diff --git a/build.rs b/build.rs
index 762a3b6b..404d0c6e 100644
--- a/build.rs
+++ b/build.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 
 fn detect_fedora_feature() -> Result<()> {
diff --git a/ci/codestyle.sh b/ci/codestyle.sh
index 05574c83..ddc00898 100755
--- a/ci/codestyle.sh
+++ b/ci/codestyle.sh
@@ -21,3 +21,13 @@ for crate in $(find -iname Cargo.toml); do
     fi
 done
 echo "ok"
+
+ident='SPDX-License-Identifier:'
+echo -n "checking \"$ident\"..."
+git ls-files '*.rs' | while read f; do
+    if ! grep -qF "$ident" $f; then
+        echo "error: File $f: Missing $ident" 1>&2
+        exit 1
+    fi
+done
+echo "ok"
diff --git a/rust/libdnf-sys/build.rs b/rust/libdnf-sys/build.rs
index 3cc46121..43f61a35 100644
--- a/rust/libdnf-sys/build.rs
+++ b/rust/libdnf-sys/build.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 
 fn main() -> Result<()> {
diff --git a/rust/rpmostree-client/src/lib.rs b/rust/rpmostree-client/src/lib.rs
index fdf678b7..f73e968f 100644
--- a/rust/rpmostree-client/src/lib.rs
+++ b/rust/rpmostree-client/src/lib.rs
@@ -1,4 +1,5 @@
 //! APIs for interacting with rpm-ostree client side.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use anyhow::Context;
 use serde_derive::Deserialize;
diff --git a/rust/rpmostree-client/tests/parse.rs b/rust/rpmostree-client/tests/parse.rs
index d6c70ffa..e4aa76e2 100644
--- a/rust/rpmostree-client/tests/parse.rs
+++ b/rust/rpmostree-client/tests/parse.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 use rpmostree_client;
 
diff --git a/rust/src/client.rs b/rust/src/client.rs
index ee5276a2..8dabede4 100644
--- a/rust/src/client.rs
+++ b/rust/src/client.rs
@@ -1,5 +1,6 @@
 //! Helpers for the client side binary that will speak DBus
 //! to rpm-ostreed.service.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::cxxrsutil::*;
 use crate::utils;
diff --git a/rust/src/cliwrap.rs b/rust/src/cliwrap.rs
index 89f6c9dc..eafdea03 100644
--- a/rust/src/cliwrap.rs
+++ b/rust/src/cliwrap.rs
@@ -1,24 +1,8 @@
-/*
- * Copyright (C) 2019 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
 //! Implements the `cliwrap` treefile option which intercepts/proxies
 //! other binaries like `/usr/bin/rpm`.
 
+// SPDX-License-Identifier: GPL-2.0-or-later
+// (FIXME: I think I really meant this to be Apache-2.0 OR MIT)
 use anyhow::{anyhow, Result};
 use std::io::prelude::*;
 use std::path;
diff --git a/rust/src/cliwrap/cliutil.rs b/rust/src/cliwrap/cliutil.rs
index 76adf9f2..5eefdfd6 100644
--- a/rust/src/cliwrap/cliutil.rs
+++ b/rust/src/cliwrap/cliutil.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 use nix::sys::statvfs;
 use std::os::unix::process::CommandExt;
diff --git a/rust/src/cliwrap/dracut.rs b/rust/src/cliwrap/dracut.rs
index 2faa28cd..3604af0b 100644
--- a/rust/src/cliwrap/dracut.rs
+++ b/rust/src/cliwrap/dracut.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 
 use crate::cliwrap::cliutil;
diff --git a/rust/src/cliwrap/grubby.rs b/rust/src/cliwrap/grubby.rs
index e88b5964..50d24456 100644
--- a/rust/src/cliwrap/grubby.rs
+++ b/rust/src/cliwrap/grubby.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 
 /// Primary entrypoint to running our wrapped `grubby` handling.
diff --git a/rust/src/cliwrap/rpm.rs b/rust/src/cliwrap/rpm.rs
index f87730ec..189b9390 100644
--- a/rust/src/cliwrap/rpm.rs
+++ b/rust/src/cliwrap/rpm.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 use anyhow::Result;
 use clap::{App, Arg};
 
