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-rw-r--r--bluez/crypto.c681
1 files changed, 681 insertions, 0 deletions
diff --git a/bluez/crypto.c b/bluez/crypto.c
new file mode 100644
index 0000000..1f5a963
--- /dev/null
+++ b/bluez/crypto.c
@@ -0,0 +1,681 @@
+/*
+ *
+ * BlueZ - Bluetooth protocol stack for Linux
+ *
+ * Copyright (C) 2012-2014 Intel Corporation. All rights reserved.
+ *
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ */
+
+#include <bluetooth/bluetooth.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/socket.h>
+
+#include "util.h"
+#include "crypto.h"
+
+#ifndef HAVE_LINUX_IF_ALG_H
+#ifndef HAVE_LINUX_TYPES_H
+typedef uint8_t __u8;
+typedef uint16_t __u16;
+typedef uint32_t __u32;
+#else
+#include <linux/types.h>
+#endif
+
+struct sockaddr_alg {
+ __u16 salg_family;
+ __u8 salg_type[14];
+ __u32 salg_feat;
+ __u32 salg_mask;
+ __u8 salg_name[64];
+};
+
+struct af_alg_iv {
+ __u32 ivlen;
+ __u8 iv[0];
+};
+
+#define ALG_SET_KEY 1
+#define ALG_SET_IV 2
+#define ALG_SET_OP 3
+
+#define ALG_OP_DECRYPT 0
+#define ALG_OP_ENCRYPT 1
+
+#define PF_ALG 38 /* Algorithm sockets. */
+#define AF_ALG PF_ALG
+#else
+#include <linux/if_alg.h>
+#endif
+
+#ifndef SOL_ALG
+#define SOL_ALG 279
+#endif
+
+/* Maximum message length that can be passed to aes_cmac */
+#define CMAC_MSG_MAX 80
+
+struct bt_crypto {
+ int ref_count;
+ int ecb_aes;
+ int urandom;
+ int cmac_aes;
+};
+
+static int urandom_setup(void)
+{
+ int fd;
+
+ fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0)
+ return -1;
+
+ return fd;
+}
+
+static int ecb_aes_setup(void)
+{
+ struct sockaddr_alg salg;
+ int fd;
+
+ 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;
+ }
+
+ return fd;
+}
+
+static int cmac_aes_setup(void)
+{
+ struct sockaddr_alg salg;
+ int fd;
+
+ 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;
+ }
+
+ return fd;
+}
+
+struct bt_crypto *bt_crypto_new(void)
+{
+ struct bt_crypto *crypto;
+
+ crypto = new0(struct bt_crypto, 1);
+ if (!crypto)
+ return NULL;
+
+ crypto->ecb_aes = ecb_aes_setup();
+ if (crypto->ecb_aes < 0) {
+ free(crypto);
+ return NULL;
+ }
+
+ crypto->urandom = urandom_setup();
+ if (crypto->urandom < 0) {
+ close(crypto->ecb_aes);
+ free(crypto);
+ return NULL;
+ }
+
+ crypto->cmac_aes = cmac_aes_setup();
+ if (crypto->cmac_aes < 0) {
+ close(crypto->urandom);
+ close(crypto->ecb_aes);
+ free(crypto);
+ return NULL;
+ }
+
+ return bt_crypto_ref(crypto);
+}
+
+struct bt_crypto *bt_crypto_ref(struct bt_crypto *crypto)
+{
+ if (!crypto)
+ return NULL;
+
+ __sync_fetch_and_add(&crypto->ref_count, 1);
+
+ return crypto;
+}
+
+void bt_crypto_unref(struct bt_crypto *crypto)
+{
+ if (!crypto)
+ return;
+
+ if (__sync_sub_and_fetch(&crypto->ref_count, 1))
+ return;
+
+ close(crypto->urandom);
+ close(crypto->ecb_aes);
+ close(crypto->cmac_aes);
+
+ free(crypto);
+}
+
+bool bt_crypto_random_bytes(struct bt_crypto *crypto,
+ uint8_t *buf, uint8_t num_bytes)
+{
+ ssize_t len;
+
+ if (!crypto)
+ return false;
+
+ len = read(crypto->urandom, buf, num_bytes);
+ if (len < num_bytes)
+ return false;
+
+ return true;
+}
+
+static int alg_new(int fd, const void *keyval, socklen_t keylen)
+{
+ if (setsockopt(fd, SOL_ALG, ALG_SET_KEY, keyval, keylen) < 0)
+ return -1;
+
+ /* 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 inline void swap_buf(const uint8_t *src, uint8_t *dst, uint16_t len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ dst[len - 1 - i] = src[i];
