair: Only immediately migrate tasks due to interrupts if prev and target CPUs share cache
sched/fair: Correct obsolete comment about cpufreq_update_util()
sched/fair: Remove impossible condition from find_idlest_group_cpu()
sched/cpufreq: Don't pass flags to sugov_set_iowait_boost()
sched/cpufreq: Initialize sg_cpu->flags to 0
sched/fair: Consider RT/IRQ pressure in capacity_spare_wake()
sched/fair: Use 'unsigned long' for utilization, consistently
sched/core: Rework and clarify prepare_lock_switch()
sched/fair: Remove unused 'curr' parameter from wakeup_gran
sched/headers: Constify object_is_on_stack()
Pull x86 RAS updates from Ingo Molnar:
- various AMD SMCA error parsing/reporting improvements (Yazen Ghannam)
- extend Intel CMCI error reporting to more cases (Xie XiuQi)
* 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/MCE: Make correctable error detection look at the Deferred bit
x86/MCE: Report only DRAM ECC as memory errors on AMD systems
x86/MCE/AMD: Define a function to get SMCA bank type
x86/mce/AMD: Don't set DEF_INT_TYPE in MSR_CU_DEF_ERR on SMCA systems
x86/MCE: Extend table to report action optional errors through CMCI too
Pull perf updates from Ingo Molnar:
"Kernel side changes:
- Clean up the x86 instruction decoder (Masami Hiramatsu)
- Add new uprobes optimization for PUSH instructions on x86 (Yonghong
Song)
- Add MSR_IA32_THERM_STATUS to the MSR events (Stephane Eranian)
- Fix misc bugs, update documentation, plus various cleanups (Jiri
Olsa)
There's a large number of tooling side improvements:
- Intel-PT/BTS improvements (Adrian Hunter)
- Numerous 'perf trace' improvements (Arnaldo Carvalho de Melo)
- Introduce an errno code to string facility (Hendrik Brueckner)
- Various build system improvements (Jiri Olsa)
- Add support for CoreSight trace decoding by making the perf tools
use the external openCSD (Mathieu Poirier, Tor Jeremiassen)
- Add ARM Statistical Profiling Extensions (SPE) support (Kim
Phillips)
- libtraceevent updates (Steven Rostedt)
- Intel vendor event JSON updates (Andi Kleen)
- Introduce 'perf report --mmaps' and 'perf report --tasks' to show
info present in 'perf.data' (Jiri Olsa, Arnaldo Carvalho de Melo)
- Add infrastructure to record first and last sample time to the
perf.data file header, so that when processing all samples in a
'perf record' session, such as when doing build-id processing, or
when specifically requesting that that info be recorded, use that
in 'perf report --time', that also got support for percent slices
in addition to absolute ones.
