[PATCH 3/3] lib/crypto: aes: Add FIPS self-tests for GCM and CCM

[Eric Biggers <ebiggers@kernel.org>]

Upcoming changes will wire up architecture-optimized implementations of
GCM and CCM.  FIPS labs can consider such designs to meet the threshold
for separate self-tests to be needed.

Therefore, add FIPS self-tests for encryption and decryption in these
modes.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 lib/crypto/aes.c                    | 81 +++++++++++++++++++++++++----
 lib/crypto/fips-aes.h               | 19 +++++++
 scripts/crypto/gen-fips-testvecs.py | 23 ++++++++
 3 files changed, 113 insertions(+), 10 deletions(-)

diff --git a/lib/crypto/aes.c b/lib/crypto/aes.c
index e9119f82b0cc..41aaa82cb1a1 100644
--- a/lib/crypto/aes.c
+++ b/lib/crypto/aes.c
@@ -737,14 +737,7 @@ void aes_cbcmac_final(struct aes_cbcmac_ctx *ctx, u8 out[AES_BLOCK_SIZE])
 }
 EXPORT_SYMBOL_NS_GPL(aes_cbcmac_final, "CRYPTO_INTERNAL");
 
-/*
- * FIPS cryptographic algorithm self-test for AES-CMAC.  As per the FIPS 140-3
- * Implementation Guidance, a cryptographic algorithm self-test for at least one
- * of AES-GCM, AES-CCM, AES-CMAC, or AES-GMAC is required if any of those modes
- * is implemented.  This fulfills that requirement via AES-CMAC.
- *
- * This is just for FIPS.  The full tests are in the KUnit test suite.
- */
+/* FIPS cryptographic algorithm self-test for AES-CMAC */
 static void __init aes_cmac_fips_test(void)
 {
 	struct aes_cmac_key key;
@@ -1745,7 +1738,37 @@ int aes_gcm_decrypt(u8 *dst, const u8 *src, size_t data_len, const u8 *authtag,
 }
 EXPORT_SYMBOL_GPL(aes_gcm_decrypt);
 
-#endif /* CONFIG_CRYPTO_LIB_AES_GCM */
+/* FIPS cryptographic algorithm self-test for AES-GCM */
+static void __init aes_gcm_fips_test(void)
+{
+	const size_t data_len = sizeof(fips_test_data);
+	u8 buf[sizeof(fips_test_data) + AES_BLOCK_SIZE];
+	struct aes_gcm_key key;
+	int err;
+
+	if (aes_gcm_preparekey(&key, fips_test_key, sizeof(fips_test_key),
+			       AES_BLOCK_SIZE) != 0)
+		panic("aes: GCM FIPS self-test failed (preparekey)\n");
+
+	aes_gcm_encrypt(buf, fips_test_data, data_len, &buf[data_len],
+			fips_test_ad, sizeof(fips_test_ad), fips_test_iv, &key);
+	if (memcmp(fips_test_aes_gcm_ctext_and_tag, buf, sizeof(buf)) != 0)
+		panic("aes: GCM FIPS self-test failed (wrong ciphertext and/or tag)\n");
+
+	err = aes_gcm_decrypt(buf, buf, data_len, &buf[data_len], fips_test_ad,
+			      sizeof(fips_test_ad), fips_test_iv, &key);
+	if (err != 0)
+		panic("aes: GCM FIPS self-test failed (decryption failed)\n");
+	if (memcmp(fips_test_data, buf, data_len) != 0)
+		panic("aes: GCM FIPS self-test failed (wrong plaintext)\n");
+
+	memzero_explicit(&key, sizeof(key));
+}
+#else /* CONFIG_CRYPTO_LIB_AES_GCM */
+static inline void aes_gcm_fips_test(void)
+{
+}
+#endif /* !CONFIG_CRYPTO_LIB_AES_GCM */
 
