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authorJouni Malinen <j@w1.fi>2012-09-08 19:08:00 (GMT)
committerJouni Malinen <j@w1.fi>2012-09-08 19:08:00 (GMT)
commit37c8fe2e3b3a9b893f89ec69b05acf7b80afe41b (patch)
treede1b485cfe32b65f4435b7387a9abf59b7bc758a /wlantest/gcmp.c
parent455bcc0f5c6347dd76fb2aeac6e1933146d58be1 (diff)
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wlantest: Move GCM-AE and GCM-AD into separate functions
This splits the more generic GCM operations from GCMP specific implementation. Signed-hostap: Jouni Malinen <j@w1.fi>
Diffstat (limited to 'wlantest/gcmp.c')
-rw-r--r--wlantest/gcmp.c345
1 files changed, 185 insertions, 160 deletions
diff --git a/wlantest/gcmp.c b/wlantest/gcmp.c
index 27beea2..d1b54ce 100644
--- a/wlantest/gcmp.c
+++ b/wlantest/gcmp.c
@@ -152,6 +152,179 @@ static void aes_gctr(void *aes, const u8 *icb, const u8 *x, size_t xlen, u8 *y)
}
+/**
+ * aes_gcm_ae - GCM-AE_K(IV, P, A) with len(IV) = 96
+ */
+static int aes_gcm_ae(const u8 *key, const u8 *iv,
+ const u8 *plain, size_t plain_len,
+ const u8 *aad, size_t aad_len,
+ u8 *crypt, u8 *tag)
+{
+ u8 *auth, *apos;
+ u8 H[AES_BLOCK_SIZE];
+ u8 J0[AES_BLOCK_SIZE];
+ u8 S[16];
+ void *aes;
+ size_t padlen;
+ size_t iv_len = 12;
+
+ aes = aes_encrypt_init(key, 16);
+ if (aes == NULL)
+ return -1;
+
+ /* 1. Generate hash subkey H = AES_K(0^128) */
+ os_memset(H, 0, sizeof(H));
+ aes_encrypt(aes, H, H);
+ wpa_hexdump_key(MSG_EXCESSIVE, "Hash subkey H for GHASH", H, sizeof(H));
+
+ /* 2. Prepare block J_0 = IV || 0^31 || 1 [len(IV) = 96] */
+ os_memcpy(J0, iv, iv_len);
+ os_memset(J0 + iv_len, 0, AES_BLOCK_SIZE - iv_len);
+ J0[AES_BLOCK_SIZE - 1] = 0x01;
+
+ /* 3. C = GCTR_K(inc_32(J_0), P) */
+ inc32(J0);
+ aes_gctr(aes, J0, plain, plain_len, crypt);
+
+ /*
+ * 4. u = 128 * ceil[len(C)/128] - len(C)
+ * v = 128 * ceil[len(A)/128] - len(A)
+ * 5. S = GHASH_H(A || 0^v || C || 0^u || [len(A)]64 || [len(C)]64)
+ * (i.e., zero padded to block size A || C and lengths of each in bits)
+ */
+ auth = os_malloc(32 + 16 + plain_len + 8 + 8);
+ if (auth == NULL) {
+ aes_encrypt_deinit(aes);
+ return -1;
+ }
+
+ apos = auth;
+
+ /* Zero-padded AAD */
+ os_memcpy(apos, aad, aad_len);
+ apos += aad_len;
+ padlen = (16 - aad_len % 16) % 16;
+ os_memset(apos, 0, padlen);
+ apos += padlen;
+
+ /* Zero-padded C */
+ os_memcpy(apos, crypt, plain_len);
+ apos += plain_len;
+ padlen = (16 - plain_len % 16) % 16;
+ os_memset(apos, 0, padlen);
+ apos += padlen;
+
+ /* Length of AAD and C in bits */
+ WPA_PUT_BE64(apos, aad_len * 8);
+ apos += 8;
+ WPA_PUT_BE64(apos, plain_len * 8);
+ apos += 8;
+
+ wpa_hexdump_key(MSG_EXCESSIVE, "GHASH_H input", auth, apos - auth);
+ ghash(H, auth, apos - auth, S);
+ wpa_hexdump_key(MSG_EXCESSIVE, "S = GHASH_H(...)", S, 16);
