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authorJouni Malinen <j@w1.fi>2012-09-09 15:00:14 (GMT)
committerJouni Malinen <j@w1.fi>2012-09-09 15:03:31 (GMT)
commit05d6054cec16a5f5647d86ad825fcf4ffa22a170 (patch)
tree4c9a4b99951ac751fd27e6287449067f1d20d85c /wlantest
parent071c6164ab1e2491e268a3100c8acc976d0f8adf (diff)
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wlantest: Move generic AES-CCM into separate functions
This part of the implementation is not specific to CCMP and could be used for other purposes, too. Signed-hostap: Jouni Malinen <j@w1.fi>
Diffstat (limited to 'wlantest')
-rw-r--r--wlantest/ccmp.c407
1 files changed, 216 insertions, 191 deletions
diff --git a/wlantest/ccmp.c b/wlantest/ccmp.c
index 6292ee0..af58062 100644
--- a/wlantest/ccmp.c
+++ b/wlantest/ccmp.c
@@ -1,6 +1,6 @@
/*
* CTR with CBC-MAC Protocol (CCMP)
- * Copyright (c) 2010, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2010-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
@@ -14,6 +14,204 @@
#include "wlantest.h"
+static void xor_aes_block(u8 *dst, const u8 *src)
+{
+ u32 *d = (u32 *) dst;
+ u32 *s = (u32 *) src;
+ *d++ ^= *s++;
+ *d++ ^= *s++;
+ *d++ ^= *s++;
+ *d++ ^= *s++;
+}
+
+
+static void aes_ccm_auth_start(void *aes, size_t M, size_t L, const u8 *nonce,
+ const u8 *aad, size_t aad_len, size_t plain_len,
+ u8 *x)
+{
+ u8 aad_buf[2 * AES_BLOCK_SIZE];
+ u8 b[AES_BLOCK_SIZE];
+
+ /* Authentication */
+ /* B_0: Flags | Nonce N | l(m) */
+ b[0] = aad_len ? 0x40 : 0 /* Adata */;
+ b[0] |= (((M - 2) / 2) /* M' */ << 3);
+ b[0] |= (L - 1) /* L' */;
+ os_memcpy(&b[1], nonce, 15 - L);
+ WPA_PUT_BE16(&b[AES_BLOCK_SIZE - L], plain_len);
+
+ wpa_hexdump_key(MSG_EXCESSIVE, "CCM B_0", b, AES_BLOCK_SIZE);
+ aes_encrypt(aes, b, x); /* X_1 = E(K, B_0) */
+
+ if (!aad_len)
+ return;
+
+ WPA_PUT_BE16(aad_buf, aad_len);
+ os_memcpy(aad_buf + 2, aad, aad_len);
+ os_memset(aad_buf + 2 + aad_len, 0, sizeof(aad_buf) - 2 - aad_len);
+
+ xor_aes_block(aad_buf, x);
+ aes_encrypt(aes, aad_buf, x); /* X_2 = E(K, X_1 XOR B_1) */
+
+ if (aad_len > AES_BLOCK_SIZE - 2) {
+ xor_aes_block(&aad_buf[AES_BLOCK_SIZE], x);
+ /* X_3 = E(K, X_2 XOR B_2) */
+ aes_encrypt(aes, &aad_buf[AES_BLOCK_SIZE], x);
+ }
+}
+
+
+static void aes_ccm_auth(void *aes, const u8 *data, size_t len, u8 *x)
+{
+ size_t last = len % AES_BLOCK_SIZE;
+ size_t i;
+
+ for (i = 0; i < len / AES_BLOCK_SIZE; i++) {
+ /* X_i+1 = E(K, X_i XOR B_i) */
+ xor_aes_block(x, data);
+ data += AES_BLOCK_SIZE;
+ aes_encrypt(aes, x, x);
+ }
+ if (last) {
+ /* XOR zero-padded last block */
+ for (i = 0; i < last; i++)
+ x[i] ^= *data++;
+ aes_encrypt(aes, x, x);
