From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Jiri Kosina <jkosina@suse.cz>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Borislav Petkov <bp@suse.de>, David Woodhouse <dwmw@amazon.co.uk>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 4.14 023/104] x86/speculation: Protect against userspace-userspace spectreRSB
Date: Tue, 14 Aug 2018 19:16:37 +0200 [thread overview]
Message-ID: <20180814171516.722295468@linuxfoundation.org> (raw)
In-Reply-To: <20180814171515.270692185@linuxfoundation.org>
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Kosina <jkosina@suse.cz>
commit fdf82a7856b32d905c39afc85e34364491e46346 upstream.
The article "Spectre Returns! Speculation Attacks using the Return Stack
Buffer" [1] describes two new (sub-)variants of spectrev2-like attacks,
making use solely of the RSB contents even on CPUs that don't fallback to
BTB on RSB underflow (Skylake+).
Mitigate userspace-userspace attacks by always unconditionally filling RSB on
context switch when the generic spectrev2 mitigation has been enabled.
[1] https://arxiv.org/pdf/1807.07940.pdf
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/nycvar.YFH.7.76.1807261308190.997@cbobk.fhfr.pm
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 38 +++++++-------------------------------
1 file changed, 7 insertions(+), 31 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -311,23 +311,6 @@ static enum spectre_v2_mitigation_cmd __
return cmd;
}
-/* Check for Skylake-like CPUs (for RSB handling) */
-static bool __init is_skylake_era(void)
-{
- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
- boot_cpu_data.x86 == 6) {
- switch (boot_cpu_data.x86_model) {
- case INTEL_FAM6_SKYLAKE_MOBILE:
- case INTEL_FAM6_SKYLAKE_DESKTOP:
- case INTEL_FAM6_SKYLAKE_X:
- case INTEL_FAM6_KABYLAKE_MOBILE:
- case INTEL_FAM6_KABYLAKE_DESKTOP:
- return true;
- }
- }
- return false;
-}
-
static void __init spectre_v2_select_mitigation(void)
{
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
@@ -388,22 +371,15 @@ retpoline_auto:
pr_info("%s\n", spectre_v2_strings[mode]);
/*
- * If neither SMEP nor PTI are available, there is a risk of
- * hitting userspace addresses in the RSB after a context switch
- * from a shallow call stack to a deeper one. To prevent this fill
- * the entire RSB, even when using IBRS.
+ * If spectre v2 protection has been enabled, unconditionally fill
+ * RSB during a context switch; this protects against two independent
+ * issues:
*
- * Skylake era CPUs have a separate issue with *underflow* of the
- * RSB, when they will predict 'ret' targets from the generic BTB.
- * The proper mitigation for this is IBRS. If IBRS is not supported
- * or deactivated in favour of retpolines the RSB fill on context
- * switch is required.
+ * - RSB underflow (and switch to BTB) on Skylake+
+ * - SpectreRSB variant of spectre v2 on X86_BUG_SPECTRE_V2 CPUs
*/
- if ((!boot_cpu_has(X86_FEATURE_PTI) &&
- !boot_cpu_has(X86_FEATURE_SMEP)) || is_skylake_era()) {
- setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
- pr_info("Spectre v2 mitigation: Filling RSB on context switch\n");
- }
+ setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW);
+ pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n");
/* Initialize Indirect Branch Prediction Barrier if supported */
if (boot_cpu_has(X86_FEATURE_IBPB)) {
next prev parent reply other threads:[~2018-08-14 17:34 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-14 17:16 [PATCH 4.14 000/104] 4.14.63-stable review Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 001/104] parisc: Enable CONFIG_MLONGCALLS by default Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 003/104] scsi: hpsa: fix selection of reply queue Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 004/104] scsi: core: introduce force_blk_mq Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 005/104] scsi: virtio_scsi: fix IO hang caused by automatic irq vector affinity Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 006/104] kasan: add no_sanitize attribute for clang builds Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 007/104] Mark HI and TASKLET softirq synchronous Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 008/104] stop_machine: Disable preemption after queueing stopper threads Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 009/104] xen/netfront: dont cache skb_shinfo() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 010/104] scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 011/104] scsi: qla2xxx: Fix memory leak for allocating abort IOCB Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 012/104] init: rename and re-order boot_cpu_state_init() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 013/104] root dentries need RCU-delayed freeing Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 014/104] make sure that __dentry_kill() always invalidates d_seq, unhashed or not Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 015/104] fix mntput/mntput race Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 016/104] fix __legitimize_mnt()/mntput() race Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 017/104] mtd: nand: qcom: Add a NULL check for devm_kasprintf() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 018/104] phy: phy-mtk-tphy: use auto instead of force to bypass utmi signals Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 021/104] ARM: dts: imx6sx: fix irq for pcie bridge Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 022/104] x86/paravirt: Fix spectre-v2 mitigations for paravirt guests Greg Kroah-Hartman
2018-08-14 17:16 ` Greg Kroah-Hartman [this message]
2018-08-14 17:16 ` [PATCH 4.14 024/104] kprobes/x86: Fix %p uses in error messages Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 025/104] x86/irqflags: Provide a declaration for native_save_fl Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 026/104] x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 027/104] x86/speculation/l1tf: Change order of offset/type in swap entry Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 028/104] x86/speculation/l1tf: Protect swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 029/104] x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 030/104] x86/speculation/l1tf: Make sure the first page is always reserved Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 031/104] x86/speculation/l1tf: Add sysfs reporting for l1tf Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 032/104] x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 033/104] x86/speculation/l1tf: Limit swap file size to MAX_PA/2 Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 034/104] x86/bugs: Move the l1tf function and define pr_fmt properly Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 035/104] sched/smt: Update sched_smt_present at runtime Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 036/104] x86/smp: Provide topology_is_primary_thread() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 037/104] x86/topology: Provide topology_smt_supported() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 038/104] cpu/hotplug: Make bringup/teardown of smp threads symmetric Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 039/104] cpu/hotplug: Split do_cpu_down() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 040/104] cpu/hotplug: Provide knobs to control SMT Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 041/104] x86/cpu: Remove the pointless CPU printout Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 042/104] x86/cpu/AMD: Remove the pointless detect_ht() call Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 043/104] x86/cpu/common: Provide detect_ht_early() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 044/104] x86/cpu/topology: Provide detect_extended_topology_early() Greg Kroah-Hartman
