mac80211: aead api to reduce redundancy

Currently, the aes_ccm.c and aes_gcm.c are almost line by line copy of
each other. This patch reduce code redundancy by moving the code in these
two files to crypto/aead_api.c to make it a higher level aead api. The
file aes_ccm.c and aes_gcm.c are removed and all the functions there are
now implemented in their headers using the newly added aead api.

Signed-off-by: Xiang Gao <qasdfgtyuiop@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 115 insertions, 0 deletions

diff --git a/net/mac80211/aead_api.c b/net/mac80211/aead_api.c
new file mode 100644
index 000000000000..347f13953b2c
--- /dev/null
+++ b/net/mac80211/aead_api.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2003-2004, Instant802 Networks, Inc.
+ * Copyright 2005-2006, Devicescape Software, Inc.
+ * Copyright 2014-2015, Qualcomm Atheros, Inc.
+ *
+ * Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/err.h>
+#include <linux/scatterlist.h>
+#include <crypto/aead.h>
+
+#include "aead_api.h"
+
+int aead_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad, size_t aad_len,
+		 u8 *data, size_t data_len, u8 *mic)
+{
+	size_t mic_len = tfm->authsize;
+	struct scatterlist sg[3];
+	struct aead_request *aead_req;
+	int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
+	u8 *__aad;
+
+	aead_req = kzalloc(reqsize + aad_len, GFP_ATOMIC);
+	if (!aead_req)
+		return -ENOMEM;
+
+	__aad = (u8 *)aead_req + reqsize;
+	memcpy(__aad, aad, aad_len);
+
+	sg_init_table(sg, 3);
+	sg_set_buf(&sg[0], __aad, aad_len);
+	sg_set_buf(&sg[1], data, data_len);
+	sg_set_buf(&sg[2], mic, mic_len);
+
+	aead_request_set_tfm(aead_req, tfm);
+	aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
+	aead_request_set_ad(aead_req, sg[0].length);
+
+	crypto_aead_encrypt(aead_req);
+	kzfree(aead_req);
+
+	return 0;
+}
+
+int aead_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad, size_t aad_len,
+		 u8 *data, size_t data_len, u8 *mic)
+{
+	size_t mic_len = tfm->authsize;
+	struct scatterlist sg[3];
+	struct aead_request *aead_req;
+	int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
+	u8 *__aad;
+	int err;
+
+	if (data_len == 0)
+		return -EINVAL;
+
+	aead_req = kzalloc(reqsize + aad_len, GFP_ATOMIC);
+	if (!aead_req)
+		return -ENOMEM;
+
+	__aad = (u8 *)aead_req + reqsize;
+	memcpy(__aad, aad, aad_len);
+
+	sg_init_table(sg, 3);
+	sg_set_buf(&sg[0], __aad, aad_len);
+	sg_set_buf(&sg[1], data, data_len);
+	sg_set_buf(&sg[2], mic, mic_len);
+
+	aead_request_set_tfm(aead_req, tfm);
+	aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
+	aead_request_set_ad(aead_req, sg[0].length);
+
+	err = crypto_aead_decrypt(aead_req);
+	kzfree(aead_req);
+
+	return err;
+}
+
+struct crypto_aead *
+aead_key_setup_encrypt(const char *alg, const u8 key[],
+		       size_t key_len, size_t mic_len)
+{
+	struct crypto_aead *tfm;
+	int err;
+
+	tfm = crypto_alloc_aead(alg, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(tfm))
+		return tfm;
+
+	err = crypto_aead_setkey(tfm, key, key_len);
+	if (err)
+		goto free_aead;
+	err = crypto_aead_setauthsize(tfm, mic_len);
+	if (err)
+		goto free_aead;
+
+	return tfm;
+
+free_aead:
+	crypto_free_aead(tfm);
+	return ERR_PTR(err);
+}
+
+void aead_key_free(struct crypto_aead *tfm)
+{
+	crypto_free_aead(tfm);
+}