1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256 4 * Copyright 2015, Qualcomm Atheros, Inc. 5 */ 6 7 #include <linux/kernel.h> 8 #include <linux/types.h> 9 #include <linux/err.h> 10 #include <crypto/aead.h> 11 #include <crypto/aes.h> 12 13 #include <net/mac80211.h> 14 #include "key.h" 15 #include "aes_gmac.h" 16 17 int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce, 18 const u8 *data, size_t data_len, u8 *mic) 19 { 20 struct scatterlist sg[5]; 21 u8 *zero, *__aad, iv[AES_BLOCK_SIZE]; 22 struct aead_request *aead_req; 23 int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm); 24 const __le16 *fc; 25 int ret; 26 27 if (data_len < IEEE80211_GMAC_MIC_LEN) 28 return -EINVAL; 29 30 aead_req = kzalloc(reqsize + IEEE80211_GMAC_MIC_LEN + GMAC_AAD_LEN, 31 GFP_ATOMIC); 32 if (!aead_req) 33 return -ENOMEM; 34 35 zero = (u8 *)aead_req + reqsize; 36 __aad = zero + IEEE80211_GMAC_MIC_LEN; 37 memcpy(__aad, aad, GMAC_AAD_LEN); 38 39 fc = (const __le16 *)aad; 40 if (ieee80211_is_beacon(*fc)) { 41 /* mask Timestamp field to zero */ 42 sg_init_table(sg, 5); 43 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN); 44 sg_set_buf(&sg[1], zero, 8); 45 sg_set_buf(&sg[2], data + 8, 46 data_len - 8 - IEEE80211_GMAC_MIC_LEN); 47 sg_set_buf(&sg[3], zero, IEEE80211_GMAC_MIC_LEN); 48 sg_set_buf(&sg[4], mic, IEEE80211_GMAC_MIC_LEN); 49 } else { 50 sg_init_table(sg, 4); 51 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN); 52 sg_set_buf(&sg[1], data, data_len - IEEE80211_GMAC_MIC_LEN); 53 sg_set_buf(&sg[2], zero, IEEE80211_GMAC_MIC_LEN); 54 sg_set_buf(&sg[3], mic, IEEE80211_GMAC_MIC_LEN); 55 } 56 57 memcpy(iv, nonce, GMAC_NONCE_LEN); 58 memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); 59 iv[AES_BLOCK_SIZE - 1] = 0x01; 60 61 aead_request_set_tfm(aead_req, tfm); 62 aead_request_set_crypt(aead_req, sg, sg, 0, iv); 63 aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len); 64 65 ret = crypto_aead_encrypt(aead_req); 66 kfree_sensitive(aead_req); 67 68 return ret; 69 } 70 71 struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], 72 size_t key_len) 73 { 74 struct crypto_aead *tfm; 75 int err; 76 77 tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); 78 if (IS_ERR(tfm)) 79 return tfm; 80 81 err = crypto_aead_setkey(tfm, key, key_len); 82 if (!err) 83 err = crypto_aead_setauthsize(tfm, IEEE80211_GMAC_MIC_LEN); 84 if (!err) 85 return tfm; 86 87 crypto_free_aead(tfm); 88 return ERR_PTR(err); 89 } 90 91 void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) 92 { 93 crypto_free_aead(tfm); 94 } 95