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KVM: x86: PREFETCH and HINT_NOP should have SrcMem flag

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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: 41061cdb98
Cc: stable@vger.kernel.org
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Nadav Amit 2014-10-13 13:04:14 +03:00 committed by Paolo Bonzini
parent 13e457e0ee
commit 3f6f1480d8
1 changed files with 4 additions and 3 deletions
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7
arch/x86/kvm/emulate.c
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@ -3807,7 +3807,7 @@ 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 = { {
@ -4024,10 +4024,11 @@ static const struct opcode twobyte_table[256] = {
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),