4.4-stable review patch. If anyone has any objections, please let me know.
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From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit b85ab56c3f81c5a24b5a5213374f549df06430da ]
llc_conn_send_pdu() pushes the skb into write queue and calls llc_conn_send_pdus() to flush them out. However, the status of dev_queue_xmit() is not returned to caller, in this case, llc_conn_state_process().
llc_conn_state_process() needs hold the skb no matter success or failure, because it still uses it after that, therefore we should hold skb before dev_queue_xmit() when that skb is the one being processed by llc_conn_state_process().
For other callers, they can just pass NULL and ignore the return value as they are.
Reported-by: Noam Rathaus noamr@beyondsecurity.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/llc_conn.h | 2 +- net/llc/llc_c_ac.c | 15 +++++++++------ net/llc/llc_conn.c | 32 +++++++++++++++++++++++--------- 3 files changed, 33 insertions(+), 16 deletions(-)
--- a/include/net/llc_conn.h +++ b/include/net/llc_conn.h @@ -104,7 +104,7 @@ void llc_sk_reset(struct sock *sk);
/* Access to a connection */ int llc_conn_state_process(struct sock *sk, struct sk_buff *skb); -void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb); +int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb); void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb); void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit); void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit); --- a/net/llc/llc_c_ac.c +++ b/net/llc/llc_c_ac.c @@ -389,7 +389,7 @@ static int llc_conn_ac_send_i_cmd_p_set_ llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { - llc_conn_send_pdu(sk, skb); + rc = llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } return rc; @@ -916,7 +916,7 @@ static int llc_conn_ac_send_i_rsp_f_set_ llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { - llc_conn_send_pdu(sk, skb); + rc = llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } return rc; @@ -935,14 +935,17 @@ static int llc_conn_ac_send_i_rsp_f_set_ int llc_conn_ac_send_i_as_ack(struct sock *sk, struct sk_buff *skb) { struct llc_sock *llc = llc_sk(sk); + int ret;
if (llc->ack_must_be_send) { - llc_conn_ac_send_i_rsp_f_set_ackpf(sk, skb); + ret = llc_conn_ac_send_i_rsp_f_set_ackpf(sk, skb); llc->ack_must_be_send = 0 ; llc->ack_pf = 0; - } else - llc_conn_ac_send_i_cmd_p_set_0(sk, skb); - return 0; + } else { + ret = llc_conn_ac_send_i_cmd_p_set_0(sk, skb); + } + + return ret; }
/** --- a/net/llc/llc_conn.c +++ b/net/llc/llc_conn.c @@ -30,7 +30,7 @@ #endif
static int llc_find_offset(int state, int ev_type); -static void llc_conn_send_pdus(struct sock *sk); +static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *skb); static int llc_conn_service(struct sock *sk, struct sk_buff *skb); static int llc_exec_conn_trans_actions(struct sock *sk, struct llc_conn_state_trans *trans, @@ -193,11 +193,11 @@ out_skb_put: return rc; }
-void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb) +int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb) { /* queue PDU to send to MAC layer */ skb_queue_tail(&sk->sk_write_queue, skb); - llc_conn_send_pdus(sk); + return llc_conn_send_pdus(sk, skb); }
/** @@ -255,7 +255,7 @@ void llc_conn_resend_i_pdu_as_cmd(struct if (howmany_resend > 0) llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO; /* any PDUs to re-send are queued up; start sending to MAC */ - llc_conn_send_pdus(sk); + llc_conn_send_pdus(sk, NULL); out:; }
@@ -296,7 +296,7 @@ void llc_conn_resend_i_pdu_as_rsp(struct if (howmany_resend > 0) llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO; /* any PDUs to re-send are queued up; start sending to MAC */ - llc_conn_send_pdus(sk); + llc_conn_send_pdus(sk, NULL); out:; }
@@ -340,12 +340,16 @@ out: /** * llc_conn_send_pdus - Sends queued PDUs * @sk: active connection + * @hold_skb: the skb held by caller, or NULL if does not care * - * Sends queued pdus to MAC layer for transmission. + * Sends queued pdus to MAC layer for transmission. When @hold_skb is + * NULL, always return 0. Otherwise, return 0 if @hold_skb is sent + * successfully, or 1 for failure. */ -static void llc_conn_send_pdus(struct sock *sk) +static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb) { struct sk_buff *skb; + int ret = 0;
while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) { struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb); @@ -357,10 +361,20 @@ static void llc_conn_send_pdus(struct so skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb); if (!skb2) break; - skb = skb2; + dev_queue_xmit(skb2); + } else { + bool is_target = skb == hold_skb; + int rc; + + if (is_target) + skb_get(skb); + rc = dev_queue_xmit(skb); + if (is_target) + ret = rc; } - dev_queue_xmit(skb); } + + return ret; }
/**