[Qemu-devel] [PATCH] ps2: check PS2Queue wptr pointer in post_load routine

[Qemu-devel] [PATCH] ps2: check PS2Queue wptr pointer in post_load routine

[liujunjie]

In commit 802cbcb7300, most issues have been fixed when qemu guest
migration. But the queue size still need to check whether is equal to
PS2_QUEUE_SIZE. If yes, the wptr should set as 0. Or, wptr would larger
than PS2_QUEUE_SIZE and never come back when ps2_queue_noirq is called.
This could lead to OOB access, add check to avoid it.

Signed-off-by: liujunjie <liujunjie23@huawei.com>
---
 hw/input/ps2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/input/ps2.c b/hw/input/ps2.c
index eeec618..fdfcadf 100644
--- a/hw/input/ps2.c
+++ b/hw/input/ps2.c
@@ -927,7 +927,7 @@ static void ps2_common_post_load(PS2State *s)
 
     /* reset rptr/wptr/count */
     q->rptr = 0;
-    q->wptr = size;
+    q->wptr = (size == PS2_QUEUE_SIZE) ? 0 : size;
     q->count = size;
     s->update_irq(s->update_arg, q->count != 0);
 }
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH] ps2: check PS2Queue wptr pointer in post_load routine

[Gonglei (Arei)]

> -----Original Message-----
> From: liujunjie (A)
> Sent: Thursday, June 07, 2018 4:03 PM
> To: kraxel@redhat.com; berrange@redhat.com
> Cc: Gonglei (Arei) <arei.gonglei@huawei.com>; wangxin (U)
> <wangxinxin.wang@huawei.com>; Huangweidong (C)
> <weidong.huang@huawei.com>; fangying <fangying1@huawei.com>;
> qemu-devel@nongnu.org; liujunjie (A) <liujunjie23@huawei.com>
> Subject: [PATCH] ps2: check PS2Queue wptr pointer in post_load routine
> 
> In commit 802cbcb7300, most issues have been fixed when qemu guest
> migration. But the queue size still need to check whether is equal to
> PS2_QUEUE_SIZE. If yes, the wptr should set as 0. Or, wptr would larger
> than PS2_QUEUE_SIZE and never come back when ps2_queue_noirq is called.
> This could lead to OOB access, add check to avoid it.
> 
> Signed-off-by: liujunjie <liujunjie23@huawei.com>
> ---
>  hw/input/ps2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/input/ps2.c b/hw/input/ps2.c
> index eeec618..fdfcadf 100644
> --- a/hw/input/ps2.c
> +++ b/hw/input/ps2.c
> @@ -927,7 +927,7 @@ static void ps2_common_post_load(PS2State *s)
> 
>      /* reset rptr/wptr/count */
>      q->rptr = 0;
> -    q->wptr = size;
> +    q->wptr = (size == PS2_QUEUE_SIZE) ? 0 : size;
>      q->count = size;
>      s->update_irq(s->update_arg, q->count != 0);
>  }
> --

Reviewed-by: Gonglei <arei.gonglei@huawei.com>

Re: [Qemu-devel] [PATCH] ps2: check PS2Queue wptr pointer in post_load routine

[liujunjie (A)]

ping

> -----Original Message-----
> From: liujunjie (A)
> Sent: Thursday, June 07, 2018 4:03 PM
> To: kraxel@redhat.com; berrange@redhat.com
> Cc: Gonglei (Arei) <arei.gonglei@huawei.com>; wangxin (U)
> <wangxinxin.wang@huawei.com>; Huangweidong (C)
> <weidong.huang@huawei.com>; fangying <fangying1@huawei.com>;
> qemu-devel@nongnu.org; liujunjie (A) <liujunjie23@huawei.com>
> Subject: [PATCH] ps2: check PS2Queue wptr pointer in post_load routine
> 
> In commit 802cbcb7300, most issues have been fixed when qemu guest
> migration. But the queue size still need to check whether is equal to
> PS2_QUEUE_SIZE. If yes, the wptr should set as 0. Or, wptr would larger than
> PS2_QUEUE_SIZE and never come back when ps2_queue_noirq is called.
> This could lead to OOB access, add check to avoid it.
> 
> Signed-off-by: liujunjie <liujunjie23@huawei.com>
> ---
>  hw/input/ps2.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/input/ps2.c b/hw/input/ps2.c index eeec618..fdfcadf 100644
> --- a/hw/input/ps2.c
> +++ b/hw/input/ps2.c
> @@ -927,7 +927,7 @@ static void ps2_common_post_load(PS2State *s)
> 
>      /* reset rptr/wptr/count */
>      q->rptr = 0;
> -    q->wptr = size;
> +    q->wptr = (size == PS2_QUEUE_SIZE) ? 0 : size;
>      q->count = size;
>      s->update_irq(s->update_arg, q->count != 0);  }
> --
> 1.8.3.1
> 

Re: [Qemu-devel] [PATCH] ps2: check PS2Queue wptr pointer in post_load routine

[kraxel]

On Thu, Jun 14, 2018 at 10:50:47AM +0000, liujunjie (A) wrote:
> ping

Not much activity on input devices, so we have rare pull requests ...

Preparing one now, with this patch added.

cheers,
  Gerd