2024-04-08 13:05:38

by Aleksandr Mishin

Subject: [PATCH] drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference

In cdns_mhdp_atomic_enable(), the return value of drm_mode_duplicate() is
assigned to mhdp_state->current_mode, and there is a dereference of it in
drm_mode_set_name(), which will lead to a NULL pointer dereference on
failure of drm_mode_duplicate().

Fix this bug add a check of mhdp_state->current_mode.

Fixes: fb43aa0acdfd ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge")
Signed-off-by: Aleksandr Mishin <[email protected]>
---
drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index e226acc5c15e..8a91ef0ae065 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2059,6 +2059,9 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
mhdp_state = to_cdns_mhdp_bridge_state(new_state);

mhdp_state->current_mode = drm_mode_duplicate(bridge->dev, mode);
+ if (!mhdp_state->current_mode)
+ return;
+
drm_mode_set_name(mhdp_state->current_mode);

dev_dbg(mhdp->dev, "%s: Enabling mode %s\n", __func__, mode->name);
--
2.30.2

2024-04-08 15:40:36

by Robert Foss

Subject: Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference

On Mon, 8 Apr 2024 15:58:10 +0300, Aleksandr Mishin wrote:
> In cdns_mhdp_atomic_enable(), the return value of drm_mode_duplicate() is
> assigned to mhdp_state->current_mode, and there is a dereference of it in
> drm_mode_set_name(), which will lead to a NULL pointer dereference on
> failure of drm_mode_duplicate().
>
> Fix this bug add a check of mhdp_state->current_mode.
>
> [...]

Applied, thanks!

[1/1] drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=935a92a1c400



Rob