| /* |
| * AEAD: Authenticated Encryption with Associated Data |
| * |
| * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au> |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| * |
| */ |
| |
| #ifndef _CRYPTO_AEAD_H |
| #define _CRYPTO_AEAD_H |
| |
| #include <linux/crypto.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| |
| /** |
| * DOC: Authenticated Encryption With Associated Data (AEAD) Cipher API |
| * |
| * The AEAD cipher API is used with the ciphers of type CRYPTO_ALG_TYPE_AEAD |
| * (listed as type "aead" in /proc/crypto) |
| * |
| * The most prominent examples for this type of encryption is GCM and CCM. |
| * However, the kernel supports other types of AEAD ciphers which are defined |
| * with the following cipher string: |
| * |
| * authenc(keyed message digest, block cipher) |
| * |
| * For example: authenc(hmac(sha256), cbc(aes)) |
| * |
| * The example code provided for the symmetric key cipher operation |
| * applies here as well. Naturally all *skcipher* symbols must be exchanged |
| * the *aead* pendants discussed in the following. In addition, for the AEAD |
| * operation, the aead_request_set_ad function must be used to set the |
| * pointer to the associated data memory location before performing the |
| * encryption or decryption operation. In case of an encryption, the associated |
| * data memory is filled during the encryption operation. For decryption, the |
| * associated data memory must contain data that is used to verify the integrity |
| * of the decrypted data. Another deviation from the asynchronous block cipher |
| * operation is that the caller should explicitly check for -EBADMSG of the |
| * crypto_aead_decrypt. That error indicates an authentication error, i.e. |
| * a breach in the integrity of the message. In essence, that -EBADMSG error |
| * code is the key bonus an AEAD cipher has over "standard" block chaining |
| * modes. |
| * |
| * Memory Structure: |
| * |
| * To support the needs of the most prominent user of AEAD ciphers, namely |
| * IPSEC, the AEAD ciphers have a special memory layout the caller must adhere |
| * to. |
| * |
| * The scatter list pointing to the input data must contain: |
| * |
| * * for RFC4106 ciphers, the concatenation of |
| * associated authentication data || IV || plaintext or ciphertext. Note, the |
| * same IV (buffer) is also set with the aead_request_set_crypt call. Note, |
| * the API call of aead_request_set_ad must provide the length of the AAD and |
| * the IV. The API call of aead_request_set_crypt only points to the size of |
| * the input plaintext or ciphertext. |
| * |
| * * for "normal" AEAD ciphers, the concatenation of |
| * associated authentication data || plaintext or ciphertext. |
| * |
| * It is important to note that if multiple scatter gather list entries form |
| * the input data mentioned above, the first entry must not point to a NULL |
| * buffer. If there is any potential where the AAD buffer can be NULL, the |
| * calling code must contain a precaution to ensure that this does not result |
| * in the first scatter gather list entry pointing to a NULL buffer. |
| */ |
| |
| struct crypto_aead; |
| |
| /** |
| * struct aead_request - AEAD request |
| * @base: Common attributes for async crypto requests |
| * @assoclen: Length in bytes of associated data for authentication |
| * @cryptlen: Length of data to be encrypted or decrypted |
| * @iv: Initialisation vector |
| * @src: Source data |
| * @dst: Destination data |
| * @__ctx: Start of private context data |
| */ |
| struct aead_request { |
| struct crypto_async_request base; |
| |
| unsigned int assoclen; |
| unsigned int cryptlen; |
| |
| u8 *iv; |
| |
| struct scatterlist *src; |
| struct scatterlist *dst; |
| |
| void *__ctx[] CRYPTO_MINALIGN_ATTR; |
| }; |
| |
| /** |
| * 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 skcipher_alg |
| * @encrypt: see struct skcipher_alg |
