3.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
commit 3f6f1480d86bf9fc16c160d803ab1d006e3058d5 upstream.
The decode phase of the x86 emulator assumes that every instruction with the
ModRM flag, and which can be used with RIP-relative addressing, has either
SrcMem or DstMem. This is not the case for several instructions - prefetch,
hint-nop and clflush.
Adding SrcMem|NoAccess for prefetch and hint-nop and SrcMem for clflush.
This fixes CVE-2014-8480.
Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3715,7 +3715,7 @@ static const struct opcode group11[] = {
};
static const struct gprefix pfx_0f_ae_7 = {
- I(0, em_clflush), N, N, N,
+ I(SrcMem | ByteOp, em_clflush), N, N, N,
};
static const struct group_dual group15 = { {
@@ -3928,10 +3928,11 @@ static const struct opcode twobyte_table
N, I(ImplicitOps | EmulateOnUD, em_syscall),
II(ImplicitOps | Priv, em_clts, clts), N,
DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
- N, D(ImplicitOps | ModRM), N, N,
+ N, D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N,
/* 0x10 - 0x1F */
N, N, N, N, N, N, N, N,
- D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
+ D(ImplicitOps | ModRM | SrcMem | NoAccess),
+ N, N, N, N, N, N, D(ImplicitOps | ModRM | SrcMem | NoAccess),
/* 0x20 - 0x2F */
DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read),
DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),
--
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