+ }
+}
+
+
+static void aes_ccm_encr_start(size_t L, const u8 *nonce, u8 *a)
+{
+ /* A_i = Flags | Nonce N | Counter i */
+ a[0] = L - 1; /* Flags = L' */
+ os_memcpy(&a[1], nonce, 15 - L);
+}
+
+
+static void aes_ccm_encr(void *aes, size_t L, const u8 *in, size_t len, u8 *out,
+ u8 *a)
+{
+ size_t last = len % AES_BLOCK_SIZE;
+ size_t i;
+
+ /* crypt = msg XOR (S_1 | S_2 | ... | S_n) */
+ for (i = 1; i <= len / AES_BLOCK_SIZE; i++) {
+ WPA_PUT_BE16(&a[AES_BLOCK_SIZE - 2], i);
+ /* S_i = E(K, A_i) */
+ aes_encrypt(aes, a, out);
+ xor_aes_block(out, in);
+ out += AES_BLOCK_SIZE;
+ in += AES_BLOCK_SIZE;
+ }
+ if (last) {
+ WPA_PUT_BE16(&a[AES_BLOCK_SIZE - 2], i);
+ aes_encrypt(aes, a, out);
+ /* XOR zero-padded last block */
+ for (i = 0; i < last; i++)
+ *out++ ^= *in++;
+ }
+}
+
+
+static void aes_ccm_encr_auth(void *aes, size_t M, u8 *x, u8 *a, u8 *auth)
+{
+ size_t i;
+ u8 tmp[AES_BLOCK_SIZE];
+
+ wpa_hexdump_key(MSG_EXCESSIVE, "CCM T", x, M);
+ /* U = T XOR S_0; S_0 = E(K, A_0) */
+ WPA_PUT_BE16(&a[AES_BLOCK_SIZE - 2], 0);
+ aes_encrypt(aes, a, tmp);
+ for (i = 0; i < M; i++)
+ auth[i] = x[i] ^ tmp[i];
+ wpa_hexdump_key(MSG_EXCESSIVE, "CCM U", auth, M);
+}
+
+
+static void aes_ccm_decr_auth(void *aes, size_t M, u8 *a, const u8 *auth, u8 *t)
+{
+ size_t i;
+ u8 tmp[AES_BLOCK_SIZE];
+
+ wpa_hexdump_key(MSG_EXCESSIVE, "CCM U", auth, M);
+ /* U = T XOR S_0; S_0 = E(K, A_0) */
+ WPA_PUT_BE16(&a[AES_BLOCK_SIZE - 2], 0);
+ aes_encrypt(aes, a, tmp);
+ for (i = 0; i < M; i++)
+ t[i] = auth[i] ^ tmp[i];
+ wpa_hexdump_key(MSG_EXCESSIVE, "CCM T", t, M);
+}
+
+
+/* AES-CCM with fixed L=2 and aad_len <= 30 assumption */
+static int aes_ccm_ae(const u8 *key, size_t key_len, const u8 *nonce,
+ size_t M, const u8 *plain, size_t plain_len,
+ const u8 *aad, size_t aad_len, u8 *crypt, u8 *auth)
+{
+ const size_t L = 2;
+ void *aes;
+ u8 x[AES_BLOCK_SIZE], a[AES_BLOCK_SIZE];
+
+ if (aad_len > 30 || M > AES_BLOCK_SIZE)
+ return -1;
+
+ aes = aes_encrypt_init(key, key_len);
+ if (aes == NULL)
+ return -1;
+
+ aes_ccm_auth_start(aes, M, L, nonce, aad, aad_len, plain_len, x);
+ aes_ccm_auth(aes, plain, plain_len, x);
+
+ /* Encryption */
+ aes_ccm_encr_start(L, nonce, a);
+ aes_ccm_encr(aes, L, plain, plain_len, crypt, a);
+ aes_ccm_encr_auth(aes, M, x, a, auth);
+
+ aes_encrypt_deinit(aes);
+
+ return 0;
+}
+
+
+/* AES-CCM with fixed L=2 and aad_len <= 30 assumption */
+static int aes_ccm_ad(const u8 *key, size_t key_len, const u8 *nonce,
+ size_t M, const u8 *crypt, size_t crypt_len,
+ const u8 *aad, size_t aad_len, const u8 *auth, u8 *plain)
+{
+ const size_t L = 2;
+ void *aes;
+ u8 x[AES_BLOCK_SIZE], a[AES_BLOCK_SIZE];
