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@xxxxxxxxxx>
---
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 452fc5104260..bd272b4736fb 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 ||
--
2.47.1
