From e6fd07c899cd719bb5517bc7f32ce03a62220351 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 11 Dec 2013 13:08:33 +0800 Subject: tun: unbreak truncated packet signalling Commit 6680ec68eff47d36f67b4351bc9836fd6cba9532 (tuntap: hardware vlan tx support) breaks the truncated packet signal by nev return a length greater than iov length in tun_put_user(). This patch fixes by always return the length of packet plus possible vlan header. Caller can detect the truncated packet by comparing the return value and the size of io length. Cc: Zhi Yong Wu Cc: Michael S. Tsirkin Signed-off-by: Vlad Yasevich Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/net/tun.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index e26cbea1ce68..7c8343a4f918 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1184,7 +1184,7 @@ static ssize_t tun_put_user(struct tun_struct *tun, { struct tun_pi pi = { 0, skb->protocol }; ssize_t total = 0; - int vlan_offset = 0; + int vlan_offset = 0, copied; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) < 0) @@ -1248,6 +1248,8 @@ static ssize_t tun_put_user(struct tun_struct *tun, total += tun->vnet_hdr_sz; } + copied = total; + total += skb->len; if (!vlan_tx_tag_present(skb)) { len = min_t(int, skb->len, len); } else { @@ -1262,24 +1264,24 @@ static ssize_t tun_put_user(struct tun_struct *tun, vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); len = min_t(int, skb->len + VLAN_HLEN, len); + total += VLAN_HLEN; copy = min_t(int, vlan_offset, len); - ret = skb_copy_datagram_const_iovec(skb, 0, iv, total, copy); + ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); len -= copy; - total += copy; + copied += copy; if (ret || !len) goto done; copy = min_t(int, sizeof(veth), len); - ret = memcpy_toiovecend(iv, (void *)&veth, total, copy); + ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); len -= copy; - total += copy; + copied += copy; if (ret || !len) goto done; } - skb_copy_datagram_const_iovec(skb, vlan_offset, iv, total, len); - total += len; + skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); done: tun->dev->stats.tx_packets++; -- cgit v1.2.3-59-g8ed1b