Bluetooth: Return RFCOMM session ptrs to avoid freed session
Unfortunately, the design retains local copies of the s RFCOMM session pointer in various code blocks and this invites the erroneous access to a freed RFCOMM session structure. Therefore, return the RFCOMM session pointer back up the call stack to avoid accessing a freed RFCOMM session structure. When the RFCOMM session is deleted, NULL is passed up the call stack. If active DLCs exist when the rfcomm session is terminating, avoid a memory leak of rfcomm_dlc structures by ensuring that rfcomm_session_close() is used instead of rfcomm_session_del(). Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
This commit is contained in:
Dean Jenkins
Gustavo Padovan
parent
c06f7d532a
commit
8ff52f7d04
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@ -278,7 +278,8 @@ void rfcomm_session_getaddr(struct rfcomm_session *s, bdaddr_t *src,
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static inline void rfcomm_session_hold(struct rfcomm_session *s)
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{
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atomic_inc(&s->refcnt);
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if (s)
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atomic_inc(&s->refcnt);
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}
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/* ---- RFCOMM sockets ---- */
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@ -69,7 +69,7 @@ static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
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u8 sec_level,
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int *err);
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static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst);
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static void rfcomm_session_del(struct rfcomm_session *s);
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static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s);
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/* ---- RFCOMM frame parsing macros ---- */
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#define __get_dlci(b) ((b & 0xfc) >> 2)
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@ -108,10 +108,12 @@ static void rfcomm_schedule(void)
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wake_up_process(rfcomm_thread);
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}
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static void rfcomm_session_put(struct rfcomm_session *s)
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static struct rfcomm_session *rfcomm_session_put(struct rfcomm_session *s)
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{
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if (atomic_dec_and_test(&s->refcnt))
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rfcomm_session_del(s);
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if (s && atomic_dec_and_test(&s->refcnt))
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s = rfcomm_session_del(s);
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return s;
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}
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/* ---- RFCOMM FCS computation ---- */
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@ -631,7 +633,7 @@ static struct rfcomm_session *rfcomm_session_add(struct socket *sock, int state)
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return s;
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}
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static void rfcomm_session_del(struct rfcomm_session *s)
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static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s)
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{
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int state = s->state;
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@ -648,6 +650,8 @@ static void rfcomm_session_del(struct rfcomm_session *s)
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if (state != BT_LISTEN)
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module_put(THIS_MODULE);
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return NULL;
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}
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static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst)
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@ -666,7 +670,8 @@ static struct rfcomm_session *rfcomm_session_get(bdaddr_t *src, bdaddr_t *dst)
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return NULL;
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}
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static void rfcomm_session_close(struct rfcomm_session *s, int err)
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static struct rfcomm_session *rfcomm_session_close(struct rfcomm_session *s,
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int err)
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{
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struct rfcomm_dlc *d;
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struct list_head *p, *n;
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@ -685,7 +690,7 @@ static void rfcomm_session_close(struct rfcomm_session *s, int err)
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}
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rfcomm_session_clear_timer(s);
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rfcomm_session_put(s);
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return rfcomm_session_put(s);
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}
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static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
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@ -737,8 +742,7 @@ static struct rfcomm_session *rfcomm_session_create(bdaddr_t *src,
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if (*err == 0 || *err == -EINPROGRESS)
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return s;
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rfcomm_session_del(s);
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return NULL;
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return rfcomm_session_del(s);
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failed:
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sock_release(sock);
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@ -1127,7 +1131,7 @@ static void rfcomm_make_uih(struct sk_buff *skb, u8 addr)
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}
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/* ---- RFCOMM frame reception ---- */
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static int rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
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static struct rfcomm_session *rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
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{
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BT_DBG("session %p state %ld dlci %d", s, s->state, dlci);
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@ -1136,7 +1140,7 @@ static int rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
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struct rfcomm_dlc *d = rfcomm_dlc_get(s, dlci);
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if (!d) {
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rfcomm_send_dm(s, dlci);
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return 0;
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return s;
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}
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switch (d->state) {
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@ -1172,25 +1176,14 @@ static int rfcomm_recv_ua(struct rfcomm_session *s, u8 dlci)
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break;
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case BT_DISCONN:
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/* rfcomm_session_put is called later so don't do
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* anything here otherwise we will mess up the session
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* reference counter:
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*
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* (a) when we are the initiator dlc_unlink will drive
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* the reference counter to 0 (there is no initial put
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* after session_add)
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*
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* (b) when we are not the initiator rfcomm_rx_process
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* will explicitly call put to balance the initial hold
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* done after session add.
