tun_get_user() used to track the length of iov_iter with another variable. We can use iov_iter_count() to determine the current length to avoid such chores.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com Reviewed-by: Willem de Bruijn willemb@google.com --- drivers/net/tun.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 452fc5104260fe7ff5fdd5cedc5d2647cbe35c79..bd272b4736fb7e9004f7d91dc83c69af5239bfe0 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1742,7 +1742,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; size_t total_len = iov_iter_count(from); - size_t len = total_len, align = tun->align, linear; + size_t len, align = tun->align, linear; struct virtio_net_hdr gso = { 0 }; int good_linear; int copylen; @@ -1754,9 +1754,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
if (!(tun->flags & IFF_NO_PI)) { - if (len < sizeof(pi)) + if (iov_iter_count(from) < sizeof(pi)) return -EINVAL; - len -= sizeof(pi);
if (!copy_from_iter_full(&pi, sizeof(pi), from)) return -EFAULT; @@ -1765,9 +1764,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (tun->flags & IFF_VNET_HDR) { int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
- if (len < vnet_hdr_sz) + if (iov_iter_count(from) < vnet_hdr_sz) return -EINVAL; - len -= vnet_hdr_sz;
if (!copy_from_iter_full(&gso, sizeof(gso), from)) return -EFAULT; @@ -1776,11 +1774,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len)) gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
- if (tun16_to_cpu(tun, gso.hdr_len) > len) + if (tun16_to_cpu(tun, gso.hdr_len) > iov_iter_count(from)) return -EINVAL; iov_iter_advance(from, vnet_hdr_sz - sizeof(gso)); }
+ len = iov_iter_count(from); + if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { align += NET_IP_ALIGN; if (unlikely(len < ETH_HLEN ||