* [PATCH v2 net 1/2] tuntap: correctly linearize skb when zerocopy is used
@ 2013-07-10 5:43 Jason Wang
2013-07-10 5:43 ` [PATCH v2 net 2/2] macvtap: " Jason Wang
2013-07-10 6:15 ` [PATCH v2 net 1/2] tuntap: " Michael S. Tsirkin
0 siblings, 2 replies; 4+ messages in thread
From: Jason Wang @ 2013-07-10 5:43 UTC (permalink / raw)
To: davem, mst, netdev, linux-kernel; +Cc: Jason Wang
Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to
linearize parts of the skb to let the rest of iov to be fit in
the frags, we need count copylen into linear when calling tun_alloc_skb()
instead of partly counting it into data_len. Since this breaks
zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should
be zero at beginning. This cause nr_frags to be increased wrongly without
setting the correct frags.
This bug were introduced from 0690899b4d4501b3505be069b9a687e68ccbe15b
(tun: experimental zero copy tx support)
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
- This patch is needed for stable.
- Changes from v1: introduce a local variable to track linear size
---
drivers/net/tun.c | 9 ++++++---
1 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9c61f87..c3cb60b 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1044,7 +1044,7 @@ 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 len = total_len, align = NET_SKB_PAD;
+ size_t len = total_len, align = NET_SKB_PAD, linear;
struct virtio_net_hdr gso = { 0 };
int offset = 0;
int copylen;
@@ -1108,10 +1108,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
copylen = gso.hdr_len;
if (!copylen)
copylen = GOODCOPY_LEN;
- } else
+ linear = copylen;
+ } else {
copylen = len;
+ linear = gso.hdr_len;
+ }
- skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
+ skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
if (IS_ERR(skb)) {
if (PTR_ERR(skb) != -EAGAIN)
tun->dev->stats.rx_dropped++;
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 net 2/2] macvtap: correctly linearize skb when zerocopy is used
2013-07-10 5:43 [PATCH v2 net 1/2] tuntap: correctly linearize skb when zerocopy is used Jason Wang
@ 2013-07-10 5:43 ` Jason Wang
2013-07-10 6:15 ` Michael S. Tsirkin
2013-07-10 6:15 ` [PATCH v2 net 1/2] tuntap: " Michael S. Tsirkin
1 sibling, 1 reply; 4+ messages in thread
From: Jason Wang @ 2013-07-10 5:43 UTC (permalink / raw)
To: davem, mst, netdev, linux-kernel; +Cc: Jason Wang
Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to
linearize parts of the skb to let the rest of iov to be fit in
the frags, we need count copylen into linear when calling macvtap_alloc_skb()
instead of partly counting it into data_len. Since this breaks
zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should
be zero at beginning. This cause nr_frags to be increased wrongly without
setting the correct frags.
This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73
(macvtap: zerocopy: validate vectors before building skb).
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
- This patch is needed for stable.
- Changes from v1: introduce a local variable to track linear size.
---
drivers/net/macvtap.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index b6dd6a7..502d948 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -647,6 +647,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
int vnet_hdr_len = 0;
int copylen = 0;
bool zerocopy = false;
+ size_t linear;
if (q->flags & IFF_VNET_HDR) {
vnet_hdr_len = q->vnet_hdr_sz;
@@ -701,11 +702,14 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
copylen = vnet_hdr.hdr_len;
if (!copylen)
copylen = GOODCOPY_LEN;
- } else
+ linear = copylen;
+ } else {
copylen = len;
+ linear = vnet_hdr.hdr_len;
+ }
skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen,
- vnet_hdr.hdr_len, noblock, &err);
+ linear, noblock, &err);
if (!skb)
goto err;
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 net 1/2] tuntap: correctly linearize skb when zerocopy is used
2013-07-10 5:43 [PATCH v2 net 1/2] tuntap: correctly linearize skb when zerocopy is used Jason Wang
2013-07-10 5:43 ` [PATCH v2 net 2/2] macvtap: " Jason Wang
@ 2013-07-10 6:15 ` Michael S. Tsirkin
1 sibling, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2013-07-10 6:15 UTC (permalink / raw)
To: Jason Wang; +Cc: davem, netdev, linux-kernel
On Wed, Jul 10, 2013 at 01:43:27PM +0800, Jason Wang wrote:
> Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to
> linearize parts of the skb to let the rest of iov to be fit in
> the frags, we need count copylen into linear when calling tun_alloc_skb()
> instead of partly counting it into data_len. Since this breaks
> zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should
> be zero at beginning. This cause nr_frags to be increased wrongly without
> setting the correct frags.
