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-rw-r--r--include/crypto/xts.h47
1 files changed, 47 insertions, 0 deletions
diff --git a/include/crypto/xts.h b/include/crypto/xts.h
new file mode 100644
index 000000000..0f8dba69f
--- /dev/null
+++ b/include/crypto/xts.h
@@ -0,0 +1,47 @@
+/* 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
+
+static inline int xts_check_key(struct crypto_tfm *tfm,
+ const u8 *key, unsigned int keylen)
+{
+ /*
+ * key consists of keys of equal size concatenated, therefore
+ * the length must be even.
+ */
+ if (keylen % 2)
+ return -EINVAL;
+
+ /* ensure that the AES and tweak key are not identical */
+ if (fips_enabled && !crypto_memneq(key, key + (keylen / 2), keylen / 2))
+ 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)
+ return -EINVAL;
+
+ /* ensure that the AES and tweak key are not identical */
+ if ((fips_enabled || (crypto_skcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)) &&
+ !crypto_memneq(key, key + (keylen / 2), keylen / 2))
+ return -EINVAL;
+
+ return 0;
+}
+
+#endif /* _CRYPTO_XTS_H */