The data structure of struct crypto_alg together with various other
data structures needed by cipher developers is documented wit all
parameters that can be set by a developer of a transformation. All
parameters that are internal to the crypto API are marked as such.
Signed-off-by: Stephan Mueller <smuel...@chronox.de>
---
include/linux/crypto.h | 246 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 243 insertions(+), 3 deletions(-)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index d45e949..752360e 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -127,6 +127,13 @@ struct skcipher_givcrypt_request;
typedef void (*crypto_completion_t)(struct crypto_async_request *req, int err);
+/**
+ * DOC: Block Cipher Context Data Structures
+ *
+ * These data structures define the operating context for each block cipher
+ * type.
+ */
+
struct crypto_async_request {
struct list_head list;
crypto_completion_t complete;
@@ -194,9 +201,63 @@ struct hash_desc {
u32 flags;
};
-/*
- * Algorithms: modular crypto algorithm implementations, managed
- * via crypto_register_alg() and crypto_unregister_alg().
+/**
+ * DOC: Block Cipher Algorithm Definitions
+ *
+ * These data structures define modular crypto algorithm implementations,
+ * managed via crypto_register_alg() and crypto_unregister_alg().
+ */
+
+/**
+ * struct ablkcipher_alg - asynchronous block cipher definition
+ * @min_keysize: Minimum key size supported by the transformation. This is the
+ * smallest key length supported by this transformation algorithm.
+ * This must be set to one of the pre-defined values as this is
+ * not hardware specific. Possible values for this field can be
+ * found via git grep "_MIN_KEY_SIZE" include/crypto/
+ * @max_keysize: Maximum key size supported by the transformation. This is the
+ * largest key length supported by this transformation algorithm.
+ * This must be set to one of the pre-defined values as this is
+ * not hardware specific. Possible values for this field can be
+ * found via git grep "_MAX_KEY_SIZE" include/crypto/
+ * @setkey: Set key for the transformation. This function is used to either
+ * program a supplied key into the hardware or store the key in the
+ * transformation context for programming it later. Note that this
+ * function does modify the transformation context. This function can
+ * be called multiple times during the existence of the transformation
+ * object, so one must make sure the key is properly reprogrammed into
+ * the hardware. This function is also responsible for checking the key
+ * length for validity. In case a software fallback was put in place in
+ * the @cra_init call, this function might need to use the fallback if
+ * the algorithm doesn't support all of the key sizes.
+ * @encrypt: Encrypt a scatterlist of blocks. This function is used to encrypt
+ * the supplied scatterlist containing the blocks of data. The crypto
+ * API consumer is responsible for aligning the entries of the
+ * scatterlist properly and making sure the chunks are correctly
+ * sized. In case a software fallback was put in place in the
+ * @cra_init call, this function might need to use the fallback if
+ * the algorithm doesn't support all of the key sizes. In case the
+ * key was stored in transformation context, the key might need to be
+ * re-programmed into the hardware in this function. This function
+ * shall not modify the transformation context, as this function may
+ * be called in parallel with the same transformation object.
+ * @decrypt: Decrypt a single block. This is a reverse counterpart to @encrypt
+ * and the conditions are exactly the same.
+ * @givencrypt: Update the IV for encryption. With this function, a cipher
+ * implementation may provide the function on how to update the IV
+ * for encryption.
+ * @givdecrypt: Update the IV for decryption. This is the reverse of
+ * @givencrypt .
+ * @geniv: The transformation implementation may use an "IV generator" provided
+ * by the kernel crypto API. Several use cases have a predefined
+ * approach how IVs are to be updated. For such use cases, the kernel
+ * crypto API provides ready-to-use implementations that can be
+ * referenced with this variable.
+ * @ivsize: IV size applicable for transformation. The consumer must provide an
+ * IV of exactly that size to perform the encrypt or decrypt operation.
+ *
+ * All fields except @givencrypt , @givdecrypt , @geniv and @ivsize are
+ * mandatory and must be filled.
*/
struct ablkcipher_alg {
int (*setkey)(struct crypto_ablkcipher *tfm, const u8 *key,
@@ -213,6 +274,32 @@ struct ablkcipher_alg {
unsigned int ivsize;
};
+/**
+ * struct aead_alg - AEAD cipher definition
+ * @maxauthsize: Set the maximum authentication tag size supported by the
+ * transformation. A transformation may support smaller tag sizes.
+ * As the authentication tag is a message digest to ensure the
+ * integrity of the encrypted data, a consumer typically wants the
+ * largest authentication tag possible as defined by this
+ * variable.
+ * @setauthsize: Set authentication size for the AEAD transformation. This
+ * function is used to specify the consumer requested size of the
+ * authentication tag to be either generated by the transformation
+ * during encryption or the size of the authentication tag to be
+ * supplied during the decryption operation. This function is also
+ * responsible for checking the authentication tag size for
+ * validity.
