1 files changed, 182 insertions, 121 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index efccd1ac9a66..0522b2b1fd95 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -458,10 +458,63 @@ void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 }
 EXPORT_SYMBOL(genlmsg_put);
 
+static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
+{
+	return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
+}
+
+static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
+{
+	kfree(info);
+}
+
+static struct nlattr **
+genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
+				struct nlmsghdr *nlh,
+				struct netlink_ext_ack *extack,
+				const struct genl_ops *ops,
+				int hdrlen,
+				enum genl_validate_flags no_strict_flag,
+				bool parallel)
+{
+	enum netlink_validation validate = ops->validate & no_strict_flag ?
+					   NL_VALIDATE_LIBERAL :
+					   NL_VALIDATE_STRICT;
+	struct nlattr **attrbuf;
+	int err;
+
+	if (!family->maxattr)
+		return NULL;
+
+	if (parallel) {
+		attrbuf = kmalloc_array(family->maxattr + 1,
+					sizeof(struct nlattr *), GFP_KERNEL);
+		if (!attrbuf)
+			return ERR_PTR(-ENOMEM);
+	} else {
+		attrbuf = family->attrbuf;
+	}
+
+	err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
+			    family->policy, validate, extack);
+	if (err && parallel) {
+		kfree(attrbuf);
+		return ERR_PTR(err);
+	}
+	return attrbuf;
+}
+
+static void genl_family_rcv_msg_attrs_free(const struct genl_family *family,
+					   struct nlattr **attrbuf,
+					   bool parallel)
+{
+	if (parallel)
+		kfree(attrbuf);
+}
+
 static int genl_lock_start(struct netlink_callback *cb)
 {
-	/* our ops are always const - netlink API doesn't propagate that */
-	const struct genl_ops *ops = cb->data;
+	const struct genl_ops *ops = genl_dumpit_info(cb)->ops;
 	int rc = 0;
 
 	if (ops->start) {
@@ -474,8 +527,7 @@ static int genl_lock_start(struct netlink_callback *cb)
 
 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-	/* our ops are always const - netlink API doesn't propagate that */
-	const struct genl_ops *ops = cb->data;
+	const struct genl_ops *ops = genl_dumpit_info(cb)->ops;
 	int rc;
 
 	genl_lock();
@@ -486,8 +538,8 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 
 static int genl_lock_done(struct netlink_callback *cb)
 {
-	/* our ops are always const - netlink API doesn't propagate that */
-	const struct genl_ops *ops = cb->data;
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	const struct genl_ops *ops = info->ops;
 	int rc = 0;
 
 	if (ops->done) {
@@ -495,120 +547,111 @@ static int genl_lock_done(struct netlink_callback *cb)
 		rc = ops->done(cb);
 		genl_unlock();
 	}
+	genl_family_rcv_msg_attrs_free(info->family, info->attrs, true);
+	genl_dumpit_info_free(info);
 	return rc;
 }
 
-static int genl_family_rcv_msg(const struct genl_family *family,
-			       struct sk_buff *skb,
-			       struct nlmsghdr *nlh,
-			       struct netlink_ext_ack *extack)
+static int genl_parallel_done(struct netlink_callback *cb)
 {
-	const struct genl_ops *ops;
-	struct net *net = sock_net(skb->sk);
-	struct genl_info info;
-	struct genlmsghdr *hdr = nlmsg_data(nlh);
-	struct nlattr **attrbuf;
-	int hdrlen, err;
+	const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+	const struct genl_ops *ops = info->ops;
+	int rc = 0;
 
-	/* this family doesn't exist in this netns */
-	if (!family->netnsok && !net_eq(net, &init_net))
-		return -ENOENT;
+	if (ops->done)
+		rc = ops->done(cb);
+	genl_family_rcv_msg_attrs_free(info->family, info->attrs, true);
+	genl_dumpit_info_free(info);
+	return rc;
+}
 
-	hdrlen = GENL_HDRLEN + family->hdrsize;
-	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
-		return -EINVAL;
+static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
+				      struct sk_buff *skb,
+				      struct nlmsghdr *nlh,
+				      struct netlink_ext_ack *extack,
+				      const struct genl_ops *ops,
+				      int hdrlen, struct net *net)
+{
+	struct genl_dumpit_info *info;
+	struct nlattr **attrs = NULL;
+	int err;
 
-	ops = genl_get_cmd(hdr->cmd, family);
-	if (ops == NULL)
+	if (!ops->dumpit)
 		return -EOPNOTSUPP;
 
-	if ((ops->flags & GENL_ADMIN_PERM) &&
-	    !netlink_capable(skb, CAP_NET_ADMIN))
-		return -EPERM;
-
-	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
-	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
-		return -EPERM;
-
-	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP) {
-		int rc;
-
-		if (ops->dumpit == NULL)
-			return -EOPNOTSUPP;
-
-		if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) {
-			int hdrlen = GENL_HDRLEN + family->hdrsize;
-
-			if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
-				return -EINVAL;
+	if (ops->validate & GENL_DONT_VALIDATE_DUMP)
+		goto no_attrs;
 
-			if (family->maxattr) {
-				unsigned int validate = NL_VALIDATE_STRICT;
-
-				if (ops->validate &
-				    GENL_DONT_VALIDATE_DUMP_STRICT)
-					validate = NL_VALIDATE_LIBERAL;
-				rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen),
-						    nlmsg_attrlen(nlh, hdrlen),
-						    family->maxattr,
-						    family->policy,
-						    validate, extack);
-				if (rc)
-					return rc;
-			}
-		}
+	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+		return -EINVAL;
 
