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* [PATCH 0/8] replace memset by memzero_explicit
@ 2014-11-30 16:59 Julia Lawall
  0 siblings, 0 replies; 4+ messages in thread
From: Julia Lawall @ 2014-11-30 16:59 UTC (permalink / raw)
  To: linux-arm-kernel

Memset on a local variable may be removed when it is called just before the
variable goes out of scope.  Using memzero_explicit defeats this
optimization.  The complete semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
local idexpression e;
type T,T1;
@@

{
... when any
T x[...];
... when any
    when exists
(
e = (T1)x
|
e = (T1)&x[0]
)
... when any
    when exists
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when != e
    when strict
}

@@
identifier i,x;
local idexpression e;
type T;
@@

{
... when any
struct i x;
... when any
    when exists
e = (T)&x
... when any
    when exists
- memset
+ memzero_explicit
  (&x,
-0,
  ...)
... when != x
    when != e
    when strict
}

// ------------------------------------------------------------------------

@@
identifier x;
type T,T1;
expression e;
@@

{
... when any
T x[...];
... when any
    when exists
    when != e = (T1)x
    when != e = (T1)&x[0]
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when strict
}

@@
identifier i,x;
expression e;
type T;
@@

{
... when any
struct i x;
... when any
    when exists
    when != e = (T)&x
- memset
+ memzero_explicit
  (&x,
-0,
  ...)
... when != x
    when strict
}
// </smpl>

^ permalink raw reply	[flat|nested] 4+ messages in thread
* [PATCH 0/8] replace memset by memzero_explicit
@ 2014-11-30 17:03 Julia Lawall
  2014-11-30 17:03 ` [PATCH 7/8 v2] crypto: " Julia Lawall
  0 siblings, 1 reply; 4+ messages in thread
From: Julia Lawall @ 2014-11-30 17:03 UTC (permalink / raw)
  To: linux-arm-kernel

Memset on a local variable may be removed when it is called just before the
variable goes out of scope.  Using memzero_explicit defeats this
optimization.  The complete semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
local idexpression e;
type T,T1;
@@

{
... when any
T x[...];
... when any
    when exists
(
e = (T1)x
|
e = (T1)&x[0]
)
... when any
    when exists
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when != e
    when strict
}

@@
identifier i,x;
local idexpression e;
type T;
@@

{
... when any
struct i x;
... when any
    when exists
e = (T)&x
... when any
    when exists
- memset
+ memzero_explicit
  (&x,
-0,
  ...)
... when != x
    when != e
    when strict
}

// ------------------------------------------------------------------------

@@
identifier x;
type T,T1;
expression e;
@@

{
... when any
T x[...];
... when any
    when exists
    when != e = (T1)x
    when != e = (T1)&x[0]
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when strict
}

@@
identifier i,x;
expression e;
type T;
@@

{
... when any
struct i x;
... when any
    when exists
    when != e = (T)&x
- memset
+ memzero_explicit
  (&x,
-0,
  ...)
... when != x
    when strict
}
// </smpl>

^ permalink raw reply	[flat|nested] 4+ messages in thread
* [PATCH 7/8 v2] crypto: replace memset by memzero_explicit
  2014-11-30 17:03 [PATCH 0/8] replace memset by memzero_explicit Julia Lawall
@ 2014-11-30 17:03 ` Julia Lawall
  2014-11-30 19:57   ` Ard Biesheuvel
  0 siblings, 1 reply; 4+ messages in thread
From: Julia Lawall @ 2014-11-30 17:03 UTC (permalink / raw)
  To: linux-arm-kernel

From: Julia Lawall <Julia.Lawall@lip6.fr>

Memset on a local variable may be removed when it is called just before the
variable goes out of scope.  Using memzero_explicit defeats this
optimization.  A simplified version of the semantic patch that makes this
change is as follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
type T;
@@

{
... when any
T x[...];
... when any
    when exists
- memset
+ memzero_explicit
  (x,
-0,
  ...)
... when != x
    when strict
}
// </smpl>

This change was suggested by Daniel Borkmann <dborkman@redhat.com>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
Daniel Borkmann suggested that these patches could go through Herbert Xu's
cryptodev tree.

I was not able to compile this one.

v2: fixed email address

 arch/arm/crypto/sha512_neon_glue.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/crypto/sha512_neon_glue.c b/arch/arm/crypto/sha512_neon_glue.c
index f3452c6..b124dce 100644
--- a/arch/arm/crypto/sha512_neon_glue.c
+++ b/arch/arm/crypto/sha512_neon_glue.c
@@ -241,7 +241,7 @@ static int sha384_neon_final(struct shash_desc *desc, u8 *hash)
 	sha512_neon_final(desc, D);
 
 	memcpy(hash, D, SHA384_DIGEST_SIZE);
-	memset(D, 0, SHA512_DIGEST_SIZE);
+	memzero_explicit(D, SHA512_DIGEST_SIZE);
 
 	return 0;
 }

^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH 7/8 v2] crypto: replace memset by memzero_explicit
  2014-11-30 17:03 ` [PATCH 7/8 v2] crypto: " Julia Lawall
@ 2014-11-30 19:57   ` Ard Biesheuvel
  0 siblings, 0 replies; 4+ messages in thread
From: Ard Biesheuvel @ 2014-11-30 19:57 UTC (permalink / raw)
  To: linux-arm-kernel

On 30 November 2014 at 18:03, Julia Lawall <Julia.Lawall@lip6.fr> wrote:
> From: Julia Lawall <Julia.Lawall@lip6.fr>
>
> Memset on a local variable may be removed when it is called just before the
> variable goes out of scope.  Using memzero_explicit defeats this
> optimization.  A simplified version of the semantic patch that makes this
> change is as follows: (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> identifier x;
> type T;
> @@
>
> {
> ... when any
> T x[...];
> ... when any
>     when exists
> - memset
> + memzero_explicit
>   (x,
> -0,
>   ...)
> ... when != x
>     when strict
> }
> // </smpl>
>
> This change was suggested by Daniel Borkmann <dborkman@redhat.com>
>
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>
> ---
> Daniel Borkmann suggested that these patches could go through Herbert Xu's
> cryptodev tree.
>
> I was not able to compile this one.
>

Builds fine for me

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>


> v2: fixed email address
>
>  arch/arm/crypto/sha512_neon_glue.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/crypto/sha512_neon_glue.c b/arch/arm/crypto/sha512_neon_glue.c
> index f3452c6..b124dce 100644
> --- a/arch/arm/crypto/sha512_neon_glue.c
> +++ b/arch/arm/crypto/sha512_neon_glue.c
> @@ -241,7 +241,7 @@ static int sha384_neon_final(struct shash_desc *desc, u8 *hash)
>         sha512_neon_final(desc, D);
>
>         memcpy(hash, D, SHA384_DIGEST_SIZE);
> -       memset(D, 0, SHA512_DIGEST_SIZE);
> +       memzero_explicit(D, SHA512_DIGEST_SIZE);
>
>         return 0;
>  }
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 4+ messages in thread
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2014-11-30 17:03 ` [PATCH 7/8 v2] crypto: " Julia Lawall
2014-11-30 19:57   ` Ard Biesheuvel
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