[PATCH AUTOSEL 4.9 06/45] drm/edid: Fix a missing-check bug in drm_load_edid_firmware()

[Sasha Levin]

From: Gen Zhang <blackgod016574 at gmail.com>

[ Upstream commit 9f1f1a2dab38d4ce87a13565cf4dc1b73bef3a5f ]

In drm_load_edid_firmware(), fwstr is allocated by kstrdup(). And fwstr
is dereferenced in the following codes. However, memory allocation
functions such as kstrdup() may fail and returns NULL. Dereferencing
this null pointer may cause the kernel go wrong. Thus we should check
this kstrdup() operation.
Further, if kstrdup() returns NULL, we should return ERR_PTR(-ENOMEM) to
the caller site.

Signed-off-by: Gen Zhang <blackgod016574 at gmail.com>
Reviewed-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190524023222.GA5302@zhanggen-UX430UQ
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/drm_edid_load.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
index 622f788bff46..aa0e8c704c33 100644
--- a/drivers/gpu/drm/drm_edid_load.c
+++ b/drivers/gpu/drm/drm_edid_load.c
@@ -275,6 +275,8 @@ int drm_load_edid_firmware(struct drm_connector *connector)
 	 * the last one found one as a fallback.
 	 */
 	fwstr = kstrdup(edid_firmware, GFP_KERNEL);
+	if (!fwstr)
+		return ERR_PTR(-ENOMEM);
 	edidstr = fwstr;
 
 	while ((edidname = strsep(&edidstr, ","))) {
-- 
2.20.1