[PATCH 2/2] amdgpu: validate drm_amdgpu_gem_va against overflows

[Chia-I Wu]

The existing validations are incorrect and insufficient.  This is
motivated by OOB access in amdgpu_vm_update_range when
offset_in_bo+map_size overflows.

Fixes: 9f7eb5367d00 ("drm/amdgpu: actually use the VM map parameters")
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 7 +++++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 6 ++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 071f6565cf971..36d5adfdf0f69 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -688,8 +688,11 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
 		return -EINVAL;
 	}
 
-	if (args->map_size == 0) {
-		dev_dbg(dev->dev, "invalid map_size 0x%LX\n", args->map_size);
+	if (args->map_size == 0 ||
+	    args->va_address + args->map_size < args->va_address ||
+	    args->offset_in_bo + args->map_size < args->offset_in_bo) {
+		dev_dbg(dev->dev, "invalid map_size 0x%LX (va_address 0x%LX, offset_in_bo 0x%LX)\n",
+			args->map_size, args->va_address, args->offset_in_bo);
 		return -EINVAL;
 	}
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index fa5819d581655..cd0a0f06e11ef 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1437,8 +1437,7 @@ int amdgpu_vm_bo_map(struct amdgpu_device *adev,
 
 	/* make sure object fit at this offset */
 	eaddr = saddr + size - 1;
-	if (saddr >= eaddr ||
-	    (bo && offset + size > amdgpu_bo_size(bo)) ||
+	if ((bo && offset + size > amdgpu_bo_size(bo)) ||
 	    (eaddr >= adev->vm_manager.max_pfn << AMDGPU_GPU_PAGE_SHIFT))
 		return -EINVAL;
 
@@ -1498,8 +1497,7 @@ int amdgpu_vm_bo_replace_map(struct amdgpu_device *adev,
 
 	/* make sure object fit at this offset */
 	eaddr = saddr + size - 1;
-	if (saddr >= eaddr ||
-	    (bo && offset + size > amdgpu_bo_size(bo)) ||
+	if ((bo && offset + size > amdgpu_bo_size(bo)) ||
 	    (eaddr >= adev->vm_manager.max_pfn << AMDGPU_GPU_PAGE_SHIFT))
 		return -EINVAL;
 
-- 
2.40.1.521.gf1e218fcd8-goog