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2019-09-21ovl: fix regression caused by overlapping layers detectionAmir Goldstein1-1/+1
commit 0be0bfd2de9dfdd2098a9c5b14bdd8f739c9165d upstream. Once upon a time, commit 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") in v4.13 added some sanity checks on overlayfs layers. This change caused a docker regression. The root cause was mount leaks by docker, which as far as I know, still exist. To mitigate the regression, commit 85fdee1eef1a ("ovl: fix regression caused by exclusive upper/work dir protection") in v4.14 turned the mount errors into warnings for the default index=off configuration. Recently, commit 146d62e5a586 ("ovl: detect overlapping layers") in v5.2, re-introduced exclusive upper/work dir checks regardless of index=off configuration. This changes the status quo and mount leak related bug reports have started to re-surface. Restore the status quo to fix the regressions. To clarify, index=off does NOT relax overlapping layers check for this ovelayfs mount. index=off only relaxes exclusive upper/work dir checks with another overlayfs mount. To cover the part of overlapping layers detection that used the exclusive upper/work dir checks to detect overlap with self upper/work dir, add a trap also on the work base dir. Link: https://github.com/moby/moby/issues/34672 Link: https://lore.kernel.org/linux-fsdevel/20171006121405.GA32700@veci.piliscsaba.szeredi.hu/ Link: https://github.com/containers/libpod/issues/3540 Fixes: 146d62e5a586 ("ovl: detect overlapping layers") Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Tested-by: Colin Walters <walters@verbum.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-16drm/panel: Add support for Armadeus ST0700 AdaptSébastien Szymanski1-0/+9
[ Upstream commit c479450f61c7f1f248c9a54aedacd2a6ca521ff8 ] This patch adds support for the Armadeus ST0700 Adapt. It comes with a Santek ST0700I5Y-RBSLW 7.0" WVGA (800x480) TFT and an adapter board so that it can be connected on the TFT header of Armadeus Dev boards. Cc: stable@vger.kernel.org # v4.19 Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190507152713.27494-1-sebastien.szymanski@armadeus.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16dt-bindings: mmc: Add disable-cqe-dcmd property.Christoph Muellner1-0/+2
[ Upstream commit 28f22fb755ecf9f933f045bc0afdb8140641b01c ] Add disable-cqe-dcmd as optional property for MMC hosts. This property allows to disable or not enable the direct command features of the command queue engine. Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com> Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Fixes: 84362d79f436 ("mmc: sdhci-of-arasan: Add CQHCI support for arasan,sdhci-5.1") Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16dt-bindings: mmc: Add supports-cqe propertySowjanya Komatineni1-0/+2
[ Upstream commit c7fddbd5db5cffd10ed4d18efa20e36803d1899f ] Add supports-cqe optional property for MMC hosts. This property is used to identify the specific host controller supporting command queue. Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com> Reviewed-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16iio: adc: exynos-adc: Use proper number of channels for Exynos4x12Krzysztof Kozlowski1-1/+3
[ Upstream commit 103cda6a3b8d2c10d5f8cd7abad118e9db8f4776 ] Exynos4212 and Exynos4412 have only four ADC channels so using "samsung,exynos-adc-v1" compatible (for eight channels ADCv1) on them is wrong. Add a new compatible for Exynos4x12. Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16dt-bindings: iio: adc: exynos-adc: Add S5PV210 variantJonathan Bakker1-1/+3
[ Upstream commit a9b0a2a7c19316588421b94946c8e2e5a84ac14e ] Add information about new compatible for S5PV210 Signed-off-by: Jonathan Bakker <xc-racer2@live.ca> Signed-off-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-29x86/CPU/AMD: Clear RDRAND CPUID bit on AMD family 15h/16hTom Lendacky1-0/+7
commit c49a0a80137c7ca7d6ced4c812c9e07a949f6f24 upstream. There have been reports of RDRAND issues after resuming from suspend on some AMD family 15h and family 16h systems. This issue stems from a BIOS not performing the proper steps during resume to ensure RDRAND continues to function properly. RDRAND support is indicated by CPUID Fn00000001_ECX[30]. This bit can be reset by clearing MSR C001_1004[62]. Any software that checks for RDRAND support using CPUID, including the kernel, will believe that RDRAND is not supported. Update the CPU initialization to clear the RDRAND CPUID bit for any family 15h and 16h processor that supports RDRAND. If it is known that the family 15h or family 16h system does not have an RDRAND resume issue or that the system will not be placed in suspend, the "rdrand=force" kernel parameter can be used to stop the clearing of the RDRAND CPUID bit. Additionally, update the suspend and resume path to save and restore the MSR C001_1004 value to ensure that the RDRAND CPUID setting remains in place after resuming from suspend. Note, that clearing the RDRAND CPUID bit does not prevent a processor that normally supports the RDRAND instruction from executing it. So any code that determined the support based on family and model won't #UD. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chen Yu <yu.c.chen@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org> Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "x86@kernel.org" <x86@kernel.org> Link: https://lkml.kernel.org/r/7543af91666f491547bd86cebb1e17c66824ab9f.1566229943.git.thomas.lendacky@amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-06Documentation: Add swapgs description to the Spectre v1 documentationJosh Poimboeuf1-8/+80
