The AMDGPU_GEM_OP_GET_MAPPING_INFO path of amdgpu_gem_op_ioctl() looks
up the bo_va for the buffer object in the caller's VM via
amdgpu_vm_bo_find(), but uses the returned pointer without checking it.
amdgpu_vm_bo_find() returns NULL when the BO has no bo_va in that VM,
which is the normal case for a BO that has never been mapped. The result
is fed straight into amdgpu_vm_bo_va_for_each_valid_mapping(), which
expands to list_for_each_entry(mapping, &(bo_va)->valids, list) and
dereferences bo_va, causing a NULL pointer dereference.
This is reachable by any process able to issue the ioctl (render group)
simply by requesting mapping info for an unmapped BO.
Return -ENOENT when no bo_va is found, jumping to out_exec so the
drm_exec context and GEM object reference are released.
Fixes: 4d82724f7f2b ("drm/amdgpu: Add mapping info option for GEM_OP ioctl")
Signed-off-by: Mario Limonciello <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 22ec4eb6e17f8..28f89ae8ca745 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -1094,6 +1094,11 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void
*data,
* If that number is larger than the size of the array, the
ioctl must
* be retried.
*/
+ if (!bo_va) {
+ r = -ENOENT;
+ goto out_exec;
+ }
+
if (args->num_entries > INT_MAX / sizeof(*vm_entries)) {
r = -EINVAL;
goto out_exec;
--
2.43.0