| * @decrypt: see struct skcipher_alg |
| * @geniv: see struct skcipher_alg |
| * @ivsize: see struct skcipher_alg |
| * @chunksize: see struct skcipher_alg |
| * @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. |
| * @exit: Deinitialize the cryptographic transformation object. This is a |
| * counterpart to @init, used to remove various changes set in |
| * @init. |
| * @base: Definition of a generic crypto cipher algorithm. |
| * |
| * All fields except @ivsize is mandatory and must be filled. |
| */ |
| struct aead_alg { |
| int (*setkey)(struct crypto_aead *tfm, const u8 *key, |
| unsigned int keylen); |
| int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize); |
| int (*encrypt)(struct aead_request *req); |
| int (*decrypt)(struct aead_request *req); |
| int (*init)(struct crypto_aead *tfm); |
| void (*exit)(struct crypto_aead *tfm); |
| |
| const char *geniv; |
| |
| unsigned int ivsize; |
| unsigned int maxauthsize; |
| unsigned int chunksize; |
| |
| struct crypto_alg base; |
| }; |
| |
| struct crypto_aead { |
| unsigned int authsize; |
| unsigned int reqsize; |
| |
| struct crypto_tfm base; |
| }; |
| |
| static inline struct crypto_aead *__crypto_aead_cast(struct crypto_tfm *tfm) |
| { |
| return container_of(tfm, struct crypto_aead, base); |
| } |
| |
| /** |
| * crypto_alloc_aead() - allocate AEAD cipher handle |
| * @alg_name: is the cra_name / name or cra_driver_name / driver name of the |
| * AEAD cipher |
| * @type: specifies the type of the cipher |
| * @mask: specifies the mask for the cipher |
| * |
| * Allocate a cipher handle for an AEAD. The returned struct |
| * crypto_aead is the cipher handle that is required for any subsequent |
| * API invocation for that AEAD. |
| * |
| * Return: allocated cipher handle in case of success; IS_ERR() is true in case |
| * of an error, PTR_ERR() returns the error code. |
| */ |
| struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask); |
| |
| static inline struct crypto_tfm *crypto_aead_tfm(struct crypto_aead *tfm) |
| { |
| return &tfm->base; |
| } |
| |
| /** |
| * crypto_free_aead() - zeroize and free aead handle |
| * @tfm: cipher handle to be freed |
| */ |
| static inline void crypto_free_aead(struct crypto_aead *tfm) |
| { |
| crypto_destroy_tfm(tfm, crypto_aead_tfm(tfm)); |
| } |
| |
| static inline struct aead_alg *crypto_aead_alg(struct crypto_aead *tfm) |
| { |
| return container_of(crypto_aead_tfm(tfm)->__crt_alg, |
| struct aead_alg, base); |
| } |
| |
| static inline unsigned int crypto_aead_alg_ivsize(struct aead_alg *alg) |
| { |
| return alg->ivsize; |
| } |
| |
| /** |
| * crypto_aead_ivsize() - obtain IV size |
| * @tfm: cipher handle |
| * |
| * The size of the IV for the aead referenced by the cipher handle is |
| * returned. This IV size may be zero if the cipher does not need an IV. |
| * |
| * Return: IV size in bytes |
| */ |
| static inline unsigned int crypto_aead_ivsize(struct crypto_aead *tfm) |
| { |
| return crypto_aead_alg_ivsize(crypto_aead_alg(tfm)); |
| } |
| |
| /** |
| * crypto_aead_authsize() - obtain maximum authentication data size |
| * @tfm: cipher handle |
| * |
| * The maximum size of the authentication data for the AEAD cipher referenced |
| * by the AEAD cipher handle is returned. The authentication data size may be |
| * zero if the cipher implements a hard-coded maximum. |
| * |
| * The authentication data may also be known as "tag value". |
| * |
| * Return: authentication data size / tag size in bytes |
| */ |
| static inline unsigned int crypto_aead_authsize(struct crypto_aead *tfm) |
| { |
| return tfm->authsize; |
| } |
| |
| /** |
| * crypto_aead_blocksize() - obtain block size of cipher |
| * @tfm: cipher handle |
| * |
| * The block size for the AEAD referenced with the cipher handle is returned. |
| * The caller may use that information to allocate appropriate memory for the |