 #if IS_ENABLED(CONFIG_CRYPTO_LIB_AES_CCM)
 int aes_ccm_preparekey(struct aes_ccm_key *key, const u8 *in_key,
@@ -2057,7 +2080,43 @@ int aes_ccm_decrypt(u8 *dst, const u8 *src, size_t data_len, const u8 *authtag,
 	return err;
 }
 EXPORT_SYMBOL_GPL(aes_ccm_decrypt);
-#endif /* CONFIG_CRYPTO_LIB_AES_CCM */
+
+/* FIPS cryptographic algorithm self-test for AES-CCM */
+static void __init aes_ccm_fips_test(void)
+{
+	const size_t data_len = sizeof(fips_test_data);
+	const size_t nonce_len = 13;
+	u8 buf[sizeof(fips_test_data) + AES_BLOCK_SIZE];
+	struct aes_ccm_key key;
+	int err;
+
+	if (aes_ccm_preparekey(&key, fips_test_key, sizeof(fips_test_key),
+			       AES_BLOCK_SIZE) != 0)
+		panic("aes: CCM FIPS self-test failed (preparekey)\n");
+
+	err = aes_ccm_encrypt(buf, fips_test_data, data_len, &buf[data_len],
+			      fips_test_ad, sizeof(fips_test_ad), fips_test_iv,
+			      nonce_len, &key);
+	if (err != 0)
+		panic("aes: CCM FIPS self-test failed (encryption failed)\n");
+	if (memcmp(fips_test_aes_ccm_ctext_and_tag, buf, sizeof(buf)) != 0)
+		panic("aes: CCM FIPS self-test failed (wrong ciphertext and/or tag)\n");
+
+	err = aes_ccm_decrypt(buf, buf, data_len, &buf[data_len], fips_test_ad,
+			      sizeof(fips_test_ad), fips_test_iv, nonce_len,
+			      &key);
+	if (err != 0)
+		panic("aes: CCM FIPS self-test failed (decryption failed)\n");
+	if (memcmp(fips_test_data, buf, data_len) != 0)
+		panic("aes: CCM FIPS self-test failed (wrong plaintext)\n");
+
+	memzero_explicit(&key, sizeof(key));
+}
+#else /* CONFIG_CRYPTO_LIB_AES_CCM */
+static inline void aes_ccm_fips_test(void)
+{
+}
+#endif /* !CONFIG_CRYPTO_LIB_AES_CCM */
 
 static int __init aes_mod_init(void)
 {
@@ -2072,6 +2131,8 @@ static int __init aes_mod_init(void)
 		aes_cbc_cts_fips_test();
 		aes_ctr_fips_test();
 		aes_xts_fips_test();
+		aes_gcm_fips_test();
+		aes_ccm_fips_test();
 	}
 	return 0;
 }
diff --git a/lib/crypto/fips-aes.h b/lib/crypto/fips-aes.h
index cfacf5d98e07..2a1746606533 100644
--- a/lib/crypto/fips-aes.h
+++ b/lib/crypto/fips-aes.h
@@ -9,6 +9,11 @@ static const u8 fips_test_data[] __initconst __maybe_unused = {
 	0x74, 0x20, 0x64, 0x61, 0x74, 0x61, 0x00, 0x00,
 };
 
