diff options
| -rw-r--r-- | drivers/net/tun.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 7cb105c103fe..782e38bfc1ee 100644 --- 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); |