| * data returned by the encryption or decryption operation |
| * |
| * Return: block size of cipher |
| */ |
| static inline unsigned int crypto_aead_blocksize(struct crypto_aead *tfm) |
| { |
| return crypto_tfm_alg_blocksize(crypto_aead_tfm(tfm)); |
| } |
| |
| static inline unsigned int crypto_aead_alignmask(struct crypto_aead *tfm) |
| { |
| return crypto_tfm_alg_alignmask(crypto_aead_tfm(tfm)); |
| } |
| |
| static inline u32 crypto_aead_get_flags(struct crypto_aead *tfm) |
| { |
| return crypto_tfm_get_flags(crypto_aead_tfm(tfm)); |
| } |
| |
| static inline void crypto_aead_set_flags(struct crypto_aead *tfm, u32 flags) |
| { |
| crypto_tfm_set_flags(crypto_aead_tfm(tfm), flags); |
| } |
| |
| static inline void crypto_aead_clear_flags(struct crypto_aead *tfm, u32 flags) |
| { |
| crypto_tfm_clear_flags(crypto_aead_tfm(tfm), flags); |
| } |
| |
| /** |
| * crypto_aead_setkey() - set key for cipher |
| * @tfm: cipher handle |
| * @key: buffer holding the key |
| * @keylen: length of the key in bytes |
| * |
| * The caller provided key is set for the AEAD referenced by the cipher |
| * handle. |
| * |
| * Note, the key length determines the cipher type. Many block ciphers implement |
| * different cipher modes depending on the key size, such as AES-128 vs AES-192 |
| * vs. AES-256. When providing a 16 byte key for an AES cipher handle, AES-128 |
| * is performed. |
| * |
| * Return: 0 if the setting of the key was successful; < 0 if an error occurred |
| */ |
| int crypto_aead_setkey(struct crypto_aead *tfm, |
| const u8 *key, unsigned int keylen); |
| |
| /** |
| * crypto_aead_setauthsize() - set authentication data size |
| * @tfm: cipher handle |
| * @authsize: size of the authentication data / tag in bytes |
| * |
| * Set the authentication data size / tag size. AEAD requires an authentication |
| * tag (or MAC) in addition to the associated data. |
| * |
| * Return: 0 if the setting of the key was successful; < 0 if an error occurred |
| */ |
| int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize); |
| |
| static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req) |
| { |
| return __crypto_aead_cast(req->base.tfm); |
| } |
| |
| static inline void crypto_stat_aead_encrypt(struct aead_request *req, int ret) |
| { |
| #ifdef CONFIG_CRYPTO_STATS |
| struct crypto_aead *tfm = crypto_aead_reqtfm(req); |
| |
| if (ret && ret != -EINPROGRESS && ret != -EBUSY) { |
| atomic_inc(&tfm->base.__crt_alg->aead_err_cnt); |
| } else { |
| atomic_inc(&tfm->base.__crt_alg->encrypt_cnt); |
| atomic64_add(req->cryptlen, &tfm->base.__crt_alg->encrypt_tlen); |
| } |
| #endif |
| } |
| |
| static inline void crypto_stat_aead_decrypt(struct aead_request *req, int ret) |
| { |
| #ifdef CONFIG_CRYPTO_STATS |
| struct crypto_aead *tfm = crypto_aead_reqtfm(req); |
| |
| if (ret && ret != -EINPROGRESS && ret != -EBUSY) { |
| atomic_inc(&tfm->base.__crt_alg->aead_err_cnt); |
| } else { |
| atomic_inc(&tfm->base.__crt_alg->decrypt_cnt); |
| atomic64_add(req->cryptlen, &tfm->base.__crt_alg->decrypt_tlen); |
| } |
| #endif |
| } |
| |
| /** |
| * crypto_aead_encrypt() - encrypt plaintext |
| * @req: reference to the aead_request handle that holds all information |
| * needed to perform the cipher operation |
| * |
| * Encrypt plaintext data using the aead_request handle. That data structure |
| * and how it is filled with data is discussed with the aead_request_* |
| * functions. |
| * |
| * IMPORTANT NOTE The encryption operation creates the authentication data / |
| * tag. That data is concatenated with the created ciphertext. |
| * The ciphertext memory size is therefore the given number of |
| * block cipher blocks + the size defined by the |
| * crypto_aead_setauthsize invocation. The caller must ensure |
| * that sufficient memory is available for the ciphertext and |
| * the authentication tag. |
| * |
| * Return: 0 if the cipher operation was successful; < 0 if an error occurred |