I.e. now it is possible to ask for the samples in the 10%-20% time
slice of a perf.data file (Jin Yao)
- Allow system wide 'perf stat --per-thread', sorting the result (Jin
Yao)
E.g.:
[root@jouet ~]# perf stat --per-thread --metrics IPC
^C
Performance counter stats for 'system wide':
make-22229 23,012,094,032 inst_retired.any # 0.8 IPC
cc1-22419 692,027,497 inst_retired.any # 0.8 IPC
gcc-22418 328,231,855 inst_retired.any # 0.9 IPC
cc1-22509 220,853,647 inst_retired.any # 0.8 IPC
gcc-22486 199,874,810 inst_retired.any # 1.0 IPC
as-22466 177,896,365 inst_retired.any # 0.9 IPC
cc1-22465 150,732,374 inst_retired.any # 0.8 IPC
gcc-22508 112,555,593 inst_retired.any # 0.9 IPC
cc1-22487 108,964,079 inst_retired.any # 0.7 IPC
qemu-system-x86-2697 21,330,550 inst_retired.any # 0.3 IPC
systemd-journal-551 20,642,951 inst_retired.any # 0.4 IPC
docker-containe-17651 9,552,892 inst_retired.any # 0.5 IPC
dockerd-current-9809 7,528,586 inst_retired.any # 0.5 IPC
make-22153 12,504,194,380 inst_retired.any # 0.8 IPC
python2-22429 12,081,290,954 inst_retired.any # 0.8 IPC
<SNIP>
python2-22429 15,026,328,103 cpu_clk_unhalted.thread
cc1-22419 826,660,193 cpu_clk_unhalted.thread
gcc-22418 365,321,295 cpu_clk_unhalted.thread
cc1-22509 279,169,362 cpu_clk_unhalted.thread
gcc-22486 210,156,950 cpu_clk_unhalted.thread
<SNIP>
5.638075538 seconds time elapsed
[root@jouet ~]#
- Improve shell auto-completion of perf events (Jin Yao)
- 'perf probe' improvements (Masami Hiramatsu)
- Improve PMU infrastructure to support amp64's ThunderX2
implementation defined core events (Ganapatrao Kulkarni)
- Various annotation related improvements and fixes (Thomas Richter)
- Clarify usage of 'overwrite' and 'backward' in the evlist/mmap
code, removing the 'overwrite' parameter from several functions as
it was always used it as 'false' (Wang Nan)
- Fix/improve 'perf record' reverse recording support (Wang Nan)
- Improve command line options documentation (Sihyeon Jang)
- Optimize sample parsing for ordering events, where we don't need to
parse all the PERF_SAMPLE_ bits, just the ones leading to the
timestamp needed to reorder events (Jiri Olsa)
- Generalize the annotation code to support other source information
besides objdump/DWARF obtained ones, starting with python scripts,
that will is slated to be merged soon (Jiri Olsa)
- ... and a lot more that I failed to list, see the shortlog and
changelog for details"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (262 commits)
perf trace beauty flock: Move to separate object file
perf evlist: Remove fcntl.h from evlist.h
perf trace beauty futex: Beautify FUTEX_BITSET_MATCH_ANY
perf trace: Do not print from time delta for interrupted syscall lines
perf trace: Add --print-sample
perf bpf: Remove misplaced __maybe_unused attribute
MAINTAINERS: Adding entry for CoreSight trace decoding
perf tools: Add mechanic to synthesise CoreSight trace packets
perf tools: Add full support for CoreSight trace decoding
pert tools: Add queue management functionality
perf tools: Add functionality to communicate with the openCSD decoder
perf tools: Add support for decoding CoreSight trace data
perf tools: Add decoder mechanic to support dumping trace data
perf tools: Add processing of coresight metadata
perf tools: Add initial entry point for decoder CoreSight traces
perf tools: Integrating the CoreSight decoding library
perf vendor events intel: Update IvyTown files to V20
perf vendor events intel: Update IvyBridge files to V20
perf vendor events intel: Update BroadwellDE events to V7
perf vendor events intel: Update SkylakeX events to V1.06
...
Pull locking updates from Ingo Molnar:
"The main changes relate to making lock_is_held() et al (and external
wrappers of them) work on const data types - this requires const
propagation through the depths of lockdep.
This removes a number of ugly type hacks the external helpers used"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep: Convert some users to const
lockdep: Make lockdep checking constant
lockdep: Assign lock keys on registration
Pull EFI updates from Ingo Molnar:
"The biggest change in this cycle was the addition of ARM CPER error
decoding when printing EFI errors into the kernel log.
There are also misc smaller updates: documentation update, cleanups
and an EFI memory map permissions quirk"
* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Clarify that reset attack mitigation needs appropriate userspace
efi: Parse ARM error information value
efi: Move ARM CPER code to new file
efi: Use PTR_ERR_OR_ZERO()
arm64/efi: Ignore EFI_MEMORY_XP attribute if RP and/or WP are set
efi/capsule-loader: Fix pr_err() string to end with newline
Pull RCU updates from Ingo Molnar:
"The main RCU changes in this cycle were:
- Updates to use cond_resched() instead of cond_resched_rcu_qs()
where feasible (currently everywhere except in kernel/rcu and in
kernel/torture.c). Also a couple of fixes to avoid sending IPIs to
offline CPUs.