+ u8 t[AES_BLOCK_SIZE];
+
+ if (aad_len > 30 || M > AES_BLOCK_SIZE)
+ return -1;
+
+ aes = aes_encrypt_init(key, key_len);
+ if (aes == NULL)
+ return -1;
+
+ /* Decryption */
+ aes_ccm_encr_start(L, nonce, a);
+ aes_ccm_decr_auth(aes, M, a, auth, t);
+
+ /* plaintext = msg XOR (S_1 | S_2 | ... | S_n) */
+ aes_ccm_encr(aes, L, crypt, crypt_len, plain, a);
+
+ aes_ccm_auth_start(aes, M, L, nonce, aad, aad_len, crypt_len, x);
+ aes_ccm_auth(aes, plain, crypt_len, x);
+
+ aes_encrypt_deinit(aes);
+
+ if (os_memcmp(x, t, M) != 0) {
+ wpa_printf(MSG_EXCESSIVE, "CCM: Auth mismatch");
+ return -1;
+ }
+
+ return 0;
+}
+
+
static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
u8 *aad, size_t *aad_len, u8 *nonce)
{
@@ -76,29 +274,13 @@ static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
}
-static void xor_aes_block(u8 *dst, const u8 *src)
-{
- u32 *d = (u32 *) dst;
- u32 *s = (u32 *) src;
- *d++ ^= *s++;
- *d++ ^= *s++;
- *d++ ^= *s++;
- *d++ ^= *s++;
-}
-
-
u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len)
{
- u8 aad[2 + 30], nonce[13];
+ u8 aad[30], nonce[13];
size_t aad_len;
- u8 b[AES_BLOCK_SIZE], x[AES_BLOCK_SIZE], a[AES_BLOCK_SIZE];
- void *aes;
- const u8 *m, *mpos, *mic;
- size_t mlen, last;
- int i;
- u8 *plain, *ppos;
- u8 t[8];
+ size_t mlen;
+ u8 *plain;
if (data_len < 8 + 8)
return NULL;
@@ -107,95 +289,15 @@ u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
if (plain == NULL)
return NULL;
- aes = aes_encrypt_init(tk, 16);
- if (aes == NULL) {
- os_free(plain);
- return NULL;
- }
-
- m = data + 8;
mlen = data_len - 8 - 8;
- last = mlen % AES_BLOCK_SIZE;
os_memset(aad, 0, sizeof(aad));
- ccmp_aad_nonce(hdr, data, &aad[2], &aad_len, nonce);
- WPA_PUT_BE16(aad, aad_len);
- wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", &aad[2], aad_len);
+ ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
+ wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
- /* CCM: M=8 L=2, Adata=1, M' = (M-2)/2 = 3, L' = L-1 = 1 */
-
- /* A_i = Flags | Nonce N | Counter i */
- a[0] = 0x01; /* Flags = L' */
- os_memcpy(&a[1], nonce, 13);
-
- /* Decryption */
-
- mic = data + data_len - 8;
- wpa_hexdump(MSG_EXCESSIVE, "CCMP U", mic, 8);
- /* U = T XOR S_0; S_0 = E(K, A_0) */
- WPA_PUT_BE16(&a[14], 0);
- aes_encrypt(aes, a, x);
- for (i = 0; i < 8; i++)
- t[i] = mic[i] ^ x[i];
- wpa_hexdump(MSG_EXCESSIVE, "CCMP T", t, 8);
-
- /* plaintext = msg XOR (S_1 | S_2 | ... | S_n) */
- ppos = plain;
- mpos = m;
- for (i = 1; i <= mlen / AES_BLOCK_SIZE; i++) {
- WPA_PUT_BE16(&a[14], i);
- /* S_i = E(K, A_i) */
- aes_encrypt(aes, a, ppos);
- xor_aes_block(ppos, mpos);