diff --git a/rust/src/core.rs b/rust/src/core.rs
index e9f7d747..746d507b 100644
--- a/rust/src/core.rs
+++ b/rust/src/core.rs
@@ -1,6 +1,7 @@
 //! Code mirroring rpmostree-core.cxx which is the shared "core"
 //! binding of rpm and ostree, used by both client-side layering/overrides
 //! and server side composes.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::cxxrsutil::CxxResult;
 use crate::ffiutil;
diff --git a/rust/src/countme.rs b/rust/src/countme.rs
index afb837f0..a22bc1fc 100644
--- a/rust/src/countme.rs
+++ b/rust/src/countme.rs
@@ -1,23 +1,6 @@
-/*
- * Copyright (C) 2020 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
 //! Implementation of the "DNF Count Me" system.
-
+// SPDX-License-Identifier: GPL-2.0-or-later
+// (FIXME: Convert to Apache-2.0 OR MIT for consistency?)
 use anyhow::{bail, Context, Result};
 use curl::easy::Easy;
 use os_release::OsRelease;
diff --git a/rust/src/countme/cookie.rs b/rust/src/countme/cookie.rs
index 8f6e341c..03cc1ae1 100644
--- a/rust/src/countme/cookie.rs
+++ b/rust/src/countme/cookie.rs
@@ -1,21 +1,5 @@
-/*
- * Copyright (C) 2020 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
+// SPDX-License-Identifier: GPL-2.0-or-later
+// (FIXME: Convert to Apache-2.0 OR MIT for consistency?)
 use anyhow::{bail, Result};
 use chrono::prelude::*;
 use openat_ext::OpenatDirExt;
diff --git a/rust/src/countme/repo.rs b/rust/src/countme/repo.rs
index 414c5b16..0f962290 100644
--- a/rust/src/countme/repo.rs
+++ b/rust/src/countme/repo.rs
@@ -1,20 +1,5 @@
-/*
- * Copyright (C) 2020 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
+// SPDX-License-Identifier: GPL-2.0-or-later
+// (FIXME: Convert to Apache-2.0 OR MIT for consistency?)
 
 use anyhow::{Context, Result};
 use std::fs;
diff --git a/rust/src/cxxrsutil.rs b/rust/src/cxxrsutil.rs
index 2c370dc9..17023e21 100644
--- a/rust/src/cxxrsutil.rs
+++ b/rust/src/cxxrsutil.rs
@@ -7,6 +7,7 @@
 //! the *_sys type (e.g. ostree_sys::OstreeRepo) but the `ostree::Repo` type.
 //! So for now, we define a `FFIGObjectWrapper` trait that helps with this.
 //! In the future though hopefully cxx.rs improves this situation.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use cxx::{type_id, ExternType};
 use glib::translate::ToGlibPtr;
diff --git a/rust/src/fedora_integration.rs b/rust/src/fedora_integration.rs
index ebbc34fc..36590d54 100644
--- a/rust/src/fedora_integration.rs
+++ b/rust/src/fedora_integration.rs
@@ -1,4 +1,5 @@
 //! APIs used to talk to Fedora Infrastructure tooling (Koji, Bodhi).
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::cxxrsutil::CxxResult;
 use anyhow::{Context, Result};
diff --git a/rust/src/history.rs b/rust/src/history.rs
index c301c3d0..a8c39585 100644
--- a/rust/src/history.rs
+++ b/rust/src/history.rs
@@ -1,21 +1,3 @@
-/*
- * Copyright (C) 2019 Jonathan Lebon <jonathan@jlebon.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
 //! High-level interface to retrieve host rpm-ostree history.
 //!
 //! The basic idea is that at deployment creation time, the upgrader does two
@@ -49,6 +31,8 @@
 //! than scanning the whole journal upfront. This can then be e.g. piped through
 //! a pager, stopped after N entries, etc...
 