| */ |
| static inline int crypto_aead_encrypt(struct aead_request *req) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| int ret; |
| |
| if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) |
| ret = -ENOKEY; |
| else |
| ret = crypto_aead_alg(aead)->encrypt(req); |
| crypto_stat_aead_encrypt(req, ret); |
| return ret; |
| } |
| |
| /** |
| * crypto_aead_decrypt() - decrypt ciphertext |
| * @req: reference to the ablkcipher_request handle that holds all information |
| * needed to perform the cipher operation |
| * |
| * Decrypt ciphertext data using the aead_request handle. That data structure |
| * and how it is filled with data is discussed with the aead_request_* |
| * functions. |
| * |
| * IMPORTANT NOTE The caller must concatenate the ciphertext followed by the |
| * authentication data / tag. That authentication data / tag |
| * must have the size defined by the crypto_aead_setauthsize |
| * invocation. |
| * |
| * |
| * Return: 0 if the cipher operation was successful; -EBADMSG: The AEAD |
| * cipher operation performs the authentication of the data during the |
| * decryption operation. Therefore, the function returns this error if |
| * the authentication of the ciphertext was unsuccessful (i.e. the |
| * integrity of the ciphertext or the associated data was violated); |
| * < 0 if an error occurred. |
| */ |
| static inline int crypto_aead_decrypt(struct aead_request *req) |
| { |
| struct crypto_aead *aead = crypto_aead_reqtfm(req); |
| int ret; |
| |
| if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) |
| ret = -ENOKEY; |
| else if (req->cryptlen < crypto_aead_authsize(aead)) |
| ret = -EINVAL; |
| else |
| ret = crypto_aead_alg(aead)->decrypt(req); |
| crypto_stat_aead_decrypt(req, ret); |
| return ret; |
| } |
| |
| /** |
| * DOC: Asynchronous AEAD Request Handle |
| * |
| * The aead_request data structure contains all pointers to data required for |
| * the AEAD cipher operation. This includes the cipher handle (which can be |
| * used by multiple aead_request instances), pointer to plaintext and |
| * ciphertext, asynchronous callback function, etc. It acts as a handle to the |
| * aead_request_* API calls in a similar way as AEAD handle to the |
| * crypto_aead_* API calls. |
| */ |
| |
| /** |
| * crypto_aead_reqsize() - obtain size of the request data structure |
| * @tfm: cipher handle |
| * |
| * Return: number of bytes |
| */ |
| static inline unsigned int crypto_aead_reqsize(struct crypto_aead *tfm) |
| { |
| return tfm->reqsize; |
| } |
| |
| /** |
| * aead_request_set_tfm() - update cipher handle reference in request |
| * @req: request handle to be modified |
| * @tfm: cipher handle that shall be added to the request handle |
| * |
| * Allow the caller to replace the existing aead handle in the request |
| * data structure with a different one. |
| */ |
| static inline void aead_request_set_tfm(struct aead_request *req, |
| struct crypto_aead *tfm) |
| { |
| req->base.tfm = crypto_aead_tfm(tfm); |
| } |
| |
| /** |
| * aead_request_alloc() - allocate request data structure |
| * @tfm: cipher handle to be registered with the request |
| * @gfp: memory allocation flag that is handed to kmalloc by the API call. |
| * |
| * Allocate the request data structure that must be used with the AEAD |
| * encrypt and decrypt API calls. During the allocation, the provided aead |
| * handle is registered in the request data structure. |
| * |
| * Return: allocated request handle in case of success, or NULL if out of memory |
| */ |
| static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm, |
| gfp_t gfp) |
| { |
| struct aead_request *req; |
| |
| req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp); |
| |
| if (likely(req)) |
| aead_request_set_tfm(req, tfm); |
| |
| return req; |
| } |
| |
| /** |
| * aead_request_free() - zeroize and free request data structure |