- Updates to simplify RCU's dyntick-idle handling.
- Updates to remove almost all uses of smp_read_barrier_depends() and
read_barrier_depends().
- Torture-test updates.
- Miscellaneous fixes"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
torture: Save a line in stutter_wait(): while -> for
torture: Eliminate torture_runnable and perf_runnable
torture: Make stutter less vulnerable to compilers and races
locking/locktorture: Fix num reader/writer corner cases
locking/locktorture: Fix rwsem reader_delay
torture: Place all torture-test modules in one MAINTAINERS group
rcutorture/kvm-build.sh: Skip build directory check
rcutorture: Simplify functions.sh include path
rcutorture: Simplify logging
rcutorture/kvm-recheck-*: Improve result directory readability check
rcutorture/kvm.sh: Support execution from any directory
rcutorture/kvm.sh: Use consistent help text for --qemu-args
rcutorture/kvm.sh: Remove unused variable, `alldone`
rcutorture: Remove unused script, config2frag.sh
rcutorture/configinit: Fix build directory error message
rcutorture: Preempt RCU-preempt readers more vigorously
torture: Reduce #ifdefs for preempt_schedule()
rcu: Remove have_rcu_nocb_mask from tree_plugin.h
rcu: Add comment giving debug strategy for double call_rcu()
tracing, rcu: Hide trace event rcu_nocb_wake when not used
...
Pull STRICT_DEVMEM default from Ingo Molnar:
"Make CONFIG_STRICT_DEVMEM default-y on x86 and arm64 as well, to
follow the distro status quo"
* 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Kconfig: Make STRICT_DEVMEM default-y on x86 and arm64
200 milliseconds is a very long time to keep the CPU busy looping.
Use msleep instead.
Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
There is no entry file_mapped in the memory.stat file. This looks like a
simple word flip that's gone unnoticed since 2010 (dc10e281f5,
memcg: update documentation).
Signed-off-by: Florian Schmidt <florian.schmidt@neclab.eu>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Some of the info, warning, and error messages are missing their trailing
newline.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Now that the DT core code handles bootmem arches, we can remove the xtensa
specific early_init_dt_alloc_memory_arch function. The common
early_init_dt_add_memory_arch can be used too now that xtensa switched to
memblock.
Cc: Chris Zankel <chris@zankel.net>
Cc: linux-xtensa@linux-xtensa.org
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the DT core code handles bootmem arches, we can remove the x86
specific early_init_dt_alloc_memory_arch function.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the DT core code handles bootmem arches, we can remove the nios2
specific early_init_dt_alloc_memory_arch function.
Cc: Ley Foon Tan <lftan@altera.com>
Cc: nios2-dev@lists.rocketboards.org
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the DT core code handles bootmem arches, we can remove the MIPS
specific early_init_dt_alloc_memory_arch function.
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the DT core code handles bootmem arches, we can remove the metag
specific early_init_dt_alloc_memory_arch function. As the default
early_init_dt_add_memory_arch just does a WARN, we can remove it too.
Cc: James Hogan <jhogan@kernel.org>
Cc: linux-metag@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Now that the DT core code handles bootmem arches, we can remove the cris
specific early_init_dt_alloc_memory_arch function. As the default
early_init_dt_add_memory_arch just does a WARN, we can just remove the
entire devicetree.c file.
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: linux-cris-kernel@axis.com
Signed-off-by: Rob Herring <robh@kernel.org>
The vfs clears the I_DIRTY inode flag before calling gfs2_write_inode()
having queued any data that needed to be written to disk.
This is a good time to remove such inodes from our ordered write list
so they don't hang around for long periods of time.
