1 files changed, 60 insertions, 0 deletions
diff --git a/include/crypto/xts.h b/include/crypto/xts.h
new file mode 100644
index 000000000..34d94c954
--- /dev/null
+++ b/include/crypto/xts.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CRYPTO_XTS_H
+#define _CRYPTO_XTS_H
+
+#include <crypto/b128ops.h>
+#include <crypto/internal/skcipher.h>
+#include <linux/fips.h>
+
+#define XTS_BLOCK_SIZE 16
+
+#define XTS_TWEAK_CAST(x) ((void (*)(void *, u8*, const u8*))(x))
+
+static inline int xts_check_key(struct crypto_tfm *tfm,
+				const u8 *key, unsigned int keylen)
+{
+	u32 *flags = &tfm->crt_flags;
+
+	/*
+	 * key consists of keys of equal size concatenated, therefore
+	 * the length must be even.
+	 */
+	if (keylen % 2) {
+		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	}
+
+	/* ensure that the AES and tweak key are not identical */
+	if (fips_enabled &&
+	    !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
+		*flags |= CRYPTO_TFM_RES_WEAK_KEY;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline int xts_verify_key(struct crypto_skcipher *tfm,
+				 const u8 *key, unsigned int keylen)
+{
+	/*
+	 * key consists of keys of equal size concatenated, therefore
+	 * the length must be even.
+	 */
+	if (keylen % 2) {
+		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+
+	/* ensure that the AES and tweak key are not identical */
+	if ((fips_enabled || crypto_skcipher_get_flags(tfm) &
+			     CRYPTO_TFM_REQ_WEAK_KEY) &&
+	    !crypto_memneq(key, key + (keylen / 2), keylen / 2)) {
+		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+#endif  /* _CRYPTO_XTS_H */