* [PATCH] vhost: fix end of range for access_ok
@ 2017-08-21 19:45 Michael S. Tsirkin
2017-08-22 14:49 ` Koichiro Den
0 siblings, 1 reply; 4+ messages in thread
From: Michael S. Tsirkin @ 2017-08-21 19:45 UTC (permalink / raw)
To: linux-kernel
Cc: Koichiro Den, Jason Wang, kvm, virtualization, netdev, David Miller
During access_ok checks, addr increases as we iterate over the data
structure, thus addr + len - 1 will point beyond the end of region we
are translating. Harmless since we then verify that the region covers
addr, but let's not waste cpu cycles.
Reported-by: Koichiro Den <den@klaipeden.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Lightly tested, would appreciate an ack from reporter.
drivers/vhost/vhost.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e4613a3..ecd70e4 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
{
const struct vhost_umem_node *node;
struct vhost_umem *umem = vq->iotlb;
- u64 s = 0, size, orig_addr = addr;
+ u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
if (vhost_vq_meta_fetch(vq, addr, len, type))
return true;
@@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
while (len > s) {
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
addr,
- addr + len - 1);
+ last);
if (node == NULL || node->start > addr) {
vhost_iotlb_miss(vq, addr, access);
return false;
--
MST
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] vhost: fix end of range for access_ok
2017-08-21 19:45 [PATCH] vhost: fix end of range for access_ok Michael S. Tsirkin
@ 2017-08-22 14:49 ` Koichiro Den
0 siblings, 0 replies; 4+ messages in thread
From: Koichiro Den @ 2017-08-22 14:49 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel
Cc: Jason Wang, kvm, virtualization, netdev, David Miller
On Mon, 2017-08-21 at 22:45 +0300, Michael S. Tsirkin wrote:
> During access_ok checks, addr increases as we iterate over the data
> structure, thus addr + len - 1 will point beyond the end of region we
> are translating. Harmless since we then verify that the region covers
> addr, but let's not waste cpu cycles.
>
> Reported-by: Koichiro Den <den@klaipeden.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> Lightly tested, would appreciate an ack from reporter.
>
> drivers/vhost/vhost.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e4613a3..ecd70e4 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
> {
> const struct vhost_umem_node *node;
> struct vhost_umem *umem = vq->iotlb;
> - u64 s = 0, size, orig_addr = addr;
> + u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
>
> if (vhost_vq_meta_fetch(vq, addr, len, type))
> return true;
> @@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
> while (len > s) {
> node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
> addr,
> - addr + len - 1);
> + last);
> if (node == NULL || node->start > addr) {
> vhost_iotlb_miss(vq, addr, access);
> return false;
Michael, Thank you for this one.
Acked-by: Koichiro Den <den@klaipeden.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] vhost: fix end of range for access_ok
@ 2017-08-22 14:49 ` Koichiro Den
0 siblings, 0 replies; 4+ messages in thread
From: Koichiro Den @ 2017-08-22 14:49 UTC (permalink / raw)
To: Michael S. Tsirkin, linux-kernel
Cc: netdev, David Miller, kvm, virtualization
On Mon, 2017-08-21 at 22:45 +0300, Michael S. Tsirkin wrote:
> During access_ok checks, addr increases as we iterate over the data
> structure, thus addr + len - 1 will point beyond the end of region we
> are translating. Harmless since we then verify that the region covers
> addr, but let's not waste cpu cycles.
>
> Reported-by: Koichiro Den <den@klaipeden.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>
> Lightly tested, would appreciate an ack from reporter.
>
> drivers/vhost/vhost.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index e4613a3..ecd70e4 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
> {
> const struct vhost_umem_node *node;
> struct vhost_umem *umem = vq->iotlb;
> - u64 s = 0, size, orig_addr = addr;
> + u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
>
> if (vhost_vq_meta_fetch(vq, addr, len, type))
> return true;
> @@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
> while (len > s) {
> node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
> addr,
> - addr + len - 1);
> + last);
> if (node == NULL || node->start > addr) {
> vhost_iotlb_miss(vq, addr, access);
> return false;
Michael, Thank you for this one.
Acked-by: Koichiro Den <den@klaipeden.com>
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Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] vhost: fix end of range for access_ok
@ 2017-08-21 19:45 Michael S. Tsirkin
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2017-08-21 19:45 UTC (permalink / raw)
To: linux-kernel; +Cc: kvm, netdev, Koichiro Den, virtualization, David Miller
During access_ok checks, addr increases as we iterate over the data
structure, thus addr + len - 1 will point beyond the end of region we
are translating. Harmless since we then verify that the region covers
addr, but let's not waste cpu cycles.
Reported-by: Koichiro Den <den@klaipeden.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Lightly tested, would appreciate an ack from reporter.
drivers/vhost/vhost.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e4613a3..ecd70e4 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1176,7 +1176,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
{
const struct vhost_umem_node *node;
struct vhost_umem *umem = vq->iotlb;
- u64 s = 0, size, orig_addr = addr;
+ u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
if (vhost_vq_meta_fetch(vq, addr, len, type))
return true;
@@ -1184,7 +1184,7 @@ static int iotlb_access_ok(struct vhost_virtqueue *vq,
while (len > s) {
node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
addr,
- addr + len - 1);
+ last);
if (node == NULL || node->start > addr) {
vhost_iotlb_miss(vq, addr, access);
return false;
--
MST
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2017-08-22 14:49 ` Koichiro Den
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