For the cases where user includes a non-zero value in 'token_uuid_ptr' field of 'struct vfio_device_bind_iommufd', the copy_struct_from_user() in vfio_df_ioctl_bind_iommufd() fails with -E2BIG. For the 'minsz' passed, copy_struct_from_user() expects the newly introduced field to be zero-ed, which would be incorrect in this case.
Fix this by passing the actual size of the kernel struct. If working with a newer userspace, copy_struct_from_user() would copy the 'token_uuid_ptr' field, and if working with an old userspace, it would zero out this field, thus still retaining backward compatibility.
Fixes: 86624ba3b522 ("vfio/pci: Do vf_token checks for VFIO_DEVICE_BIND_IOMMUFD") Cc: stable@vger.kernel.org Signed-off-by: Raghavendra Rao Ananta rananta@google.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com --- drivers/vfio/device_cdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c index 480cac3a0c274..8ceca24ac136c 100644 --- a/drivers/vfio/device_cdev.c +++ b/drivers/vfio/device_cdev.c @@ -99,7 +99,7 @@ long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, return ret; if (user_size < minsz) return -EINVAL; - ret = copy_struct_from_user(&bind, minsz, arg, user_size); + ret = copy_struct_from_user(&bind, sizeof(bind), arg, user_size); if (ret) return ret;