2022-01-26 03:12:29

by Gustavo A. R. Silva

Subject: [PATCH][next] Drivers: hv: vmbus: Use struct_size() helper in kmalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/hv/vmbus_drv.c:1132:31: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/hv/vmbus_drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55fe3169..cd193456cd84 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1129,7 +1129,7 @@ void vmbus_on_msg_dpc(unsigned long data)
}

if (entry->handler_type == VMHT_BLOCKING) {
- ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
+ ctx = kmalloc(struct_size(ctx, msg.payload, payload_size), GFP_ATOMIC);
if (ctx == NULL)
return;

--
2.27.0

2022-01-28 08:37:10

by Michael Kelley (LINUX)

Subject: RE: [PATCH][next] Drivers: hv: vmbus: Use struct_size() helper in kmalloc()

From: Gustavo A. R. Silva <[email protected]> Sent: Tuesday, January 25, 2022 10:02 AM
>
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> drivers/hv/vmbus_drv.c:1132:31: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> ---
> drivers/hv/vmbus_drv.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 17bf55fe3169..cd193456cd84 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1129,7 +1129,7 @@ void vmbus_on_msg_dpc(unsigned long data)
> }
>
> if (entry->handler_type == VMHT_BLOCKING) {
> - ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
> + ctx = kmalloc(struct_size(ctx, msg.payload, payload_size), GFP_ATOMIC);
> if (ctx == NULL)
> return;
>
> --
> 2.27.0

Reviewed-by: Michael Kelley <[email protected]>

2022-02-03 17:21:55

by Wei Liu

Subject: Re: [PATCH][next] Drivers: hv: vmbus: Use struct_size() helper in kmalloc()

On Thu, Jan 27, 2022 at 04:01:28PM +0000, Michael Kelley (LINUX) wrote:
> From: Gustavo A. R. Silva <[email protected]> Sent: Tuesday, January 25, 2022 10:02 AM
> >
> > Make use of the struct_size() helper instead of an open-coded version,
> > in order to avoid any potential type mistakes or integer overflows that,
> > in the worst scenario, could lead to heap overflows.
> >
> > Also, address the following sparse warnings:
> > drivers/hv/vmbus_drv.c:1132:31: warning: using sizeof on a flexible structure
> >
> > Link: https://github.com/KSPP/linux/issues/174
> > ---
> > drivers/hv/vmbus_drv.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> > index 17bf55fe3169..cd193456cd84 100644
> > --- a/drivers/hv/vmbus_drv.c
> > +++ b/drivers/hv/vmbus_drv.c
> > @@ -1129,7 +1129,7 @@ void vmbus_on_msg_dpc(unsigned long data)
> > }
> >
> > if (entry->handler_type == VMHT_BLOCKING) {
> > - ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
> > + ctx = kmalloc(struct_size(ctx, msg.payload, payload_size), GFP_ATOMIC);
> > if (ctx == NULL)
> > return;
> >
> > --
> > 2.27.0
>
> Reviewed-by: Michael Kelley <[email protected]>
>

Applied to hyperv-next. Thanks.