+// SPDX-License-Identifier: GPL-2.0-or-later
+// (FIXME: Convert to Apache-2.0 OR MIT for consistency?)
 use crate::cxxrsutil::*;
 use crate::ffi::HistoryEntry;
 use anyhow::{anyhow, Context, Result};
diff --git a/rust/src/includes.rs b/rust/src/includes.rs
index a52f5ead..49cf5b3e 100644
--- a/rust/src/includes.rs
+++ b/rust/src/includes.rs
@@ -7,6 +7,7 @@ strings more efficient).
 NOTICE: The C header definitions are canonical, please update those first
 then synchronize the entries here.
 !*/
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use libdnf_sys::DnfPackage;
 
diff --git a/rust/src/initramfs.rs b/rust/src/initramfs.rs
index 60420543..55a3aaf4 100644
--- a/rust/src/initramfs.rs
+++ b/rust/src/initramfs.rs
@@ -1,4 +1,5 @@
 //! Generate an "overlay" initramfs image
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::cxxrsutil::*;
 use anyhow::{Context, Result};
diff --git a/rust/src/main.rs b/rust/src/main.rs
index a40c6440..6e07636c 100644
--- a/rust/src/main.rs
+++ b/rust/src/main.rs
@@ -1,4 +1,5 @@
 //! The main CLI logic.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use anyhow::Result;
 
diff --git a/rust/src/nameservice/group.rs b/rust/src/nameservice/group.rs
index 300a7690..d71e8203 100644
--- a/rust/src/nameservice/group.rs
+++ b/rust/src/nameservice/group.rs
@@ -1,4 +1,5 @@
 //! Helpers for [user passwd file](https://man7.org/linux/man-pages/man5/passwd.5.html).
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use anyhow::{anyhow, Context, Result};
 use std::io::{BufRead, Write};
diff --git a/rust/src/nameservice/mod.rs b/rust/src/nameservice/mod.rs
index ac91bcc2..65f6387f 100644
--- a/rust/src/nameservice/mod.rs
+++ b/rust/src/nameservice/mod.rs
@@ -1,5 +1,5 @@
 //! Linux name-service information helpers.
-
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 // TODO(lucab): consider moving this to its own crate.
 
 pub(crate) mod group;
diff --git a/rust/src/nameservice/passwd.rs b/rust/src/nameservice/passwd.rs
index 2f9bb285..e2628dff 100644
--- a/rust/src/nameservice/passwd.rs
+++ b/rust/src/nameservice/passwd.rs
@@ -1,4 +1,5 @@
 //! Helpers for [user group file](https://man7.org/linux/man-pages/man5/group.5.html).
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use anyhow::{anyhow, Context, Result};
 use std::io::{BufRead, Write};
diff --git a/rust/src/ostree_utils.rs b/rust/src/ostree_utils.rs
index e16ee643..aaaf394a 100644
--- a/rust/src/ostree_utils.rs
+++ b/rust/src/ostree_utils.rs
@@ -1,4 +1,6 @@
 //! Utility helpers or workarounds for incorrectly bound things in ostree-rs
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use glib::translate::*;
 use std::ptr;
 
diff --git a/rust/src/passwd.rs b/rust/src/passwd.rs
index 7ff27bd0..f8c3bb8c 100644
--- a/rust/src/passwd.rs
+++ b/rust/src/passwd.rs
@@ -1,5 +1,6 @@
 //! APIs for interacting with `/etc/passwd` and `/etc/group`, including
 //! handling the "nss-altfiles" split into `/usr/lib/{passwd,group}`.
+// SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::cxxrsutil::{self, FFIGObjectWrapper};
 use crate::ffiutil;