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
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Merge tag v4.15 of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
To resolve conflicts in:
drivers/infiniband/hw/mlx5/main.c
drivers/infiniband/hw/mlx5/qp.c
From patches merged into the -rc cycle. The conflict resolution matches
what linux-next has been carrying.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
The TS_COMPAT bit is very hot and is accessed from code paths that mostly
also touch thread_info::flags. Move it into struct thread_info to improve
cache locality.
The only reason it was in thread_struct is that there was a brief period
during which arch-specific fields were not allowed in struct thread_info.
Linus suggested further changing:
ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
to:
if (unlikely(ti->status & (TS_COMPAT|TS_I386_REGS_POKED)))
ti->status &= ~(TS_COMPAT|TS_I386_REGS_POKED);
on the theory that frequently dirtying the cacheline even in pure 64-bit
code that never needs to modify status hurts performance. That could be a
reasonable followup patch, but I suspect it matters less on top of this
patch.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Link: https://lkml.kernel.org/r/03148bcc1b217100e6e8ecf6a5468c45cf4304b6.1517164461.git.luto@kernel.org
With the fast path removed there is no point in splitting the push of the
normal and the extra register set. Just push the extra regs right away.
[ tglx: Split out from 'x86/entry/64: Remove the SYSCALL64 fast path' ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Link: https://lkml.kernel.org/r/462dff8d4d64dfbfc851fbf3130641809d980ecd.1517164461.git.luto@kernel.org
The SYCALLL64 fast path was a nice, if small, optimization back in the good
old days when syscalls were actually reasonably fast. Now there is PTI to
slow everything down, and indirect branches are verboten, making everything
messier. The retpoline code in the fast path is particularly nasty.
Just get rid of the fast path. The slow path is barely slower.
[ tglx: Split out the 'push all extra regs' part ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Link: https://lkml.kernel.org/r/462dff8d4d64dfbfc851fbf3130641809d980ecd.1517164461.git.luto@kernel.org
Since commit 92a0f81d89 ("x86/cpu_entry_area: Move it out of the
fixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area just
below FIXADDR_START. But already immediately before FIXADDR_START is the
FIX_BTMAP area, which means that early_ioremap can collide with the entry
area.
It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactly
match CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers the
IDT and causes interrupts during early boot to reset the system.
The overlap wasn't a problem before the CPU entry area was introduced,
as the fixmap has classically been preceded by the pkmap or vmalloc
areas, neither of which is used until early_ioremap is out of the
picture.
Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanent
fixmap area.
Fixes: commit 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
Signed-off-by: William Grant <william.grant@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com
ipmr_vif_seq_show() prints the difference between two pointers with the
format string %2zd (z for size_t), however the correct format string is
%2td instead (t for ptrdiff_t).
The same bug in ip6mr_vif_seq_show() was already fixed long ago by
commit d430a227d2 ("bogus format in ip6mr").
Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
When using mcp23s08 module with gpio-keys, often (50% of boots)
it fails to get irq numbers with message:
"gpio-keys keys: Unable to get irq number for GPIO 0, error -6".
Seems that irqs must be setup before devm_gpiochip_add_data().
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Mastykin <mastichi@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
With the following fix:
2a0098d706 ("objtool: Fix seg fault with gold linker")
... a seg fault was avoided, but the original seg fault condition in
objtool wasn't fixed. Replace the seg fault with an error message.
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/dc4585a70d6b975c99fc51d1957ccdde7bd52f3a.1517284349.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the previous patch gave objtool the ability to read retpoline
alternatives, it shows a new warning:
arch/x86/entry/entry_64.o: warning: objtool: .entry_trampoline: don't know how to handle alternatives at end of section
This is due to the JMP_NOSPEC in entry_SYSCALL_64_trampoline().