- ppos += AES_BLOCK_SIZE;
- mpos += AES_BLOCK_SIZE;
- }
- if (last) {
- WPA_PUT_BE16(&a[14], i);
- aes_encrypt(aes, a, ppos);
- /* XOR zero-padded last block */
- for (i = 0; i < last; i++)
- *ppos++ ^= *mpos++;
- }
- wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
-
- /* Authentication */
- /* B_0: Flags | Nonce N | l(m) */
- b[0] = 0x40 /* Adata */ | (3 /* M' */ << 3) | 1 /* L' */;
- os_memcpy(&b[1], nonce, 13);
- WPA_PUT_BE16(&b[14], mlen);
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_0", b, AES_BLOCK_SIZE);
- aes_encrypt(aes, b, x); /* X_1 = E(K, B_0) */
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_1", aad, AES_BLOCK_SIZE);
- xor_aes_block(aad, x);
- aes_encrypt(aes, aad, x); /* X_2 = E(K, X_1 XOR B_1) */
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_2", &aad[AES_BLOCK_SIZE],
- AES_BLOCK_SIZE);
- xor_aes_block(&aad[AES_BLOCK_SIZE], x);
- aes_encrypt(aes, &aad[AES_BLOCK_SIZE], x); /* X_3 = E(K, X_2 XOR B_2)
- */
-
- ppos = plain;
- for (i = 0; i < mlen / AES_BLOCK_SIZE; i++) {
- /* X_i+1 = E(K, X_i XOR B_i) */
- xor_aes_block(x, ppos);
- ppos += AES_BLOCK_SIZE;
- aes_encrypt(aes, x, x);
- }
- if (last) {
- /* XOR zero-padded last block */
- for (i = 0; i < last; i++)
- x[i] ^= *ppos++;
- aes_encrypt(aes, x, x);
- }
-
- aes_encrypt_deinit(aes);
-
- if (os_memcmp(x, t, 8) != 0) {
+ if (aes_ccm_ad(tk, 16, nonce, 8, data + 8, mlen, aad, aad_len,
+ data + 8 + mlen, plain) < 0) {
u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
wpa_printf(MSG_INFO, "Invalid CCMP MIC in frame: A1=" MACSTR
" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
@@ -203,10 +305,10 @@ u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
MAC2STR(hdr->addr3),
WLAN_GET_SEQ_SEQ(seq_ctrl),
WLAN_GET_SEQ_FRAG(seq_ctrl));
- wpa_hexdump(MSG_DEBUG, "CCMP decrypted", plain, mlen);
os_free(plain);
return NULL;
}
+ wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
*decrypted_len = mlen;
return plain;
@@ -227,19 +329,14 @@ void ccmp_get_pn(u8 *pn, const u8 *data)
u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
u8 *pn, int keyid, size_t *encrypted_len)
{
- u8 aad[2 + 30], nonce[13];
- size_t aad_len;
- u8 b[AES_BLOCK_SIZE], x[AES_BLOCK_SIZE], a[AES_BLOCK_SIZE];
- void *aes;
- u8 *crypt, *pos, *ppos, *mpos;
- size_t plen, last;
+ u8 aad[30], nonce[13];
+ size_t aad_len, plen;
+ u8 *crypt, *pos;
struct ieee80211_hdr *hdr;
- int i;
if (len < hdrlen || hdrlen < 24)
return NULL;
plen = len - hdrlen;
- last = plen % AES_BLOCK_SIZE;
crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
if (crypt == NULL)
@@ -258,91 +355,19 @@ u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