commit 4c92057661a3412f547ede95715641d7ee16ddac upstream Add documentation to the Spectre document about the new swapgs variant of Spectre v1. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-06x86/speculation: Enable Spectre v1 swapgs mitigationsJosh Poimboeuf1-3/+4
commit a2059825986a1c8143fd6698774fa9d83733bb11 upstream The previous commit added macro calls in the entry code which mitigate the Spectre v1 swapgs issue if the X86_FEATURE_FENCE_SWAPGS_* features are enabled. Enable those features where applicable. The mitigations may be disabled with "nospectre_v1" or "mitigations=off". There are different features which can affect the risk of attack: - When FSGSBASE is enabled, unprivileged users are able to place any value in GS, using the wrgsbase instruction. This means they can write a GS value which points to any value in kernel space, which can be useful with the following gadget in an interrupt/exception/NMI handler: if (coming from user space) swapgs mov %gs:<percpu_offset>, %reg1 // dependent load or store based on the value of %reg // for example: mov %(reg1), %reg2 If an interrupt is coming from user space, and the entry code speculatively skips the swapgs (due to user branch mistraining), it may speculatively execute the GS-based load and a subsequent dependent load or store, exposing the kernel data to an L1 side channel leak. Note that, on Intel, a similar attack exists in the above gadget when coming from kernel space, if the swapgs gets speculatively executed to switch back to the user GS. On AMD, this variant isn't possible because swapgs is serializing with respect to future GS-based accesses. NOTE: The FSGSBASE patch set hasn't been merged yet, so the above case doesn't exist quite yet. - When FSGSBASE is disabled, the issue is mitigated somewhat because unprivileged users must use prctl(ARCH_SET_GS) to set GS, which restricts GS values to user space addresses only. That means the gadget would need an additional step, since the target kernel address needs to be read from user space first. Something like: if (coming from user space) swapgs mov %gs:<percpu_offset>, %reg1 mov (%reg1), %reg2 // dependent load or store based on the value of %reg2 // for example: mov %(reg2), %reg3 It's difficult to audit for this gadget in all the handlers, so while there are no known instances of it, it's entirely possible that it exists somewhere (or could be introduced in the future). Without tooling to analyze all such code paths, consider it vulnerable. Effects of SMAP on the !FSGSBASE case: - If SMAP is enabled, and the CPU reports RDCL_NO (i.e., not susceptible to Meltdown), the kernel is prevented from speculatively reading user space memory, even L1 cached values. This effectively disables the !FSGSBASE attack vector. - If SMAP is enabled, but the CPU *is* susceptible to Meltdown, SMAP still prevents the kernel from speculatively reading user space memory. But it does *not* prevent the kernel from reading the user value from L1, if it has already been cached. This is probably only a small hurdle for an attacker to overcome. Thanks to Dave Hansen for contributing the speculative_smap() function. Thanks to Andrew Cooper for providing the inside scoop on whether swapgs is serializing on AMD. [ tglx: Fixed the USER fence decision and polished the comment as suggested by Dave Hansen ] Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-26dt-bindings: allow up to four clocks for orion-mdioJosua Mayer1-1/+1
commit 80785f5a22e9073e2ded5958feb7f220e066d17b upstream. Armada 8040 needs four clocks to be enabled for MDIO accesses to work. Update the binding to allow the extra clock to be specified. Cc: stable@vger.kernel.org Fixes: 6d6a331f44a1 ("dt-bindings: allow up to three clocks for orion-mdio") Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Josua Mayer <josua@solid-run.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-26x86/atomic: Fix smp_mb__{before,after}_atomic()Peter Zijlstra1-0/+3
