Bluetooth: Replace L2CAP link mode with security level

Change the L2CAP internals to use the new security levels and remove
the link mode details.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 113 insertions, 52 deletions

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 73e115bc12dd..29f720e6188a 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -237,8 +237,9 @@ struct l2cap_pinfo {
         __u16           imtu;
         __u16           omtu;
         __u16           flush_to;
-
-        __u32           link_mode;
+        __u8            sec_level;
+        __u8            role_switch;
+        __u8            force_reliable;
 
         __u8            conf_req[64];
         __u8            conf_len;
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index eadf09231866..e899a9371c00 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -78,8 +78,7 @@ static void l2cap_sock_timeout(unsigned long arg)
         bh_lock_sock(sk);
 
         if (sk->sk_state == BT_CONNECT &&
-                        (l2cap_pi(sk)->link_mode & (L2CAP_LM_AUTH |
-                                        L2CAP_LM_ENCRYPT | L2CAP_LM_SECURE)))
+                                l2cap_pi(sk)->sec_level != BT_SECURITY_SDP)
                 reason = ECONNREFUSED;
         else
                 reason = ETIMEDOUT;
@@ -259,23 +258,11 @@ static void l2cap_chan_del(struct sock *sk, int err)
 }
 
 /* Service level security */
-static inline int l2cap_check_link_mode(struct sock *sk)
+static inline int l2cap_check_security(struct sock *sk)
 {
         struct l2cap_conn *conn = l2cap_pi(sk)->conn;
 
-        if (l2cap_pi(sk)->link_mode & L2CAP_LM_SECURE)
-                return hci_conn_security(conn->hcon, BT_SECURITY_HIGH);
-
-        if (l2cap_pi(sk)->link_mode & L2CAP_LM_ENCRYPT)
-                return hci_conn_security(conn->hcon, BT_SECURITY_MEDIUM);
-
-        if (l2cap_pi(sk)->link_mode & L2CAP_LM_AUTH)
-                return hci_conn_security(conn->hcon, BT_SECURITY_LOW);
-
-        if (l2cap_pi(sk)->psm == cpu_to_le16(0x0001))
-                return hci_conn_security(conn->hcon, BT_SECURITY_SDP);
-
-        return 1;
+        return hci_conn_security(conn->hcon, l2cap_pi(sk)->sec_level);
 }
 
 static inline u8 l2cap_get_ident(struct l2cap_conn *conn)
@@ -317,7 +304,7 @@ static void l2cap_do_start(struct sock *sk)
         struct l2cap_conn *conn = l2cap_pi(sk)->conn;
 
         if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) {
-                if (l2cap_check_link_mode(sk)) {
+                if (l2cap_check_security(sk)) {
                         struct l2cap_conn_req req;
                         req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
                         req.psm  = l2cap_pi(sk)->psm;
@@ -361,7 +348,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
                 }
 
                 if (sk->sk_state == BT_CONNECT) {
-                        if (l2cap_check_link_mode(sk)) {
+                        if (l2cap_check_security(sk)) {
                                 struct l2cap_conn_req req;
                                 req.scid = cpu_to_le16(l2cap_pi(sk)->scid);
                                 req.psm  = l2cap_pi(sk)->psm;
@@ -376,7 +363,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
                         rsp.scid = cpu_to_le16(l2cap_pi(sk)->dcid);
                         rsp.dcid = cpu_to_le16(l2cap_pi(sk)->scid);
 
-                        if (l2cap_check_link_mode(sk)) {
+                        if (l2cap_check_security(sk)) {
                                 if (bt_sk(sk)->defer_setup) {
                                         struct sock *parent = bt_sk(sk)->parent;
                                         rsp.result = cpu_to_le16(L2CAP_CR_PEND);
@@ -439,7 +426,7 @@ static void l2cap_conn_unreliable(struct l2cap_conn *conn, int err)
         read_lock(&l->lock);
 
         for (sk = l->head; sk; sk = l2cap_pi(sk)->next_c) {
-                if (l2cap_pi(sk)->link_mode & L2CAP_LM_RELIABLE)
+                if (l2cap_pi(sk)->force_reliable)
                         sk->sk_err = err;
         }
 
@@ -690,11 +677,15 @@ static void l2cap_sock_init(struct sock *sk, struct sock *parent)
 
                 pi->imtu = l2cap_pi(parent)->imtu;
                 pi->omtu = l2cap_pi(parent)->omtu;
-                pi->link_mode = l2cap_pi(parent)->link_mode;
+                pi->sec_level = l2cap_pi(parent)->sec_level;
+                pi->role_switch = l2cap_pi(parent)->role_switch;
+                pi->force_reliable = l2cap_pi(parent)->force_reliable;
         } else {
                 pi->imtu = L2CAP_DEFAULT_MTU;
                 pi->omtu = 0;
-                pi->link_mode = 0;
+                pi->sec_level = BT_SECURITY_LOW;
+                pi->role_switch = 0;
+                pi->force_reliable = 0;
         }
 
