RE: [RFC PATCH 2/3] security: add TLS record processing

[Anoob Joseph <anoobj@marvell.com>]

Hi Harry,

Thanks for the review. Please see inline.

Thanks,
Anoob

> -----Original Message-----
> From: Van Haaren, Harry <harry.van.haaren@intel.com>
> Sent: Wednesday, September 20, 2023 2:53 PM
> To: Anoob Joseph <anoobj@marvell.com>; Thomas Monjalon
> <thomas@monjalon.net>; Akhil Goyal <gakhil@marvell.com>; Jerin Jacob
> Kollanukkaran <jerinj@marvell.com>; Konstantin Ananyev
> <konstantin.v.ananyev@yandex.ru>
> Cc: Hemant Agrawal <hemant.agrawal@nxp.com>; dev@dpdk.org; Matz,
> Olivier <olivier.matz@6wind.com>; Vidya Sagar Velumuri
> <vvelumuri@marvell.com>
> Subject: [EXT] RE: [RFC PATCH 2/3] security: add TLS record processing
> 
> External Email
> 
> ----------------------------------------------------------------------
> > -----Original Message-----
> > From: Anoob Joseph <anoobj@marvell.com>
> > Sent: Friday, August 11, 2023 8:17 AM
> > To: Thomas Monjalon <thomas@monjalon.net>; Akhil Goyal
> > <gakhil@marvell.com>; Jerin Jacob <jerinj@marvell.com>; Konstantin
> > Ananyev <konstantin.v.ananyev@yandex.ru>
> > Cc: Hemant Agrawal <hemant.agrawal@nxp.com>; dev@dpdk.org; Matz,
> > Olivier <olivier.matz@6wind.com>; Vidya Sagar Velumuri
> > <vvelumuri@marvell.com>
> > Subject: [RFC PATCH 2/3] security: add TLS record processing
> >
> > Add Transport Layer Security (TLS) and Datagram Transport Layer
> > Security (DTLS). The protocols provide communications privacy for L4
> > protocols such as TCP & UDP.
> >
> > TLS (and DTLS) protocol is composed of two layers, 1. TLS Record
> > Protocol 2. TLS Handshake Protocol
> >
> > While TLS Handshake Protocol helps in establishing security parameters
> > by which client and server can communicate, TLS Record Protocol
> > provides the connection security. TLS Record Protocol leverages
> > symmetric cryptographic operations such as data encryption and
> > authentication for providing security to the communications.
> >
> > Cryptodevs that are capable of offloading TLS Record Protocol may
> > perform other operations like IV generation, header insertion, atomic
> > sequence number updates and anti-replay window check in addition to
> > cryptographic transformations.
> >
> > The support is added for TLS 1.2, TLS 1.3 and DTLS 1.2.
> 
> From the code below, my understanding is that *ONLY* the record layer is
> being added/supported? The difference is described well above, but the
> intended support added is not clearly defined.
> 
> Suggest reword the last line to clarify:
> "Support for TLS record protocol is added for TLS 1.2, TLS 1.3 and DTLS 1.2."

[Anoob] Indeed. Will reword as suggested.