[ Upstream commit 69d927bba39517d0980462efc051875b7f4db185 ] Recent probing at the Linux Kernel Memory Model uncovered a 'surprise'. Strongly ordered architectures where the atomic RmW primitive implies full memory ordering and smp_mb__{before,after}_atomic() are a simple barrier() (such as x86) fail for: *x = 1; atomic_inc(u); smp_mb__after_atomic(); r0 = *y; Because, while the atomic_inc() implies memory order, it (surprisingly) does not provide a compiler barrier. This then allows the compiler to re-order like so: atomic_inc(u); *x = 1; smp_mb__after_atomic(); r0 = *y; Which the CPU is then allowed to re-order (under TSO rules) like: atomic_inc(u); r0 = *y; *x = 1; And this very much was not intended. Therefore strengthen the atomic RmW ops to include a compiler barrier. NOTE: atomic_{or,and,xor} and the bitops already had the compiler barrier. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-26sched/fair: Fix "runnable_avg_yN_inv" not used warningsQian Cai1-1/+2
[ Upstream commit 509466b7d480bc5d22e90b9fbe6122ae0e2fbe39 ] runnable_avg_yN_inv[] is only used in kernel/sched/pelt.c but was included in several other places because they need other macros all came from kernel/sched/sched-pelt.h which was generated by Documentation/scheduler/sched-pelt. As the result, it causes compilation a lot of warnings, kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] kernel/sched/sched-pelt.h:4:18: warning: 'runnable_avg_yN_inv' defined but not used [-Wunused-const-variable=] ... Silence it by appending the __maybe_unused attribute for it, so all generated variables and macros can still be kept in the same file. Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1559596304-31581-1-git-send-email-cai@lca.pw Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-14Documentation/admin: Remove the vsyscall=native documentationAndy Lutomirski1-6/+0
commit d974ffcfb7447db5f29a4b662a3eaf99a4e1109e upstream. The vsyscall=native feature is gone -- remove the docs. Fixes: 076ca272a14c ("x86/vsyscall/64: Drop "native" vsyscalls") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Cc: Florian Weimer <fweimer@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: stable@vger.kernel.org Cc: Borislav Petkov <bp@alien8.de> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/d77c7105eb4c57c1a95a95b6a5b8ba194a18e764.1561610354.git.luto@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-14Documentation: Add section about CPU vulnerabilities for SpectreTim Chen3-0/+700
commit 6e88559470f581741bcd0f2794f9054814ac9740 upstream. Add documentation for Spectre vulnerability and the mitigation mechanisms: - Explain the problem and risks - Document the mitigation mechanisms - Document the command line controls - Document the sysfs files Co-developed-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Co-developed-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-14qmi_wwan: extend permitted QMAP mux_id value rangeReinhard Speyerer1-2/+2
[ Upstream commit 36815b416fa48766ac5a98e4b2dc3ebc5887222e ] Permit mux_id values up to 254 to be used in qmimux_register_device() for compatibility with ip(8) and the rmnet driver. Fixes: c6adf77953bc ("net: usb: qmi_wwan: add qmap mux protocol support") Cc: Daniele Palmas <dnlplm@gmail.com> Signed-off-by: Reinhard Speyerer <rspmn@arcor.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-14dt-bindings: can: mcp251x: add mcp25625 supportSean Nyekjaer1-0/+1
[ Upstream commit 0df82dcd55832a99363ab7f9fab954fcacdac3ae ] Fully compatible with mcp2515, the mcp25625 have integrated transceiver. This patch add the mcp25625 to the device tree bindings documentation. Signed-off-by: Sean Nyekjaer <sean@geanix.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-03futex: Update comments and docs about return values of arch futex codeWill Deacon1-2/+1
commit 427503519739e779c0db8afe876c1b33f3ac60ae upstream. The architecture implementations of 'arch_futex_atomic_op_inuser()' and 'futex_atomic_cmpxchg_inatomic()' are permitted to return only -EFAULT, -EAGAIN or -ENOSYS in the case of failure. Update the comments in the asm-generic/ implementation and also a stray reference in the robust futex documentation. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-17tcp: add tcp_min_snd_mss sysctlEric Dumazet1-0/+8
commit 5f3e2bf008c2221478101ee72f5cb4654b9fc363 upstream. Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Jonathan Looney <jtl@netflix.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Bruce Curtis <brucec@netflix.com> Cc: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-09doc: Cope with Sphinx logging deprecationsJonathan Corbet3-21/+59
commit 096ea522e84ea68f8e6c41e5e7294731a81e29bc upstream. Recent versions of sphinx will emit messages like: Documentation/sphinx/kerneldoc.py:103: RemovedInSphinx20Warning: app.warning() is now deprecated. Use sphinx.util.logging instead. Switch to sphinx.util.logging to make this unsightly message go away. Alas, that interface was only added in version 1.6, so we have to add a version check to keep things working with older sphinxes. Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-09doc: Cope with the deprecation of AutoReporterJonathan Corbet1-8/+26
commit 2404dad1f67f8917e30fc22a85e0dbcc85b99955 upstream. AutoReporter is going away; recent versions of sphinx emit a warning like: Documentation/sphinx/kerneldoc.py:125: RemovedInSphinx20Warning: AutodocReporter is now deprecated. Use sphinx.util.docutils.switch_source_input() instead. Make the switch. But switch_source_input() only showed up in 1.7, so we have to do ugly version checks to keep things working in older versions. Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-09docs: Fix conf.py for Sphinx 2.0Jonathan Corbet1-1/+1
