LinuxLists.cc - [PATCH] In function nvkm_ioctl_map(), the variable "type" could be uninitialized if "nvkm_object_map()" returns error code, however, it does not check the return value and directly use the "type" in the if statement, which is potentially unsafe.

2021-11-16 07:07:59

Subject: [PATCH] In function nvkm_ioctl_map(), the variable "type" could be uninitialized if "nvkm_object_map()" returns error code, however, it does not check the return value and directly use the "type" in the if statement, which is potentially unsafe.

Fixes:01326050391ce("drm/nouveau/core/object: allow arguments to
be passed to map function")
Signed-off-by: Yizhuo Zhai <[email protected]>
---
drivers/gpu/drm/nouveau/nvkm/core/ioctl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
index 735cb6816f10..4264d9d79783 100644
--- a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
+++ b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
@@ -266,6 +266,8 @@ nvkm_ioctl_map(struct nvkm_client *client,
ret = nvkm_object_map(object, data, size, &type,
&args->v0.handle,
&args->v0.length);
+ if (ret)
+ return ret;
if (type == NVKM_OBJECT_MAP_IO)
args->v0.type = NVIF_IOCTL_MAP_V0_IO;
else
--
2.25.1

2021-11-16 07:09:46

by Yizhuo Zhai

[permalink] [raw]

Subject: [PATCH] In function nvkm_ioctl_map(), the variable "type" could be uninitialized if "nvkm_object_map()" returns error code, however, it does not check the return value and directly use the "type" in the if statement, which is potentially unsafe.

2021-11-16 21:18:03

by Lyude Paul

[permalink] [raw]

Subject: Re: [PATCH] In function nvkm_ioctl_map(), the variable "type" could be uninitialized if "nvkm_object_map()" returns error code, however, it does not check the return value and directly use the "type" in the if statement, which is potentially unsafe.

This is a very long patch name, it should probably be shorter and the
details in the patch title moved into the actual commit description
instead. Also a couple of things aren't formatted correctly:

* Cc tag for stable is missing, see
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
* Fixes tag isn't formatted properly

I generally recommend using `dim fixes` from
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
in order to get the correct stable kernel CC tag and Fixes: tag (you can
drop any of the Ccs it gives you beyond the one to stable at vger dot
kernel dot org.

Also, if you could try to Cc: me on the next version - will help me
respond faster :).

On Mon, 2021-11-15 at 23:07 -0800, Yizhuo Zhai wrote:
> Fixes:01326050391ce("drm/nouveau/core/object: allow arguments to
> be passed to map function")
> Signed-off-by: Yizhuo Zhai <[email protected]>
> ---
> drivers/gpu/drm/nouveau/nvkm/core/ioctl.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> index 735cb6816f10..4264d9d79783 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> @@ -266,6 +266,8 @@ nvkm_ioctl_map(struct nvkm_client *client,
>                 ret = nvkm_object_map(object, data, size, &type,
>                                       &args->v0.handle,
>                                       &args->v0.length);
> +               if (ret)
> +                       return ret;
>                 if (type == NVKM_OBJECT_MAP_IO)
>                         args->v0.type = NVIF_IOCTL_MAP_V0_IO;
>                 else

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat

2021-12-18 02:58:18

by Yizhuo Zhai

[permalink] [raw]

Subject: Re: [PATCH] In function nvkm_ioctl_map(), the variable "type" could be uninitialized if "nvkm_object_map()" returns error code, however, it does not check the return value and directly use the "type" in the if statement, which is potentially unsafe.

Hi Lyude:
I appreciate your feedback and I misplaced the commit message to the
title, I have modified it and resend the patch.
I made my linux development tree a mess, so I sent a brandly new one
and cc you. Thanks again for your help: )

On Tue, Nov 16, 2021 at 1:18 PM Lyude Paul <[email protected]> wrote:
>
> This is a very long patch name, it should probably be shorter and the
> details in the patch title moved into the actual commit description
> instead. Also a couple of things aren't formatted correctly:
>
> * Cc tag for stable is missing, see
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> * Fixes tag isn't formatted properly
>
> I generally recommend using `dim fixes` from
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> in order to get the correct stable kernel CC tag and Fixes: tag (you can
> drop any of the Ccs it gives you beyond the one to stable at vger dot
> kernel dot org.
>
> Also, if you could try to Cc: me on the next version - will help me
> respond faster :).
>
> On Mon, 2021-11-15 at 23:07 -0800, Yizhuo Zhai wrote:
> > Fixes:01326050391ce("drm/nouveau/core/object: allow arguments to
> > be passed to map function")
> > Signed-off-by: Yizhuo Zhai <[email protected]>
> > ---
> > drivers/gpu/drm/nouveau/nvkm/core/ioctl.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> > b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> > index 735cb6816f10..4264d9d79783 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/core/ioctl.c
> > @@ -266,6 +266,8 @@ nvkm_ioctl_map(struct nvkm_client *client,
> > ret = nvkm_object_map(object, data, size, &type,
> > &args->v0.handle,
> > &args->v0.length);
> > + if (ret)
> > + return ret;
> > if (type == NVKM_OBJECT_MAP_IO)
> > args->v0.type = NVIF_IOCTL_MAP_V0_IO;
> > else
>
> --
> Cheers,
> Lyude Paul (she/her)
> Software Engineer at Red Hat
>

--
Kind Regards,

Yizhuo Zhai

Computer Science, Graduate Student
University of California, Riverside