mesh: Convert crypto to use ELL wrappers

Use ELL implementations of aead-ccm(aes), ecb(aes) and cmac(aes). These
standard encryption and hashing routines are provided by ELL.
This commit is contained in:
Brian Gix 2019-05-29 10:28:18 -07:00
parent 75cd5b382e
commit dfed483946
2 changed files with 58 additions and 464 deletions

View File

@ -116,6 +116,8 @@ ell_headers = ell/util.h \
ell/random.h \
ell/signal.h \
ell/timeout.h \
ell/cipher.h \
ell/checksum.h \
ell/io.h \
ell/idle.h \
ell/main.h \
@ -138,6 +140,8 @@ ell_sources = ell/private.h ell/missing.h \
ell/main.c \
ell/strv.c \
ell/string.c \
ell/cipher.c \
ell/checksum.c \
ell/dbus-private.h \
ell/dbus.c \
ell/dbus-message.c \

View File

@ -44,193 +44,52 @@
/* Multiply used Zero array */
static const uint8_t zero[16] = { 0, };
static int alg_new(int fd, const void *keyval, socklen_t keylen,
size_t mic_size)
static bool aes_ecb_one(const uint8_t key[16], const uint8_t in[16],
uint8_t out[16])
{
if (setsockopt(fd, SOL_ALG, ALG_SET_KEY, keyval, keylen) < 0)
return -1;
void *cipher;
bool result = false;
if (mic_size &&
setsockopt(fd, SOL_ALG, ALG_SET_AEAD_AUTHSIZE,
NULL, mic_size) < 0)
return -1;
cipher = l_cipher_new(L_CIPHER_AES, key, 16);
/* FIXME: This should use accept4() with SOCK_CLOEXEC */
return accept(fd, NULL, 0);
}
static bool alg_encrypt(int fd, const void *inbuf, size_t inlen,
void *outbuf, size_t outlen)
{
__u32 alg_op = ALG_OP_ENCRYPT;
char cbuf[CMSG_SPACE(sizeof(alg_op))];
struct cmsghdr *cmsg;
struct msghdr msg;
struct iovec iov;
ssize_t len;
memset(cbuf, 0, sizeof(cbuf));
memset(&msg, 0, sizeof(msg));
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_ALG;
cmsg->cmsg_type = ALG_SET_OP;
cmsg->cmsg_len = CMSG_LEN(sizeof(alg_op));
memcpy(CMSG_DATA(cmsg), &alg_op, sizeof(alg_op));
iov.iov_base = (void *) inbuf;
iov.iov_len = inlen;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
len = sendmsg(fd, &msg, 0);
if (len < 0)
return false;
len = read(fd, outbuf, outlen);
if (len < 0)
return false;
return true;
}
static int aes_ecb_setup(const uint8_t key[16])
{
struct sockaddr_alg salg;
int fd, nfd;
fd = socket(PF_ALG, SOCK_SEQPACKET | SOCK_CLOEXEC, 0);
if (fd < 0)
return -1;
memset(&salg, 0, sizeof(salg));
salg.salg_family = AF_ALG;
strcpy((char *) salg.salg_type, "skcipher");
strcpy((char *) salg.salg_name, "ecb(aes)");
if (bind(fd, (struct sockaddr *) &salg, sizeof(salg)) < 0) {
close(fd);
return -1;
if (cipher) {
result = l_cipher_encrypt(cipher, in, out, 16);
l_cipher_free(cipher);
}
nfd = alg_new(fd, key, 16, 0);
close(fd);
return nfd;
}
static bool aes_ecb(int fd, const uint8_t plaintext[16], uint8_t encrypted[16])
{
return alg_encrypt(fd, plaintext, 16, encrypted, 16);
}
static void aes_ecb_destroy(int fd)
{
close(fd);
}
static bool aes_ecb_one(const uint8_t key[16],
const uint8_t plaintext[16], uint8_t encrypted[16])
{
bool result;
int fd;
fd = aes_ecb_setup(key);
if (fd < 0)
return false;
result = aes_ecb(fd, plaintext, encrypted);
aes_ecb_destroy(fd);
return result;
}
bool mesh_aes_ecb_one(const uint8_t key[16],
const uint8_t plaintext[16], uint8_t encrypted[16])
{
return aes_ecb_one(key, plaintext, encrypted);
}
/* Maximum message length that can be passed to aes_cmac */
