From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, "Andrew Honig" <ahonig@google.com>,
"Jim Mattson" <jmattson@google.com>,
kvm@vger.kernel.org, "Paolo Bonzini" <pbonzini@redhat.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Dan Williams" <dan.j.williams@intel.com>
Subject: [PATCH 3.16 62/76] x86/kvm: Update spectre-v1 mitigation
Date: Mon, 12 Mar 2018 03:06:12 +0000 [thread overview]
Message-ID: <lsq.1520823972.361057584@decadent.org.uk> (raw)
In-Reply-To: <lsq.1520823971.5976735@decadent.org.uk>
3.16.56-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Dan Williams <dan.j.williams@intel.com>
commit 085331dfc6bbe3501fb936e657331ca943827600 upstream.
Commit 75f139aaf896 "KVM: x86: Add memory barrier on vmcs field lookup"
added a raw 'asm("lfence");' to prevent a bounds check bypass of
'vmcs_field_to_offset_table'.
The lfence can be avoided in this path by using the array_index_nospec()
helper designed for these types of fixes.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andrew Honig <ahonig@google.com>
Cc: kvm@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>
Link: https://lkml.kernel.org/r/151744959670.6342.3001723920950249067.stgit@dwillia2-desk3.amr.corp.intel.com
[bwh: Backported to 3.16:
- Replace max_vmcs_field with the local size variable
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -32,6 +32,7 @@
#include <linux/slab.h>
#include <linux/tboot.h>
#include <linux/hrtimer.h>
+#include <linux/nospec.h>
#include "kvm_cache_regs.h"
#include "x86.h"
@@ -695,23 +696,21 @@ static const unsigned short vmcs_field_t
FIELD(HOST_RSP, host_rsp),
FIELD(HOST_RIP, host_rip),
};
-static const int max_vmcs_field = ARRAY_SIZE(vmcs_field_to_offset_table);
static inline short vmcs_field_to_offset(unsigned long field)
{
- if (field >= max_vmcs_field)
- return -1;
+ const size_t size = ARRAY_SIZE(vmcs_field_to_offset_table);
+ unsigned short offset;
- /*
- * FIXME: Mitigation for CVE-2017-5753. To be replaced with a
- * generic mechanism.
- */
- asm("lfence");
-
- if (vmcs_field_to_offset_table[field] == 0)
+ BUILD_BUG_ON(size > SHRT_MAX);
+ if (field >= size)
return -1;
- return vmcs_field_to_offset_table[field];
+ field = array_index_nospec(field, size);
+ offset = vmcs_field_to_offset_table[field];
+ if (offset == 0)
+ return -1;
+ return offset;
}
static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu)
next prev parent reply other threads:[~2018-03-12 3:12 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 3:06 [PATCH 3.16 00/76] 3.16.56-rc1 review Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 28/76] x86/retpoline/hyperv: Convert assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 21/76] x86: Clean up current_stack_pointer Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 38/76] x86/pti: Document fix wrong index Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 34/76] x86/retpoline: Add LFENCE to the retpoline/RSB filling RSB macros Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 63/76] x86/retpoline: Avoid retpolines for built-in __init functions Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 17/76] x86/cpu/AMD: Make LFENCE a serializing instruction Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 06/76] x86/cpu, x86/pti: Do not enable PTI on AMD processors Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 54/76] x86: Introduce barrier_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 05/76] x86/cpufeatures: Add X86_BUG_CPU_INSECURE Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 14/76] x86/alternatives: Fix ALTERNATIVE_2 padding generation properly Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 31/76] x86/retpoline/irq32: Convert assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 49/76] x86/cpu/bugs: Make retpoline module warning conditional Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 01/76] kvm: vmx: Scrub hardware GPRs at VM-exit Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 44/76] KVM: x86: Make indirect calls in emulator speculation safe Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 42/76] x86/cpu: Change type of x86_cache_size variable to unsigned int Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 59/76] x86/spectre: Report get_user mitigation for spectre_v1 Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 71/76] x86: reorganize SMAP handling in user space accesses Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 56/76] x86/syscall: Sanitize syscall table de-references under speculation Ben Hutchings
2018-03-12 7:32 ` Jiri Slaby
2018-03-19 0:59 ` Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 73/76] x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 07/76] x86/pti: Rename BUG_CPU_INSECURE to BUG_CPU_MELTDOWN Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 36/76] kprobes/x86: Blacklist indirect thunk functions for kprobes Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 47/76] x86/nospec: Fix header guards names Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 67/76] x86/spectre: Fix an error message Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 15/76] x86/alternatives: Make optimize_nops() interrupt safe and synced Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 53/76] x86: Implement array_index_mask_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 19/76] x86/asm: Make asm/alternative.h safe from assembly Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 