commit 3bc8088464712fdcb078eefb68837ccfcc413c88 upstream. Our version check in Documentation/conf.py never envisioned a world where Sphinx moved beyond 1.x. Now that the unthinkable has happened, fix our version check to handle higher version numbers correctly. Cc: stable@vger.kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-31arm64: errata: Add workaround for Cortex-A76 erratum #1463225Will Deacon1-0/+1
commit 969f5ea627570e91c9d54403287ee3ed657f58fe upstream. Revisions of the Cortex-A76 CPU prior to r4p0 are affected by an erratum that can prevent interrupts from being taken when single-stepping. This patch implements a software workaround to prevent userspace from effectively being able to disable interrupts. Cc: <stable@vger.kernel.org> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-31bpf: add bpf_jit_limit knob to restrict unpriv allocationsDaniel Borkmann1-0/+8
commit ede95a63b5e84ddeea6b0c473b36ab8bfd8c6ce3 upstream. Rick reported that the BPF JIT could potentially fill the entire module space with BPF programs from unprivileged users which would prevent later attempts to load normal kernel modules or privileged BPF programs, for example. If JIT was enabled but unsuccessful to generate the image, then before commit 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config") we would always fall back to the BPF interpreter. Nowadays in the case where the CONFIG_BPF_JIT_ALWAYS_ON could be set, then the load will abort with a failure since the BPF interpreter was compiled out. Add a global limit and enforce it for unprivileged users such that in case of BPF interpreter compiled out we fail once the limit has been reached or we fall back to BPF interpreter earlier w/o using module mem if latter was compiled in. In a next step, fair share among unprivileged users can be resolved in particular for the case where we would fail hard once limit is reached. Fixes: 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config") Fixes: 0a14842f5a3c ("net: filter: Just In Time compiler for x86-64") Co-Developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: LKML <linux-kernel@vger.kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-25dcache: sort the freeing-without-RCU-delay mess for good.Al Viro1-0/+5
commit 5467a68cbf6884c9a9d91e2a89140afb1839c835 upstream. For lockless accesses to dentries we don't have pinned we rely (among other things) upon having an RCU delay between dropping the last reference and actually freeing the memory. On the other hand, for things like pipes and sockets we neither do that kind of lockless access, nor want to deal with the overhead of an RCU delay every time a socket gets closed. So delay was made optional - setting DCACHE_RCUACCESS in ->d_flags made sure it would happen. We tried to avoid setting it unless we knew we need it. Unfortunately, that had led to recurring class of bugs, in which we missed the need to set it. We only really need it for dentries that are created by d_alloc_pseudo(), so let's not bother with trying to be smart - just make having an RCU delay the default. The ones that do *not* get it set the replacement flag (DCACHE_NORCU) and we'd better use that sparingly. d_alloc_pseudo() is the only such user right now. FWIW, the race that finally prompted that switch had been between __lock_parent() of immediate subdirectory of what's currently the root of a disconnected tree (e.g. from open-by-handle in progress) racing with d_splice_alias() elsewhere picking another alias for the same inode, either on outright corrupted fs image, or (in case of open-by-handle on NFS) that subdirectory having been just moved on server. It's not easy to hit, so the sky is not falling, but that's not the first race on similar missed cases and the logics for settinf DCACHE_RCUACCESS has gotten ridiculously convoluted. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22x86/speculation/mds: Improve CPU buffer clear documentationAndy Lutomirski1-32/+7
commit 9d8d0294e78a164d407133dea05caf4b84247d6a upstream. On x86_64, all returns to usermode go through prepare_exit_to_usermode(), with the sole exception of do_nmi(). This even includes machine checks -- this was added several years ago to support MCE recovery. Update the documentation. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jon Masters <jcm@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user") Link: http://lkml.kernel.org/r/999fa9e126ba6a48e9d214d2f18dbde5c62ac55c.1557865329.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22x86/speculation/mds: Revert CPU buffer clear on double fault exitAndy Lutomirski1-7/+0