         /* Default config options */
@@ -792,6 +783,9 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int addr_
                 l2cap_pi(sk)->psm   = la->l2_psm;
                 l2cap_pi(sk)->sport = la->l2_psm;
                 sk->sk_state = BT_BOUND;
+
+                if (btohs(la->l2_psm) == 0x0001)
+                        l2cap_pi(sk)->sec_level = BT_SECURITY_SDP;
         }
 
         write_unlock_bh(&l2cap_sk_list.lock);
@@ -808,7 +802,6 @@ static int l2cap_do_connect(struct sock *sk)
         struct l2cap_conn *conn;
         struct hci_conn *hcon;
         struct hci_dev *hdev;
-        __u8 sec_level;
         __u8 auth_type;
         int err = 0;
 
@@ -821,37 +814,39 @@ static int l2cap_do_connect(struct sock *sk)
 
         err = -ENOMEM;
 
-        if (l2cap_pi(sk)->link_mode & L2CAP_LM_SECURE)
-                sec_level = BT_SECURITY_HIGH;
-        else if (l2cap_pi(sk)->psm == cpu_to_le16(0x0001))
-                sec_level = BT_SECURITY_SDP;
-        else if (l2cap_pi(sk)->link_mode & L2CAP_LM_ENCRYPT)
-                sec_level = BT_SECURITY_MEDIUM;
-        else
-                sec_level = BT_SECURITY_LOW;
-
         if (sk->sk_type == SOCK_RAW) {
-                if (l2cap_pi(sk)->link_mode & L2CAP_LM_SECURE)
+                switch (l2cap_pi(sk)->sec_level) {
+                case BT_SECURITY_HIGH:
                         auth_type = HCI_AT_DEDICATED_BONDING_MITM;
-                else if (l2cap_pi(sk)->link_mode & L2CAP_LM_ENCRYPT)
+                        break;
+                case BT_SECURITY_MEDIUM:
                         auth_type = HCI_AT_DEDICATED_BONDING;
-                else
+                        break;
+                default:
                         auth_type = HCI_AT_NO_BONDING;
+                        break;
+                }
         } else if (l2cap_pi(sk)->psm == cpu_to_le16(0x0001)) {
-                if (l2cap_pi(sk)->link_mode & L2CAP_LM_SECURE)
+                if (l2cap_pi(sk)->sec_level == BT_SECURITY_HIGH)
                         auth_type = HCI_AT_NO_BONDING_MITM;
                 else
                         auth_type = HCI_AT_NO_BONDING;
         } else {
-                if (l2cap_pi(sk)->link_mode & L2CAP_LM_SECURE)
+                switch (l2cap_pi(sk)->sec_level) {
+                case BT_SECURITY_HIGH:
                         auth_type = HCI_AT_GENERAL_BONDING_MITM;
-                else if (l2cap_pi(sk)->link_mode & L2CAP_LM_ENCRYPT)
+                        break;
+                case BT_SECURITY_MEDIUM:
                         auth_type = HCI_AT_GENERAL_BONDING;
-                else
+                        break;
+                default:
                         auth_type = HCI_AT_NO_BONDING;
+                        break;
+                }
         }
 
-        hcon = hci_connect(hdev, ACL_LINK, dst, sec_level, auth_type);
+        hcon = hci_connect(hdev, ACL_LINK, dst,
+                                        l2cap_pi(sk)->sec_level, auth_type);
         if (!hcon)
                 goto done;
 
@@ -1219,7 +1214,15 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us
                         break;
                 }
 
-                l2cap_pi(sk)->link_mode = opt;
+                if (opt & L2CAP_LM_AUTH)
+                        l2cap_pi(sk)->sec_level = BT_SECURITY_LOW;
+                if (opt & L2CAP_LM_ENCRYPT)
+                        l2cap_pi(sk)->sec_level = BT_SECURITY_MEDIUM;
+                if (opt & L2CAP_LM_SECURE)
+                        l2cap_pi(sk)->sec_level = BT_SECURITY_HIGH;
+
+                l2cap_pi(sk)->role_switch    = (opt & L2CAP_LM_MASTER);
+                l2cap_pi(sk)->force_reliable = (opt & L2CAP_LM_RELIABLE);
                 break;
 
         default:
@@ -1234,7 +1237,8 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, char __us
 static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, char __user *optval, int optlen)
 {
         struct sock *sk = sock->sk;
-        int err = 0;
+        struct bt_security sec;
+        int len, err = 0;
         u32 opt;
 
         BT_DBG("sk %p", sk);
@@ -1245,6 +1249,24 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, ch
         lock_sock(sk);
 
         switch (optname) {
+        case BT_SECURITY:
+                sec.level = BT_SECURITY_LOW;
+
+                len = min_t(unsigned int, sizeof(sec), optlen);
+                if (copy_from_user((char *) &sec, optval, len)) {
+                        err = -EFAULT;
+                        break;
+                }
+
+                if (sec.level < BT_SECURITY_LOW ||
+                                        sec.level > BT_SECURITY_HIGH) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                l2cap_pi(sk)->sec_level = sec.level;
+                break;
+
         case BT_DEFER_SETUP:
                 if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
                         err = -EINVAL;
@@ -1274,6 +1296,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us
         struct l2cap_options opts;
         struct l2cap_conninfo cinfo;
         int len, err = 0;
+        u32 opt;
 