76/76] x86: fix build warnign with 32-bit PAE Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 32/76] x86/retpoline: Fill return stack buffer on vmexit Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 65/76] x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 57/76] vfs, fdtable: Prevent bounds-check bypass via speculative execution Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 58/76] nl80211: Sanitize array index in parse_txq_params Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 16/76] x86/alternatives: Fix optimize_nops() checking Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 10/76] sysfs/cpu: Add vulnerability folder Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 41/76] x86/retpoline: Fill RSB on context switch for affected CPUs Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 12/76] sysfs/cpu: Fix typos in vulnerability documentation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 51/76] Documentation: Document array_index_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 29/76] x86/retpoline/xen: Convert Xen hypercall indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 13/76] x86/alternatives: Guard NOPs optimization Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 20/76] kconfig.h: use __is_defined() to check if MODULE is defined Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 08/76] x86/cpufeatures: Add X86_BUG_SPECTRE_V[12] Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 37/76] kprobes/x86: Disable optimizing on the function jumps to indirect thunk Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 33/76] x86/retpoline: Remove compile time warning Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 09/76] x86/cpu: Merge bugs.c and bugs_64.c Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 48/76] x86/bugs: Drop one "mitigation" from dmesg Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 43/76] x86/retpoline: Remove the esp/rsp thunk Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 02/76] x86/Documentation: Add PTI description Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 04/76] x86/cpufeatures: Make CPU bugs sticky Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 25/76] x86/retpoline/crypto: Convert crypto assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 52/76] array_index_nospec: Sanitize speculative array de-references Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 68/76] nospec: Move array_index_nospec() parameter checking into separate macro Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 74/76] x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end} Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 27/76] x86/retpoline/ftrace: Convert ftrace assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 26/76] x86/retpoline/entry: Convert entry " Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 30/76] x86/retpoline/checksum32: Convert " Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 69/76] nospec: Kill array_index_nospec_mask_check() Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 40/76] x86/cpu/intel: Introduce macros for Intel family numbers Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 75/76] x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 39/76] x86/retpoline: Optimize inline assembler for vmexit_fill_RSB Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 45/76] KVM: VMX: Make indirect call speculation safe Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 03/76] x86/cpu: Factor out application of forced CPU caps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 18/76] x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC Ben Hutchings
2018-03-12 3:06 ` Ben Hutchings [this message]
2018-03-12 3:06 ` [PATCH 3.16 35/76] retpoline: Introduce start/end markers of indirect thunk Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 72/76] x86: fix SMAP in 32-bit environments Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 24/76] x86/spectre: Add boot time option to select Spectre v2 mitigation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 61/76] x86/paravirt: Remove 'noreplace-paravirt' cmdline option Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 23/76] x86/retpoline: Add initial retpoline support Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 22/76] x86/asm: Use register variable to get stack pointer value Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 66/76] x86/cpufeatures: Clean up Spectre v2 related CPUID flags Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 64/76] x86/spectre: Simplify spectre_v2 command line parsing Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 55/76] x86/get_user: Use pointer masking to limit speculation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 70/76] nospec: Include <asm/barrier.h> dependency Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 60/76] x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable" Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 11/76] x86/cpu: Implement CPU vulnerabilites sysfs functions Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 46/76] module/retpoline: Warn about missing retpoline in module Ben Hutchings
2018-03-12 15:00 ` [PATCH 3.16 00/76] 3.16.56-rc1 review Guenter Roeck
2018-03-12 16:45 ` Guenter Roeck
2018-03-20 17:25 ` Ben Hutchings
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