commit 88640e1dcd089879530a49a8d212d1814678dfe7 upstream. The double fault ESPFIX path doesn't return to user mode at all -- it returns back to the kernel by simulating a #GP fault. prepare_exit_to_usermode() will run on the way out of general_protection before running user code. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jon Masters <jcm@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 04dcbdb80578 ("x86/speculation/mds: Clear CPU buffers on exit to user") Link: http://lkml.kernel.org/r/ac97612445c0a44ee10374f6ea79c222fe22a5c4.1557865329.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Fix documentation typoJosh Poimboeuf1-1/+1
commit 95310e348a321b45fb746c176961d4da72344282 upstream Fix a minor typo in the MDS documentation: "eanbled" -> "enabled". Reported-by: Jeff Bastian <jbastian@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14Documentation: Correct the possible MDS sysfs valuesTyler Hicks1-16/+13
commit ea01668f9f43021b28b3f4d5ffad50106a1e1301 upstream Adjust the last two rows in the table that display possible values when MDS mitigation is enabled. They both were slightly innacurate. In addition, convert the table of possible values and their descriptions to a list-table. The simple table format uses the top border of equals signs to determine cell width which resulted in the first column being far too wide in comparison to the second column that contained the majority of the text. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/mds: Add MDSUM variant to the MDS documentationspeck for Pawan Gupta2-2/+8
commit e672f8bf71c66253197e503f75c771dd28ada4a0 upstream Updated the documentation for a new CVE-2019-11091 Microarchitectural Data Sampling Uncacheable Memory (MDSUM) which is a variant of Microarchitectural Data Sampling (MDS). MDS is a family of side channel attacks on internal buffers in Intel CPUs. MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from memory that takes a fault or assist can leave data in a microarchitectural structure that may later be observed using one of the same methods used by MSBDS, MFBDS or MLPDS. There are no new code changes expected for MDSUM. The existing mitigation for MDS applies to MDSUM as well. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Reviewed-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add 'mitigations=' support for MDSJosh Poimboeuf1-0/+2
commit 5c14068f87d04adc73ba3f41c2a303d3c3d1fa12 upstream Add MDS to the new 'mitigations=' cmdline option. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14s390/speculation: Support 'mitigations=' cmdline optionJosh Poimboeuf1-2/+3
commit 0336e04a6520bdaefdb0769d2a70084fa52e81ed upstream Configure s390 runtime CPU speculation bug mitigations in accordance with the 'mitigations=' cmdline option. This affects Spectre v1 and Spectre v2. The default behavior is unchanged. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Price <steven.price@arm.com> Cc: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/e4a161805458a5ec88812aac0307ae3908a030fc.1555085500.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14powerpc/speculation: Support 'mitigations=' cmdline optionJosh Poimboeuf1-4/+5
commit 782e69efb3dfed6e8360bc612e8c7827a901a8f9 upstream Configure powerpc CPU runtime speculation bug mitigations in accordance with the 'mitigations=' cmdline option. This affects Meltdown, Spectre v1, Spectre v2, and Speculative Store Bypass. The default behavior is unchanged. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Price <steven.price@arm.com> Cc: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/245a606e1a42a558a310220312d9b6adb9159df6.1555085500.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation: Support 'mitigations=' cmdline optionJosh Poimboeuf1-5/+11
commit d68be4c4d31295ff6ae34a8ddfaa4c1a8ff42812 upstream Configure x86 runtime CPU speculation bug mitigations in accordance with the 'mitigations=' cmdline option. This affects Meltdown, Spectre v2, Speculative Store Bypass, and L1TF. The default behavior is unchanged. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Price <steven.price@arm.com> Cc: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/6616d0ae169308516cfdf5216bedd169f8a8291b.1555085500.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14cpu/speculation: Add 'mitigations=' cmdline optionJosh Poimboeuf1-0/+24
commit 98af8452945c55652de68536afdde3b520fec429 upstream Keeping track of the number of mitigations for all the CPU speculation bugs has become overwhelming for many users. It's getting more and more complicated to decide which mitigations are needed for a given architecture. Complicating matters is the fact that each arch tends to have its own custom way to mitigate the same vulnerability. Most users fall into a few basic categories: a) they want all mitigations off; b) they want all reasonable mitigations on, with SMT enabled even if it's vulnerable; or c) they want all reasonable mitigations on, with SMT disabled if vulnerable. Define a set of curated, arch-independent options, each of which is an aggregation of existing options: - mitigations=off: Disable all mitigations. - mitigations=auto: [default] Enable all the default mitigations, but leave SMT enabled, even if it's vulnerable. - mitigations=auto,nosmt: Enable all the default mitigations, disabling SMT if needed by a mitigation. Currently, these options are placeholders which don't actually do anything. They will be fleshed out in upcoming patches. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jiri Kosina <jkosina@suse.cz> (on x86) Reviewed-by: Jiri Kosina <jkosina@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Steven Price <steven.price@arm.com> Cc: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/b07a8ef9b7c5055c3a4637c87d07c296d5016fe0.1555085500.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add mds=full,nosmt cmdline optionJosh Poimboeuf2-2/+7