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*/
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s = rfcomm_session_close(s, ECONNRESET);
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break;
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}
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}
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return 0;
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return s;
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}
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static int rfcomm_recv_dm(struct rfcomm_session *s, u8 dlci)
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static struct rfcomm_session *rfcomm_recv_dm(struct rfcomm_session *s, u8 dlci)
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{
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int err = 0;
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@ -1215,12 +1208,13 @@ static int rfcomm_recv_dm(struct rfcomm_session *s, u8 dlci)
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err = ECONNRESET;
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s->state = BT_CLOSED;
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rfcomm_session_close(s, err);
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s = rfcomm_session_close(s, err);
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}
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return 0;
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return s;
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}
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static int rfcomm_recv_disc(struct rfcomm_session *s, u8 dlci)
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static struct rfcomm_session *rfcomm_recv_disc(struct rfcomm_session *s,
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u8 dlci)
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{
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int err = 0;
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@ -1250,10 +1244,9 @@ static int rfcomm_recv_disc(struct rfcomm_session *s, u8 dlci)
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err = ECONNRESET;
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s->state = BT_CLOSED;
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rfcomm_session_close(s, err);
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s = rfcomm_session_close(s, err);
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}
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return 0;
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return s;
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}
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void rfcomm_dlc_accept(struct rfcomm_dlc *d)
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@ -1674,11 +1667,18 @@ drop:
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return 0;
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}
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static int rfcomm_recv_frame(struct rfcomm_session *s, struct sk_buff *skb)
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static struct rfcomm_session *rfcomm_recv_frame(struct rfcomm_session *s,
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struct sk_buff *skb)
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{
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struct rfcomm_hdr *hdr = (void *) skb->data;
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u8 type, dlci, fcs;
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if (!s) {
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/* no session, so free socket data */
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kfree_skb(skb);
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return s;
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}
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dlci = __get_dlci(hdr->addr);
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type = __get_type(hdr->ctrl);
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@ -1689,7 +1689,7 @@ static int rfcomm_recv_frame(struct rfcomm_session *s, struct sk_buff *skb)
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if (__check_fcs(skb->data, type, fcs)) {
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BT_ERR("bad checksum in packet");
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kfree_skb(skb);
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return -EILSEQ;
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return s;
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}
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if (__test_ea(hdr->len))
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@ -1705,22 +1705,23 @@ static int rfcomm_recv_frame(struct rfcomm_session *s, struct sk_buff *skb)
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case RFCOMM_DISC:
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if (__test_pf(hdr->ctrl))
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rfcomm_recv_disc(s, dlci);
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s = rfcomm_recv_disc(s, dlci);
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break;
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case RFCOMM_UA:
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if (__test_pf(hdr->ctrl))
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rfcomm_recv_ua(s, dlci);
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s = rfcomm_recv_ua(s, dlci);
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break;
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case RFCOMM_DM:
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rfcomm_recv_dm(s, dlci);
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s = rfcomm_recv_dm(s, dlci);
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break;
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case RFCOMM_UIH:
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if (dlci)
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return rfcomm_recv_data(s, dlci, __test_pf(hdr->ctrl), skb);
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if (dlci) {
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rfcomm_recv_data(s, dlci, __test_pf(hdr->ctrl), skb);
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return s;
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}
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rfcomm_recv_mcc(s, skb);
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break;
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@ -1729,7 +1730,7 @@ static int rfcomm_recv_frame(struct rfcomm_session *s, struct sk_buff *skb)
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break;
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}
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kfree_skb(skb);
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return 0;
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return s;
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}
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/* ---- Connection and data processing ---- */
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@ -1866,7 +1867,7 @@ static void rfcomm_process_dlcs(struct rfcomm_session *s)
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}
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}
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static void rfcomm_process_rx(struct rfcomm_session *s)
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static struct rfcomm_session *rfcomm_process_rx(struct rfcomm_session *s)
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{
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struct socket *sock = s->sock;
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struct sock *sk = sock->sk;
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@ -1878,17 +1879,20 @@ static void rfcomm_process_rx(struct rfcomm_session *s)
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while ((skb = skb_dequeue(&sk->sk_receive_queue))) {
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skb_orphan(skb);
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if (!skb_linearize(skb))
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rfcomm_recv_frame(s, skb);
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s = rfcomm_recv_frame(s, skb);
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else
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kfree_skb(skb);
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}
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if (sk->sk_state == BT_CLOSED) {
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if (s && (sk->sk_state == BT_CLOSED)) {
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if (!s->initiator)
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rfcomm_session_put(s);
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s = rfcomm_session_put(s);
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rfcomm_session_close(s, sk->sk_err);
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if (s)
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s = rfcomm_session_close(s, sk->sk_err);
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}
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return s;
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}
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static void rfcomm_accept_connection(struct rfcomm_session *s)
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@ -1925,7 +1929,7 @@ static void rfcomm_accept_connection(struct rfcomm_session *s)
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sock_release(nsock);
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}
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static void rfcomm_check_connection(struct rfcomm_session *s)
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static struct rfcomm_session *rfcomm_check_connection(struct rfcomm_session *s)
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{
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struct sock *sk = s->sock->sk;
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@ -1944,9 +1948,10 @@ static void rfcomm_check_connection(struct rfcomm_session *s)
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case BT_CLOSED:
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s->state = BT_CLOSED;
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rfcomm_session_close(s, sk->sk_err);
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s = rfcomm_session_close(s, sk->sk_err);
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break;
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}
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return s;
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}
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static void rfcomm_process_sessions(void)
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@ -1975,15 +1980,16 @@ static void rfcomm_process_sessions(void)
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switch (s->state) {
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case BT_BOUND:
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rfcomm_check_connection(s);
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s = rfcomm_check_connection(s);
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break;
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default:
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rfcomm_process_rx(s);
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s = rfcomm_process_rx(s);
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break;
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}
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rfcomm_process_dlcs(s);
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if (s)
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rfcomm_process_dlcs(s);
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rfcomm_session_put(s);
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}
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