| * @req: request data structure cipher handle to be freed |
| */ |
| static inline void aead_request_free(struct aead_request *req) |
| { |
| kzfree(req); |
| } |
| |
| /** |
| * aead_request_set_callback() - set asynchronous callback function |
| * @req: request handle |
| * @flags: specify zero or an ORing of the flags |
| * CRYPTO_TFM_REQ_MAY_BACKLOG the request queue may back log and |
| * increase the wait queue beyond the initial maximum size; |
| * CRYPTO_TFM_REQ_MAY_SLEEP the request processing may sleep |
| * @compl: callback function pointer to be registered with the request handle |
| * @data: The data pointer refers to memory that is not used by the kernel |
| * crypto API, but provided to the callback function for it to use. Here, |
| * the caller can provide a reference to memory the callback function can |
| * operate on. As the callback function is invoked asynchronously to the |
| * related functionality, it may need to access data structures of the |
| * related functionality which can be referenced using this pointer. The |
| * callback function can access the memory via the "data" field in the |
| * crypto_async_request data structure provided to the callback function. |
| * |
| * Setting the callback function that is triggered once the cipher operation |
| * completes |
| * |
| * The callback function is registered with the aead_request handle and |
| * must comply with the following template:: |
| * |
| * void callback_function(struct crypto_async_request *req, int error) |
| */ |
| static inline void aead_request_set_callback(struct aead_request *req, |
| u32 flags, |
| crypto_completion_t compl, |
| void *data) |
| { |
| req->base.complete = compl; |
| req->base.data = data; |
| req->base.flags = flags; |
| } |
| |
| /** |
| * aead_request_set_crypt - set data buffers |
| * @req: request handle |
| * @src: source scatter / gather list |
| * @dst: destination scatter / gather list |
| * @cryptlen: number of bytes to process from @src |
| * @iv: IV for the cipher operation which must comply with the IV size defined |
| * by crypto_aead_ivsize() |
| * |
| * Setting the source data and destination data scatter / gather lists which |
| * hold the associated data concatenated with the plaintext or ciphertext. See |
| * below for the authentication tag. |
| * |
| * For encryption, the source is treated as the plaintext and the |
| * destination is the ciphertext. For a decryption operation, the use is |
| * reversed - the source is the ciphertext and the destination is the plaintext. |
| * |
| * The memory structure for cipher operation has the following structure: |
| * |
| * - AEAD encryption input: assoc data || plaintext |
| * - AEAD encryption output: assoc data || cipherntext || auth tag |
| * - AEAD decryption input: assoc data || ciphertext || auth tag |
| * - AEAD decryption output: assoc data || plaintext |
| * |
| * Albeit the kernel requires the presence of the AAD buffer, however, |
| * the kernel does not fill the AAD buffer in the output case. If the |
| * caller wants to have that data buffer filled, the caller must either |
| * use an in-place cipher operation (i.e. same memory location for |
| * input/output memory location). |
| */ |
| static inline void aead_request_set_crypt(struct aead_request *req, |
| struct scatterlist *src, |
| struct scatterlist *dst, |
| unsigned int cryptlen, u8 *iv) |
| { |
| req->src = src; |
| req->dst = dst; |
| req->cryptlen = cryptlen; |
| req->iv = iv; |
| } |
| |
| /** |
| * aead_request_set_ad - set associated data information |
| * @req: request handle |
| * @assoclen: number of bytes in associated data |
| * |
| * Setting the AD information. This function sets the length of |
| * the associated data. |
| */ |
| static inline void aead_request_set_ad(struct aead_request *req, |
| unsigned int assoclen) |
| { |
| req->assoclen = assoclen; |
| } |
| |
| #endif /* _CRYPTO_AEAD_H */ |