drm/amdgpu: Fix buffer overflow in INFO ioctl

The values for "se_num" and "sh_num" come from the user in the ioctl.
They can be in the 0-255 range but if they're more than
AMDGPU_GFX_MAX_SE (4) or AMDGPU_GFX_MAX_SH_PER_SE (2) then it results in
an out of bounds read.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 0047da0..a1706b9 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -678,8 +678,12 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
                 * in the bitfields */
                if (se_num == AMDGPU_INFO_MMR_SE_INDEX_MASK)
                        se_num = 0xffffffff;
+               else if (se_num >= AMDGPU_GFX_MAX_SE)
+                       return -EINVAL;
                if (sh_num == AMDGPU_INFO_MMR_SH_INDEX_MASK)
                        sh_num = 0xffffffff;
+               else if (sh_num >= AMDGPU_GFX_MAX_SH_PER_SE)
+                       return -EINVAL;
 
                if (info->read_mmr_reg.count > 128)
                        return -EINVAL;