/* * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256 * Copyright 2015, Qualcomm Atheros, Inc. * * 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/crypto.h> #include <linux/err.h> #include <crypto/aes.h> #include <net/mac80211.h> #include "key.h" #include "aes_gmac.h" #define GMAC_MIC_LEN 16 #define GMAC_NONCE_LEN 12 #define AAD_LEN 20 int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce, const u8 *data, size_t data_len, u8 *mic) { struct scatterlist sg[3], ct[1]; char aead_req_data[sizeof(struct aead_request) + crypto_aead_reqsize(tfm)] __aligned(__alignof__(struct aead_request)); struct aead_request *aead_req = (void *)aead_req_data; u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE]; if (data_len < GMAC_MIC_LEN) return -EINVAL; memset(aead_req, 0, sizeof(aead_req_data)); memset(zero, 0, GMAC_MIC_LEN); sg_init_table(sg, 3); sg_set_buf(&sg[0], aad, AAD_LEN); sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN); sg_set_buf(&sg[2], zero, GMAC_MIC_LEN); memcpy(iv, nonce, GMAC_NONCE_LEN); memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); iv[AES_BLOCK_SIZE - 1] = 0x01; sg_init_table(ct, 1); sg_set_buf(&ct[0], mic, GMAC_MIC_LEN); aead_request_set_tfm(aead_req, tfm); aead_request_set_assoc(aead_req, sg, AAD_LEN + data_len); aead_request_set_crypt(aead_req, NULL, ct, 0, iv); crypto_aead_encrypt(aead_req); return 0; } struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], size_t key_len) { struct crypto_aead *tfm; int err; tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) return tfm; err = crypto_aead_setkey(tfm, key, key_len); if (!err) err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN); if (!err) return tfm; crypto_free_aead(tfm); return ERR_PTR(err); } void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) { crypto_free_aead(tfm); }