*pos++ = pn[1]; /* PN4 */
*pos++ = pn[0]; /* PN5 */
- aes = aes_encrypt_init(tk, 16);
- if (aes == NULL) {
- os_free(crypt);
- return NULL;
- }
-
os_memset(aad, 0, sizeof(aad));
- ccmp_aad_nonce(hdr, crypt + hdrlen, &aad[2], &aad_len, nonce);
- WPA_PUT_BE16(aad, aad_len);
- wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", &aad[2], aad_len);
+ ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
+ wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
- /* Authentication */
- /* B_0: Flags | Nonce N | l(m) */
- b[0] = 0x40 /* Adata */ | (3 /* M' */ << 3) | 1 /* L' */;
- os_memcpy(&b[1], nonce, 13);
- WPA_PUT_BE16(&b[14], plen);
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_0", b, AES_BLOCK_SIZE);
- aes_encrypt(aes, b, x); /* X_1 = E(K, B_0) */
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_1", aad, AES_BLOCK_SIZE);
- xor_aes_block(aad, x);
- aes_encrypt(aes, aad, x); /* X_2 = E(K, X_1 XOR B_1) */
-
- wpa_hexdump(MSG_EXCESSIVE, "CCMP B_2", &aad[AES_BLOCK_SIZE],
- AES_BLOCK_SIZE);
- xor_aes_block(&aad[AES_BLOCK_SIZE], x);
- aes_encrypt(aes, &aad[AES_BLOCK_SIZE], x); /* X_3 = E(K, X_2 XOR B_2)
- */
-
- ppos = frame + hdrlen;
- for (i = 0; i < plen / AES_BLOCK_SIZE; i++) {
- /* X_i+1 = E(K, X_i XOR B_i) */
- xor_aes_block(x, ppos);
- ppos += AES_BLOCK_SIZE;
- aes_encrypt(aes, x, x);
- }
- if (last) {
- /* XOR zero-padded last block */
- for (i = 0; i < last; i++)
- x[i] ^= *ppos++;
- aes_encrypt(aes, x, x);
- }
-
- /* Encryption */
-
- /* CCM: M=8 L=2, Adata=1, M' = (M-2)/2 = 3, L' = L-1 = 1 */
-
- /* A_i = Flags | Nonce N | Counter i */
- a[0] = 0x01; /* Flags = L' */
- os_memcpy(&a[1], nonce, 13);
-
- ppos = crypt + hdrlen + 8;
-
- /* crypt = msg XOR (S_1 | S_2 | ... | S_n) */
- mpos = frame + hdrlen;
- for (i = 1; i <= plen / AES_BLOCK_SIZE; i++) {
- WPA_PUT_BE16(&a[14], i);
- /* S_i = E(K, A_i) */
- aes_encrypt(aes, a, ppos);
- xor_aes_block(ppos, mpos);
- ppos += AES_BLOCK_SIZE;
- mpos += AES_BLOCK_SIZE;
- }
- if (last) {
- WPA_PUT_BE16(&a[14], i);
- aes_encrypt(aes, a, ppos);
- /* XOR zero-padded last block */
- for (i = 0; i < last; i++)
- *ppos++ ^= *mpos++;
+ if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
+ pos, pos + plen) < 0) {
+ os_free(crypt);
+ return NULL;
}
- wpa_hexdump(MSG_EXCESSIVE, "CCMP T", x, 8);
- /* U = T XOR S_0; S_0 = E(K, A_0) */
- WPA_PUT_BE16(&a[14], 0);
- aes_encrypt(aes, a, b);
- for (i = 0; i < 8; i++)
- ppos[i] = x[i] ^ b[i];
- wpa_hexdump(MSG_EXCESSIVE, "CCMP U", ppos, 8);
-
wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen + 8, plen);
- aes_encrypt_deinit(aes);
-
*encrypted_len = hdrlen + 8 + plen + 8;
return crypt;