From: Stephan Mueller Subject: [PATCH v3 1/7] crypto: AF_ALG: add user space interface for AEAD Date: Fri, 21 Nov 2014 06:30:18 +0100 Message-ID: <5694690.RURGUoE58b@tachyon.chronox.de> References: <4088013.2O8zCP0xXa@tachyon.chronox.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: Daniel Borkmann , 'Quentin Gouchet' , lkml - Kernel Mailing List , linux-crypto@vger.kernel.org, linux-api@vger.kernel.org To: Herbert Xu Return-path: In-Reply-To: <4088013.2O8zCP0xXa@tachyon.chronox.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org AEAD requires the following data in addition to normal symmetric ciphers: * Associated authentication data of arbitrary length and length * Authentication tag for decryption and length * Length of authentication tag for encryption The memory structure for the data received by the kernel via sendmsg must follow this structure: * Symmetric encryption input: plaintext * Symmetric encryption output: ciphertext * AEAD encryption input: assoc data || plaintext * AEAD encryption output: cipherntext || auth tag * Symmetric decryption input: ciphertext * Symmetric decryption output: plaintext * AEAD decryption input: assoc data || ciphertext || authtag * AEAD decryption output: plaintext Therefore, in addition to submitting the data, AEAD requires that the associated data length and the tag length must be communicated. The plaintext/ciphertext length can be derived from the other two size fields. Therefore, This patch adds setting the associated data length and tag length as part of the sendmsg communication. Signed-off-by: Stephan Mueller --- crypto/af_alg.c | 12 ++++++++++++ include/crypto/if_alg.h | 2 ++ include/uapi/linux/if_alg.h | 2 ++ 3 files changed, 16 insertions(+) diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 6a3ad80..75eb88c 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -421,6 +421,18 @@ int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con) con->op = *(u32 *)CMSG_DATA(cmsg); break; + case ALG_SET_AEAD_AUTHSIZE: + if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32))) + return -EINVAL; + con->aead_authsize = *(u32 *)CMSG_DATA(cmsg); + break; + + case ALG_SET_AEAD_ASSOCLEN: + if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32))) + return -EINVAL; + con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg); + break; + default: return -EINVAL; } diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h index d61c111..60ed1b7 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -42,6 +42,8 @@ struct af_alg_completion { struct af_alg_control { struct af_alg_iv *iv; int op; + unsigned int aead_authsize; + unsigned int aead_assoclen; }; struct af_alg_type { diff --git a/include/uapi/linux/if_alg.h b/include/uapi/linux/if_alg.h index 0f9acce..f2acd2f 100644 --- a/include/uapi/linux/if_alg.h +++ b/include/uapi/linux/if_alg.h @@ -32,6 +32,8 @@ struct af_alg_iv { #define ALG_SET_KEY 1 #define ALG_SET_IV 2 #define ALG_SET_OP 3 +#define ALG_SET_AEAD_ASSOCLEN 4 +#define ALG_SET_AEAD_AUTHSIZE 5 /* Operations */ #define ALG_OP_DECRYPT 0 -- 2.1.0