[dpdk-dev] [PATCH] [RFC] cryptodev: move AES-GMAC to aead algorithms

[Kusztal, ArkadiuszX]

Hi All,

I would give bit more introduction to this change:
Right now AES-GMAC is auth only algorithm (previously it was cipher+auth -> GCM + GMAC),
but since it is variant of AES-GCM implementation it should probably be AEAD right now (people often wondering why at all it is auth instead of AEAD).
There are few possible implementations let me introduce two of them:
1) As in this patch GMAC is added to AEAD enum, aad_len is set to 0, aad_pointer is unused and authentication length is set in aead.data.length - this is probably the easiest one, but not totally conformant to GMAC spec.
2) Another option could be to use GCM only and add new field aad_len in rte_crypto_sym_op, so when cipher_len == 0 GMAC is used -> this would be conformant implementation but bit trickier.

Sorry if I not included someone in cc list.

> -----Original Message-----
> From: Kusztal, ArkadiuszX <arkadiuszx.kusztal at intel.com>
> Sent: Wednesday, July 29, 2020 4:22 PM
> To: dev at dpdk.org
> Cc: akhil.goyal at nxp.com; Trahe, Fiona <fiona.trahe at intel.com>;
> anoobj at marvell.com; shallyv at marvell.com; Doherty, Declan
> <declan.doherty at intel.com>; Zhang, Roy Fan <roy.fan.zhang at intel.com>;
> Ananyev, Konstantin <konstantin.ananyev at intel.com>; Kusztal, ArkadiuszX
> <arkadiuszx.kusztal at intel.com>
> Subject: [PATCH] [RFC] cryptodev: move AES-GMAC to aead algorithms
> 
> This is proposal to move AES-GMAC algorithm to AEAD set of algorithms. It is
> however not 100% conformant GMAC as instead of aad pointer data to be
> authenticated is passed normally and  aead.data.length field is used to
> specify length of data to be authenticated.
> Reason behind this move is that GMAC is variant of GCM so it may simplify
> implementations that are using these algorithms (mainly IPsec).
> AES-GMAC therefore needs to be removed from auth algorithms.
> 
> Signed-off-by: Arek Kusztal <arkadiuszx.kusztal at intel.com>
> ---
>  lib/librte_cryptodev/rte_crypto_sym.h | 15 +++++++++++----
> lib/librte_cryptodev/rte_cryptodev.c  |  4 ++--
>  2 files changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/lib/librte_cryptodev/rte_crypto_sym.h
> b/lib/librte_cryptodev/rte_crypto_sym.h
> index f29c980..1b43c6e 100644
> --- a/lib/librte_cryptodev/rte_crypto_sym.h
> +++ b/lib/librte_cryptodev/rte_crypto_sym.h
> @@ -255,8 +255,6 @@ enum rte_crypto_auth_algorithm {
>  	/**< AES-CBC-MAC algorithm. Only 128-bit keys are supported. */
>  	RTE_CRYPTO_AUTH_AES_CMAC,
>  	/**< AES CMAC algorithm. */
> -	RTE_CRYPTO_AUTH_AES_GMAC,
> -	/**< AES GMAC algorithm. */
>  	RTE_CRYPTO_AUTH_AES_XCBC_MAC,
>  	/**< AES XCBC algorithm. */
> 
> @@ -414,6 +412,8 @@ enum rte_crypto_aead_algorithm {
>  	/**< AES algorithm in GCM mode. */
>  	RTE_CRYPTO_AEAD_CHACHA20_POLY1305,
>  	/**< Chacha20 cipher with poly1305 authenticator */
> +	RTE_CRYPTO_AEAD_AES_GMAC,
> +	/**< AES-GCM algorithm in GMAC mode. */
>  	RTE_CRYPTO_AEAD_LIST_END
>  };
> 
> @@ -468,7 +468,7 @@ struct rte_crypto_aead_xform {
>  		uint16_t length;
>  		/**< Length of valid IV data.
>  		 *
> -		 * - For GCM mode, this is either:
> +		 * - For GCM and GMAC mode, this is either:
>  		 * 1) Number greater or equal to one, which means that IV
>  		 *    is used and J0 will be computed internally, a minimum
>  		 *    of 16 bytes must be allocated.
> @@ -490,6 +490,8 @@ struct rte_crypto_aead_xform {
>  	 * For CCM mode, this is the length of the actual AAD, even though
>  	 * it is required to reserve 18 bytes before the AAD and padding
>  	 * at the end of it, so a multiple of 16 bytes is allocated.
> +	 *
> +	 * For RTE_CRYPTO_AEAD_AES_GMAC this field should be set to 0.
>  	 */
>  };
> 
> @@ -584,7 +586,10 @@ struct rte_crypto_sym_op {
>  				uint32_t length;
>  				 /**< The message length, in bytes, of the
> source buffer
>  				  * on which the cryptographic operation will
> be
> -				  * computed. This must be a multiple of the
> block size
> +				  * computed.
> +				  *
> +				  * For RTE_CRYPTO_AEAD_AES_GMAC this is
> length of data to be
> +				  * authenticated.
>  				  */
>  			} data; /**< Data offsets and length for AEAD */
>  			struct {
> @@ -617,6 +622,8 @@ struct rte_crypto_sym_op {
>  				 * needed for authenticated cipher
> mechanisms (CCM and
>  				 * GCM)
>  				 *
> +				 * For GCM this field is unused
> +				 *
>  				 * Specifically for CCM (@ref
> RTE_CRYPTO_AEAD_AES_CCM),
>  				 * the caller should setup this field as follows:
>  				 *
> diff --git a/lib/librte_cryptodev/rte_cryptodev.c
> b/lib/librte_cryptodev/rte_cryptodev.c
> index 1dd795b..e14fd09 100644
> --- a/lib/librte_cryptodev/rte_cryptodev.c
> +++ b/lib/librte_cryptodev/rte_cryptodev.c
> @@ -129,7 +129,6 @@ const char *
>  rte_crypto_auth_algorithm_strings[] = {
>  	[RTE_CRYPTO_AUTH_AES_CBC_MAC]	= "aes-cbc-mac",
>  	[RTE_CRYPTO_AUTH_AES_CMAC]	= "aes-cmac",
> -	[RTE_CRYPTO_AUTH_AES_GMAC]	= "aes-gmac",
>  	[RTE_CRYPTO_AUTH_AES_XCBC_MAC]	= "aes-xcbc-mac",
> 
>  	[RTE_CRYPTO_AUTH_MD5]		= "md5",
> @@ -162,7 +161,8 @@ const char *
>  rte_crypto_aead_algorithm_strings[] = {
>  	[RTE_CRYPTO_AEAD_AES_CCM]	= "aes-ccm",
>  	[RTE_CRYPTO_AEAD_AES_GCM]	= "aes-gcm",
> -	[RTE_CRYPTO_AEAD_CHACHA20_POLY1305] = "chacha20-poly1305"
> +	[RTE_CRYPTO_AEAD_CHACHA20_POLY1305] = "chacha20-poly1305",
> +	[RTE_CRYPTO_AEAD_AES_GMAC] = "aes-gmac"
>  };
> 
>  /**
> --
> 2.1.0