#define CMAC_MSG_MAX (64 + 64 + 17)
static int aes_cmac_setup(const uint8_t key[16])
{
struct sockaddr_alg salg;
int fd, nfd;
fd = socket(PF_ALG, SOCK_SEQPACKET | SOCK_CLOEXEC, 0);
if (fd < 0)
return -1;
memset(&salg, 0, sizeof(salg));
salg.salg_family = AF_ALG;
strcpy((char *) salg.salg_type, "hash");
strcpy((char *) salg.salg_name, "cmac(aes)");
if (bind(fd, (struct sockaddr *) &salg, sizeof(salg)) < 0) {
close(fd);
return -1;
}
nfd = alg_new(fd, key, 16, 0);
close(fd);
return nfd;
}
static bool aes_cmac(int fd, const uint8_t *msg,
static bool aes_cmac(void *checksum, const uint8_t *msg,
size_t msg_len, uint8_t res[16])
{
ssize_t len;
if (msg_len > CMAC_MSG_MAX)
if (!l_checksum_update(checksum, msg, msg_len))
return false;
len = send(fd, msg, msg_len, 0);
if (len < 0)
return false;
if (16 == l_checksum_get_digest(checksum, res, 16))
return true;
len = read(fd, res, 16);
if (len < 0)
return false;
return true;
}
static void aes_cmac_destroy(int fd)
{
close(fd);
}
static int aes_cmac_N_start(const uint8_t N[16])
{
int fd;
fd = aes_cmac_setup(N);
return fd;
return false;
}
static bool aes_cmac_one(const uint8_t key[16], const void *msg,
size_t msg_len, uint8_t res[16])
{
void *checksum;
bool result;
int fd;
fd = aes_cmac_setup(key);
if (fd < 0)
checksum = l_checksum_new_cmac_aes(key, 16);
if (!checksum)
return false;
result = aes_cmac(fd, msg, msg_len, res);
result = l_checksum_update(checksum, msg, msg_len);
aes_cmac_destroy(fd);
if (result) {
ssize_t len = l_checksum_get_digest(checksum, res, 16);
result = !!(len == 16);
}
l_checksum_free(checksum);
return result;
}
@ -247,161 +106,22 @@ bool mesh_crypto_aes_ccm_encrypt(const uint8_t nonce[13], const uint8_t key[16],
uint8_t *out_msg,
void *out_mic, size_t mic_size)
{
uint8_t pmsg[16], cmic[16], cmsg[16];
uint8_t mic[16], Xn[16];
uint16_t blk_cnt, last_blk;
void *cipher;
bool result;
size_t i, j;
int fd;
/* Mesh limits AAD length to 16 */
if (aad_len > 16)
return false;
cipher = l_aead_cipher_new(L_AEAD_CIPHER_AES_CCM, key, 16, mic_size);
fd = aes_ecb_setup(key);
if (fd < 0)
return false;
result = l_aead_cipher_encrypt(cipher, msg, msg_len, aad, aad_len,
nonce, 13, out_msg, msg_len + mic_size);
/* C_mic = e(AppKey, 0x01 || nonce || 0x0000) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(0x0000, pmsg + 14);
result = aes_ecb(fd, pmsg, cmic);
if (!result)
goto done;
/* X_0 = e(AppKey, 0x09 || nonce || length) */
if (mic_size == 8)
pmsg[0] = 0x19 | (aad_len ? 0x40 : 0x00);
else
pmsg[0] = 0x09 | (aad_len ? 0x40 : 0x00);
memcpy(pmsg + 1, nonce, 13);
l_put_be16(msg_len, pmsg + 14);
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
/* If AAD is being used to authenticate, include it here */
if (aad_len) {
l_put_be16(aad_len, pmsg);
for (i = 0; i < sizeof(uint16_t); i++)
pmsg[i] = Xn[i] ^ pmsg[i];
j = 0;
aad_len += sizeof(uint16_t);
while (aad_len > 16) {
do {
pmsg[i] = Xn[i] ^ aad[j];
i++, j++;
} while (i < 16);
aad_len -= 16;
i = 0;
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
}
for (i = 0; i < aad_len; i++, j++)
pmsg[i] = Xn[i] ^ aad[j];
for (i = aad_len; i < 16; i++)
pmsg[i] = Xn[i];
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
if (result && out_mic) {
