Documentation/process/deprecated.rst recommends against the use of kmalloc
with dynamic size calculations due to the risk of overflow and smaller
allocation being made than the caller was expecting. This could lead to
buffer overflow in code similar to the memcpy in
amdgpu_dm_plane_add_modifier().
Signed-off-by: James Flowers <bold.zone2...@fastmail.com>
---
I see that in amdgpu_dm_plane_get_plane_modifiers, capacity is initialized to
only 128, but it is probably preferable to refactor.
Tested on a Steam Deck OLED with no apparent regressions using these test
suites from
igt-gpu-tools:
1) kms_plane
2) amd_plane
3) amd_fuzzing
4) testdisplay
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
index b7c6e8d13435..b587d2033f0b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
@@ -146,7 +146,7 @@ static void amdgpu_dm_plane_add_modifier(uint64_t **mods,
uint64_t *size, uint64
if (*cap - *size < 1) {
uint64_t new_cap = *cap * 2;
- uint64_t *new_mods = kmalloc(new_cap * sizeof(uint64_t),
GFP_KERNEL);
+ uint64_t *new_mods = kmalloc_array(new_cap, sizeof(uint64_t),
GFP_KERNEL);
if (!new_mods) {
kfree(*mods);
@@ -732,7 +732,7 @@ static int amdgpu_dm_plane_get_plane_modifiers(struct
amdgpu_device *adev, unsig
if (adev->family < AMDGPU_FAMILY_AI)
return 0;
- *mods = kmalloc(capacity * sizeof(uint64_t), GFP_KERNEL);
+ *mods = kmalloc_array(capacity, sizeof(uint64_t), GFP_KERNEL);
if (plane_type == DRM_PLANE_TYPE_CURSOR) {
amdgpu_dm_plane_add_modifier(mods, &size, &capacity,
DRM_FORMAT_MOD_LINEAR);
--
2.51.0
