[NETFILTER]: Fix Module Usage in ipchains and ipfwadm.

Gets rid of some warnings.  Manipulating our own module count inside the
sockopt is safe, because unregistering that sockopt will block.

net/ipv4/netfilter/ipchains_core.c

@@ -839,7 +839,9 @@ static int clear_fw_chain(struct ip_chain *chainptr)
 			i->branch->refcount--;
 		kfree(i);
 		i = tmp;
-		MOD_DEC_USE_COUNT;
+		/* We will block in cleanup's unregister sockopt if unloaded,
+		   so this is safe. */
+		module_put(THIS_MODULE);
 	}
 	return 0;
 }
@@ -870,6 +872,11 @@ static int append_to_chain(struct ip_chain *chainptr, struct ip_fwkernel *rule)
 	struct ip_fwkernel *i;
 
 	FWC_HAVE_LOCK(fwc_wlocks);
+
+	/* Are we unloading now?  We will block on nf_unregister_sockopt */
+	if (!try_module_get(THIS_MODULE))
+		return ENOPROTOOPT;
+
 	/* Special case if no rules already present */
 	if (chainptr->chain == NULL) {
 
@@ -886,7 +893,6 @@ static int append_to_chain(struct ip_chain *chainptr, struct ip_fwkernel *rule)
 	if (rule->branch) rule->branch->refcount++;
 
 append_successful:
-	MOD_INC_USE_COUNT;
 	return 0;
 }
 
@@ -900,6 +906,11 @@ static int insert_in_chain(struct ip_chain *chainptr,
 	struct ip_fwkernel *f = chainptr->chain;
 
 	FWC_HAVE_LOCK(fwc_wlocks);
+
+	/* Are we unloading now?  We will block on nf_unregister_sockopt */
+	if (!try_module_get(THIS_MODULE))
+		return ENOPROTOOPT;
+
 	/* special case if the position is number 1 */
 	if (position == 1) {
 		frwl->next = chainptr->chain;
@@ -917,7 +928,6 @@ static int insert_in_chain(struct ip_chain *chainptr,
 	f->next = frwl;
 
 insert_successful:
-	MOD_INC_USE_COUNT;
 	return 0;
 }
 
@@ -952,7 +962,9 @@ static int del_num_from_chain(struct ip_chain *chainptr, __u32 rulenum)
 		kfree(tmp);
 	}
 
-	MOD_DEC_USE_COUNT;
+	/* We will block in cleanup's unregister sockopt if unloaded,
+	   so this is safe. */
+	module_put(THIS_MODULE);
 	return 0;
 }
 
@@ -1059,7 +1071,9 @@ static int del_rule_from_chain(struct ip_chain *chainptr,
 		else
 			chainptr->chain = ftmp->next;
 		kfree(ftmp);
-		MOD_DEC_USE_COUNT;
+		/* We will block in cleanup's unregister sockopt if unloaded,
+		   so this is safe. */
+		module_put(THIS_MODULE);
 		break;
 	}
 
@@ -1101,7 +1115,9 @@ static int del_chain(ip_chainlabel label)
 	tmp->next = tmp2->next;
 	kfree(tmp2);
 
-	MOD_DEC_USE_COUNT;
+	/* We will block in cleanup's unregister sockopt if unloaded,
+	   so this is safe. */
+	module_put(THIS_MODULE);
 	return 0;
 }
 
@@ -1149,12 +1165,15 @@ static int create_chain(ip_chainlabel label)
 	if (strcmp(tmp->label,label) == 0)
 		return EEXIST;
 
+	/* Are we unloading now?  We will block on nf_unregister_sockopt */
+	if (!try_module_get(THIS_MODULE))
+		return ENOPROTOOPT;
+
 	tmp->next = ip_init_chain(label, 0, FW_SKIP); /* refcount is
 					      * zero since this is a
 					      * user defined chain *
 					      * and therefore can be
 					      * deleted */
-	MOD_INC_USE_COUNT;
 	return 0;
 }
 

net/ipv4/netfilter/ipfwadm_core.c

@@ -707,7 +707,9 @@ static void free_fw_chain(struct ip_fw *volatile* chainptr)
 		ftmp = *chainptr;
 		*chainptr = ftmp->fw_next;
 		kfree(ftmp);
-		MOD_DEC_USE_COUNT;
+		/* We will block in cleanup's unregister sockopt if unloaded,
+		   so this is safe. */
+		module_put(THIS_MODULE);
 	}
 	WRITE_UNLOCK(&ip_fw_lock);
 }
@@ -718,6 +720,10 @@ static int insert_in_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,
 {
 	struct ip_fw *ftmp;
 
+	/* Are we unloading now?  We will block on nf_unregister_sockopt */
+	if (!try_module_get(THIS_MODULE))
+		return ENOPROTOOPT;
+
 	ftmp = kmalloc( sizeof(struct ip_fw), GFP_KERNEL );
 	if ( ftmp == NULL )
 	{
@@ -748,7 +754,6 @@ static int insert_in_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,
 	ftmp->fw_next = *chainptr;
        	*chainptr=ftmp;
 	WRITE_UNLOCK(&ip_fw_lock);
-	MOD_INC_USE_COUNT;
 	return(0);
 }
 
@@ -758,6 +763,10 @@ static int append_to_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,
 	struct ip_fw *chtmp=NULL;
 	struct ip_fw *volatile chtmp_prev=NULL;
 
+	/* Are we unloading now?  We will block on nf_unregister_sockopt */
+	if (!try_module_get(THIS_MODULE))
+		return ENOPROTOOPT;
+
 	ftmp = kmalloc( sizeof(struct ip_fw), GFP_KERNEL );
 	if ( ftmp == NULL )
 	{
@@ -796,7 +805,6 @@ static int append_to_chain(struct ip_fw *volatile* chainptr, struct ip_fw *frwl,
 	else
         	*chainptr=ftmp;
 	WRITE_UNLOCK(&ip_fw_lock);
-	MOD_INC_USE_COUNT;
 	return(0);
 }
 
@@ -869,7 +877,9 @@ static int del_from_chain(struct ip_fw *volatile*chainptr, struct ip_fw *frwl)
 	}
 	WRITE_UNLOCK(&ip_fw_lock);
 	if (was_found) {
-		MOD_DEC_USE_COUNT;
+		/* We will block in cleanup's unregister sockopt if unloaded,
+		   so this is safe. */
+		module_put(THIS_MODULE);
 		return 0;
 	} else
 		return(EINVAL);