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-rw-r--r--include/crypto/internal/des.h127
1 files changed, 127 insertions, 0 deletions
diff --git a/include/crypto/internal/des.h b/include/crypto/internal/des.h
new file mode 100644
index 000000000..723fe5bf1
--- /dev/null
+++ b/include/crypto/internal/des.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * DES & Triple DES EDE key verification helpers
+ */
+
+#ifndef __CRYPTO_INTERNAL_DES_H
+#define __CRYPTO_INTERNAL_DES_H
+
+#include <linux/crypto.h>
+#include <linux/fips.h>
+#include <crypto/des.h>
+#include <crypto/aead.h>
+#include <crypto/skcipher.h>
+
+/**
+ * crypto_des_verify_key - Check whether a DES key is weak
+ * @tfm: the crypto algo
+ * @key: the key buffer
+ *
+ * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
+ * keys. Otherwise, 0 is returned.
+ *
+ * It is the job of the caller to ensure that the size of the key equals
+ * DES_KEY_SIZE.
+ */
+static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
+{
+ struct des_ctx tmp;
+ int err;
+
+ err = des_expand_key(&tmp, key, DES_KEY_SIZE);
+ if (err == -ENOKEY) {
+ if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
+ err = -EINVAL;
+ else
+ err = 0;
+ }
+ memzero_explicit(&tmp, sizeof(tmp));
+ return err;
+}
+
+/*
+ * RFC2451:
+ *
+ * For DES-EDE3, there is no known need to reject weak or
+ * complementation keys. Any weakness is obviated by the use of
+ * multiple keys.
+ *
+ * However, if the first two or last two independent 64-bit keys are
+ * equal (k1 == k2 or k2 == k3), then the DES3 operation is simply the
+ * same as DES. Implementers MUST reject keys that exhibit this
+ * property.
+ *
+ */
+static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,
+ bool check_weak)
+{
+ int ret = fips_enabled ? -EINVAL : -ENOKEY;
+ u32 K[6];
+
+ memcpy(K, key, DES3_EDE_KEY_SIZE);
+
+ if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
+ !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
+ (fips_enabled || check_weak))
+ goto bad;
+
+ if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
+ goto bad;
+
+ ret = 0;
+bad:
+ memzero_explicit(K, DES3_EDE_KEY_SIZE);
+
+ return ret;
+}
+
+/**
+ * crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak
+ * @tfm: the crypto algo
+ * @key: the key buffer
+ *
+ * Returns -EINVAL if the key is weak and the crypto TFM does not permit weak
+ * keys or when running in FIPS mode. Otherwise, 0 is returned. Note that some
+ * keys are rejected in FIPS mode even if weak keys are permitted by the TFM
+ * flags.
+ *
+ * It is the job of the caller to ensure that the size of the key equals
+ * DES3_EDE_KEY_SIZE.
+ */
+static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,
+ const u8 *key)
+{
+ return des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,
+ crypto_tfm_get_flags(tfm) &
+ CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+}
+
+static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,
+ const u8 *key)
+{
+ return crypto_des_verify_key(crypto_skcipher_tfm(tfm), key);
+}
+
+static inline int verify_skcipher_des3_key(struct crypto_skcipher *tfm,
+ const u8 *key)
+{
+ return crypto_des3_ede_verify_key(crypto_skcipher_tfm(tfm), key);
+}
+
+static inline int verify_aead_des_key(struct crypto_aead *tfm, const u8 *key,
+ int keylen)
+{
+ if (keylen != DES_KEY_SIZE)
+ return -EINVAL;
+ return crypto_des_verify_key(crypto_aead_tfm(tfm), key);
+}
+
+static inline int verify_aead_des3_key(struct crypto_aead *tfm, const u8 *key,
+ int keylen)
+{
+ if (keylen != DES3_EDE_KEY_SIZE)
+ return -EINVAL;
+ return crypto_des3_ede_verify_key(crypto_aead_tfm(tfm), key);
+}
+
+#endif /* __CRYPTO_INTERNAL_DES_H */