>
> This bug were introduced from 0690899b4d4501b3505be069b9a687e68ccbe15b
> (tun: experimental zero copy tx support)
>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> - This patch is needed for stable.
> - Changes from v1: introduce a local variable to track linear size
> ---
> drivers/net/tun.c | 9 ++++++---
> 1 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index 9c61f87..c3cb60b 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1044,7 +1044,7 @@ 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 len = total_len, align = NET_SKB_PAD;
> + size_t len = total_len, align = NET_SKB_PAD, linear;
> struct virtio_net_hdr gso = { 0 };
> int offset = 0;
> int copylen;
> @@ -1108,10 +1108,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
> copylen = gso.hdr_len;
> if (!copylen)
> copylen = GOODCOPY_LEN;
> - } else
> + linear = copylen;
> + } else {
> copylen = len;
> + linear = gso.hdr_len;
> + }
>
> - skb = tun_alloc_skb(tfile, align, copylen, gso.hdr_len, noblock);
> + skb = tun_alloc_skb(tfile, align, copylen, linear, noblock);
> if (IS_ERR(skb)) {
> if (PTR_ERR(skb) != -EAGAIN)
> tun->dev->stats.rx_dropped++;
> --
> 1.7.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 net 2/2] macvtap: correctly linearize skb when zerocopy is used
2013-07-10 5:43 ` [PATCH v2 net 2/2] macvtap: " Jason Wang
@ 2013-07-10 6:15 ` Michael S. Tsirkin
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2013-07-10 6:15 UTC (permalink / raw)
To: Jason Wang; +Cc: davem, netdev, linux-kernel
On Wed, Jul 10, 2013 at 01:43:28PM +0800, Jason Wang wrote:
> Userspace may produce vectors greater than MAX_SKB_FRAGS. When we try to
> linearize parts of the skb to let the rest of iov to be fit in
> the frags, we need count copylen into linear when calling macvtap_alloc_skb()
> instead of partly counting it into data_len. Since this breaks
> zerocopy_sg_from_iovec() since its inner counter assumes nr_frags should
> be zero at beginning. This cause nr_frags to be increased wrongly without
> setting the correct frags.
>
> This bug were introduced from b92946e2919134ebe2a4083e4302236295ea2a73
> (macvtap: zerocopy: validate vectors before building skb).
>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> - This patch is needed for stable.
> - Changes from v1: introduce a local variable to track linear size.
> ---
> drivers/net/macvtap.c | 8 ++++++--
> 1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index b6dd6a7..502d948 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -647,6 +647,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
> int vnet_hdr_len = 0;
> int copylen = 0;
> bool zerocopy = false;
> + size_t linear;
>
> if (q->flags & IFF_VNET_HDR) {
> vnet_hdr_len = q->vnet_hdr_sz;
> @@ -701,11 +702,14 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
> copylen = vnet_hdr.hdr_len;
> if (!copylen)
> copylen = GOODCOPY_LEN;
> - } else
> + linear = copylen;
> + } else {
> copylen = len;
> + linear = vnet_hdr.hdr_len;
> + }
>
> skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen,
> - vnet_hdr.hdr_len, noblock, &err);
> + linear, noblock, &err);
> if (!skb)
> goto err;
>
> --
> 1.7.1
^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-07-10 5:43 [PATCH v2 net 1/2] tuntap: correctly linearize skb when zerocopy is used Jason Wang
2013-07-10 5:43 ` [PATCH v2 net 2/2] macvtap: " Jason Wang
2013-07-10 6:15 ` Michael S. Tsirkin
2013-07-10 6:15 ` [PATCH v2 net 1/2] tuntap: " Michael S. Tsirkin
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