crypto: algboss - Avoid spurious modprobe on LOADED

crypto: algboss - Avoid spurious modprobe on LOADED

[Herbert Xu]

As it stands when any algorithm finishes testing a notification
is generated which triggers an unnecessary modprobe because algboss
returns NOTIFY_DONE instead of NOTIFY_OK (this denotes an event
that is not handled properly).

This patch changes the return value in algboss so that we don't
do an unnecessary modprobe.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/algboss.c b/crypto/algboss.c
index 527b44d0af21..01feb8234053 100644
--- a/crypto/algboss.c
+++ b/crypto/algboss.c
@@ -275,7 +275,7 @@ static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
 	case CRYPTO_MSG_ALG_REGISTER:
 		return cryptomgr_schedule_test(data);
 	case CRYPTO_MSG_ALG_LOADED:
-		break;
+		return NOTIFY_OK;
 	}
 
 	return NOTIFY_DONE;
-- 
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

Re: crypto: algboss - Avoid spurious modprobe on LOADED

[Eric Biggers]

On Tue, Apr 07, 2020 at 01:00:03PM +1000, Herbert Xu wrote:
> As it stands when any algorithm finishes testing a notification
> is generated which triggers an unnecessary modprobe because algboss
> returns NOTIFY_DONE instead of NOTIFY_OK (this denotes an event
> that is not handled properly).
> 
> This patch changes the return value in algboss so that we don't
> do an unnecessary modprobe.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Needs a Fixes tag?

Fixes: dd8b083f9a5e ("crypto: api - Introduce notifier for new crypto algorithms")
Cc: <stable@vger.kernel.org> # v4.20+

> 
> diff --git a/crypto/algboss.c b/crypto/algboss.c
> index 527b44d0af21..01feb8234053 100644
> --- a/crypto/algboss.c
> +++ b/crypto/algboss.c
> @@ -275,7 +275,7 @@ static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
>  	case CRYPTO_MSG_ALG_REGISTER:
>  		return cryptomgr_schedule_test(data);
>  	case CRYPTO_MSG_ALG_LOADED:
> -		break;
> +		return NOTIFY_OK;
>  	}
>  
>  	return NOTIFY_DONE;

It's hard to remember the difference between NOTIFY_OK and NOTIFY_DONE.  Isn't
it wrong to call request_module() in the first place for a message that
"cryptomgr" doesn't care about?  Wouldn't the following make more sense?:

diff --git a/crypto/algapi.c b/crypto/algapi.c
index 69605e21af92..849254d7e627 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -403,7 +403,7 @@ static void crypto_wait_for_test(struct crypto_larval *larval)
 	err = wait_for_completion_killable(&larval->completion);
 	WARN_ON(err);
 	if (!err)
-		crypto_probing_notify(CRYPTO_MSG_ALG_LOADED, larval);
+		crypto_notify(CRYPTO_MSG_ALG_LOADED, larval);
 
 out:
 	crypto_larval_kill(&larval->alg);

Re: crypto: algboss - Avoid spurious modprobe on LOADED

[Herbert Xu]

On Mon, Apr 06, 2020 at 09:58:35PM -0700, Eric Biggers wrote:
>
> Needs a Fixes tag?
> 
> Fixes: dd8b083f9a5e ("crypto: api - Introduce notifier for new crypto algorithms")
> Cc: <stable@vger.kernel.org> # v4.20+

Ah thanks, I had thought this was an ancient bug and therefore
the fixes wouldn't have been that useful.  The fact that it is
a recent introduction means that we definitely should have the
tags.