+ * @setkey: see struct ablkcipher_alg
+ * @encrypt: see struct ablkcipher_alg
+ * @decrypt: see struct ablkcipher_alg
+ * @givencrypt: see struct ablkcipher_alg
+ * @givdecrypt: see struct ablkcipher_alg
+ * @geniv: see struct ablkcipher_alg
+ * @ivsize: see struct ablkcipher_alg
+ *
+ * All fields except @givencrypt , @givdecrypt , @geniv and @ivsize are
+ * mandatory and must be filled.
+ */
struct aead_alg {
int (*setkey)(struct crypto_aead *tfm, const u8 *key,
unsigned int keylen);
@@ -228,6 +315,18 @@ struct aead_alg {
unsigned int maxauthsize;
};
+/**
+ * struct blkcipher_alg - synchronous block cipher definition
+ * @min_keysize: see struct ablkcipher_alg
+ * @max_keysize: see struct ablkcipher_alg
+ * @setkey: see struct ablkcipher_alg
+ * @encrypt: see struct ablkcipher_alg
+ * @decrypt: see struct ablkcipher_alg
+ * @geniv: see struct ablkcipher_alg
+ * @ivsize: see struct ablkcipher_alg
+ *
+ * All fields except @geniv and @ivsize are mandatory and must be filled.
+ */
struct blkcipher_alg {
int (*setkey)(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen);
@@ -245,6 +344,53 @@ struct blkcipher_alg {
unsigned int ivsize;
};
+/**
+ * struct cipher_alg - single-block symmetric ciphers definition
+ * @cia_min_keysize: Minimum key size supported by the transformation. This is
+ * the smallest key length supported by this transformation
+ * algorithm. This must be set to one of the pre-defined
+ * values as this is not hardware specific. Possible values
+ * for this field can be found via git grep "_MIN_KEY_SIZE"
+ * include/crypto/
+ * @cia_max_keysize: Maximum key size supported by the transformation. This is
+ * the largest key length supported by this transformation
+ * algorithm. This must be set to one of the pre-defined values
+ * as this is not hardware specific. Possible values for this
+ * field can be found via git grep "_MAX_KEY_SIZE"
+ * include/crypto/
+ * @cia_setkey: Set key for the transformation. This function is used to either
+ * program a supplied key into the hardware or store the key in the
+ * transformation context for programming it later. Note that this
+ * function does modify the transformation context. This function
+ * can be called multiple times during the existence of the
+ * transformation object, so one must make sure the key is properly
+ * reprogrammed into the hardware. This function is also
+ * responsible for checking the key length for validity.
+ * @cia_encrypt: Encrypt a single block. This function is used to encrypt a
+ * single block of data, which must be @cra_blocksize big. This
+ * always operates on a full @cra_blocksize and it is not possible
+ * to encrypt a block of smaller size. The supplied buffers must
+ * therefore also be at least of @cra_blocksize size. Both the
+ * input and output buffers are always aligned to @cra_alignmask.
+ * In case either of the input or output buffer supplied by user
+ * of the crypto API is not aligned to @cra_alignmask, the crypto
+ * API will re-align the buffers. The re-alignment means that a
+ * new buffer will be allocated, the data will be copied into the
+ * new buffer, then the processing will happen on the new buffer,
+ * then the data will be copied back into the original buffer and
+ * finally the new buffer will be freed. In case a software
+ * fallback was put in place in the @cra_init call, this function
+ * might need to use the fallback if the algorithm doesn't support
+ * all of the key sizes. In case the key was stored in
+ * transformation context, the key might need to be re-programmed
+ * into the hardware in this function. This function shall not
+ * modify the transformation context, as this function may be
+ * called in parallel with the same transformation object.
+ * @cia_decrypt: Decrypt a single block. This is a reverse counterpart to
+ * @cia_encrypt, and the conditions are exactly the same.
+ *
+ * All fields are mandatory and must be filled.
+ */
struct cipher_alg {
unsigned int cia_min_keysize;
unsigned int cia_max_keysize;
@@ -261,6 +407,25 @@ struct compress_alg {
unsigned int slen, u8 *dst, unsigned int *dlen);
};
+/**
+ * struct rng_alg - random number generator definition
+ * @rng_make_random: The function defined by this variable obtains a random
+ * number. The random number generator transform must generate
+ * the random number out of the context provided with this
+ * call.
+ * @rng_reset: Reset of the random number generator by clearing the entire
state.
