2023-10-13 01:21:02

by Ma Ke

Subject: [PATCH] drm/nouveau/dispnv04: fix a possible null pointer dereference

In nv17_tv_get_hd_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference on
failure of drm_mode_duplicate(). The same applies to drm_cvt_mode().
Add a check to avoid null pointer dereference.

Signed-off-by: Ma Ke <[email protected]>
---
drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 670c9739e5e1..9c3dc9a5bb46 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -258,6 +258,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
if (modes[i].hdisplay == output_mode->hdisplay &&
modes[i].vdisplay == output_mode->vdisplay) {
mode = drm_mode_duplicate(encoder->dev, output_mode);
+ if (!mode)
+ continue;
mode->type |= DRM_MODE_TYPE_PREFERRED;

} else {
@@ -265,6 +267,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
modes[i].vdisplay, 60, false,
(output_mode->flags &
DRM_MODE_FLAG_INTERLACE), false);
+ if (!mode)
+ continue;
}

/* CVT modes are sometimes unsuitable... */
--
2.37.2

2023-10-23 21:30:37

by Danilo Krummrich

Subject: Re: [Nouveau] [PATCH] drm/nouveau/dispnv04: fix a possible null pointer dereference

On 10/13/23 03:18, Ma Ke wrote:
> In nv17_tv_get_hd_modes(), the return value of drm_mode_duplicate()
> is assigned to mode, which will lead to a NULL pointer dereference on
> failure of drm_mode_duplicate(). The same applies to drm_cvt_mode().
> Add a check to avoid null pointer dereference.
>
> Signed-off-by: Ma Ke <[email protected]>

For this one and the previous patch, please add the corresponding
'Fixes:' [1] and stable [2] tags and split the commits accordingly.

[1] https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes
[2] https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

> ---
> drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> index 670c9739e5e1..9c3dc9a5bb46 100644
> --- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> +++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
> @@ -258,6 +258,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
> if (modes[i].hdisplay == output_mode->hdisplay &&
> modes[i].vdisplay == output_mode->vdisplay) {
> mode = drm_mode_duplicate(encoder->dev, output_mode);
> + if (!mode)
> + continue;
> mode->type |= DRM_MODE_TYPE_PREFERRED;
>
> } else {
> @@ -265,6 +267,8 @@ static int nv17_tv_get_hd_modes(struct drm_encoder *encoder,
> modes[i].vdisplay, 60, false,
> (output_mode->flags &
> DRM_MODE_FLAG_INTERLACE), false);
> + if (!mode)
> + continue;
> }
>
> /* CVT modes are sometimes unsuitable... */