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 <smueller@xxxxxxxxxx>
---
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
--
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