> 
> 
> > Signed-off-by: Akhil Goyal <gakhil@marvell.com>
> > Signed-off-by: Anoob Joseph <anoobj@marvell.com>
> > Signed-off-by: Vidya Sagar Velumuri <vvelumuri@marvell.com>
> > ---
> >  doc/guides/prog_guide/rte_security.rst |  58 +++++++++++++
> >  lib/security/rte_security.c            |   4 +
> >  lib/security/rte_security.h            | 110 +++++++++++++++++++++++++
> >  3 files changed, 172 insertions(+)
> >
> > diff --git a/doc/guides/prog_guide/rte_security.rst
> > b/doc/guides/prog_guide/rte_security.rst
> > index 7418e35c1b..7716d7239f 100644
> > --- a/doc/guides/prog_guide/rte_security.rst
> > +++ b/doc/guides/prog_guide/rte_security.rst
> > @@ -399,6 +399,64 @@ The API ``rte_security_macsec_sc_create`` returns
> > a handle for SC,  and this handle is set in
> > ``rte_security_macsec_xform``  to create a MACsec session using
> > ``rte_security_session_create``.
> >
> > +TLS-Record Protocol
> > +~~~~~~~~~~~~~~~~~~~
> > +
> > +The Transport Layer Protocol provides communications security over
> > +the
> > Internet. The protocol
> > +allows client/server applications to communicate in a way that is
> > +designed to
> > prevent eavesdropping,
> > +tampering, or message forgery.
> > +
> > +TLS protocol is composed of two layers: the TLS Record Protocol and
> > +the TLS
> > Handshake Protocol. At
> > +the lowest level, layered on top of some reliable transport protocol
> > +(e.g., TCP),
> > is the TLS Record
> > +Protocol. The TLS Record Protocol provides connection security that
> > +has two
> > basic properties:
> > +
> > +   -  The connection is private.  Symmetric cryptography is used for data
> > +      encryption (e.g., AES, DES, etc.).  The keys for this symmetric
> encryption
> > +      are generated uniquely for each connection and are based on a secret
> > +      negotiated by another protocol (such as the TLS Handshake Protocol).
> The
> > +      Record Protocol can also be used without encryption.
> > +
> > +   -  The connection is reliable.  Message transport includes a message
> > +      integrity check using a keyed MAC.  Secure hash functions (e.g.,
> > +      SHA-1, etc.) are used for MAC computations.  The Record Protocol
> > +      can operate without a MAC, but is generally only used in this mode
> > +      while another protocol is using the Record Protocol as a transport
> > +      for negotiating security parameters.
> > +
> > +.. code-block:: c
> 
> The code block below isn't C? Is there a better code block type for a text
> diagram?

[Anoob] Valid point. I was just following the general scheme followed in this file. May be, I'll introduce a .svg image for newly added code.

> 
> > +             Record Write                   Record Read
> > +             ------------                   -----------
> > +
> > +             TLSPlaintext                  TLSCiphertext
> > +                  |                              |
> > +                  ~                              ~
> > +                  |                              |
> > +                  V                              V
> > +        +---------|----------+        +----------|---------+
> > +        | Seq. no generation |        | Seq. no generation |
> > +        +---------|----------+        +----------|---------+
> > +                  |                              |
> > +        +---------|----------+        +----------|---------+
> > +        |  Header insertion  |        |    Decryption &    |
> > +        +---------|----------+        |  MAC verification  |
> > +                  |                   +----------|---------+
> > +        +---------|----------+                   |
> > +        |  MAC generation &  |        +----------|---------+
> > +        |     Encryption     |        | TLS Header removal |
> > +        +---------|----------+        +----------|---------+
> > +                  |                              |
> > +                  ~                              ~
> > +                  |                              |
> > +                  V                              V
> > +            TLSCiphertext                  TLSPlaintext
> > +
> > +Supported Versions
> > +^^^^^^^^^^^^^^^^^^
> > +
> > +* TLS 1.2
> > +* TLS 1.3
> > +* DTLS 1.2
> >
> >  Device Features and Capabilities
> >  ---------------------------------
> > diff --git a/lib/security/rte_security.c b/lib/security/rte_security.c
> > index c4d64bb8e9..bd7b026547 100644
> > --- a/lib/security/rte_security.c
> > +++ b/lib/security/rte_security.c
> > @@ -282,6 +282,10 @@ rte_security_capability_get(struct
> > rte_security_ctx *instance,
> >  				if (capability->docsis.direction ==
> >  							idx->docsis.direction)
> >  					return capability;
> > +			} else if (idx->protocol ==
> > RTE_SECURITY_PROTOCOL_TLS_RECORD) {
> > +				if (capability->tls_record.ver == idx-
> > >tls_record.ver &&
> > +				    capability->tls_record.type == idx-
> > >tls_record.type)
> > +					return capability;
> >  			}
> >  		}
> >  	}
> > diff --git a/lib/security/rte_security.h b/lib/security/rte_security.h
> > index 3b2df526ba..b9d064ed84 100644
> > --- a/lib/security/rte_security.h
> > +++ b/lib/security/rte_security.h
> > @@ -620,6 +620,99 @@ struct rte_security_docsis_xform {
> >  	/**< DOCSIS direction */
> >  };
> >
> > +/** Salt len to be used with AEAD algos in TLS 1.2 */ #define
> > +RTE_SECURITY_TLS_1_2_SALT_LEN 4
> > +/** Salt len to be used with AEAD algos in TLS 1.3 */ #define
> > +RTE_SECURITY_TLS_1_3_SALT_LEN 12
> > +/** Salt len to be used with AEAD algos in DTLS 1.2 */ #define
> > +RTE_SECURITY_DTLS_1_2_SALT_LEN 4
> > +
> > +/** TLS version */
> > +enum rte_security_tls_version {
> > +	RTE_SECURITY_VERSION_TLS_1_2,	/**< TLS 1.2 */
> > +	RTE_SECURITY_VERSION_TLS_1_3,	/**< TLS 1.3 */
> > +	RTE_SECURITY_VERSION_DTLS_1_2,	/**< DTLS 1.2 */
> > +};
> > +
> > +/** TLS session type */
> > +enum rte_security_tls_sess_type {
> > +	/** Record read session
> > +	 * - Decrypt & digest verification.
> > +	 */
> > +	RTE_SECURITY_TLS_SESS_TYPE_READ,
> > +	/** Record write session
> > +	 * - Encrypt & digest generation.
> > +	 */
> > +	RTE_SECURITY_TLS_SESS_TYPE_WRITE,
> > +};
> > +
> > +/**
> > + * Configure soft and hard lifetime of a TLS record session
> > + *
> > + * Lifetime of a TLS record session would specify the maximum number
> > +of
> > packets that can be
> > + * processed. TLS record processing operations would start failing
> > + once hard
> > limit is reached.
> > + *
> > + * Soft limits can be specified to generate notification when the TLS
> > + record
> > session is approaching
> > + * hard limits for lifetime. This would result in a warning returned
> > + in
> > ``rte_crypto_op.aux_flags``.
> 
> Can we define "a warning" better? Perhaps an example of a soft-limit and
> hard-limit, what the user can check aux_flags for, to identify? Or link to the
> appropriate part of the crypto_op.aux_flags documentation to help the user.
> 