+ os_free(auth);
+
+ /* 6. T = MSB_t(GCTR_K(J_0, S)) */
+ J0[AES_BLOCK_SIZE - 1] = 0x01;
+ aes_gctr(aes, J0, S, sizeof(S), tag);
+
+ /* 7. Return (C, T) */
+
+ aes_encrypt_deinit(aes);
+
+ return 0;
+}
+
+
+/**
+ * aes_gcm_ad - GCM-AD_K(IV, C, A, T) with len(IV) = 96
+ */
+static int aes_gcm_ad(const u8 *key, const u8 *iv,
+ const u8 *crypt, size_t crypt_len,
+ const u8 *aad, size_t aad_len, const u8 *tag,
+ u8 *plain)
+{
+ u8 *auth, *apos;
+ u8 H[AES_BLOCK_SIZE];
+ u8 J0[AES_BLOCK_SIZE];
+ u8 S[16], T[16];
+ void *aes;
+ size_t padlen;
+ size_t iv_len = 12;
+
+ aes = aes_encrypt_init(key, 16);
+ if (aes == NULL)
+ return -1;
+
+ /* 2. Generate hash subkey H = AES_K(0^128) */
+ os_memset(H, 0, sizeof(H));
+ aes_encrypt(aes, H, H);
+ wpa_hexdump(MSG_EXCESSIVE, "Hash subkey H for GHASH", H, sizeof(H));
+
+ /* 3. Prepare block J_0 = IV || 0^31 || 1 [len(IV) = 96] */
+ os_memcpy(J0, iv, iv_len);
+ os_memset(J0 + iv_len, 0, AES_BLOCK_SIZE - iv_len);
+ J0[AES_BLOCK_SIZE - 1] = 0x01;
+
+ /* 4. C = GCTR_K(inc_32(J_0), C) */
+ inc32(J0);
+ aes_gctr(aes, J0, crypt, crypt_len, plain);
+
+ /*
+ * 5. u = 128 * ceil[len(C)/128] - len(C)
+ * v = 128 * ceil[len(A)/128] - len(A)
+ * 6. S = GHASH_H(A || 0^v || C || 0^u || [len(A)]64 || [len(C)]64)
+ * (i.e., zero padded to block size A || C and lengths of each in bits)
+ */
+ auth = os_malloc(32 + 16 + crypt_len + 8 + 8);
+ if (auth == NULL) {
+ aes_encrypt_deinit(aes);
+ return -1;
+ }
+
+ apos = auth;
+
+ /* Zero-padded AAD */
+ os_memcpy(apos, aad, aad_len);
+ apos += aad_len;
+ padlen = (16 - aad_len % 16) % 16;
+ os_memset(apos, 0, padlen);
+ apos += padlen;
+
+ /* Zero-padded C */
+ os_memcpy(apos, crypt, crypt_len);
+ apos += crypt_len;
+ padlen = (16 - crypt_len % 16) % 16;
+ os_memset(apos, 0, padlen);
+ apos += padlen;
+
+ /* Length of AAD and C in bits */
+ WPA_PUT_BE64(apos, aad_len * 8);
+ apos += 8;
+ WPA_PUT_BE64(apos, crypt_len * 8);
+ apos += 8;
+
+ wpa_hexdump(MSG_EXCESSIVE, "GHASH_H input", auth, apos - auth);
+ ghash(H, auth, apos - auth, S);
+ wpa_hexdump(MSG_EXCESSIVE, "S = GHASH_H(...)", S, 16);
+ os_free(auth);
+
+ /* 7. T' = MSB_t(GCTR_K(J_0, S)) */
+ J0[AES_BLOCK_SIZE - 1] = 0x01;
+ aes_gctr(aes, J0, S, sizeof(S), T);
+
+ aes_encrypt_deinit(aes);
+
+ if (os_memcmp(tag, T, 16) != 0) {
+ wpa_printf(MSG_EXCESSIVE, "GCM: Tag mismatch");
+ return -1;
+ }
+
+ return 0;
+}
+
+
static void gcmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
u8 *aad, size_t *aad_len, u8 *nonce)
{
@@ -213,12 +386,8 @@ static void gcmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
u8 * gcmp_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[12], *plain, *auth, *apos;
- u8 H[AES_BLOCK_SIZE];
- u8 J0[AES_BLOCK_SIZE];
- u8 S[16], T[16];
- size_t aad_len, padlen, mlen;
- void *aes;
+ u8 aad[2 + 30], nonce[12], *plain;
