diff options
| -rw-r--r-- | crypto/algif_aead.c | 14 | ||||
| -rw-r--r-- | include/crypto/aead.h | 36 |
2 files changed, 14 insertions, 36 deletions
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c index 80a0f1a78551..a0d8377729a4 100644 --- a/crypto/algif_aead.c +++ b/crypto/algif_aead.c @@ -551,18 +551,8 @@ static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags) lock_sock(sk); /* - * AEAD memory structure: For encryption, the tag is appended to the - * ciphertext which implies that the memory allocated for the ciphertext - * must be increased by the tag length. For decryption, the tag - * is expected to be concatenated to the ciphertext. The plaintext - * therefore has a memory size of the ciphertext minus the tag length. - * - * The memory structure for cipher operation has the following - * structure: - * AEAD encryption input: assoc data || plaintext - * AEAD encryption output: cipherntext || auth tag - * AEAD decryption input: assoc data || ciphertext || auth tag - * AEAD decryption output: plaintext + * Please see documentation of aead_request_set_crypt for the + * description of the AEAD memory structure expected from the caller. */ if (ctx->more) { diff --git a/include/crypto/aead.h b/include/crypto/aead.h index e725155c6389..03b97629442c 100644 --- a/include/crypto/aead.h +++ b/include/crypto/aead.h @@ -483,30 +483,18 @@ static inline void aead_request_set_callback(struct aead_request *req, * destination is the ciphertext. For a decryption operation, the use is * reversed - the source is the ciphertext and the destination is the plaintext. * - * For both src/dst the layout is associated data, plain/cipher text, - * authentication tag. - * - * The content of the AD in the destination buffer after processing - * will either be untouched, or it will contain a copy of the AD - * from the source buffer. In order to ensure that it always has - * a copy of the AD, the user must copy the AD over either before - * or after processing. Of course this is not relevant if the user - * is doing in-place processing where src == dst. - * - * IMPORTANT NOTE AEAD requires an authentication tag (MAC). For decryption, - * the caller must concatenate the ciphertext followed by the - * authentication tag and provide the entire data stream to the - * decryption operation (i.e. the data length used for the - * initialization of the scatterlist and the data length for the - * decryption operation is identical). For encryption, however, - * the authentication tag is created while encrypting the data. - * The destination buffer must hold sufficient space for the - * ciphertext and the authentication tag while the encryption - * invocation must only point to the plaintext data size. The - * following code snippet illustrates the memory usage - * buffer = kmalloc(ptbuflen + (enc ? authsize : 0)); - * sg_init_one(&sg, buffer, ptbuflen + (enc ? authsize : 0)); - * aead_request_set_crypt(req, &sg, &sg, ptbuflen, iv); + * 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, |