Commit 4f54607c authored by Aleksandr Mishin's avatar Aleksandr Mishin Committed by Zheng Zucheng
Browse files

drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference 

stable inclusion
from stable-v6.6.33
commit dcf53e6103b26e7458be71491d0641f49fbd5840
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SEW
CVE: CVE-2024-38548

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dcf53e6103b26e7458be71491d0641f49fbd5840



--------------------------------

[ Upstream commit 935a92a1c400285545198ca2800a4c6c519c650a ]

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: fb43aa0a ("drm: bridge: Add support for Cadence MHDP8546 DPI/DP bridge")
Signed-off-by: default avatarAleksandr Mishin <amishin@t-argos.ru>
Reviewed-by: default avatarRobert Foss <rfoss@kernel.org>
Signed-off-by: default avatarRobert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240408125810.21899-1-amishin@t-argos.ru


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: default avatarZheng Zucheng <zhengzucheng@huawei.com>
parent 3486fdb9

drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c

+3 −0
Original line number Diff line number Diff line
@@ -1978,6 +1978,9 @@ 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);