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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-06 10:49:28 +0000
committerJohannes Berg <johannes.berg@intel.com>2017-02-08 09:19:33 +0100
commit26717828b75dd5c46e97f7f4a9b937d038bb2852 (patch)
treecb192493dd8bb60c52260932877cd7e23de96a81 /net/mac80211/aes_cmac.c
parentfe8de3da13bdbcbe8b583a3bbadf677da0f04f83 (diff)
downloadblackbird-op-linux-26717828b75dd5c46e97f7f4a9b937d038bb2852.tar.gz
blackbird-op-linux-26717828b75dd5c46e97f7f4a9b937d038bb2852.zip
mac80211: aes-cmac: switch to shash CMAC driver
Instead of open coding the CMAC algorithm in the mac80211 driver using byte wide xors and calls into the crypto layer for each block of data, instantiate a cmac(aes) synchronous hash and pass all the data into it directly. This does not only simplify the code, it also allows the use of more efficient and more secure implementations, especially on platforms where SIMD ciphers have a considerable setup cost. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/aes_cmac.c')
-rw-r--r--net/mac80211/aes_cmac.c126
1 files changed, 25 insertions, 101 deletions
diff --git a/net/mac80211/aes_cmac.c b/net/mac80211/aes_cmac.c
index d0bd5fff5f0a..2fb65588490c 100644
--- a/net/mac80211/aes_cmac.c
+++ b/net/mac80211/aes_cmac.c
@@ -22,126 +22,50 @@
#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
#define AAD_LEN 20
+static const u8 zero[CMAC_TLEN_256];
-void gf_mulx(u8 *pad)
-{
- int i, carry;
-
- carry = pad[0] & 0x80;
- for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
- pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
- pad[AES_BLOCK_SIZE - 1] <<= 1;
- if (carry)
- pad[AES_BLOCK_SIZE - 1] ^= 0x87;
-}
-
-void aes_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
- const u8 *addr[], const size_t *len, u8 *mac,
- size_t mac_len)
-{
- u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
- const u8 *pos, *end;
- size_t i, e, left, total_len;
-
- memset(cbc, 0, AES_BLOCK_SIZE);
-
- total_len = 0;
- for (e = 0; e < num_elem; e++)
- total_len += len[e];
- left = total_len;
-
- e = 0;
- pos = addr[0];
- end = pos + len[0];
-
- while (left >= AES_BLOCK_SIZE) {
- for (i = 0; i < AES_BLOCK_SIZE; i++) {
- cbc[i] ^= *pos++;
- if (pos >= end) {
- e++;
- pos = addr[e];
- end = pos + len[e];
- }
- }
- if (left > AES_BLOCK_SIZE)
- crypto_cipher_encrypt_one(tfm, cbc, cbc);
- left -= AES_BLOCK_SIZE;
- }
-
- memset(pad, 0, AES_BLOCK_SIZE);
- crypto_cipher_encrypt_one(tfm, pad, pad);
- gf_mulx(pad);
-
- if (left || total_len == 0) {
- for (i = 0; i < left; i++) {
- cbc[i] ^= *pos++;
- if (pos >= end) {
- e++;
- pos = addr[e];
- end = pos + len[e];
- }
- }
- cbc[left] ^= 0x80;
- gf_mulx(pad);
- }
-
- for (i = 0; i < AES_BLOCK_SIZE; i++)
- pad[i] ^= cbc[i];
- crypto_cipher_encrypt_one(tfm, pad, pad);
- memcpy(mac, pad, mac_len);
-}
-
-
-void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
+void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
const u8 *data, size_t data_len, u8 *mic)
{
- const u8 *addr[3];
- size_t len[3];
- u8 zero[CMAC_TLEN];
+ SHASH_DESC_ON_STACK(desc, tfm);
+ u8 out[AES_BLOCK_SIZE];
- memset(zero, 0, CMAC_TLEN);
- addr[0] = aad;
- len[0] = AAD_LEN;
- addr[1] = data;
- len[1] = data_len - CMAC_TLEN;
- addr[2] = zero;
- len[2] = CMAC_TLEN;
+ desc->tfm = tfm;
- aes_cmac_vector(tfm, 3, addr, len, mic, CMAC_TLEN);
+ crypto_shash_init(desc);
+ crypto_shash_update(desc, aad, AAD_LEN);
+ crypto_shash_update(desc, data, data_len - CMAC_TLEN);
+ crypto_shash_finup(desc, zero, CMAC_TLEN, out);
+
+ memcpy(mic, out, CMAC_TLEN);
}
-void ieee80211_aes_cmac_256(struct crypto_cipher *tfm, const u8 *aad,
+void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
const u8 *data, size_t data_len, u8 *mic)
{
- const u8 *addr[3];
- size_t len[3];
- u8 zero[CMAC_TLEN_256];
+ SHASH_DESC_ON_STACK(desc, tfm);
- memset(zero, 0, CMAC_TLEN_256);
- addr[0] = aad;
- len[0] = AAD_LEN;
- addr[1] = data;
- len[1] = data_len - CMAC_TLEN_256;
- addr[2] = zero;
- len[2] = CMAC_TLEN_256;
+ desc->tfm = tfm;
- aes_cmac_vector(tfm, 3, addr, len, mic, CMAC_TLEN_256);
+ crypto_shash_init(desc);
+ crypto_shash_update(desc, aad, AAD_LEN);
+ crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
+ crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic);
}
-struct crypto_cipher *ieee80211_aes_cmac_key_setup(const u8 key[],
- size_t key_len)
+struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[],
+ size_t key_len)
{
- struct crypto_cipher *tfm;
+ struct crypto_shash *tfm;
- tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
+ tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
if (!IS_ERR(tfm))
- crypto_cipher_setkey(tfm, key, key_len);
+ crypto_shash_setkey(tfm, key, key_len);
return tfm;
}
-
-void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm)
+void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm)
{
- crypto_free_cipher(tfm);
+ crypto_free_shash(tfm);
}
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