Restructure the crypto checksum implementation to minimize

dependencies on the internals of modules.

* Keyhash providers are gone.
* The cksumtypes table contains checksum and verify functions,
  similar to the etypes encrypt and decrypt functions.  New checksum
  functions parallel the old keyhash providers, and there are also
  functions for unkeyed and derived-key HMAC checksums.
* The flags field is now used to indicate whether a checksum is
  unkeyed, but not whether it is a derived-key HMAC checksum.
* The descbc checksum is handled through a new enc_provider function
  which calculates a CBC MAC.

The OpenSSL module does not implement the CBC MAC function (it didn't
implement descbc before).  builtin/des could probably get rid of
f_cksum.c (the old DES CBC routine) with some alterations to
string2key.c.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@23462 dc483132-0cff-0310-8789-dd5450dbe970

4 files changed, 66 insertions, 33 deletions

diff --git a/src/lib/crypto/builtin/enc_provider/aes.c b/src/lib/crypto/builtin/enc_provider/aes.c
index d482724ca..0440f7ad0 100644
--- a/src/lib/crypto/builtin/enc_provider/aes.c
+++ b/src/lib/crypto/builtin/enc_provider/aes.c
@@ -267,6 +267,7 @@ const struct krb5_enc_provider krb5int_enc_aes128 = {
     16, 16,
     krb5int_aes_encrypt,
     krb5int_aes_decrypt,
+    NULL,
     krb5int_aes_make_key,
     aes_init_state,
     krb5int_default_free_state,
@@ -277,6 +278,7 @@ const struct krb5_enc_provider krb5int_enc_aes256 = {
     32, 32,
     krb5int_aes_encrypt,
     krb5int_aes_decrypt,
+    NULL,
     krb5int_aes_make_key,
     aes_init_state,
     krb5int_default_free_state
diff --git a/src/lib/crypto/builtin/enc_provider/des.c b/src/lib/crypto/builtin/enc_provider/des.c
index d63172778..ed79b06eb 100644
--- a/src/lib/crypto/builtin/enc_provider/des.c
+++ b/src/lib/crypto/builtin/enc_provider/des.c
@@ -31,32 +31,24 @@
 #include <aead.h>
 #include <rand2key.h>
 
-
 static krb5_error_code
-k5_des_docrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
-               size_t num_data, int enc)
+validate_and_schedule(krb5_key key, const krb5_data *ivec,
+                      const krb5_crypto_iov *data, size_t num_data,
+                      mit_des_key_schedule schedule)
 {
-    mit_des_key_schedule schedule;
-    size_t input_length = 0;
-    unsigned int i;
-    unsigned char *ivecbytes;
-
-    /* key->keyblock.enctype was checked by the caller */
-
-    if (key->keyblock.length != 8)
-        return(KRB5_BAD_KEYSIZE);
+    size_t i, input_length;
 
-    for (i = 0; i < num_data; i++) {
+    for (i = 0, input_length = 0; i < num_data; i++) {
         const krb5_crypto_iov *iov = &data[i];
 
         if (ENCRYPT_IOV(iov))
             input_length += iov->data.length;
     }
 
-    if ((input_length % 8) != 0)
-        return(KRB5_BAD_MSIZE);
-    if (ivec && (ivec->length != 8))
-        return(KRB5_BAD_MSIZE);
+    if (key->keyblock.length != 8)
+        return KRB5_BAD_KEYSIZE;
+    if (input_length % 8 != 0 || (ivec != NULL && ivec->length != 8))
+        return KRB5_BAD_MSIZE;
 
     switch (mit_des_key_sched(key->keyblock.contents, schedule)) {
     case -1:
@@ -64,38 +56,75 @@ k5_des_docrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
     case -2:
         return(KRB5DES_WEAK_KEY);
     }
+    return 0;
+}
+
+static krb5_error_code
+des_encrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
+            size_t num_data)
+{
+    mit_des_key_schedule schedule;
+    krb5_error_code err;
 