commit d71eb0ce109a124b0fa714832823b9452f2762cf upstream Add the mds=full,nosmt cmdline option. This is like mds=full, but with SMT disabled if the CPU is vulnerable. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14Documentation: Add MDS vulnerability documentationThomas Gleixner5-2/+312
commit 5999bbe7a6ea3c62029532ec84dc06003a1fa258 upstream Add the initial MDS vulnerability documentation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14Documentation: Move L1TF to separate directoryThomas Gleixner5-6/+16
commit 65fd4cb65b2dad97feb8330b6690445910b56d6a upstream Move L!TF to a separate directory so the MDS stuff can be added at the side. Otherwise the all hardware vulnerabilites have their own top level entry. Should have done that right away. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add mitigation mode VMWERVThomas Gleixner1-0/+27
commit 22dd8365088b6403630b82423cf906491859b65e upstream In virtualized environments it can happen that the host has the microcode update which utilizes the VERW instruction to clear CPU buffers, but the hypervisor is not yet updated to expose the X86_FEATURE_MD_CLEAR CPUID bit to guests. Introduce an internal mitigation mode VMWERV which enables the invocation of the CPU buffer clearing even if X86_FEATURE_MD_CLEAR is not set. If the system has no updated microcode this results in a pointless execution of the VERW instruction wasting a few CPU cycles. If the microcode is updated, but not exposed to a guest then the CPU buffers will be cleared. That said: Virtual Machines Will Eventually Receive Vaccine Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add sysfs reporting for MDSThomas Gleixner1-0/+1
commit 8a4b06d391b0a42a373808979b5028f5c84d9c6a upstream Add the sysfs reporting file for MDS. It exposes the vulnerability and mitigation state similar to the existing files for the other speculative hardware vulnerabilities. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add mitigation control for MDSThomas Gleixner1-0/+22
commit bc1241700acd82ec69fde98c5763ce51086269f8 upstream Now that the mitigations are in place, add a command line parameter to control the mitigation, a mitigation selector function and a SMT update mechanism. This is the minimal straight forward initial implementation which just provides an always on/off mode. The command line parameter is: mds=[full|off] This is consistent with the existing mitigations for other speculative hardware vulnerabilities. The idle invocation is dynamically updated according to the SMT state of the system similar to the dynamic update of the STIBP mitigation. The idle mitigation is limited to CPUs which are only affected by MSBDS and not any other variant, because the other variants cannot be mitigated on SMT enabled systems. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Conditionally clear CPU buffers on idle entryThomas Gleixner1-0/+42
commit 07f07f55a29cb705e221eda7894dd67ab81ef343 upstream Add a static key which controls the invocation of the CPU buffer clear mechanism on idle entry. This is independent of other MDS mitigations because the idle entry invocation to mitigate the potential leakage due to store buffer repartitioning is only necessary on SMT systems. Add the actual invocations to the different halt/mwait variants which covers all usage sites. mwaitx is not patched as it's not available on Intel CPUs. The buffer clear is only invoked before entering the C-State to prevent that stale data from the idling CPU is spilled to the Hyper-Thread sibling after the Store buffer got repartitioned and all entries are available to the non idle sibling. When coming out of idle the store buffer is partitioned again so each sibling has half of it available. Now CPU which returned from idle could be speculatively exposed to contents of the sibling, but the buffers are flushed either on exit to user space or on VMENTER. When later on conditional buffer clearing is implemented on top of this, then there is no action required either because before returning to user space the context switch will set the condition flag which causes a flush on the return to user path. Note, that the buffer clearing on idle is only sensible on CPUs which are solely affected by MSBDS and not any other variant of MDS because the other MDS variants cannot be mitigated when SMT is enabled, so the buffer clearing on idle would be a window dressing exercise. This intentionally does not handle the case in the acpi/processor_idle driver which uses the legacy IO port interface for C-State transitions for two reasons: - The acpi/processor_idle driver was replaced by the intel_idle driver almost a decade ago. Anything Nehalem upwards supports it and defaults to that new driver. - The legacy IO port interface is likely to be used on older and therefore unaffected CPUs or on systems which do not receive microcode updates anymore, so there is no point in adding that. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Clear CPU buffers on exit to userThomas Gleixner1-0/+52
