tun: unbreak truncated packet signalling

[firefly-linux-kernel-4.4.55.git] / drivers / net / tun.c

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 7cb105c103fe9408eb7c02b96dac4f4bfb702456..7c8343a4f91823a579910cbcccc5827a2eb1d986 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -981,6 +981,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
        struct sk_buff *skb;
        size_t len = total_len, align = NET_SKB_PAD, linear;
        struct virtio_net_hdr gso = { 0 };
+       int good_linear;
        int offset = 0;
        int copylen;
        bool zerocopy = false;
@@ -1021,12 +1022,16 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
                        return -EINVAL;
        }
 
+       good_linear = SKB_MAX_HEAD(align);
+
        if (msg_control) {
                /* There are 256 bytes to be copied in skb, so there is
                 * enough room for skb expand head in case it is used.
                 * The rest of the buffer is mapped from userspace.
                 */
                copylen = gso.hdr_len ? gso.hdr_len : GOODCOPY_LEN;
+               if (copylen > good_linear)
+                       copylen = good_linear;
                linear = copylen;
                if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
                        zerocopy = true;
@@ -1034,7 +1039,10 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 
        if (!zerocopy) {
                copylen = len;
-               linear = gso.hdr_len;
+               if (gso.hdr_len > good_linear)
+                       linear = good_linear;
+               else
+                       linear = gso.hdr_len;
        }
 
        skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
@@ -1176,7 +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)
@@ -1240,6 +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 {
@@ -1254,24 +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++;
@@ -1348,6 +1358,8 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
        ret = tun_do_read(tun, tfile, iocb, iv, len,
                          file->f_flags & O_NONBLOCK);
        ret = min_t(ssize_t, ret, len);
+       if (ret > 0)
+               iocb->ki_pos = ret;
 out:
        tun_put(tun);
        return ret;