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Commit 0536add6 authored by Wei Xu's avatar Wei Xu Committed by Greg Kroah-Hartman
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tun: free skb in early errors 




[ Upstream commit c33ee15b ]

tun_recvmsg() supports accepting skb by msg_control after
commit ac77cfd4 ("tun: support receiving skb through msg_control"),
the skb if presented should be freed no matter how far it can go
along, otherwise it would be leaked.

This patch fixes several missed cases.

Signed-off-by: default avatarWei Xu <wexu@redhat.com>
Reported-by: default avatarMatthew Rosato <mjrosato@linux.vnet.ibm.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 241eb29c

drivers/net/tun.c

+18 −6
Original line number Diff line number Diff line
@@ -1734,8 +1734,11 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile, 


	tun_debug(KERN_INFO, tun, "tun_do_read\n");



	if (!iov_iter_count(to))

	if (!iov_iter_count(to)) {

		if (skb)

			kfree_skb(skb);

		return 0;

	}



	if (!skb) {

		/* Read frames from ring */
@@ -1851,22 +1854,24 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 
{

	struct tun_file *tfile = container_of(sock, struct tun_file, socket);

	struct tun_struct *tun = __tun_get(tfile);

	struct sk_buff *skb = m->msg_control;

	int ret;



	if (!tun)

		return -EBADFD;

	if (!tun) {

		ret = -EBADFD;

		goto out_free_skb;

	}



	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {

		ret = -EINVAL;

		goto out;

		goto out_put_tun;

	}

	if (flags & MSG_ERRQUEUE) {

		ret = sock_recv_errqueue(sock->sk, m, total_len,

					 SOL_PACKET, TUN_TX_TIMESTAMP);

		goto out;

	}

	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT,

			  m->msg_control);

	ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT, skb);

	if (ret > (ssize_t)total_len) {

		m->msg_flags |= MSG_TRUNC;

		ret = flags & MSG_TRUNC ? ret : total_len;
@@ -1874,6 +1879,13 @@ static int tun_recvmsg(struct socket *sock, struct msghdr *m, size_t total_len, 
out:

	tun_put(tun);

	return ret;



out_put_tun:

	tun_put(tun);

out_free_skb:

	if (skb)

		kfree_skb(skb);

	return ret;

}



static int tun_peek_len(struct socket *sock)