2018-08-14 17:16 ` [PATCH 4.14 045/104] x86/cpu/intel: Evaluate smp_num_siblings early Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 046/104] x86/CPU/AMD: Do not check CPUID max ext level before parsing SMP info Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 047/104] x86/cpu/AMD: Evaluate smp_num_siblings early Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 049/104] x86/speculation/l1tf: Extend 64bit swap file size limit Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 050/104] x86/cpufeatures: Add detection of L1D cache flush support Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 051/104] x86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 052/104] x86/speculation/l1tf: Protect PAE swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 053/104] x86/speculation/l1tf: Fix up pte->pfn conversion for PAE Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 054/104] Revert "x86/apic: Ignore secondary threads if nosmt=force" Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 055/104] cpu/hotplug: Boot HT siblings at least once Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 056/104] x86/KVM: Warn user if KVM is loaded SMT and L1TF CPU bug being present Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 057/104] x86/KVM/VMX: Add module argument for L1TF mitigation Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 058/104] x86/KVM/VMX: Add L1D flush algorithm Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 059/104] x86/KVM/VMX: Add L1D MSR based flush Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 060/104] x86/KVM/VMX: Add L1D flush logic Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 061/104] x86/KVM/VMX: Split the VMX MSR LOAD structures to have an host/guest numbers Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 062/104] x86/KVM/VMX: Add find_msr() helper function Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 063/104] x86/KVM/VMX: Separate the VMX AUTOLOAD guest/host number accounting Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 064/104] x86/KVM/VMX: Extend add_atomic_switch_msr() to allow VMENTER only MSRs Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 065/104] x86/KVM/VMX: Use MSR save list for IA32_FLUSH_CMD if required Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 066/104] cpu/hotplug: Online siblings when SMT control is turned on Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 067/104] x86/litf: Introduce vmx status variable Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 068/104] x86/kvm: Drop L1TF MSR list approach Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 069/104] x86/l1tf: Handle EPT disabled state proper Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 070/104] x86/kvm: Move l1tf setup function Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 071/104] x86/kvm: Add static key for flush always Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 072/104] x86/kvm: Serialize L1D flush parameter setter Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 073/104] x86/kvm: Allow runtime control of L1D flush Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 074/104] cpu/hotplug: Expose SMT control init function Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 075/104] cpu/hotplug: Set CPU_SMT_NOT_SUPPORTED early Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 076/104] x86/bugs, kvm: Introduce boot-time control of L1TF mitigations Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 077/104] Documentation: Add section about CPU vulnerabilities Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 078/104] x86/KVM/VMX: Initialize the vmx_l1d_flush_pages content Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 079/104] Documentation/l1tf: Fix typos Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 080/104] cpu/hotplug: detect SMT disabled by BIOS Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 081/104] x86/KVM/VMX: Dont set l1tf_flush_l1d to true from vmx_l1d_flush() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 082/104] x86/KVM/VMX: Replace vmx_l1d_flush_always with vmx_l1d_flush_cond Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 083/104] x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 084/104] x86/irq: Demote irq_cpustat_t::__softirq_pending to u16 Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 085/104] x86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 086/104] x86: Dont include linux/irq.h from asm/hardirq.h Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 087/104] x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 088/104] x86/KVM/VMX: Dont set l1tf_flush_l1d from vmx_handle_external_intr() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 089/104] Documentation/l1tf: Remove Yonah processors from not vulnerable list Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 094/104] KVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSR Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 095/104] x86/speculation: Simplify sysfs report of VMX L1TF vulnerability Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 096/104] x86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 097/104] KVM: VMX: Tell the nested hypervisor " Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 098/104] cpu/hotplug: Fix SMT supported evaluation Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 099/104] x86/speculation/l1tf: Invert all not present mappings Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 100/104] x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 101/104] x86/mm/pat: Make set_memory_np() L1TF safe Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 102/104] x86/mm/kmmio: Make the tracer robust against L1TF Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 103/104] tools headers: Synchronise x86 cpufeatures.h for L1TF additions Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.14 104/104] x86/microcode: Allow late microcode loading with SMT disabled Greg Kroah-Hartman
2018-08-15 6:14 ` [PATCH 4.14 000/104] 4.14.63-stable review Greg Kroah-Hartman
[not found] ` <CA+res+SSVV04eawQ6wDX6_gdd9G0FbQ=uWFy0tOgSX=+T0s2MA@mail.gmail.com>
2018-08-15 15:02 ` Jinpu Wang
2018-08-15 15:31 ` Greg Kroah-Hartman
2018-08-15 13:14 ` Guenter Roeck
2018-08-15 20:38 ` Dan Rue
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