commit 04dcbdb8057827b043b3c71aa397c4c63e67d086 upstream Add a static key which controls the invocation of the CPU buffer clear mechanism on exit to user space and add the call into prepare_exit_to_usermode() and do_nmi() right before actually returning. Add documentation which kernel to user space transition this covers and explain why some corner cases are not mitigated. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14x86/speculation/mds: Add mds_clear_cpu_buffers()Thomas Gleixner4-0/+118
commit 6a9e529272517755904b7afa639f6db59ddb793e upstream The Microarchitectural Data Sampling (MDS) vulernabilities are mitigated by clearing the affected CPU buffers. The mechanism for clearing the buffers uses the unused and obsolete VERW instruction in combination with a microcode update which triggers a CPU buffer clear when VERW is executed. Provide a inline function with the assembly magic. The argument of the VERW instruction must be a memory operand as documented: "MD_CLEAR enumerates that the memory-operand variant of VERW (for example, VERW m16) has been extended to also overwrite buffers affected by MDS. This buffer overwriting functionality is not guaranteed for the register operand variant of VERW." Documentation also recommends to use a writable data segment selector: "The buffer overwriting occurs regardless of the result of the VERW permission check, as well as when the selector is null or causes a descriptor load segment violation. However, for lowest latency we recommend using a selector that indicates a valid writable data segment." Add x86 specific documentation about MDS and the internal workings of the mitigation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Jon Masters <jcm@redhat.com> Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14Documentation/l1tf: Fix small spelling typoSalvatore Bonaccorso1-1/+1
commit 60ca05c3b44566b70d64fbb8e87a6e0c67725468 upstream Fix small typo (wiil -> will) in the "3.4. Nested virtual machines" section. Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry") Cc: linux-kernel@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-doc@vger.kernel.org Cc: trivial@kernel.org Signed-off-by: Salvatore Bonaccorso <carnil@debian.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-08USB: core: Fix bug caused by duplicate interface PM usage counterAlan Stern1-5/+9
commit c2b71462d294cf517a0bc6e4fd6424d7cee5596f upstream. The syzkaller fuzzer reported a bug in the USB hub driver which turned out to be caused by a negative runtime-PM usage counter. This allowed a hub to be runtime suspended at a time when the driver did not expect it. The symptom is a WARNING issued because the hub's status URB is submitted while it is already active: URB 0000000031fb463e submitted while active WARNING: CPU: 0 PID: 2917 at drivers/usb/core/urb.c:363 The negative runtime-PM usage count was caused by an unfortunate design decision made when runtime PM was first implemented for USB. At that time, USB class drivers were allowed to unbind from their interfaces without balancing the usage counter (i.e., leaving it with a positive count). The core code would take care of setting the counter back to 0 before allowing another driver to bind to the interface. Later on when runtime PM was implemented for the entire kernel, the opposite decision was made: Drivers were required to balance their runtime-PM get and put calls. In order to maintain backward compatibility, however, the USB subsystem adapted to the new implementation by keeping an independent usage counter for each interface and using it to automatically adjust the normal usage counter back to 0 whenever a driver was unbound. This approach involves duplicating information, but what is worse, it doesn't work properly in cases where a USB class driver delays decrementing the usage counter until after the driver's disconnect() routine has returned and the counter has been adjusted back to 0. Doing so would cause the usage counter to become negative. There's even a warning about this in the USB power management documentation! As it happens, this is exactly what the hub driver does. The kick_hub_wq() routine increments the runtime-PM usage counter, and the corresponding decrement is carried out by hub_event() in the context of the hub_wq work-queue thread. This work routine may sometimes run after the driver has been unbound from its interface, and when it does it causes the usage counter to go negative. It is not possible for hub_disconnect() to wait for a pending hub_event() call to finish, because hub_disconnect() is called with the device lock held and hub_event() acquires that lock. The only feasible fix is to reverse the original design decision: remove the duplicate interface-specific usage counter and require USB drivers to balance their runtime PM gets and puts. As far as I know, all existing drivers currently do this. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-tested-by: syzbot+7634edaea4d0b341c625@syzkaller.appspotmail.com CC: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-04i2c: i801: Add support for Intel Comet LakeJarkko Nikula1-0/+1
