* [PATCH] x86emul: always init mmval
@ 2017-02-10 7:39 Jan Beulich
2017-02-10 10:47 ` Andrew Cooper
0 siblings, 1 reply; 2+ messages in thread
From: Jan Beulich @ 2017-02-10 7:39 UTC (permalink / raw)
To: xen-devel; +Cc: Andrew Cooper
[-- Attachment #1: Type: text/plain, Size: 546 bytes --]
... to avoid buggy read/write sizes becoming info leaks.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2671,6 +2671,8 @@ x86_emulate(
ea.reg = decode_register(modrm_rm, &_regs,
(d & ByteOp) && !rex_prefix);
+ memset(mmvalp, 0xaa /* arbitrary */, sizeof(*mmvalp));
+
/* Decode and fetch the source operand: register, memory or immediate. */
switch ( d & SrcMask )
{
[-- Attachment #2: x86emul-init-mmval.patch --]
[-- Type: text/plain, Size: 570 bytes --]
x86emul: always init mmval
... to avoid buggy read/write sizes becoming info leaks.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -2671,6 +2671,8 @@ x86_emulate(
ea.reg = decode_register(modrm_rm, &_regs,
(d & ByteOp) && !rex_prefix);
+ memset(mmvalp, 0xaa /* arbitrary */, sizeof(*mmvalp));
+
/* Decode and fetch the source operand: register, memory or immediate. */
switch ( d & SrcMask )
{
[-- Attachment #3: Type: text/plain, Size: 127 bytes --]
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^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86emul: always init mmval
2017-02-10 7:39 [PATCH] x86emul: always init mmval Jan Beulich
@ 2017-02-10 10:47 ` Andrew Cooper
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Cooper @ 2017-02-10 10:47 UTC (permalink / raw)
To: Jan Beulich, xen-devel
On 10/02/17 07:39, Jan Beulich wrote:
> ... to avoid buggy read/write sizes becoming info leaks.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
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2017-02-10 10:47 ` Andrew Cooper
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