> > diff --git a/crypto/algboss.c b/crypto/algboss.c
> > index 527b44d0af21..01feb8234053 100644
> > --- a/crypto/algboss.c
> > +++ b/crypto/algboss.c
> > @@ -275,7 +275,7 @@ static int cryptomgr_notify(struct notifier_block *this, unsigned long msg,
> >  	case CRYPTO_MSG_ALG_REGISTER:
> >  		return cryptomgr_schedule_test(data);
> >  	case CRYPTO_MSG_ALG_LOADED:
> > -		break;
> > +		return NOTIFY_OK;
> >  	}
> >  
> >  	return NOTIFY_DONE;
> 
> It's hard to remember the difference between NOTIFY_OK and NOTIFY_DONE.  Isn't
> it wrong to call request_module() in the first place for a message that
> "cryptomgr" doesn't care about?  Wouldn't the following make more sense?:

Good point.  Yes we can and should do that here.  Can you post
a patch for this please?

Cheers,
-- 
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 v2] crypto: algapi - Avoid spurious modprobe on LOADED

[Eric Biggers]

From: Eric Biggers <ebiggers@google.com>

Currently after any algorithm is registered and tested, there's an
unnecessary request_module("cryptomgr") even if it's already loaded.
Also, CRYPTO_MSG_ALG_LOADED is sent twice, and thus if the algorithm is
"crct10dif", lib/crc-t10dif.c replaces the tfm twice rather than once.

This occurs because CRYPTO_MSG_ALG_LOADED is sent using
crypto_probing_notify(), which tries to load "cryptomgr" if the
notification is not handled (NOTIFY_DONE).  This doesn't make sense
because "cryptomgr" doesn't handle this notification.

Fix this by using crypto_notify() instead of crypto_probing_notify().

Fixes: dd8b083f9a5e ("crypto: api - Introduce notifier for new crypto algorithms")
Cc: <stable@vger.kernel.org> # v4.20+
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 crypto/algapi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/algapi.c b/crypto/algapi.c
index 69605e21af92..849254d7e627 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -403,7 +403,7 @@ static void crypto_wait_for_test(struct crypto_larval *larval)
 	err = wait_for_completion_killable(&larval->completion);
 	WARN_ON(err);
 	if (!err)
-		crypto_probing_notify(CRYPTO_MSG_ALG_LOADED, larval);
+		crypto_notify(CRYPTO_MSG_ALG_LOADED, larval);
 
 out:
 	crypto_larval_kill(&larval->alg);
-- 
2.26.0

Re: [PATCH v2] crypto: algapi - Avoid spurious modprobe on LOADED

[Martin K. Petersen]

Eric,

> Currently after any algorithm is registered and tested, there's an
> unnecessary request_module("cryptomgr") even if it's already loaded.
> Also, CRYPTO_MSG_ALG_LOADED is sent twice, and thus if the algorithm
> is "crct10dif", lib/crc-t10dif.c replaces the tfm twice rather than
> once.
>
> This occurs because CRYPTO_MSG_ALG_LOADED is sent using
> crypto_probing_notify(), which tries to load "cryptomgr" if the
> notification is not handled (NOTIFY_DONE).  This doesn't make sense
> because "cryptomgr" doesn't handle this notification.
>
> Fix this by using crypto_notify() instead of crypto_probing_notify().

Looks good to me.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH v2] crypto: algapi - Avoid spurious modprobe on LOADED

[Herbert Xu]

On Mon, Apr 06, 2020 at 11:02:40PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> Currently after any algorithm is registered and tested, there's an
> unnecessary request_module("cryptomgr") even if it's already loaded.
> Also, CRYPTO_MSG_ALG_LOADED is sent twice, and thus if the algorithm is
> "crct10dif", lib/crc-t10dif.c replaces the tfm twice rather than once.
> 
> This occurs because CRYPTO_MSG_ALG_LOADED is sent using
> crypto_probing_notify(), which tries to load "cryptomgr" if the
> notification is not handled (NOTIFY_DONE).  This doesn't make sense
> because "cryptomgr" doesn't handle this notification.
> 
> Fix this by using crypto_notify() instead of crypto_probing_notify().
> 
> Fixes: dd8b083f9a5e ("crypto: api - Introduce notifier for new crypto algorithms")
> Cc: <stable@vger.kernel.org> # v4.20+
> Cc: Martin K. Petersen <martin.petersen@oracle.com>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
> ---
>  crypto/algapi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Patch applied.  Thanks.
-- 
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