From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Mon, 7 Oct 2013 14:12:31 +0200 Subject: [RFC PATCH 5/5] mac80211: Use CCM crypto driver for CCMP In-Reply-To: <1381147951-7609-1-git-send-email-ard.biesheuvel@linaro.org> References: <1381147951-7609-1-git-send-email-ard.biesheuvel@linaro.org> Message-ID: <1381147951-7609-6-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Let the crypto layer supply the CCM implementation rather than coding it directly on top of the core AES cipher. Signed-off-by: Ard Biesheuvel --- net/mac80211/Kconfig | 1 + net/mac80211/aes_ccm.c | 159 +++++++++++++++---------------------------------- net/mac80211/aes_ccm.h | 8 +-- net/mac80211/key.h | 2 +- net/mac80211/wpa.c | 21 ++++--- 5 files changed, 64 insertions(+), 127 deletions(-) diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig index 62535fe..dc31ec3 100644 --- a/net/mac80211/Kconfig +++ b/net/mac80211/Kconfig @@ -4,6 +4,7 @@ config MAC80211 select CRYPTO select CRYPTO_ARC4 select CRYPTO_AES + select CRYPTO_CCM select CRC32 select AVERAGE ---help--- diff --git a/net/mac80211/aes_ccm.c b/net/mac80211/aes_ccm.c index be7614b9..c17f3a3 100644 --- a/net/mac80211/aes_ccm.c +++ b/net/mac80211/aes_ccm.c @@ -17,134 +17,71 @@ #include "key.h" #include "aes_ccm.h" -static void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *scratch, u8 *a) -{ - int i; - u8 *b_0, *aad, *b, *s_0; - - b_0 = scratch + 3 * AES_BLOCK_SIZE; - aad = scratch + 4 * AES_BLOCK_SIZE; - b = scratch; - s_0 = scratch + AES_BLOCK_SIZE; - - crypto_cipher_encrypt_one(tfm, b, b_0); - - /* Extra Authenticate-only data (always two AES blocks) */ - for (i = 0; i < AES_BLOCK_SIZE; i++) - aad[i] ^= b[i]; - crypto_cipher_encrypt_one(tfm, b, aad); - - aad += AES_BLOCK_SIZE; - - for (i = 0; i < AES_BLOCK_SIZE; i++) - aad[i] ^= b[i]; - crypto_cipher_encrypt_one(tfm, a, aad); - - /* Mask out bits from auth-only-b_0 */ - b_0[0] &= 0x07; - - /* S_0 is used to encrypt T (= MIC) */ - b_0[14] = 0; - b_0[15] = 0; - crypto_cipher_encrypt_one(tfm, s_0, b_0); -} - - -void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch, +void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *scratch, u8 *data, size_t data_len, u8 *cdata, u8 *mic) { - int i, j, last_len, num_blocks; - u8 *pos, *cpos, *b, *s_0, *e, *b_0; + struct scatterlist aad, pt, ct; + struct aead_request req; + u8 *iv = scratch + 3 * AES_BLOCK_SIZE; /* b0 */ - b = scratch; - s_0 = scratch + AES_BLOCK_SIZE; - e = scratch + 2 * AES_BLOCK_SIZE; - b_0 = scratch + 3 * AES_BLOCK_SIZE; + sg_init_one(&pt, data, data_len); + sg_init_one(&ct, cdata, data_len + IEEE80211_CCMP_MIC_LEN); + sg_init_one(&aad, scratch + 4 * AES_BLOCK_SIZE, 2 * AES_BLOCK_SIZE - 2); - num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE); - last_len = data_len % AES_BLOCK_SIZE; - aes_ccm_prepare(tfm, scratch, b); + aead_request_set_crypt(&req, &pt, &ct, data_len, iv); + aead_request_set_assoc(&req, &aad, 2 * AES_BLOCK_SIZE - 2); - /* Process payload blocks */ - pos = data; - cpos = cdata; - for (j = 1; j <= num_blocks; j++) { - int blen = (j == num_blocks && last_len) ? - last_len : AES_BLOCK_SIZE; - - /* Authentication followed by encryption */ - for (i = 0; i < blen; i++) - b[i] ^= pos[i]; - crypto_cipher_encrypt_one(tfm, b, b); - - b_0[14] = (j >> 8) & 0xff; - b_0[15] = j & 0xff; - crypto_cipher_encrypt_one(tfm, e, b_0); - for (i = 0; i < blen; i++) - *cpos++ = *pos++ ^ e[i]; - } - - for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++) - mic[i] = b[i] ^ s_0[i]; + crypto_aead_encrypt(&req); } - -int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch, +int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *scratch, u8 *cdata, size_t data_len, u8 *mic, u8 *data) { - int i, j, last_len, num_blocks; - u8 *pos, *cpos, *b, *s_0, *a, *b_0; - - b = scratch; - s_0 = scratch + AES_BLOCK_SIZE; - a = scratch + 2 * AES_BLOCK_SIZE; - b_0 = scratch + 3 * AES_BLOCK_SIZE; - - num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE); - last_len = data_len % AES_BLOCK_SIZE; - aes_ccm_prepare(tfm, scratch, a); + struct scatterlist aad, pt, ct; + struct aead_request req; + u8 *iv = scratch + 3 * AES_BLOCK_SIZE; /* b0 */ - /* Process payload blocks */ - cpos = cdata; - pos = data; - for (j = 1; j <= num_blocks; j++) { - int blen = (j == num_blocks && last_len) ? - last_len : AES_BLOCK_SIZE; + sg_init_one(&pt, data, data_len); + sg_init_one(&ct, cdata, data_len + IEEE80211_CCMP_MIC_LEN); + sg_init_one(&aad, scratch + 4 * AES_BLOCK_SIZE, 2 * AES_BLOCK_SIZE - 2); - /* Decryption followed by authentication */ - b_0[14] = (j >> 8) & 0xff; - b_0[15] = j & 0xff; - crypto_cipher_encrypt_one(tfm, b, b_0); - for (i = 0; i < blen; i++) { - *pos = *cpos++ ^ b[i]; - a[i] ^= *pos++; - } - crypto_cipher_encrypt_one(tfm, a, a); - } + aead_request_set_crypt(&req, &ct, &pt, data_len, iv); + aead_request_set_assoc(&req, &aad, 2 * AES_BLOCK_SIZE - 2); - for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++) { - if ((mic[i] ^ s_0[i]) != a[i]) - return -1; - } - - return 0; + return crypto_aead_decrypt(&req); } - -struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]) +struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[]) { - struct crypto_cipher *tfm; - - tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); - if (!IS_ERR(tfm)) - crypto_cipher_setkey(tfm, key, WLAN_KEY_LEN_CCMP); - - return tfm; + struct crypto_aead *tfm; + int err; + + tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(tfm)) + return tfm; + + /* HACK: we use an auto variable for aead_request in the functions above + * but this only works if the reqsize is 0, i.e., the aead alg does not + * need additional space in the req struct to track its operations. + * This is a proof of concept for the Crypto Extensions based AES/CCM, + * so for now we just hack around it. + */ + err = -EINVAL; + if (crypto_aead_reqsize(tfm)) + goto out; + + err = crypto_aead_setkey(tfm, key, WLAN_KEY_LEN_CCMP); + if (!err) + err = crypto_aead_setauthsize(tfm, IEEE80211_CCMP_MIC_LEN); + if (!err) + return tfm; +out: + crypto_free_aead(tfm); + return ERR_PTR(err); } - -void ieee80211_aes_key_free(struct crypto_cipher *tfm) +void ieee80211_aes_key_free(struct crypto_aead *tfm) { - crypto_free_cipher(tfm); + crypto_free_aead(tfm); } diff --git a/net/mac80211/aes_ccm.h b/net/mac80211/aes_ccm.h index 5b7d744..797f3f0 100644 --- a/net/mac80211/aes_ccm.h +++ b/net/mac80211/aes_ccm.h @@ -12,13 +12,13 @@ #include -struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]); -void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch, +struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[]); +void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *scratch, u8 *data, size_t data_len, u8 *cdata, u8 *mic); -int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch, +int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *scratch, u8 *cdata, size_t data_len, u8 *mic, u8 *data); -void ieee80211_aes_key_free(struct crypto_cipher *tfm); +void ieee80211_aes_key_free(struct crypto_aead *tfm); #endif /* AES_CCM_H */ diff --git a/net/mac80211/key.h b/net/mac80211/key.h index 036d57e..aaae0ed 100644 --- a/net/mac80211/key.h +++ b/net/mac80211/key.h @@ -83,7 +83,7 @@ struct ieee80211_key { * Management frames. */ u8 rx_pn[IEEE80211_NUM_TIDS + 1][IEEE80211_CCMP_PN_LEN]; - struct crypto_cipher *tfm; + struct crypto_aead *tfm; u32 replays; /* dot11RSNAStatsCCMPReplays */ } ccmp; struct { diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c index c9edfcb..c3df1d7 100644 --- a/net/mac80211/wpa.c +++ b/net/mac80211/wpa.c @@ -343,7 +343,7 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, data_len -= IEEE80211_CCMP_MIC_LEN; /* First block, b_0 */ - b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */ + b_0[0] = 0x1; /* L == 1 */ /* Nonce: Nonce Flags | A2 | PN * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7) */ @@ -355,21 +355,20 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch, /* AAD (extra authenticate-only data) / masked 802.11 header * FC | A1 | A2 | A3 | SC | [A4] | [QC] */ - put_unaligned_be16(len_a, &aad[0]); - put_unaligned(mask_fc, (__le16 *)&aad[2]); - memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN); + put_unaligned(mask_fc, (__le16 *)&aad[0]); + memcpy(&aad[2], &hdr->addr1, 3 * ETH_ALEN); /* Mask Seq#, leave Frag# */ - aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f; - aad[23] = 0; + aad[20] = *((u8 *) &hdr->seq_ctrl) & 0x0f; + aad[21] = 0; if (a4_included) { - memcpy(&aad[24], hdr->addr4, ETH_ALEN); - aad[30] = qos_tid; - aad[31] = 0; + memcpy(&aad[22], hdr->addr4, ETH_ALEN); + aad[28] = qos_tid; + aad[29] = 0; } else { - memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); - aad[24] = qos_tid; + memset(&aad[22], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN); + aad[22] = qos_tid; } } -- 1.8.1.2