[Anoob] The concept of lifetime is present in most protocols. Idea is to limit the max number of operations performed with a session. Soft expiry notification is to help application prepare for an expiry and setup a new session before the current one expires. The idea was borrowed from IPsec which has the  'RTE_CRYPTO_OP_AUX_FLAGS_IPSEC_SOFT_EXPIRY' flag defined. But I realize, it should be better defined. I can rename the flag to 'RTE_CRYPTO_OP_AUX_FLAGS_SEC_SOFT_EXPIRY' to avoid redefining same flag for each security offload. Do you agree to this suggestion?

https://elixir.bootlin.com/dpdk/latest/source/lib/cryptodev/rte_crypto.h#L67

Do note that once hard expiry is hit, the operation would fail. Expectation is, cryptodev would return 'RTE_CRYPTO_OP_STATUS_ERROR' in case of errors.

> > + */
> > +struct rte_security_tls_record_lifetime {
> > +	/** Soft expiry limit in number of packets */
> > +	uint64_t packets_soft_limit;
> > +	/** Hard expiry limit in number of packets */
> > +	uint64_t packets_hard_limit;
> > +};
> > +
> > +/**
> > + * TLS record protocol session configuration.
> > + *
> > + * This structure contains data required to create a TLS record security
> session.
> > + */
> > +struct rte_security_tls_record_xform {
> > +	/** TLS record version. */
> > +	enum rte_security_tls_version ver;
> > +	/** TLS record session type. */
> > +	enum rte_security_tls_sess_type type;
> > +	/** TLS record session lifetime. */
> > +	struct rte_security_tls_record_lifetime life;
> > +	union {
> > +		/** TLS 1.2 parameters. */
> > +		struct {
> > +			/** Starting sequence number. */
> > +			uint64_t seq_no;
> > +			/** Salt to be used for AEAD algos. */
> > +			uint8_t salt[RTE_SECURITY_TLS_1_2_SALT_LEN];
> > +		} tls_1_2;
> > +
> > +		/** TLS 1.3 parameters. */
> > +		struct {
> > +			/** Starting sequence number. */
> > +			uint64_t seq_no;
> > +			/** Salt to be used for AEAD algos. */
> > +			uint8_t salt[RTE_SECURITY_TLS_1_3_SALT_LEN];
> > +			/**
> > +			 * Minimum payload length (in case of write
> sessions).
> > For shorter inputs,
> > +			 * the payload would be padded appropriately before
> > performing crypto
> 
> Replace "would be"  with "must be"? And who must do this step, is it the
> application?