if (mic_size == 4)
*(uint32_t *)out_mic = l_get_be32(out_msg + msg_len);
else
*(uint64_t *)out_mic = l_get_be64(out_msg + msg_len);
}
last_blk = msg_len % 16;
blk_cnt = (msg_len + 15) / 16;
if (!last_blk)
last_blk = 16;
for (j = 0; j < blk_cnt; j++) {
if (j + 1 == blk_cnt) {
/* X_1 = e(AppKey, X_0 ^ Payload[0-15]) */
for (i = 0; i < last_blk; i++)
pmsg[i] = Xn[i] ^ msg[(j * 16) + i];
for (i = last_blk; i < 16; i++)
pmsg[i] = Xn[i] ^ 0x00;
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
/* MIC = C_mic ^ X_1 */
for (i = 0; i < sizeof(mic); i++)
mic[i] = cmic[i] ^ Xn[i];
/* C_1 = e(AppKey, 0x01 || nonce || 0x0001) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(j + 1, pmsg + 14);
result = aes_ecb(fd, pmsg, cmsg);
if (!result)
goto done;
if (out_msg) {
/* Encrypted = Payload[0-15] ^ C_1 */
for (i = 0; i < last_blk; i++)
out_msg[(j * 16) + i] =
msg[(j * 16) + i] ^ cmsg[i];
}
} else {
/* X_1 = e(AppKey, X_0 ^ Payload[0-15]) */
for (i = 0; i < 16; i++)
pmsg[i] = Xn[i] ^ msg[(j * 16) + i];
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
/* C_1 = e(AppKey, 0x01 || nonce || 0x0001) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(j + 1, pmsg + 14);
result = aes_ecb(fd, pmsg, cmsg);
if (!result)
goto done;
if (out_msg) {
/* Encrypted = Payload[0-15] ^ C_N */
for (i = 0; i < 16; i++)
out_msg[(j * 16) + i] =
msg[(j * 16) + i] ^ cmsg[i];
}
}
}
if (out_msg)
memcpy(out_msg + msg_len, mic, mic_size);
if (out_mic) {
switch (mic_size) {
case 4:
*(uint32_t *)out_mic = l_get_be32(mic);
break;
case 8:
*(uint64_t *)out_mic = l_get_be64(mic);
break;
default:
/* Unsupported MIC size */
result = false;
}
}
done:
aes_ecb_destroy(fd);
l_aead_cipher_free(cipher);
return result;
}
@ -412,156 +132,26 @@ bool mesh_crypto_aes_ccm_decrypt(const uint8_t nonce[13], const uint8_t key[16],
uint8_t *out_msg,
void *out_mic, size_t mic_size)
{
uint8_t msg[16], pmsg[16], cmic[16], cmsg[16], Xn[16];
uint8_t mic[16];
uint16_t msg_len = enc_msg_len - mic_size;
uint16_t last_blk, blk_cnt;
void *cipher;
bool result;
size_t i, j;
int fd;
size_t out_msg_len = enc_msg_len - mic_size;
if (enc_msg_len < 5 || aad_len > 16)
return false;
cipher = l_aead_cipher_new(L_AEAD_CIPHER_AES_CCM, key, 16, mic_size);
fd = aes_ecb_setup(key);
if (fd < 0)
return false;
result = l_aead_cipher_decrypt(cipher, enc_msg, enc_msg_len,
aad, aad_len, nonce, 13,
out_msg, out_msg_len);
/* C_mic = e(AppKey, 0x01 || nonce || 0x0000) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(0x0000, pmsg + 14);
result = aes_ecb(fd, pmsg, cmic);
if (!result)
goto done;
/* X_0 = e(AppKey, 0x09 || nonce || length) */
if (mic_size == 8)
pmsg[0] = 0x19 | (aad_len ? 0x40 : 0x00);
else
pmsg[0] = 0x09 | (aad_len ? 0x40 : 0x00);
memcpy(pmsg + 1, nonce, 13);
l_put_be16(msg_len, pmsg + 14);
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
/* If AAD is being used to authenticate, include it here */
if (aad_len) {
l_put_be16(aad_len, pmsg);
for (i = 0; i < sizeof(uint16_t); i++)
pmsg[i] = Xn[i] ^ pmsg[i];
j = 0;
aad_len += sizeof(uint16_t);
while (aad_len > 16) {
do {
pmsg[i] = Xn[i] ^ aad[j];
i++, j++;
} while (i < 16);
aad_len -= 16;
i = 0;
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
}
for (i = 0; i < aad_len; i++, j++)