+ * With the invocation of this function call, the random number
+ * generator shall completely reinitialize its state. If the random
+ * number generator requires a seed for setting up a new state,
+ * the seed must be provided by the consumer while invoking this
+ * function. The required size of the seed is defined with
+ * @seedsize .
+ * @seedsize: The seed size required for a random number generator
+ * initialization defined with this variable. Some random number
+ * generators like the SP800-90A DRBG does not require a seed as the
+ * seeding is implemented internally without the need of support by
+ * the consumer. In this case, the seed size is set to zero.
+ */
struct rng_alg {
int (*rng_make_random)(struct crypto_rng *tfm, u8 *rdata,
unsigned int dlen);
@@ -277,6 +442,81 @@ struct rng_alg {
#define cra_compress cra_u.compress
#define cra_rng cra_u.rng
+/**
+ * struct crypto_alg - definition of a cryptograpic cipher algorithm
+ * @cra_flags: Flags describing this transformation. See include/linux/crypto.h
+ * CRYPTO_ALG_* flags for the flags which go in here. Those are
+ * used for fine-tuning the description of the transformation
+ * algorithm.
+ * @cra_blocksize: Minimum block size of this transformation. The size in bytes
+ * of the smallest possible unit which can be transformed with
+ * this algorithm. The users must respect this value.
+ * In case of HASH transformation, it is possible for a smaller
+ * block than @cra_blocksize to be passed to the crypto API for
+ * transformation, in case of any other transformation type, an
+ * error will be returned upon any attempt to transform smaller
+ * than @cra_blocksize chunks.
+ * @cra_ctxsize: Size of the operational context of the transformation. This
+ * value informs the kernel crypto API about the memory size
+ * needed to be allocated for the transformation context.
+ * @cra_alignmask: Alignment mask for the input and output data buffer. The
data
+ * buffer containing the input data for the algorithm must be
+ * aligned to this alignment mask. The data buffer for the
+ * output data must be aligned to this alignment mask. Note that
+ * the Crypto API will do the re-alignment in software, but
+ * only under special conditions and there is a performance hit.
+ * The re-alignment happens at these occasions for different
+ * @cra_u types: cipher -- For both input data and output data
+ * buffer; ahash -- For output hash destination buf; shash --
+ * For output hash destination buf.
+ * This is needed on hardware which is flawed by design and
+ * cannot pick data from arbitrary addresses.
+ * @cra_priority: Priority of this transformation implementation. In case
+ * multiple transformations with same @cra_name are available to
+ * the Crypto API, the kernel will use the one with highest
+ * @cra_priority.
+ * @cra_name: Generic name (usable by multiple implementations) of the
+ * transformation algorithm. This is the name of the transformation
+ * itself. This field is used by the kernel when looking up the
+ * providers of particular transformation.
+ * @cra_driver_name: Unique name of the transformation provider. This is the
+ * name of the provider of the transformation. This can be any
+ * arbitrary value, but in the usual case, this contains the
+ * name of the chip or provider and the name of the
+ * transformation algorithm.
+ * @cra_type: Type of the cryptographic transformation. This is a pointer to
+ * struct crypto_type, which implements callbacks common for all
+ * trasnformation types. There are multiple options:
+ * &crypto_blkcipher_type, &crypto_ablkcipher_type,
+ * &crypto_ahash_type, &crypto_aead_type, &crypto_rng_type.
+ * This field might be empty. In that case, there are no common
+ * callbacks. This is the case for: cipher, compress, shash.
+ * @cra_u: Callbacks implementing the transformation. This is a union of
+ * multiple structures. Depending on the type of transformation selected
+ * by @cra_type and @cra_flags above, the associated structure must be
+ * filled with callbacks. This field might be empty. This is the case
+ * for ahash, shash.
+ * @cra_init: Initialize the cryptographic transformation object. This function
+ * is used to initialize the cryptographic transformation object.
+ * This function is called only once at the instantiation time, right
+ * after the transformation context was allocated. In case the
+ * cryptographic hardware has some special requirements which need to
+ * be handled by software, this function shall check for the precise
+ * requirement of the transformation and put any software fallbacks
+ * in place.
+ * @cra_exit: Deinitialize the cryptographic transformation object. This is a
+ * counterpart to @cra_init, used to remove various changes set in
+ * @cra_init.
+ * @cra_module: Owner of this transformation implementation. Set to THIS_MODULE
+ * @cra_list: internally used
+ * @cra_users: internally used
+ * @cra_refcnt: internally used
+ * @cra_destroy: internally used
+ *
+ * The struct crypto_alg describes a generic Crypto API algorithm and is common
+ * for all of the transformations. Any variable not documented here shall not
+ * be used by a cipher implementation as it is internal to the Crypto API.
+ */
struct crypto_alg {
struct list_head cra_list;
struct list_head cra_users;
--
2.1.0
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