-    /* this has a return value, but the code always returns zero */
-    ivecbytes = ivec ? (unsigned char *) ivec->data : NULL;
-    if (enc)
-        krb5int_des_cbc_encrypt(data, num_data, schedule, ivecbytes);
-    else
-        krb5int_des_cbc_decrypt(data, num_data, schedule, ivecbytes);
+    err = validate_and_schedule(key, ivec, data, num_data, schedule);
+    if (err)
+        return err;
 
-    memset(schedule, 0, sizeof(schedule));
+    krb5int_des_cbc_encrypt(data, num_data, schedule,
+                            ivec != NULL ? (unsigned char *) ivec->data :
+                            NULL);
 
-    return(0);
+    zap(schedule, sizeof(schedule));
+    return 0;
 }
 
 static krb5_error_code
-k5_des_encrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
-               size_t num_data)
+des_decrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
+            size_t num_data)
 {
-    return k5_des_docrypt(key, ivec, data, num_data, 1);
+    mit_des_key_schedule schedule;
+    krb5_error_code err;
+
+    err = validate_and_schedule(key, ivec, data, num_data, schedule);
+    if (err)
+        return err;
+
+    krb5int_des_cbc_decrypt(data, num_data, schedule,
+                            ivec != NULL ? (unsigned char *) ivec->data :
+                            NULL);
+
+    zap(schedule, sizeof(schedule));
+    return 0;
 }
 
 static krb5_error_code
-k5_des_decrypt(krb5_key key, const krb5_data *ivec, krb5_crypto_iov *data,
-               size_t num_data)
+des_cbc_mac(krb5_key key, const krb5_crypto_iov *data, size_t num_data,
+            const krb5_data *ivec, krb5_data *output)
 {
-    return k5_des_docrypt(key, ivec, data, num_data, 0);
+    mit_des_key_schedule schedule;
+    krb5_error_code err;
+
+    err = validate_and_schedule(key, ivec, data, num_data, schedule);
+    if (err)
+        return err;
+
+    if (output->length != 8)
+        return KRB5_CRYPTO_INTERNAL;
+
+    krb5int_des_cbc_mac(data, num_data, schedule,
+                        ivec != NULL ? (unsigned char *) ivec->data : NULL,
+                        (unsigned char *) output->data);
+
+    zap(schedule, sizeof(schedule));
+    return 0;
 }
 
 const struct krb5_enc_provider krb5int_enc_des = {
     8,
     7, 8,
-    k5_des_encrypt,
-    k5_des_decrypt,
+    des_encrypt,
+    des_decrypt,
+    des_cbc_mac,
     krb5int_des_make_key,
     krb5int_des_init_state,
     krb5int_default_free_state
diff --git a/src/lib/crypto/builtin/enc_provider/des3.c b/src/lib/crypto/builtin/enc_provider/des3.c
index 17c343399..e08cc62d6 100644
--- a/src/lib/crypto/builtin/enc_provider/des3.c
+++ b/src/lib/crypto/builtin/enc_provider/des3.c
@@ -110,6 +110,7 @@ const struct krb5_enc_provider krb5int_enc_des3 = {
     21, 24,
     k5_des3_encrypt,
     k5_des3_decrypt,
+    NULL,
     krb5int_des3_make_key,
     krb5int_des_init_state,
     krb5int_default_free_state
diff --git a/src/lib/crypto/builtin/enc_provider/rc4.c b/src/lib/crypto/builtin/enc_provider/rc4.c
index d024e4a96..a8e0721c9 100644
--- a/src/lib/crypto/builtin/enc_provider/rc4.c
+++ b/src/lib/crypto/builtin/enc_provider/rc4.c
@@ -206,6 +206,7 @@ const struct krb5_enc_provider krb5int_enc_arcfour = {
     16, 16,
     k5_arcfour_docrypt,
     k5_arcfour_docrypt,
+    NULL,
     krb5int_arcfour_make_key,
     k5_arcfour_init_state, /*xxx not implemented yet*/
     krb5int_default_free_state