+static const u8 fips_test_ad[] __initconst __maybe_unused = {
+	0x66, 0x69, 0x70, 0x73, 0x20, 0x74, 0x65, 0x73,
+	0x74, 0x20, 0x61, 0x64, 0x00, 0x00, 0x00, 0x00,
+};
+
 static const u8 fips_test_iv[] __initconst __maybe_unused = {
 	0x66, 0x69, 0x70, 0x73, 0x20, 0x74, 0x65, 0x73,
 	0x74, 0x20, 0x69, 0x76, 0x00, 0x00, 0x00, 0x00,
@@ -57,3 +62,17 @@ static const u8 fips_test_aes_xts_ctext[] __initconst __maybe_unused = {
 	0xd4, 0x51, 0x7f, 0x01, 0x14, 0x91, 0x16, 0x29,
 	0x26, 0xbe, 0xec, 0x9b, 0x90, 0xed, 0x59, 0x30,
 };
+
+static const u8 fips_test_aes_gcm_ctext_and_tag[] __initconst __maybe_unused = {
+	0x12, 0x0c, 0x5d, 0x03, 0x32, 0x93, 0x13, 0x44,
+	0x06, 0x35, 0x26, 0x9d, 0xe0, 0xea, 0xbc, 0xe2,
+	0x30, 0xa9, 0xa4, 0x15, 0xc5, 0x3d, 0xb3, 0xf9,
+	0x30, 0x82, 0xdf, 0x9c, 0xd8, 0xc4, 0x3f, 0x2f,
+};
+
+static const u8 fips_test_aes_ccm_ctext_and_tag[] __initconst __maybe_unused = {
+	0x11, 0x8e, 0x01, 0xcb, 0xb5, 0x22, 0x6d, 0xb4,
+	0x66, 0x98, 0x97, 0x1d, 0x35, 0x53, 0x78, 0xdd,
+	0xd1, 0xc5, 0xff, 0xb6, 0x90, 0xcf, 0xb1, 0xf2,
+	0x87, 0x99, 0xd6, 0x1e, 0xd5, 0xd1, 0xed, 0x63,
+};
diff --git a/scripts/crypto/gen-fips-testvecs.py b/scripts/crypto/gen-fips-testvecs.py
index a79eaf081c26..b8c8a78cb8a8 100755
--- a/scripts/crypto/gen-fips-testvecs.py
+++ b/scripts/crypto/gen-fips-testvecs.py
@@ -8,6 +8,7 @@
 # Copyright 2025 Google LLC
 
 import cryptography.hazmat.primitives.ciphers
+import cryptography.hazmat.primitives.ciphers.aead
 import cryptography.hazmat.primitives.cmac
 import hashlib
 import hmac
@@ -32,12 +33,14 @@ def print_header(file):
 
 def gen_aes_test_data(file):
     fips_test_data = b"fips test data\0\0"
+    fips_test_ad = b"fips test ad\0\0\0\0"
     fips_test_iv = b"fips test iv\0\0\0\0"
     fips_test_key = b"fips test key\0\0\0"
     fips_test_xts_key = b"key1" + (b"\0" * 12) + b"key2" + (b"\0" * 12)
 
     print_header(file)
     print_static_u8_array_definition(file, "fips_test_data", fips_test_data)
+    print_static_u8_array_definition(file, "fips_test_ad", fips_test_ad)
     print_static_u8_array_definition(file, "fips_test_iv", fips_test_iv)
     print_static_u8_array_definition(file, "fips_test_key", fips_test_key)
     print_static_u8_array_definition(file, "fips_test_xts_key", fips_test_xts_key)
@@ -93,6 +96,26 @@ def gen_aes_test_data(file):
     ctext = encryptor.update(fips_test_data) + encryptor.finalize()
     print_static_u8_array_definition(file, "fips_test_aes_xts_ctext", ctext)
 
+    # AES-GCM
+    cipher = cryptography.hazmat.primitives.ciphers.aead.AESGCM(fips_test_key)
+    ct_and_tag = cipher.encrypt(
+        nonce=fips_test_iv[:12], data=fips_test_data, associated_data=fips_test_ad
+    )
+    print_static_u8_array_definition(
+        file, "fips_test_aes_gcm_ctext_and_tag", ct_and_tag
+    )
+
+    # AES-CCM
+    cipher = cryptography.hazmat.primitives.ciphers.aead.AESCCM(
+        fips_test_key, tag_length=16
+    )
+    ct_and_tag = cipher.encrypt(
+        nonce=fips_test_iv[:13], data=fips_test_data, associated_data=fips_test_ad
+    )
+    print_static_u8_array_definition(
+        file, "fips_test_aes_ccm_ctext_and_tag", ct_and_tag
+    )
+
 
 def gen_sha_test_data(file):
     fips_test_data = b"fips test data\0\0"
-- 
2.55.0