caif: Bugfix add check NULL pointer before calling functions.

Add check on layer->dn != NULL before calling functions in
layer below.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 9 deletions

diff --git a/net/caif/cfctrl.c b/net/caif/cfctrl.c
index 0c00a6015dda..f8ac31371a4a 100644
--- a/net/caif/cfctrl.c
+++ b/net/caif/cfctrl.c
@@ -178,20 +178,23 @@ static void init_info(struct caif_payload_info *info, struct cfctrl *cfctrl)
 void cfctrl_enum_req(struct cflayer *layer, u8 physlinkid)
 {
         struct cfctrl *cfctrl = container_obj(layer);
-        int ret;
         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+        struct cflayer *dn = cfctrl->serv.layer.dn;
         if (!pkt) {
                 pr_warn("Out of memory\n");
                 return;
         }
+        if (!dn) {
+                pr_debug("not able to send enum request\n");
+                return;
+        }
         caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
         init_info(cfpkt_info(pkt), cfctrl);
         cfpkt_info(pkt)->dev_info->id = physlinkid;
         cfctrl->serv.dev_info.id = physlinkid;
         cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
         cfpkt_addbdy(pkt, physlinkid);
-        ret =
-            cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+        dn->transmit(dn, pkt);
 }
 
 int cfctrl_linkup_request(struct cflayer *layer,
@@ -206,6 +209,12 @@ int cfctrl_linkup_request(struct cflayer *layer,
         int ret;
         char utility_name[16];
         struct cfpkt *pkt;
+        struct cflayer *dn = cfctrl->serv.layer.dn;
+
+        if (!dn) {
+                pr_debug("not able to send linkup request\n");
+                return -ENODEV;
+        }
 
         if (cfctrl_cancel_req(layer, user_layer) > 0) {
                 /* Slight Paranoia, check if already connecting */
@@ -282,7 +291,7 @@ int cfctrl_linkup_request(struct cflayer *layer,
          */
         cfpkt_info(pkt)->dev_info->id = param->phyid;
         ret =
-            cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+            dn->transmit(dn, pkt);
         if (ret < 0) {
                 int count;
 
@@ -301,15 +310,23 @@ int cfctrl_linkdown_req(struct cflayer *layer, u8 channelid,
         int ret;
         struct cfctrl *cfctrl = container_obj(layer);
         struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+        struct cflayer *dn = cfctrl->serv.layer.dn;
+
         if (!pkt) {
                 pr_warn("Out of memory\n");
                 return -ENOMEM;
         }
+
+        if (!dn) {
+                pr_debug("not able to send link-down request\n");
+                return -ENODEV;
+        }
+
         cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
         cfpkt_addbdy(pkt, channelid);
         init_info(cfpkt_info(pkt), cfctrl);
         ret =
-            cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+            dn->transmit(dn, pkt);
 #ifndef CAIF_NO_LOOP
         cfctrl->loop_linkused[channelid] = 0;
 #endif
@@ -477,7 +494,7 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
                                 cfpkt_extr_head(pkt, &param, len);
                                 break;
                         default:
-                                pr_warn("Request setup - invalid link type (%d)\n",
+                                pr_warn("Request setup, invalid type (%d)\n",
                                         serv);
                                 goto error;
                         }
@@ -489,7 +506,8 @@ static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
 
                         if (CFCTRL_ERR_BIT == (CFCTRL_ERR_BIT & cmdrsp) ||
                                 cfpkt_erroneous(pkt)) {
-                                pr_err("Invalid O/E bit or parse error on CAIF control channel\n");
+                                pr_err("Invalid O/E bit or parse error "
+                                                "on CAIF control channel\n");
                                 cfctrl->res.reject_rsp(cfctrl->serv.layer.up,
                                                        0,
                                                        req ? req->client_layer
@@ -550,9 +568,8 @@ static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
         case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
         case CAIF_CTRLCMD_FLOW_OFF_IND:
                 spin_lock_bh(&this->info_list_lock);
-                if (!list_empty(&this->list)) {
+                if (!list_empty(&this->list))
                         pr_debug("Received flow off in control layer\n");
-                }
                 spin_unlock_bh(&this->info_list_lock);
                 break;
         case _CAIF_CTRLCMD_PHYIF_DOWN_IND: {