-		if (!family->parallel_ops) {
-			struct netlink_dump_control c = {
-				.module = family->module,
-				/* we have const, but the netlink API doesn't */
-				.data = (void *)ops,
-				.start = genl_lock_start,
-				.dump = genl_lock_dumpit,
-				.done = genl_lock_done,
-			};
+	attrs = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
+						ops, hdrlen,
+						GENL_DONT_VALIDATE_DUMP_STRICT,
+						true);
+	if (IS_ERR(attrs))
+		return PTR_ERR(attrs);
+
+no_attrs:
+	/* Allocate dumpit info. It is going to be freed by done() callback. */
+	info = genl_dumpit_info_alloc();
+	if (!info) {
+		genl_family_rcv_msg_attrs_free(family, attrs, true);
+		return -ENOMEM;
+	}
 
-			genl_unlock();
-			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-			genl_lock();
+	info->family = family;
+	info->ops = ops;
+	info->attrs = attrs;
 
-		} else {
-			struct netlink_dump_control c = {
-				.module = family->module,
-				.start = ops->start,
-				.dump = ops->dumpit,
-				.done = ops->done,
-			};
+	if (!family->parallel_ops) {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			.data = info,
+			.start = genl_lock_start,
+			.dump = genl_lock_dumpit,
+			.done = genl_lock_done,
+		};
 
-			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-		}
+		genl_unlock();
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+		genl_lock();
 
-		return rc;
+	} else {
+		struct netlink_dump_control c = {
+			.module = family->module,
+			.data = info,
+			.start = ops->start,
+			.dump = ops->dumpit,
+			.done = genl_parallel_done,
+		};
+
+		err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 	}
 
-	if (ops->doit == NULL)
-		return -EOPNOTSUPP;
-
-	if (family->maxattr && family->parallel_ops) {
-		attrbuf = kmalloc_array(family->maxattr + 1,
-					sizeof(struct nlattr *),
-					GFP_KERNEL);
-		if (attrbuf == NULL)
-			return -ENOMEM;
-	} else
-		attrbuf = family->attrbuf;
+	return err;
+}
 
-	if (attrbuf) {
-		enum netlink_validation validate = NL_VALIDATE_STRICT;
+static int genl_family_rcv_msg_doit(const struct genl_family *family,
+				    struct sk_buff *skb,
+				    struct nlmsghdr *nlh,
+				    struct netlink_ext_ack *extack,
+				    const struct genl_ops *ops,
+				    int hdrlen, struct net *net)
+{
+	struct nlattr **attrbuf;
+	struct genl_info info;
+	int err;
 
-		if (ops->validate & GENL_DONT_VALIDATE_STRICT)
-			validate = NL_VALIDATE_LIBERAL;
+	if (!ops->doit)
+		return -EOPNOTSUPP;
 
-		err = __nlmsg_parse(nlh, hdrlen, attrbuf, family->maxattr,
-				    family->policy, validate, extack);
-		if (err < 0)
-			goto out;
-	}
+	attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
+						  ops, hdrlen,
+						  GENL_DONT_VALIDATE_STRICT,
+						  family->parallel_ops);
+	if (IS_ERR(attrbuf))
+		return PTR_ERR(attrbuf);
 
 	info.snd_seq = nlh->nlmsg_seq;
 	info.snd_portid = NETLINK_CB(skb).portid;
@@ -632,12 +675,49 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 		family->post_doit(ops, skb, &info);
 
 out:
-	if (family->parallel_ops)
-		kfree(attrbuf);
+	genl_family_rcv_msg_attrs_free(family, attrbuf, family->parallel_ops);
 
 	return err;
 }
 
+static int genl_family_rcv_msg(const struct genl_family *family,
+			       struct sk_buff *skb,
+			       struct nlmsghdr *nlh,
+			       struct netlink_ext_ack *extack)
+{
+	const struct genl_ops *ops;
+	struct net *net = sock_net(skb->sk);
+	struct genlmsghdr *hdr = nlmsg_data(nlh);
+	int hdrlen;
+
+	/* this family doesn't exist in this netns */
+	if (!family->netnsok && !net_eq(net, &init_net))
+		return -ENOENT;
+
+	hdrlen = GENL_HDRLEN + family->hdrsize;
+	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
+		return -EINVAL;
+
+	ops = genl_get_cmd(hdr->cmd, family);
+	if (ops == NULL)
+		return -EOPNOTSUPP;
+
+	if ((ops->flags & GENL_ADMIN_PERM) &&
+	    !netlink_capable(skb, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((ops->flags & GENL_UNS_ADMIN_PERM) &&
+	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
+		return -EPERM;
+
+	if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
+		return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
+						  ops, hdrlen, net);
+	else
+		return genl_family_rcv_msg_doit(family, skb, nlh, extack,
+						ops, hdrlen, net);
+}
+
 static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 			struct netlink_ext_ack *extack)
 {
@@ -1088,25 +1168,6 @@ problem:
 
 subsys_initcall(genl_init);
 
-/**
- * genl_family_attrbuf - return family's attrbuf
- * @family: the family
- *
- * Return the family's attrbuf, while validating that it's
- * actually valid to access it.
- *
- * You cannot use this function with a family that has parallel_ops
- * and you can only use it within (pre/post) doit/dumpit callbacks.
- */
-struct nlattr **genl_family_attrbuf(const struct genl_family *family)
-{
-	if (!WARN_ON(family->parallel_ops))
-		lockdep_assert_held(&genl_mutex);
-
-	return family->attrbuf;
-}
-EXPORT_SYMBOL(genl_family_attrbuf);
-
 static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group,
 			 gfp_t flags)
 {