+ size_t aad_len, mlen;
const u8 *m;
if (data_len < 8 + 16)
@@ -228,12 +397,6 @@ u8 * gcmp_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 - 16;
@@ -243,86 +406,20 @@ u8 * gcmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
wpa_hexdump(MSG_EXCESSIVE, "GCMP AAD", &aad[2], aad_len);
wpa_hexdump(MSG_EXCESSIVE, "GCMP nonce", nonce, sizeof(nonce));
- /* GCM-AD_K(IV, C, A, T)
- *
- * IV = GCMP nonce
- * A = AAD
- * C | T = received frame
- */
-
- /* 2. Generate hash subkey H = AES_K(0^128) */
- os_memset(H, 0, sizeof(H));
- aes_encrypt(aes, H, H);
- wpa_hexdump(MSG_EXCESSIVE, "Hash subkey H for GHASH", H, sizeof(H));
-
- /* 3. Prepare block J_0 = IV || 0^31 || 1 [len(IV) = 96] */
- os_memcpy(J0, nonce, sizeof(nonce));
- os_memset(J0 + sizeof(nonce), 0, AES_BLOCK_SIZE - sizeof(nonce));
- J0[AES_BLOCK_SIZE - 1] = 0x01;
-
- /* 4. C = GCTR_K(inc_32(J_0), C) */
- inc32(J0);
- aes_gctr(aes, J0, m, mlen, plain);
-
- /*
- * 5. u = 128 * ceil[len(C)/128] - len(C)
- * v = 128 * ceil[len(A)/128] - len(A)
- * 6. S = GHASH_H(A || 0^v || C || 0^u || [len(A)]64 || [len(C)]64)
- * (i.e., zero padded to block size A || C and lengths of each in bits)
- */
- auth = os_malloc(32 + 16 + data_len - 16 + 8 + 8);
- if (auth == NULL) {
- os_free(plain);
- return NULL;
- }
-
- apos = auth;
-
- /* Zero-padded AAD */
- os_memcpy(apos, &aad[2], aad_len);
- apos += aad_len;
- padlen = (16 - aad_len % 16) % 16;
- os_memset(apos, 0, padlen);
- apos += padlen;
-
- /* Zero-padded C */
- os_memcpy(apos, m, mlen);
- apos += mlen;
- padlen = (16 - mlen % 16) % 16;
- os_memset(apos, 0, padlen);
- apos += padlen;
-
- /* Length of AAD and C in bits */
- WPA_PUT_BE64(apos, aad_len * 8);
- apos += 8;
- WPA_PUT_BE64(apos, mlen * 8);
- apos += 8;
-
- wpa_hexdump(MSG_EXCESSIVE, "GCMP GHASH_H input", auth, apos - auth);
- ghash(H, auth, apos - auth, S);
- wpa_hexdump(MSG_EXCESSIVE, "GCMP S = GHASH_H(...)", S, 16);
- os_free(auth);
-
- /* 7. T' = MSB_t(GCTR_K(J_0, S)) */
- J0[AES_BLOCK_SIZE - 1] = 0x01;
- aes_gctr(aes, J0, S, sizeof(S), T);
-
- aes_encrypt_deinit(aes);
-
- if (os_memcmp(data + data_len - 16, T, 16) != 0) {
+ if (aes_gcm_ad(tk, nonce, m, mlen, &aad[2], aad_len, m + mlen, plain) <
+ 0) {
u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
- wpa_printf(MSG_INFO, "Invalid GCMP MIC in frame: A1=" MACSTR
+ wpa_printf(MSG_INFO, "Invalid GCMP frame: A1=" MACSTR
" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
MAC2STR(hdr->addr3),
WLAN_GET_SEQ_SEQ(seq_ctrl),
WLAN_GET_SEQ_FRAG(seq_ctrl));
- wpa_hexdump(MSG_DEBUG, "GCMP decrypted", plain, data_len - 16);
os_free(plain);
return NULL;
}
- *decrypted_len = data_len - 8 - 16;
+ *decrypted_len = mlen;
return plain;
}
@@ -330,13 +427,9 @@ u8 * gcmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
