drm/amdgpu: Fix integer overflow issues in amdgpu_userq_fence.c

This patch only affects 32bit systems.  There are several integer
overflows bugs here but only the "sizeof(u32) * num_syncobj"
multiplication is a problem at runtime.  (The last lines of this patch).

These variables are u32 variables that come from the user.  The issue
is the multiplications can overflow leading to us allocating a smaller
buffer than intended.  For the first couple integer overflows, the
syncobj_handles = memdup_user() allocation is immediately followed by
a kmalloc_array():

	syncobj = kmalloc_array(num_syncobj_handles, sizeof(*syncobj), GFP_KERNEL);

In that situation the kmalloc_array() works as a bounds check and we
haven't accessed the syncobj_handlesp[] array yet so the integer overflow
is harmless.

But the "num_syncobj" multiplication doesn't have that and the integer
overflow could lead to an out of bounds access.

Fixes: a292fdecd728 ("drm/amdgpu: Implement userqueue signal/wait IOCTL")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
index fc4d0d42e2238f71d970b9fb81c23c36c7e7ef07..a86616c6deeff9926a9ae6605b8ea2550a161a00 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c
@@ -430,7 +430,7 @@ int amdgpu_userq_signal_ioctl(struct drm_device *dev, void *data,
 
        num_syncobj_handles = args->num_syncobj_handles;
        syncobj_handles = memdup_user(u64_to_user_ptr(args->syncobj_handles),
-                                     sizeof(u32) * num_syncobj_handles);
+                                     size_mul(sizeof(u32), num_syncobj_handles));
        if (IS_ERR(syncobj_handles))
                return PTR_ERR(syncobj_handles);
 
@@ -612,13 +612,13 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 
        num_read_bo_handles = wait_info->num_bo_read_handles;
        bo_handles_read = memdup_user(u64_to_user_ptr(wait_info->bo_read_handles),
-                                     sizeof(u32) * num_read_bo_handles);
+                                     size_mul(sizeof(u32), num_read_bo_handles));
        if (IS_ERR(bo_handles_read))
                return PTR_ERR(bo_handles_read);
 
        num_write_bo_handles = wait_info->num_bo_write_handles;
        bo_handles_write = memdup_user(u64_to_user_ptr(wait_info->bo_write_handles),
-                                      sizeof(u32) * num_write_bo_handles);
+                                      size_mul(sizeof(u32), num_write_bo_handles));
        if (IS_ERR(bo_handles_write)) {
                r = PTR_ERR(bo_handles_write);
                goto free_bo_handles_read;
@@ -626,7 +626,7 @@ int amdgpu_userq_wait_ioctl(struct drm_device *dev, void *data,
 
        num_syncobj = wait_info->num_syncobj_handles;
        syncobj_handles = memdup_user(u64_to_user_ptr(wait_info->syncobj_handles),
-                                     sizeof(u32) * num_syncobj);
+                                     size_mul(sizeof(u32), num_syncobj));
        if (IS_ERR(syncobj_handles)) {
                r = PTR_ERR(syncobj_handles);
                goto free_bo_handles_write;