+}
+
+bool bt_crypto_sign_att(struct bt_crypto *crypto, const uint8_t key[16],
+ const uint8_t *m, uint16_t m_len,
+ uint32_t sign_cnt, uint8_t signature[12])
+{
+ int fd;
+ int len;
+ uint8_t tmp[16], out[16];
+ uint16_t msg_len = m_len + sizeof(uint32_t);
+ uint8_t msg[msg_len];
+ uint8_t msg_s[msg_len];
+
+ if (!crypto)
+ return false;
+
+ memset(msg, 0, msg_len);
+ memcpy(msg, m, m_len);
+
+ /* Add sign_counter to the message */
+ put_le32(sign_cnt, msg + m_len);
+
+ /* The most significant octet of key corresponds to key[0] */
+ swap_buf(key, tmp, 16);
+
+ fd = alg_new(crypto->cmac_aes, tmp, 16);
+ if (fd < 0)
+ return false;
+
+ /* Swap msg before signing */
+ swap_buf(msg, msg_s, msg_len);
+
+ len = send(fd, msg_s, msg_len, 0);
+ if (len < 0) {
+ close(fd);
+ return false;
+ }
+
+ len = read(fd, out, 16);
+ if (len < 0) {
+ close(fd);
+ return false;
+ }
+
+ close(fd);
+
+ /*
+ * As to BT spec. 4.1 Vol[3], Part C, chapter 10.4.1 sign counter should
+ * be placed in the signature
+ */
+ put_be32(sign_cnt, out + 8);
+
+ /*
+ * The most significant octet of hash corresponds to out[0] - swap it.
+ * Then truncate in most significant bit first order to a length of
+ * 12 octets
+ */
+ swap_buf(out, tmp, 16);
+ memcpy(signature, tmp + 4, 12);
+
+ return true;
+}
+/*
+ * Security function e
+ *
+ * Security function e generates 128-bit encryptedData from a 128-bit key
+ * and 128-bit plaintextData using the AES-128-bit block cypher:
+ *
+ * encryptedData = e(key, plaintextData)
+ *
+ * The most significant octet of key corresponds to key[0], the most
+ * significant octet of plaintextData corresponds to in[0] and the
+ * most significant octet of encryptedData corresponds to out[0].
+ *
+ */
+bool bt_crypto_e(struct bt_crypto *crypto, const uint8_t key[16],
+ const uint8_t plaintext[16], uint8_t encrypted[16])
+{
+ uint8_t tmp[16], in[16], out[16];
+ int fd;
+
+ if (!crypto)
+ return false;
+
+ /* The most significant octet of key corresponds to key[0] */
+ swap_buf(key, tmp, 16);
+
+ fd = alg_new(crypto->ecb_aes, tmp, 16);
+ if (fd < 0)
+ return false;
+
+
+ /* Most significant octet of plaintextData corresponds to in[0] */
+ swap_buf(plaintext, in, 16);
+
+ if (!alg_encrypt(fd, in, 16, out, 16)) {
+ close(fd);
+ return false;
+ }
+
+ /* Most significant octet of encryptedData corresponds to out[0] */
+ swap_buf(out, encrypted, 16);
+
+ close(fd);
+
+ return true;
+}
+
+/*
+ * Random Address Hash function ah
+ *
+ * The random address hash function ah is used to generate a hash value
+ * that is used in resolvable private addresses.
+ *
+ * The following are inputs to the random address hash function ah:
+ *
+ * k is 128 bits
+ * r is 24 bits
+ * padding is 104 bits
+ *
+ * r is concatenated with padding to generate r' which is used as the
+ * 128-bit input parameter plaintextData to security function e:
+ *
+ * r' = padding || r
+ *
+ * The least significant octet of r becomes the least significant octet
+ * of r’ and the most significant octet of padding becomes the most
+ * significant octet of r'.
+ *
+ * For example, if the 24-bit value r is 0x423456 then r' is
+ * 0x00000000000000000000000000423456.
+ *
+ * The output of the random address function ah is:
+ *
+ * ah(k, r) = e(k, r') mod 2^24
+ *
+ * The output of the security function e is then truncated to 24 bits by
+ * taking the least significant 24 bits of the output of e as the result
+ * of ah.
+ */
+bool bt_crypto_ah(struct bt_crypto *crypto, const uint8_t k[16],
+ const uint8_t r[3], uint8_t hash[3])
+{
+ uint8_t rp[16];
+ uint8_t encrypted[16];
+
+ if (!crypto)
+ return false;
+
+ /* r' = padding || r */
+ memcpy(rp, r, 3);
+ memset(rp + 3, 0, 13);
+
+ /* e(k, r') */
+ if (!bt_crypto_e(crypto, k, rp, encrypted))
+ return false;
+
+ /* ah(k, r) = e(k, r') mod 2^24 */
+ memcpy(hash, encrypted, 3);
+
+ return true;
+}
+
+typedef struct {
+ uint64_t a, b;
+} u128;
+
+static inline void u128_xor(const uint8_t p[16], const uint8_t q[16],
+ uint8_t r[16])
+{
+ u128 pp, qq, rr;
+
+ memcpy(&pp, p, 16);
+ memcpy(&qq, q, 16);
+
+ rr.a = pp.a ^ qq.a;
+ rr.b = pp.b ^ qq.b;
+
+ memcpy(r, &rr, 16);
+}
+
+/*
+ * Confirm value generation function c1
+ *
+ * During the pairing process confirm values are exchanged. This confirm
+ * value generation function c1 is used to generate the confirm values.
+ *
+ * The following are inputs to the confirm value generation function c1:
+ *
+ * k is 128 bits
+ * r is 128 bits
+ * pres is 56 bits
+ * preq is 56 bits
+ * iat is 1 bit
+ * ia is 48 bits
+ * rat is 1 bit
+ * ra is 48 bits
+ * padding is 32 bits of 0
+ *
+ * iat is concatenated with 7-bits of 0 to create iat' which is 8 bits
+ * in length. iat is the least significant bit of iat'
+ *
+ * rat is concatenated with 7-bits of 0 to create rat' which is 8 bits
+ * in length. rat is the least significant bit of rat'
+ *
+ * pres, preq, rat' and iat' are concatenated to generate p1 which is
+ * XORed with r and used as 128-bit input parameter plaintextData to
+ * security function e:
+ *
+ * p1 = pres || preq || rat' || iat'
+ *
+ * The octet of iat' becomes the least significant octet of p1 and the
+ * most significant octet of pres becomes the most significant octet of
+ * p1.
+ *
+ * ra is concatenated with ia and padding to generate p2 which is XORed
+ * with the result of the security function e using p1 as the input
+ * paremter plaintextData and is then used as the 128-bit input
+ * parameter plaintextData to security function e:
+ *
+ * p2 = padding || ia || ra
+ *
+ * The least significant octet of ra becomes the least significant octet
+ * of p2 and the most significant octet of padding becomes the most
+ * significant octet of p2.
+ *
+ * The output of the confirm value generation function c1 is:
+ *
+ * c1(k, r, preq, pres, iat, rat, ia, ra) = e(k, e(k, r XOR p1) XOR p2)
+ *
+ * The 128-bit output of the security function e is used as the result
+ * of confirm value generation function c1.
+ */
+bool bt_crypto_c1(struct bt_crypto *crypto, const uint8_t k[16],
+ const uint8_t r[16], const uint8_t pres[7],
+ const uint8_t preq[7], uint8_t iat,
+ const uint8_t ia[6], uint8_t rat,
+ const uint8_t ra[6], uint8_t res[16])
+{
+ uint8_t p1[16], p2[16];
+
+ /* p1 = pres || preq || _rat || _iat */
+ p1[0] = iat;
+ p1[1] = rat;
+ memcpy(p1 + 2, preq, 7);
+ memcpy(p1 + 9, pres, 7);
+
+ /* p2 = padding || ia || ra */
+ memcpy(p2, ra, 6);
+ memcpy(p2 + 6, ia, 6);
+ memset(p2 + 12, 0, 4);
+
+ /* res = r XOR p1 */
+ u128_xor(r, p1, res);
+
+ /* res = e(k, res) */
+ if (!bt_crypto_e(crypto, k, res, res))
+ return false;
+
+ /* res = res XOR p2 */
+ u128_xor(res, p2, res);
+
+ /* res = e(k, res) */
+ return bt_crypto_e(crypto, k, res, res);
+}
+
+/*
+ * Key generation function s1
+ *
+ * The key generation function s1 is used to generate the STK during the
+ * pairing process.
+ *
+ * The following are inputs to the key generation function s1:
+ *
+ * k is 128 bits
+ * r1 is 128 bits
+ * r2 is 128 bits
+ *
+ * The most significant 64-bits of r1 are discarded to generate r1' and
+ * the most significant 64-bits of r2 are discarded to generate r2'.
+ *
+ * r1' is concatenated with r2' to generate r' which is used as the
+ * 128-bit input parameter plaintextData to security function e:
+ *
+ * r' = r1' || r2'
+ *
+ * The least significant octet of r2' becomes the least significant
+ * octet of r' and the most significant octet of r1' becomes the most
+ * significant octet of r'.
+ *
+ * The output of the key generation function s1 is:
+ *
+ * s1(k, r1, r2) = e(k, r')
+ *
+ * The 128-bit output of the security function e is used as the result
+ * of key generation function s1.
+ */
+bool bt_crypto_s1(struct bt_crypto *crypto, const uint8_t k[16],
+ const uint8_t r1[16], const uint8_t r2[16],
+ uint8_t res[16])
+{
+ memcpy(res, r2, 8);
+ memcpy(res + 8, r1, 8);
+
+ return bt_crypto_e(crypto, k, res, res);
+}
+
+static bool aes_cmac(struct bt_crypto *crypto, uint8_t key[16], uint8_t *msg,
+ size_t msg_len, uint8_t res[16])
+{
+ uint8_t key_msb[16], out[16], msg_msb[CMAC_MSG_MAX];
+ ssize_t len;
+ int fd;
+
+ if (msg_len > CMAC_MSG_MAX)
+ return false;
+
+ swap_buf(key, key_msb, 16);
+ fd = alg_new(crypto->cmac_aes, key_msb, 16);
+ if (fd < 0)
+ return false;
+
+ swap_buf(msg, msg_msb, msg_len);
+ len = send(fd, msg_msb, msg_len, 0);
+ if (len < 0) {
+ close(fd);
+ return false;
+ }
+
+ len = read(fd, out, 16);
+ if (len < 0) {
+ close(fd);
+ return false;
+ }
+
+ swap_buf(out, res, 16);
+
+ close(fd);
+
+ return true;
+}
+
+bool bt_crypto_f4(struct bt_crypto *crypto, uint8_t u[32], uint8_t v[32],
+ uint8_t x[16], uint8_t z, uint8_t res[16])
+{
+ uint8_t m[65];
+
+ if (!crypto)
+ return false;
+
+ m[0] = z;
+ memcpy(&m[1], v, 32);
+ memcpy(&m[33], u, 32);
+
+ return aes_cmac(crypto, x, m, sizeof(m), res);
+}
+
+bool bt_crypto_f5(struct bt_crypto *crypto, uint8_t w[32], uint8_t n1[16],
+ uint8_t n2[16], uint8_t a1[7], uint8_t a2[7],
+ uint8_t mackey[16], uint8_t ltk[16])
+{
+ uint8_t btle[4] = { 0x65, 0x6c, 0x74, 0x62 };
+ uint8_t salt[16] = { 0xbe, 0x83, 0x60, 0x5a, 0xdb, 0x0b, 0x37, 0x60,
+ 0x38, 0xa5, 0xf5, 0xaa, 0x91, 0x83, 0x88, 0x6c };
+ uint8_t length[2] = { 0x00, 0x01 };
+ uint8_t m[53], t[16];
+
+ if (!aes_cmac(crypto, salt, w, 32, t))
+ return false;
+
+ memcpy(&m[0], length, 2);
+ memcpy(&m[2], a2, 7);
+ memcpy(&m[9], a1, 7);
+ memcpy(&m[16], n2, 16);
+ memcpy(&m[32], n1, 16);
+ memcpy(&m[48], btle, 4);
+
+ m[52] = 0; /* Counter */
+ if (!aes_cmac(crypto, t, m, sizeof(m), mackey))
+ return false;
+
+ m[52] = 1; /* Counter */
+ return aes_cmac(crypto, t, m, sizeof(m), ltk);
+}
+
+bool bt_crypto_f6(struct bt_crypto *crypto, uint8_t w[16], uint8_t n1[16],
+ uint8_t n2[16], uint8_t r[16], uint8_t io_cap[3],
+ uint8_t a1[7], uint8_t a2[7], uint8_t res[16])
+{
+ uint8_t m[65];
+
+ memcpy(&m[0], a2, 7);
+ memcpy(&m[7], a1, 7);
+ memcpy(&m[14], io_cap, 3);
+ memcpy(&m[17], r, 16);
+ memcpy(&m[33], n2, 16);
+ memcpy(&m[49], n1, 16);
+
+ return aes_cmac(crypto, w, m, sizeof(m), res);
+}
+
+bool bt_crypto_g2(struct bt_crypto *crypto, uint8_t u[32], uint8_t v[32],
+ uint8_t x[16], uint8_t y[16], uint32_t *val)
+{
+ uint8_t m[80], tmp[16];
+
+ memcpy(&m[0], y, 16);
+ memcpy(&m[16], v, 32);
+ memcpy(&m[48], u, 32);
+
+ if (!aes_cmac(crypto, x, m, sizeof(m), tmp))
+ return false;
+
+ *val = get_le32(tmp);
+ *val %= 1000000;
+
+ return true;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-17 12:03:09 +0000