[PATCH 0/8] replace memset by memzero_explicit

[PATCH 0/8] replace memset by memzero_explicit

[Julia Lawall]

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>

[PATCH 1/8 v2] purgatory/sha256: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 arch/x86/purgatory/sha256.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/purgatory/sha256.c b/arch/x86/purgatory/sha256.c
index 548ca67..8271ca5 100644
--- a/arch/x86/purgatory/sha256.c
+++ b/arch/x86/purgatory/sha256.c
@@ -205,7 +205,7 @@ static void sha256_transform(u32 *state, const u8 *input)
 
 	/* clear any sensitive info... */
 	a = b = c = d = e = f = g = h = t1 = t2 = 0;
-	memset(W, 0, 64 * sizeof(u32));
+	memzero_explicit(W, 64 * sizeof(u32));
 }
 
 int sha256_init(struct sha256_state *sctx)

[PATCH 2/8 v2] sparc64: replace memset by memzero_explicit

[Julia Lawall]

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 these.

v2: fixed email address

 arch/sparc/crypto/sha256_glue.c |    2 +-
 arch/sparc/crypto/sha512_glue.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/crypto/sha512_glue.c b/arch/sparc/crypto/sha512_glue.c
index 9fff885..11eb36c 100644
--- a/arch/sparc/crypto/sha512_glue.c
+++ b/arch/sparc/crypto/sha512_glue.c
@@ -139,7 +139,7 @@ static int sha384_sparc64_final(struct shash_desc *desc, u8 *hash)
 	sha512_sparc64_final(desc, D);
 
 	memcpy(hash, D, 48);
-	memset(D, 0, 64);
+	memzero_explicit(D, 64);
 
 	return 0;
 }
diff --git a/arch/sparc/crypto/sha256_glue.c b/arch/sparc/crypto/sha256_glue.c
index 41f27cc..285268c 100644
--- a/arch/sparc/crypto/sha256_glue.c
+++ b/arch/sparc/crypto/sha256_glue.c
@@ -135,7 +135,7 @@ static int sha224_sparc64_final(struct shash_desc *desc, u8 *hash)
 	sha256_sparc64_final(desc, D);
 
 	memcpy(hash, D, SHA224_DIGEST_SIZE);
-	memset(D, 0, SHA256_DIGEST_SIZE);
+	memzero_explicit(D, SHA256_DIGEST_SIZE);
 
 	return 0;
 }

Re: [PATCH 2/8 v2] sparc64: replace memset by memzero_explicit

[Herbert Xu]

On Sun, Nov 30, 2014 at 06:03:43PM +0100, Julia Lawall 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>

Applied patches 2, 3, 6, 7.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 3/8 v2] crypto: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 arch/x86/crypto/sha256_ssse3_glue.c |    2 +-
 arch/x86/crypto/sha512_ssse3_glue.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/crypto/sha512_ssse3_glue.c b/arch/x86/crypto/sha512_ssse3_glue.c
index 26a5898..0b6af26 100644
--- a/arch/x86/crypto/sha512_ssse3_glue.c
+++ b/arch/x86/crypto/sha512_ssse3_glue.c
@@ -219,7 +219,7 @@ static int sha384_ssse3_final(struct shash_desc *desc, u8 *hash)
 	sha512_ssse3_final(desc, D);
 
 	memcpy(hash, D, SHA384_DIGEST_SIZE);
-	memset(D, 0, SHA512_DIGEST_SIZE);
+	memzero_explicit(D, SHA512_DIGEST_SIZE);
 
 	return 0;
 }
diff --git a/arch/x86/crypto/sha256_ssse3_glue.c b/arch/x86/crypto/sha256_ssse3_glue.c
index 4dc100d..8fad72f 100644
--- a/arch/x86/crypto/sha256_ssse3_glue.c
+++ b/arch/x86/crypto/sha256_ssse3_glue.c
@@ -211,7 +211,7 @@ static int sha224_ssse3_final(struct shash_desc *desc, u8 *hash)
 	sha256_ssse3_final(desc, D);
 
 	memcpy(hash, D, SHA224_DIGEST_SIZE);
-	memset(D, 0, SHA256_DIGEST_SIZE);
+	memzero_explicit(D, SHA256_DIGEST_SIZE);
 
 	return 0;
 }

[PATCH 4/8 v2] cifs: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 fs/cifs/smbencrypt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smbencrypt.c b/fs/cifs/smbencrypt.c
index 6c15663..6512c19 100644
--- a/fs/cifs/smbencrypt.c
+++ b/fs/cifs/smbencrypt.c
@@ -221,7 +221,7 @@ E_md4hash(const unsigned char *passwd, unsigned char *p16,
 	}
 
 	rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16));
-	memset(wpwd, 0, 129 * sizeof(__le16));
+	memzero_explicit(wpwd, 129 * sizeof(__le16));
 
 	return rc;
 }

[PATCH 5/8 v2] dm: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 drivers/md/dm-crypt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index fc93b93..08981be 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -705,7 +705,7 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
 	for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
 		crypto_xor(data + i * 8, buf, 8);
 out:
-	memset(buf, 0, sizeof(buf));
+	memzero_explicit(buf, sizeof(buf));
 	return r;
 }
 

Re: [PATCH 5/8 v2] dm: replace memset by memzero_explicit

[Milan Broz]

On 11/30/2014 06:03 PM, Julia Lawall 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/)

Ack, but I submitted the same patch a week ago....

https://www.redhat.com/archives/dm-devel/2014-November/msg00084.html

Mike, please could you add this to linux-next tree or you want this
to go through Herbert's tree?
(I do not think it is good idea for DM patches.)

