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 26 if (data_len < GMAC_MIC_LEN) 27 return -EINVAL; 28 29 aead_req = kzalloc(reqsize + GMAC_MIC_LEN + GMAC_AAD_LEN, GFP_ATOMIC); 30 if (!aead_req) 31 return -ENOMEM; 32 33 zero = (u8 *)aead_req + reqsize; 34 __aad = zero + GMAC_MIC_LEN; 35 memcpy(__aad, aad, GMAC_AAD_LEN); 36 37 fc = (const __le16 *)aad; 38 if (ieee80211_is_beacon(*fc)) { 39 /* mask Timestamp field to zero */ 40 sg_init_table(sg, 5); 41 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN); 42 sg_set_buf(&sg[1], zero, 8); 43 sg_set_buf(&sg[2], data + 8, data_len - 8 - GMAC_MIC_LEN); 44 sg_set_buf(&sg[3], zero, GMAC_MIC_LEN); 45 sg_set_buf(&sg[4], mic, GMAC_MIC_LEN); 46 } else { 47 sg_init_table(sg, 4); 48 sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN); 49 sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN); 50 sg_set_buf(&sg[2], zero, GMAC_MIC_LEN); 51 sg_set_buf(&sg[3], mic, GMAC_MIC_LEN); 52 } 53 54 memcpy(iv, nonce, GMAC_NONCE_LEN); 55 memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); 56 iv[AES_BLOCK_SIZE - 1] = 0x01; 57 58 aead_request_set_tfm(aead_req, tfm); 59 aead_request_set_crypt(aead_req, sg, sg, 0, iv); 60 aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len); 61 62 crypto_aead_encrypt(aead_req); 63 kfree_sensitive(aead_req); 64 65 return 0; 66 } 67 68 struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], 69 size_t key_len) 70 { 71 struct crypto_aead *tfm; 72 int err; 73 74 tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); 75 if (IS_ERR(tfm)) 76 return tfm; 77 78 err = crypto_aead_setkey(tfm, key, key_len); 79 if (!err) 80 err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN); 81 if (!err) 82 return tfm; 83 84 crypto_free_aead(tfm); 85 return ERR_PTR(err); 86 } 87 88 void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) 89 { 90 crypto_free_aead(tfm); 91 } 92