Previously, objtool ignored this situation because it wasn't needed, and
it would have required a bit of extra code. Now that this case exists,
add proper support for it.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2a30a3c2158af47d891a76e69bb1ef347e0443fd.1517284349.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently objtool requires all retpolines to be:
a) patched in with alternatives; and
b) annotated with ANNOTATE_NOSPEC_ALTERNATIVE.
If you forget to do both of the above, objtool segfaults trying to
dereference a NULL 'insn->call_dest' pointer.
Avoid that situation and print a more helpful error message:
quirks.o: warning: objtool: efi_delete_dummy_variable()+0x99: unsupported intra-function call
quirks.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE.
Future improvements can be made to make objtool smarter with respect to
retpolines, but this is a good incremental improvement for now.
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/819e50b6d9c2e1a22e34c1a636c0b2057cc8c6e5.1517284349.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'v4.15' into x86/pti, to be able to merge dependent changes
Time has come to switch PTI development over to a v4.15 base - we'll still
try to make sure that all PTI fixes backport cleanly to v4.14 and earlier.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit
equivalent. It converts 32-bit data structures into its 64-bit
equivalents and needs to provide the data to the 64-bit ioctl in user
space memory which is commonly allocated using
compat_alloc_user_space().
However, due to how that function is implemented, it can only be called
a single time for every syscall invocation.
Supposedly to avoid this limitation, the existing code uses a mix of
memory from the kernel stack and memory allocated through
compat_alloc_user_space().
Under normal circumstances, this would not work, because the 64-bit
ioctl expects all pointers to point to user space memory. As a
workaround, set_fs(KERNEL_DS) is called to temporarily disable this
extra safety check and allow kernel pointers. However, this might
introduce a security vulnerability: The result of the 32-bit to 64-bit
conversion is writeable by user space because the output buffer has been
allocated via compat_alloc_user_space(). A malicious user space process
could then manipulate pointers inside this output buffer, and due to the
previous set_fs(KERNEL_DS) call, functions like get_user() or put_user()
no longer prevent kernel memory access.
The new approach is to pre-calculate the total amount of user space
memory that is needed, allocate it using compat_alloc_user_space() and
then divide up the allocated memory to accommodate all data structures
that need to be converted.
An alternative approach would have been to retain the union type karg
that they allocated on the kernel stack in do_video_ioctl(), copy all
data from user space into karg and then back to user space. However, we
decided against this approach because it does not align with other
compat syscall implementations. Instead, we tried to replicate the
get_user/put_user pairs as found in other places in the kernel:
if (get_user(clipcount, &up->clipcount) ||
put_user(clipcount, &kp->clipcount)) return -EFAULT;
Notes from hans.verkuil@cisco.com:
This patch was taken from:
97b733953c
Clearly nobody could be bothered to upstream this patch or at minimum
tell us :-( We only heard about this a week ago.
This patch was rebased and cleaned up. Compared to the original I
also swapped the order of the convert_in_user arguments so that they
matched copy_in_user. It was hard to review otherwise. I also replaced
the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function.
Fixes: 6b5a9492ca ("v4l: introduce string control support.")
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Some ioctls need to copy back the result even if the ioctl returned
an error. However, don't do this for the error code -ENOTTY.
It makes no sense in that cases.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
There is nothing wrong with using an unknown buffer type. So
stop spamming the kernel log whenever this happens. The kernel
will just return -EINVAL to signal this.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
put_v4l2_window32() didn't copy back the clip list to userspace.
Drivers can update the clip rectangles, so this should be done.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
ctrl_is_pointer just hardcoded two known string controls, but that
caused problems when using e.g. custom controls that use a pointer
for the payload.
Reimplement this function: it now finds the v4l2_ctrl (if the driver
uses the control framework) or it calls vidioc_query_ext_ctrl (if the
driver implements that directly).
In both cases it can now check if the control is a pointer control
or not.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The struct v4l2_plane32 should set m.userptr as well. The same
happens in v4l2_buffer32 and v4l2-compliance tests for this.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: <stable@vger.kernel.org> # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
