6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christian König <christian.koenig@xxxxxxx>
commit 35588314e963938dfdcdb792c9170108399377d6 upstream.
The offset is just 32bits here so this can potentially overflow if
somebody specifies a large value. Instead reduce the size to calculate
the last possible offset.
The error handling path incorrectly drops the reference to the user
fence BO resulting in potential reference count underflow.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -127,7 +127,6 @@ static int amdgpu_cs_p1_user_fence(struc
struct drm_gem_object *gobj;
struct amdgpu_bo *bo;
unsigned long size;
- int r;
gobj = drm_gem_object_lookup(p->filp, data->handle);
if (gobj == NULL)
@@ -139,23 +138,14 @@ static int amdgpu_cs_p1_user_fence(struc
drm_gem_object_put(gobj);
size = amdgpu_bo_size(bo);
- if (size != PAGE_SIZE || (data->offset + 8) > size) {
- r = -EINVAL;
- goto error_unref;
- }
-
- if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm)) {
- r = -EINVAL;
- goto error_unref;
- }
+ if (size != PAGE_SIZE || data->offset > (size - 8))
+ return -EINVAL;
- *offset = data->offset;
+ if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm))
+ return -EINVAL;
+ *offset = data->offset;
return 0;
-
-error_unref:
- amdgpu_bo_unref(&bo);
- return r;
}
static int amdgpu_cs_p1_bo_handles(struct amdgpu_cs_parser *p,