u8 * gcmp_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[12], *crypt, *pos, *auth, *apos;
- u8 H[AES_BLOCK_SIZE];
- u8 J0[AES_BLOCK_SIZE];
- u8 S[16];
- size_t aad_len, plen, padlen;
+ u8 aad[2 + 30], nonce[12], *crypt, *pos;
+ size_t aad_len, plen;
struct ieee80211_hdr *hdr;
- void *aes;
if (len < hdrlen || hdrlen < 24)
return NULL;
@@ -359,88 +452,20 @@ u8 * gcmp_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));
gcmp_aad_nonce(hdr, crypt + hdrlen, &aad[2], &aad_len, nonce);
WPA_PUT_BE16(aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "GCMP AAD", &aad[2], aad_len);
wpa_hexdump(MSG_EXCESSIVE, "GCMP nonce", nonce, sizeof(nonce));
- /* GCM-AE_K(IV, P, A)
- *
- * IV = GCMP nonce
- * A = AAD
- */
-
- /* 1. Generate hash subkey H = AES_K(0^128) */
- os_memset(H, 0, sizeof(H));
- aes_encrypt(aes, H, H);
- wpa_hexdump(MSG_EXCESSIVE, "Hash subkey H for GHASH", H, sizeof(H));
-
- /* 2. Prepare block J_0 = IV || 0^31 || 1 [len(IV) = 96] */
- os_memcpy(J0, nonce, sizeof(nonce));
- os_memset(J0 + sizeof(nonce), 0, AES_BLOCK_SIZE - sizeof(nonce));
- J0[AES_BLOCK_SIZE - 1] = 0x01;
-
- /* 3. C = GCTR_K(inc_32(J_0), P) */
- inc32(J0);
- aes_gctr(aes, J0, frame + hdrlen, len - hdrlen, pos);
- pos += len - hdrlen;
-
- /*
- * 4. u = 128 * ceil[len(C)/128] - len(C)
- * v = 128 * ceil[len(A)/128] - len(A)
- * 5. S = GHASH_H(A || 0^v || C || 0^u || [len(A)]64 || [len(C)]64)
- * (i.e., zero padded to block size A || C and lengths of each in bits)
- */
- auth = os_malloc(32 + 16 + len - hdrlen + 8 + 8);
- if (auth == NULL) {
+ if (aes_gcm_ae(tk, nonce, frame + hdrlen, plen, &aad[2], aad_len,
+ pos, pos + plen) < 0) {
os_free(crypt);
return NULL;
}
- apos = auth;
-
- /* Zero-padded AAD */
- os_memcpy(apos, &aad[2], aad_len);
- apos += aad_len;
- padlen = (16 - aad_len % 16) % 16;
- os_memset(apos, 0, padlen);
- apos += padlen;
-
- /* Zero-padded C */
- os_memcpy(apos, crypt + hdrlen + 8, plen);
- apos += plen;
- padlen = (16 - plen % 16) % 16;
- os_memset(apos, 0, padlen);
- apos += padlen;
-
- /* Length of AAD and C in bits */
- WPA_PUT_BE64(apos, aad_len * 8);
- apos += 8;
- WPA_PUT_BE64(apos, plen * 8);
- apos += 8;
-
- wpa_hexdump(MSG_EXCESSIVE, "GCMP GHASH_H input", auth, apos - auth);
- ghash(H, auth, apos - auth, S);
- wpa_hexdump(MSG_EXCESSIVE, "GCMP S = GHASH_H(...)", S, 16);
- os_free(auth);
-
- /* 6. T = MSB_t(GCTR_K(J_0, S)) */
- J0[AES_BLOCK_SIZE - 1] = 0x01;
- aes_gctr(aes, J0, S, sizeof(S), pos);
- wpa_hexdump(MSG_EXCESSIVE, "GCMP MIC", pos, 16);
-
- /* 7. Return (C, T) */
-
- wpa_hexdump(MSG_EXCESSIVE, "GCMP encrypted", crypt + hdrlen + 8, plen);
-
- aes_encrypt_deinit(aes);
+ wpa_hexdump(MSG_EXCESSIVE, "GCMP MIC", pos + plen, 16);
+ wpa_hexdump(MSG_EXCESSIVE, "GCMP encrypted", pos, plen);
*encrypted_len = hdrlen + 8 + plen + 16;