[Anoob] Padding is performed by the PMD/cryptodev device. I'll change "would be" to "will be". Would that address your concern?

> 
> > +			 * transformations.
> > +			 */
> > +			uint32_t min_payload_len;
> > +		} tls_1_3;
> > +
> > +		/** DTLS 1.2 parameters */
> > +		struct {
> > +			/** Epoch value to be used. */
> > +			uint16_t epoch;
> > +			/** 6B starting sequence number to be used. */
> > +			uint64_t seq_no;
> > +			/** Salt to be used for AEAD algos. */
> > +			uint8_t salt[RTE_SECURITY_DTLS_1_2_SALT_LEN];
> > +			/** Anti replay window size to enable sequence
> replay
> > attack handling.
> > +			 * Anti replay check is disabled if the window size is 0.
> > +			 */
> > +			uint32_t ar_win_sz;
> > +		} dtls_1_2;
> > +	};
> > +};
> > +
> >  /**
> >   * Security session action type.
> >   */
> > @@ -654,6 +747,8 @@ enum rte_security_session_protocol {
> >  	/**< PDCP Protocol */
> >  	RTE_SECURITY_PROTOCOL_DOCSIS,
> >  	/**< DOCSIS Protocol */
> > +	RTE_SECURITY_PROTOCOL_TLS_RECORD,
> > +	/**< TLS Record Protocol */
> >  };
> >
> >  /**
> > @@ -670,6 +765,7 @@ struct rte_security_session_conf {
> >  		struct rte_security_macsec_xform macsec;
> >  		struct rte_security_pdcp_xform pdcp;
> >  		struct rte_security_docsis_xform docsis;
> > +		struct rte_security_tls_record_xform tls;
> 
> Do we see TLS handshake xform being added in future? If so, is 'tls' a good
> name, perhaps 'tls_record'?
> That would allow 'tls_handshake' in future, with consistent naming scheme
> without API/ABI break.

[Anoob] In the future, I would like to see TLS handshake also offloaded in a similar manner. But that would need some fundamental changes in security library. Like, current security library is pretty much tied to symmetric operations but a handshake would involve both symmetric & asymmetric operations.

Said that, I agree with your suggestion to rename the field. Will change it to 'tls_record' in next version.

> 
> 
> >  	};
> >  	/**< Configuration parameters for security session */
> >  	struct rte_crypto_sym_xform *crypto_xform; @@ -1190,6 +1286,16
> @@
> > struct rte_security_capability {
> >  			/**< DOCSIS direction */
> >  		} docsis;
> >  		/**< DOCSIS capability */
> > +		struct {
> > +			enum rte_security_tls_version ver;
> > +			/**< TLS record version. */
> > +			enum rte_security_tls_sess_type type;
> > +			/**< TLS record session type. */
> > +			uint32_t ar_win_size;
> > +			/**< Maximum anti replay window size supported
> for
> > DTLS 1.2 record read
> > +			 * operation. Value of 0 means anti replay check is
> not
> > supported.
> > +			 */
> > +		} tls_record;
> 
> Missing      /**< TLS Record Capability */     docstring here.

[Anoob] Agreed. Will add in next version.

> 
> >  	};
> >
> >  	const struct rte_cryptodev_capabilities *crypto_capabilities; @@
> > -1251,6 +1357,10 @@ struct rte_security_capability_idx {
> >  		struct {
> >  			enum rte_security_docsis_direction direction;
> >  		} docsis;
> > +		struct {
> > +			enum rte_security_tls_version ver;
> > +			enum rte_security_tls_sess_type type;
> > +		} tls_record;
> >  	};
> >  };
> >
> > --
> > 2.25.1