         BT_DBG("sk %p", sk);
 
@@ -1296,7 +1319,29 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us
                 break;
 
         case L2CAP_LM:
-                if (put_user(l2cap_pi(sk)->link_mode, (u32 __user *) optval))
+                switch (l2cap_pi(sk)->sec_level) {
+                case BT_SECURITY_LOW:
+                        opt = L2CAP_LM_AUTH;
+                        break;
+                case BT_SECURITY_MEDIUM:
+                        opt = L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT;
+                        break;
+                case BT_SECURITY_HIGH:
+                        opt = L2CAP_LM_AUTH | L2CAP_LM_ENCRYPT |
+                                                        L2CAP_LM_SECURE;
+                        break;
+                default:
+                        opt = 0;
+                        break;
+                }
+
+                if (l2cap_pi(sk)->role_switch)
+                        opt |= L2CAP_LM_MASTER;
+
+                if (l2cap_pi(sk)->force_reliable)
+                        opt |= L2CAP_LM_RELIABLE;
+
+                if (put_user(opt, (u32 __user *) optval))
                         err = -EFAULT;
                 break;
 
@@ -1329,6 +1374,7 @@ static int l2cap_sock_getsockopt_old(struct socket *sock, int optname, char __us
 static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen)
 {
         struct sock *sk = sock->sk;
+        struct bt_security sec;
         int len, err = 0;
 
         BT_DBG("sk %p", sk);
@@ -1342,6 +1388,15 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname, ch
         lock_sock(sk);
 
         switch (optname) {
+        case BT_SECURITY:
+                sec.level = l2cap_pi(sk)->sec_level;
+
+                len = min_t(unsigned int, len, sizeof(sec));
+                if (copy_to_user(optval, (char *) &sec, len))
+                        err = -EFAULT;
+
+                break;
+
         case BT_DEFER_SETUP:
                 if (sk->sk_state != BT_BOUND && sk->sk_state != BT_LISTEN) {
                         err = -EINVAL;
@@ -1771,7 +1826,7 @@ static inline int l2cap_connect_req(struct l2cap_conn *conn, struct l2cap_cmd_hd
         l2cap_pi(sk)->ident = cmd->ident;
 
         if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT) {
-                if (l2cap_check_link_mode(sk)) {
+                if (l2cap_check_security(sk)) {
                         if (bt_sk(sk)->defer_setup) {
                                 sk->sk_state = BT_CONNECT2;
                                 result = L2CAP_CR_PEND;
@@ -2299,10 +2354,15 @@ static int l2cap_connect_ind(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 type)
                         continue;
 
                 if (!bacmp(&bt_sk(sk)->src, &hdev->bdaddr)) {
-                        lm1 |= (HCI_LM_ACCEPT | l2cap_pi(sk)->link_mode);
+                        lm1 |= HCI_LM_ACCEPT;
+                        if (l2cap_pi(sk)->role_switch)
+                                lm1 |= HCI_LM_MASTER;
                         exact++;
-                } else if (!bacmp(&bt_sk(sk)->src, BDADDR_ANY))
-                        lm2 |= (HCI_LM_ACCEPT | l2cap_pi(sk)->link_mode);
+                } else if (!bacmp(&bt_sk(sk)->src, BDADDR_ANY)) {
+                        lm2 |= HCI_LM_ACCEPT;
+                        if (l2cap_pi(sk)->role_switch)
+                                lm2 |= HCI_LM_MASTER;
+                }
         }
         read_unlock(&l2cap_sk_list.lock);
 
@@ -2361,7 +2421,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
                 bh_lock_sock(sk);
 
                 if (!status && encrypt == 0x00 &&
-                                (pi->link_mode & L2CAP_LM_SECURE) &&
+                                pi->sec_level == BT_SECURITY_HIGH &&
                                         (sk->sk_state == BT_CONNECTED ||
                                                 sk->sk_state == BT_CONFIG)) {
                         __l2cap_sock_close(sk, ECONNREFUSED);
@@ -2510,10 +2570,10 @@ static ssize_t l2cap_sysfs_show(struct class *dev, char *buf)
         sk_for_each(sk, node, &l2cap_sk_list.head) {
                 struct l2cap_pinfo *pi = l2cap_pi(sk);
 
-                str += sprintf(str, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d 0x%x\n",
+                str += sprintf(str, "%s %s %d %d 0x%4.4x 0x%4.4x %d %d %d\n",
                                 batostr(&bt_sk(sk)->src), batostr(&bt_sk(sk)->dst),
                                 sk->sk_state, btohs(pi->psm), pi->scid, pi->dcid,
-                                pi->imtu, pi->omtu, pi->link_mode);
+                                pi->imtu, pi->omtu, pi->sec_level);
         }
 
         read_unlock_bh(&l2cap_sk_list.lock);