[ Upstream commit 5cd1c56c42beb6d228cc8d4373fdc5f5ec78a5ad ] Add PCI ID for Intel Comet Lake PCH. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Reviewed-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
2019-05-02powerpc/fsl: Add FSL_PPC_BOOK3E as supported arch for nospectre_v2 boot argDiana Craciun1-1/+1
commit e59f5bd759b7dee57593c5b6c0441609bda5d530 upstream. Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-02ipv4: set the tcp_min_rtt_wlen range from 0 to one dayZhangXiaoxu1-0/+1
[ Upstream commit 19fad20d15a6494f47f85d869f00b11343ee5c78 ] There is a UBSAN report as below: UBSAN: Undefined behaviour in net/ipv4/tcp_input.c:2877:56 signed integer overflow: 2147483647 * 1000 cannot be represented in type 'int' CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.1.0-rc4-00058-g582549e #1 Call Trace: <IRQ> dump_stack+0x8c/0xba ubsan_epilogue+0x11/0x60 handle_overflow+0x12d/0x170 ? ttwu_do_wakeup+0x21/0x320 __ubsan_handle_mul_overflow+0x12/0x20 tcp_ack_update_rtt+0x76c/0x780 tcp_clean_rtx_queue+0x499/0x14d0 tcp_ack+0x69e/0x1240 ? __wake_up_sync_key+0x2c/0x50 ? update_group_capacity+0x50/0x680 tcp_rcv_established+0x4e2/0xe10 tcp_v4_do_rcv+0x22b/0x420 tcp_v4_rcv+0xfe8/0x1190 ip_protocol_deliver_rcu+0x36/0x180 ip_local_deliver+0x15b/0x1a0 ip_rcv+0xac/0xd0 __netif_receive_skb_one_core+0x7f/0xb0 __netif_receive_skb+0x33/0xc0 netif_receive_skb_internal+0x84/0x1c0 napi_gro_receive+0x2a0/0x300 receive_buf+0x3d4/0x2350 ? detach_buf_split+0x159/0x390 virtnet_poll+0x198/0x840 ? reweight_entity+0x243/0x4b0 net_rx_action+0x25c/0x770 __do_softirq+0x19b/0x66d irq_exit+0x1eb/0x230 do_IRQ+0x7a/0x150 common_interrupt+0xf/0xf </IRQ> It can be reproduced by: echo 2147483647 > /proc/sys/net/ipv4/tcp_min_rtt_wlen Fixes: f672258391b42 ("tcp: track min RTT using windowed min-filter") Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-05ARM: 8833/1: Ensure that NEON code always compiles with ClangNathan Chancellor1-2/+2
[ Upstream commit de9c0d49d85dc563549972edc5589d195cd5e859 ] While building arm32 allyesconfig, I ran into the following errors: arch/arm/lib/xor-neon.c:17:2: error: You should compile this file with '-mfloat-abi=softfp -mfpu=neon' In file included from lib/raid6/neon1.c:27: /home/nathan/cbl/prebuilt/lib/clang/8.0.0/include/arm_neon.h:28:2: error: "NEON support not enabled" Building V=1 showed NEON_FLAGS getting passed along to Clang but __ARM_NEON__ was not getting defined. Ultimately, it boils down to Clang only defining __ARM_NEON__ when targeting armv7, rather than armv6k, which is the '-march' value for allyesconfig. >From lib/Basic/Targets/ARM.cpp in the Clang source: // This only gets set when Neon instructions are actually available, unlike // the VFP define, hence the soft float and arch check. This is subtly // different from gcc, we follow the intent which was that it should be set // when Neon instructions are actually available. if ((FPU & NeonFPU) && !SoftFloat && ArchVersion >= 7) { Builder.defineMacro("__ARM_NEON", "1"); Builder.defineMacro("__ARM_NEON__"); // current AArch32 NEON implementations do not support double-precision // floating-point even when it is present in VFP. Builder.defineMacro("__ARM_NEON_FP", "0x" + Twine::utohexstr(HW_FP & ~HW_FP_DP)); } Ard Biesheuvel recommended explicitly adding '-march=armv7-a' at the beginning of the NEON_FLAGS definitions so that __ARM_NEON__ always gets definined by Clang. This doesn't functionally change anything because that code will only run where NEON is supported, which is implicitly armv7. Link: https://github.com/ClangBuiltLinux/linux/issues/287 Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Nicolas Pitre <nico@linaro.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-04-03KVM: Reject device ioctls from processes other than the VM's creatorSean Christopherson1-5/+11
commit ddba91801aeb5c160b660caed1800eb3aef403f8 upstream. KVM's API requires thats ioctls must be issued from the same process that created the VM. In other words, userspace can play games with a VM's file descriptors, e.g. fork(), SCM_RIGHTS, etc..., but only the creator can do anything useful. Explicitly reject device ioctls that are issued by a process other than the VM's creator, and update KVM's API documentation to extend its requirements to device ioctls. Fixes: 852b6d57dc7f ("kvm: add device control API") Cc: <stable@vger.kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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