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| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:41 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-14 16:29:58 -0500 |
| commit | d216f65c74ddf8ae6547f8a9325f9ad15f688c97 (patch) | |
| tree | fe2af895bb7e94d10c7cd625d238b7cfd60e6220 /arch/x86/kvm | |
| parent | 0126c3ef8a3ff657bdd34c220111fdf3a365e655 (diff) | |
| download | linux-stable-d216f65c74ddf8ae6547f8a9325f9ad15f688c97.tar.gz linux-stable-d216f65c74ddf8ae6547f8a9325f9ad15f688c97.tar.bz2 linux-stable-d216f65c74ddf8ae6547f8a9325f9ad15f688c97.zip | |
KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks
commit 3c9053a2cae7ba2ba73766a34cea41baa70f57f7 upstream.
This fixes a Spectre-v1/L1TF vulnerability in x86_decode_insn().
kvm_emulate_instruction() (an ancestor of x86_decode_insn()) is an exported
symbol, so KVM should treat it conservatively from a security perspective.
Fixes: 045a282ca415 ("KVM: emulator: implement fninit, fnstsw, fnstcw")
Signed-off-by: Nick Finco <nifi@google.com>
Signed-off-by: Marios Pomonis <pomonis@google.com>
Reviewed-by: Andrew Honig <ahonig@google.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 52e8203bdc42..ffbdd201c1f1 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -23,6 +23,7 @@ #include <linux/kvm_host.h> #include "kvm_cache_regs.h" #include <linux/module.h> +#include <linux/nospec.h> #include <asm/kvm_emulate.h> #include <linux/stringify.h> #include <asm/debugreg.h> @@ -5146,10 +5147,15 @@ done_prefixes: } break; case Escape: - if (ctxt->modrm > 0xbf) - opcode = opcode.u.esc->high[ctxt->modrm - 0xc0]; - else + if (ctxt->modrm > 0xbf) { + size_t size = ARRAY_SIZE(opcode.u.esc->high); + u32 index = array_index_nospec( + ctxt->modrm - 0xc0, size); + + opcode = opcode.u.esc->high[index]; + } else { opcode = opcode.u.esc->op[(ctxt->modrm >> 3) & 7]; + } break; case InstrDual: if ((ctxt->modrm >> 6) == 3) |