Thanks,
Milan

> 
> // <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.
> 
> v2: fixed email address
> 
>  drivers/md/dm-crypt.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index fc93b93..08981be 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -705,7 +705,7 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
>  	for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++)
>  		crypto_xor(data + i * 8, buf, 8);
>  out:
> -	memset(buf, 0, sizeof(buf));
> +	memzero_explicit(buf, sizeof(buf));
>  	return r;
>  }
>  
> 

Re: [PATCH 5/8 v2] dm: replace memset by memzero_explicit

[Mike Snitzer]

On Mon, Dec 01 2014 at  4:03pm -0500,
Milan Broz <gmazyland@gmail.com> wrote:

> On 11/30/2014 06:03 PM, Julia Lawall 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/)
> 
> Ack, but I submitted the same patch a week ago....
> 
> https://www.redhat.com/archives/dm-devel/2014-November/msg00084.html
> 
> Mike, please could you add this to linux-next tree or you want this
> to go through Herbert's tree?
> (I do not think it is good idea for DM patches.)

I staged it in linux-next for 3.19 inclusion, see:
https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-for-3.19&id=a722201f9075b28be140bc13f8ec07bf6a42edd4

[PATCH 6/8 v2] crypto: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 arch/powerpc/crypto/sha1.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/crypto/sha1.c b/arch/powerpc/crypto/sha1.c
index 0f88c7b..d3feba5 100644
--- a/arch/powerpc/crypto/sha1.c
+++ b/arch/powerpc/crypto/sha1.c
@@ -66,7 +66,7 @@ static int sha1_update(struct shash_desc *desc, const u8 *data,
 			src = data + done;
 		} while (done + 63 < len);
 
-		memset(temp, 0, sizeof(temp));
+		memzero_explicit(temp, sizeof(temp));
 		partial = 0;
 	}
 	memcpy(sctx->buffer + partial, src, len - done);

Re: [PATCH 6/8 v2] crypto: replace memset by memzero_explicit

[Michael Ellerman]

On Sun, 2014-11-30 at 18:03 +0100, Julia Lawall 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
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
> 
> ---
> Daniel Borkmann suggested that these patches could go through Herbert Xu's
> cryptodev tree.

That's fine by me:

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers

[PATCH 7/8 v2] crypto: replace memset by memzero_explicit

[Julia Lawall]

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;
 }

Re: [PATCH 7/8 v2] crypto: replace memset by memzero_explicit

[Ard Biesheuvel]

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@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 8/8 v2] wusb: replace memset by memzero_explicit

[Julia Lawall]

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.

v2: fixed email address

 drivers/usb/wusbcore/dev-sysfs.c |    2 +-
 drivers/usb/wusbcore/security.c  |    8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/wusbcore/dev-sysfs.c b/drivers/usb/wusbcore/dev-sysfs.c
index 1018345..415b140 100644
--- a/drivers/usb/wusbcore/dev-sysfs.c
+++ b/drivers/usb/wusbcore/dev-sysfs.c
@@ -101,7 +101,7 @@ static ssize_t wusb_ck_store(struct device *dev,
 	if (wusbhc == NULL)
 		return -ENODEV;
 	result = wusb_dev_4way_handshake(wusbhc, usb_dev->wusb_dev, &ck);
-	memset(&ck, 0, sizeof(ck));
+	memzero_explicit(&ck, sizeof(ck));
 	wusbhc_put(wusbhc);
 	return result < 0 ? result : size;
 }
diff --git a/drivers/usb/wusbcore/security.c b/drivers/usb/wusbcore/security.c
index cc74d66..b66faaf 100644
--- a/drivers/usb/wusbcore/security.c
+++ b/drivers/usb/wusbcore/security.c
@@ -522,10 +522,10 @@ error_hs3:
 error_hs2:
 error_hs1:
 	memset(hs, 0, 3*sizeof(hs[0]));
-	memset(&keydvt_out, 0, sizeof(keydvt_out));
-	memset(&keydvt_in, 0, sizeof(keydvt_in));
-	memset(&ccm_n, 0, sizeof(ccm_n));
-	memset(mic, 0, sizeof(mic));
+	memzero_explicit(&keydvt_out, sizeof(keydvt_out));
+	memzero_explicit(&keydvt_in, sizeof(keydvt_in));
+	memzero_explicit(&ccm_n, sizeof(ccm_n));
+	memzero_explicit(mic, sizeof(mic));
 	if (result < 0)
 		wusb_dev_set_encryption(usb_dev, 0);
 error_dev_set_encryption: