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Diffstat (limited to 'net/bluetooth/smp.c')
-rw-r--r--net/bluetooth/smp.c158
1 files changed, 135 insertions, 23 deletions
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 1ab3dc9c8f99..3d0f7d2a0616 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -33,6 +33,9 @@
#include "ecc.h"
#include "smp.h"
+#define SMP_DEV(hdev) \
+ ((struct smp_dev *)((struct l2cap_chan *)((hdev)->smp_data))->data)
+
/* Low-level debug macros to be used for stuff that we don't want
* accidentially in dmesg, i.e. the values of the various crypto keys
* and the inputs & outputs of crypto functions.
@@ -81,6 +84,9 @@ struct smp_dev {
u8 local_rand[16];
bool debug_key;
+ u8 min_key_size;
+ u8 max_key_size;
+
struct crypto_blkcipher *tfm_aes;
struct crypto_hash *tfm_cmac;
};
@@ -371,6 +377,8 @@ static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r)
uint8_t tmp[16], data[16];
int err;
+ SMP_DBG("k %16phN r %16phN", k, r);
+
if (!tfm) {
BT_ERR("tfm %p", tfm);
return -EINVAL;
@@ -400,6 +408,8 @@ static int smp_e(struct crypto_blkcipher *tfm, const u8 *k, u8 *r)
/* Most significant octet of encryptedData corresponds to data[0] */
swap_buf(data, r, 16);
+ SMP_DBG("r %16phN", r);
+
return err;
}
@@ -410,6 +420,10 @@ static int smp_c1(struct crypto_blkcipher *tfm_aes, const u8 k[16],
u8 p1[16], p2[16];
int err;
+ SMP_DBG("k %16phN r %16phN", k, r);
+ SMP_DBG("iat %u ia %6phN rat %u ra %6phN", _iat, ia, _rat, ra);
+ SMP_DBG("preq %7phN pres %7phN", preq, pres);
+
memset(p1, 0, 16);
/* p1 = pres || preq || _rat || _iat */
@@ -418,10 +432,7 @@ static int smp_c1(struct crypto_blkcipher *tfm_aes, const u8 k[16],
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);
+ SMP_DBG("p1 %16phN", p1);
/* res = r XOR p1 */
u128_xor((u128 *) res, (u128 *) r, (u128 *) p1);
@@ -433,6 +444,13 @@ static int smp_c1(struct crypto_blkcipher *tfm_aes, const u8 k[16],
return err;
}
+ /* p2 = padding || ia || ra */
+ memcpy(p2, ra, 6);
+ memcpy(p2 + 6, ia, 6);
+ memset(p2 + 12, 0, 4);
+
+ SMP_DBG("p2 %16phN", p2);
+
/* res = res XOR p2 */
u128_xor((u128 *) res, (u128 *) res, (u128 *) p2);
@@ -696,7 +714,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
if (rsp == NULL) {
req->io_capability = conn->hcon->io_capability;
req->oob_flag = oob_flag;
- req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
+ req->max_key_size = SMP_DEV(hdev)->max_key_size;
req->init_key_dist = local_dist;
req->resp_key_dist = remote_dist;
req->auth_req = (authreq & AUTH_REQ_MASK(hdev));
@@ -707,7 +725,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
rsp->io_capability = conn->hcon->io_capability;
rsp->oob_flag = oob_flag;
- rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
+ rsp->max_key_size = SMP_DEV(hdev)->max_key_size;
rsp->init_key_dist = req->init_key_dist & remote_dist;
rsp->resp_key_dist = req->resp_key_dist & local_dist;
rsp->auth_req = (authreq & AUTH_REQ_MASK(hdev));
@@ -718,10 +736,11 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)
{
struct l2cap_chan *chan = conn->smp;
+ struct hci_dev *hdev = conn->hcon->hdev;
struct smp_chan *smp = chan->data;
- if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) ||
- (max_key_size < SMP_MIN_ENC_KEY_SIZE))
+ if (max_key_size > SMP_DEV(hdev)->max_key_size ||
+ max_key_size < SMP_MIN_ENC_KEY_SIZE)
return SMP_ENC_KEY_SIZE;
smp->enc_key_size = max_key_size;
@@ -985,13 +1004,10 @@ static u8 smp_random(struct smp_chan *smp)
smp_s1(smp->tfm_aes, smp->tk, smp->rrnd, smp->prnd, stk);
- memset(stk + smp->enc_key_size, 0,
- SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size);
-
if (test_and_set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags))
return SMP_UNSPECIFIED;
- hci_le_start_enc(hcon, ediv, rand, stk);
+ hci_le_start_enc(hcon, ediv, rand, stk, smp->enc_key_size);
hcon->enc_key_size = smp->enc_key_size;
set_bit(HCI_CONN_STK_ENCRYPT, &hcon->flags);
} else {
@@ -1004,9 +1020,6 @@ static u8 smp_random(struct smp_chan *smp)
smp_s1(smp->tfm_aes, smp->tk, smp->prnd, smp->rrnd, stk);
- memset(stk + smp->enc_key_size, 0,
- SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size);
-
if (hcon->pending_sec_level == BT_SECURITY_HIGH)
auth = 1;
else
@@ -1144,9 +1157,6 @@ static void sc_add_ltk(struct smp_chan *smp)
else
auth = 0;
- memset(smp->tk + smp->enc_key_size, 0,
- SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size);
-
smp->ltk = hci_add_ltk(hcon->hdev, &hcon->dst, hcon->dst_type,
key_type, auth, smp->tk, smp->enc_key_size,
0, 0);
@@ -1268,7 +1278,14 @@ static void smp_distribute_keys(struct smp_chan *smp)
__le16 ediv;
__le64 rand;
- get_random_bytes(enc.ltk, sizeof(enc.ltk));
+ /* Make sure we generate only the significant amount of
+ * bytes based on the encryption key size, and set the rest
+ * of the value to zeroes.
+ */
+ get_random_bytes(enc.ltk, smp->enc_key_size);
+ memset(enc.ltk + smp->enc_key_size, 0,
+ sizeof(enc.ltk) - smp->enc_key_size);
+
get_random_bytes(&ediv, sizeof(ediv));
get_random_bytes(&rand, sizeof(rand));
@@ -1688,7 +1705,7 @@ static void build_bredr_pairing_cmd(struct smp_chan *smp,
req->init_key_dist = local_dist;
req->resp_key_dist = remote_dist;
- req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
+ req->max_key_size = conn->hcon->enc_key_size;
smp->remote_key_dist = remote_dist;
@@ -1697,7 +1714,7 @@ static void build_bredr_pairing_cmd(struct smp_chan *smp,
memset(rsp, 0, sizeof(*rsp));
- rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
+ rsp->max_key_size = conn->hcon->enc_key_size;
rsp->init_key_dist = req->init_key_dist & remote_dist;
rsp->resp_key_dist = req->resp_key_dist & local_dist;
@@ -2190,7 +2207,7 @@ static bool smp_ltk_encrypt(struct l2cap_conn *conn, u8 sec_level)
if (test_and_set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->flags))
return true;
- hci_le_start_enc(hcon, key->ediv, key->rand, key->val);
+ hci_le_start_enc(hcon, key->ediv, key->rand, key->val, key->enc_size);
hcon->enc_key_size = key->enc_size;
/* We never store STKs for master role, so clear this flag */
@@ -2738,7 +2755,7 @@ static int smp_cmd_dhkey_check(struct l2cap_conn *conn, struct sk_buff *skb)
sc_add_ltk(smp);
if (hcon->out) {
- hci_le_start_enc(hcon, 0, 0, smp->tk);
+ hci_le_start_enc(hcon, 0, 0, smp->tk, smp->enc_key_size);
hcon->enc_key_size = smp->enc_key_size;
}
@@ -3120,6 +3137,8 @@ static struct l2cap_chan *smp_add_cid(struct hci_dev *hdev, u16 cid)
smp->tfm_aes = tfm_aes;
smp->tfm_cmac = tfm_cmac;
+ smp->min_key_size = SMP_MIN_ENC_KEY_SIZE;
+ smp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
create_chan:
chan = l2cap_chan_create();
@@ -3242,6 +3261,94 @@ static const struct file_operations force_bredr_smp_fops = {
.llseek = default_llseek,
};
+static ssize_t le_min_key_size_read(struct file *file,
+ char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct hci_dev *hdev = file->private_data;
+ char buf[4];
+
+ snprintf(buf, sizeof(buf), "%2u\n", SMP_DEV(hdev)->min_key_size);
+
+ return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+}
+
+static ssize_t le_min_key_size_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct hci_dev *hdev = file->private_data;
+ char buf[32];
+ size_t buf_size = min(count, (sizeof(buf) - 1));
+ u8 key_size;
+
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+
+ buf[buf_size] = '\0';
+
+ sscanf(buf, "%hhu", &key_size);
+
+ if (key_size > SMP_DEV(hdev)->max_key_size ||
+ key_size < SMP_MIN_ENC_KEY_SIZE)
+ return -EINVAL;
+
+ SMP_DEV(hdev)->min_key_size = key_size;
+
+ return count;
+}
+
+static const struct file_operations le_min_key_size_fops = {
+ .open = simple_open,
+ .read = le_min_key_size_read,
+ .write = le_min_key_size_write,
+ .llseek = default_llseek,
+};
+
+static ssize_t le_max_key_size_read(struct file *file,
+ char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct hci_dev *hdev = file->private_data;
+ char buf[4];
+
+ snprintf(buf, sizeof(buf), "%2u\n", SMP_DEV(hdev)->max_key_size);
+
+ return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+}
+
+static ssize_t le_max_key_size_write(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct hci_dev *hdev = file->private_data;
+ char buf[32];
+ size_t buf_size = min(count, (sizeof(buf) - 1));
+ u8 key_size;
+
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+
+ buf[buf_size] = '\0';
+
+ sscanf(buf, "%hhu", &key_size);
+
+ if (key_size > SMP_MAX_ENC_KEY_SIZE ||
+ key_size < SMP_DEV(hdev)->min_key_size)
+ return -EINVAL;
+
+ SMP_DEV(hdev)->max_key_size = key_size;
+
+ return count;
+}
+
+static const struct file_operations le_max_key_size_fops = {
+ .open = simple_open,
+ .read = le_max_key_size_read,
+ .write = le_max_key_size_write,
+ .llseek = default_llseek,
+};
+
int smp_register(struct hci_dev *hdev)
{
struct l2cap_chan *chan;
@@ -3266,6 +3373,11 @@ int smp_register(struct hci_dev *hdev)
hdev->smp_data = chan;
+ debugfs_create_file("le_min_key_size", 0644, hdev->debugfs, hdev,
+ &le_min_key_size_fops);
+ debugfs_create_file("le_max_key_size", 0644, hdev->debugfs, hdev,
+ &le_max_key_size_fops);
+
/* If the controller does not support BR/EDR Secure Connections
* feature, then the BR/EDR SMP channel shall not be present.
*