pmsg[i] = Xn[i] ^ aad[j];
for (i = aad_len; i < 16; i++)
pmsg[i] = Xn[i];
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
if (result && out_mic) {
if (mic_size == 4)
*(uint32_t *)out_mic =
l_get_be32(enc_msg + enc_msg_len - mic_size);
else
*(uint64_t *)out_mic =
l_get_be64(enc_msg + enc_msg_len - mic_size);
}
last_blk = msg_len % 16;
blk_cnt = (msg_len + 15) / 16;
if (!last_blk)
last_blk = 16;
for (j = 0; j < blk_cnt; j++) {
if (j + 1 == blk_cnt) {
/* C_1 = e(AppKey, 0x01 || nonce || 0x0001) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(j + 1, pmsg + 14);
result = aes_ecb(fd, pmsg, cmsg);
if (!result)
goto done;
/* Encrypted = Payload[0-15] ^ C_1 */
for (i = 0; i < last_blk; i++)
msg[i] = enc_msg[(j * 16) + i] ^ cmsg[i];
if (out_msg)
memcpy(out_msg + (j * 16), msg, last_blk);
/* X_1 = e(AppKey, X_0 ^ Payload[0-15]) */
for (i = 0; i < last_blk; i++)
pmsg[i] = Xn[i] ^ msg[i];
for (i = last_blk; i < 16; i++)
pmsg[i] = Xn[i] ^ 0x00;
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
/* MIC = C_mic ^ X_1 */
for (i = 0; i < sizeof(mic); i++)
mic[i] = cmic[i] ^ Xn[i];
} else {
/* C_1 = e(AppKey, 0x01 || nonce || 0x0001) */
pmsg[0] = 0x01;
memcpy(pmsg + 1, nonce, 13);
l_put_be16(j + 1, pmsg + 14);
result = aes_ecb(fd, pmsg, cmsg);
if (!result)
goto done;
/* Encrypted = Payload[0-15] ^ C_1 */
for (i = 0; i < 16; i++)
msg[i] = enc_msg[(j * 16) + i] ^ cmsg[i];
if (out_msg)
memcpy(out_msg + (j * 16), msg, 16);
/* X_1 = e(AppKey, X_0 ^ Payload[0-15]) */
for (i = 0; i < 16; i++)
pmsg[i] = Xn[i] ^ msg[i];
result = aes_ecb(fd, pmsg, Xn);
if (!result)
goto done;
}
}
if (out_mic) {
switch (mic_size) {
case 4:
*(uint32_t *)out_mic = l_get_be32(mic);
break;
case 8:
*(uint64_t *)out_mic = l_get_be64(mic);
break;
default:
/* Unsupported MIC size */
result = false;
}
}
done:
aes_ecb_destroy(fd);
l_aead_cipher_free(cipher);
return result;
}
@ -582,7 +172,7 @@ bool mesh_crypto_k2(const uint8_t n[16], const uint8_t *p, size_t p_len,
uint8_t enc_key[16],
uint8_t priv_key[16])
{
int fd;
void *checksum;
uint8_t output[16];
uint8_t t[16];
uint8_t *stage;
@ -598,14 +188,14 @@ bool mesh_crypto_k2(const uint8_t n[16], const uint8_t *p, size_t p_len,
if (!aes_cmac_one(stage, n, 16, t))
goto fail;
fd = aes_cmac_N_start(t);
if (fd < 0)
checksum = l_checksum_new_cmac_aes(t, 16);
if (!checksum)
goto fail;
memcpy(stage, p, p_len);
stage[p_len] = 1;
if (!aes_cmac(fd, stage, p_len + 1, output))
if (!aes_cmac(checksum, stage, p_len + 1, output))
goto done;
net_id[0] = output[15] & 0x7f;
@ -614,7 +204,7 @@ bool mesh_crypto_k2(const uint8_t n[16], const uint8_t *p, size_t p_len,
memcpy(stage + 16, p, p_len);
stage[p_len + 16] = 2;
if (!aes_cmac(fd, stage, p_len + 16 + 1, output))
if (!aes_cmac(checksum, stage, p_len + 16 + 1, output))
goto done;
memcpy(enc_key, output, 16);
@ -623,14 +213,14 @@ bool mesh_crypto_k2(const uint8_t n[16], const uint8_t *p, size_t p_len,
memcpy(stage + 16, p, p_len);
stage[p_len + 16] = 3;
if (!aes_cmac(fd, stage, p_len + 16 + 1, output))
if (!aes_cmac(checksum, stage, p_len + 16 + 1, output))
goto done;
memcpy(priv_key, output, 16);
success = true;
done:
aes_cmac_destroy(fd);
l_checksum_free(checksum);
fail:
l_free(stage);