cmac: enumerate cipher algorithms

Identify the CMAC ciphers with an enum instead of string.

client.c

@@ -2985,7 +2985,7 @@ process_cmd_keygen(char *line)
     ;
 
 #ifdef HAVE_CMAC
-  cmac_length = CMC_GetKeyLength(type);
+  cmac_length = CMC_GetKeyLength(UTI_CmacNameToAlgorithm(type));
 #else
   cmac_length = 0;
 #endif

cmac.h

@@ -28,10 +28,17 @@
 #ifndef GOT_CMAC_H
 #define GOT_CMAC_H
 
+/* Avoid overlapping with the hash enumeration */
+typedef enum {
+  CMC_INVALID = 0,
+  CMC_AES128 = 13,
+  CMC_AES256 = 14,
+} CMC_Algorithm;
+
 typedef struct CMC_Instance_Record *CMC_Instance;
 
-extern unsigned int CMC_GetKeyLength(const char *cipher);
-extern CMC_Instance CMC_CreateInstance(const char *cipher, const unsigned char *key,
+extern unsigned int CMC_GetKeyLength(CMC_Algorithm algorithm);
+extern CMC_Instance CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key,
                                        unsigned int length);
 extern unsigned int CMC_Hash(CMC_Instance inst, const unsigned char *in, unsigned int in_len,
                              unsigned char *out, unsigned int out_len);

cmac_nettle.c

@@ -45,11 +45,11 @@ struct CMC_Instance_Record {
 /* ================================================== */
 
 unsigned int
-CMC_GetKeyLength(const char *cipher)
+CMC_GetKeyLength(CMC_Algorithm algorithm)
 {
-  if (strcmp(cipher, "AES128") == 0)
+  if (algorithm == CMC_AES128)
     return AES128_KEY_SIZE;
-  else if (strcmp(cipher, "AES256") == 0)
+  else if (algorithm == CMC_AES256)
     return AES256_KEY_SIZE;
   return 0;
 }
@@ -57,11 +57,11 @@ CMC_GetKeyLength(const char *cipher)
 /* ================================================== */
 
 CMC_Instance
-CMC_CreateInstance(const char *cipher, const unsigned char *key, unsigned int length)
+CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key, unsigned int length)
 {
   CMC_Instance inst;
 
-  if (length == 0 || length != CMC_GetKeyLength(cipher))
+  if (length == 0 || length != CMC_GetKeyLength(algorithm))
     return NULL;
 
   inst = MallocNew(struct CMC_Instance_Record);

keys.c

@@ -202,6 +202,7 @@ KEY_Reload(void)
   char line[2048], *key_file, *key_value;
   const char *key_type;
   HSH_Algorithm hash_algorithm;
+  CMC_Algorithm cmac_algorithm;
   int hash_id;
   Key key;
 
@@ -239,8 +240,8 @@ KEY_Reload(void)
       continue;
     }
 
-    cmac_key_length = CMC_GetKeyLength(key_type);
     hash_algorithm = UTI_HashNameToAlgorithm(key_type);
+    cmac_algorithm = UTI_CmacNameToAlgorithm(key_type);
 
     if (hash_algorithm != 0) {
       hash_id = HSH_GetHashId(hash_algorithm);
@@ -253,18 +254,23 @@ KEY_Reload(void)
       memcpy(key.data.ntp_mac.value, key_value, key_length);
       key.data.ntp_mac.length = key_length;
       key.data.ntp_mac.hash_id = hash_id;
-    } else if (cmac_key_length > 0) {
-      if (cmac_key_length != key_length) {
+    } else if (cmac_algorithm != 0) {
+      cmac_key_length = CMC_GetKeyLength(cmac_algorithm);
+      if (cmac_key_length == 0) {
+        LOG(LOGS_WARN, "Unsupported %s in key %"PRIu32, "cipher", key.id);
+        continue;
+      } else if (cmac_key_length != key_length) {
         LOG(LOGS_WARN, "Invalid length of %s key %"PRIu32" (expected %u bits)",
             key_type, key.id, 8 * cmac_key_length);
         continue;
       }
 
       key.class = CMAC;
-      key.data.cmac = CMC_CreateInstance(key_type, (unsigned char *)key_value, key_length);
+      key.data.cmac = CMC_CreateInstance(cmac_algorithm, (unsigned char *)key_value,
+                                         key_length);
       assert(key.data.cmac);
     } else {
-      LOG(LOGS_WARN, "Unknown hash function or cipher in key %"PRIu32, key.id);
+      LOG(LOGS_WARN, "Invalid type in key %"PRIu32, key.id);
       continue;
     }
 

stubs.c

@@ -432,13 +432,13 @@ NSD_SignAndSendPacket(uint32_t key_id, NTP_Packet *packet, NTP_PacketInfo *info,
 #ifndef HAVE_CMAC
 
 unsigned int
-CMC_GetKeyLength(const char *cipher)
+CMC_GetKeyLength(CMC_Algorithm algorithm)
 {
   return 0;
 }
 
 CMC_Instance
-CMC_CreateInstance(const char *cipher, const unsigned char *key, unsigned int length)
+CMC_CreateInstance(CMC_Algorithm algorithm, const unsigned char *key, unsigned int length)
 {
   return NULL;
 }

test/unit/cmac.c

@@ -22,6 +22,7 @@
 #include <sysincl.h>
 #include <cmac.h>
 #include <logging.h>
+#include <util.h>
 #include "test.h"
 
 #define MAX_KEY_LENGTH 64
@@ -49,6 +50,7 @@ test_unit(void)
     { "", "", 0, "", 0 }
   };
 
+  CMC_Algorithm algorithm;
   CMC_Instance inst;
   unsigned int length;
   int i, j;
@@ -57,21 +59,25 @@ test_unit(void)
   TEST_REQUIRE(0);
 #endif
 
+  TEST_CHECK(CMC_INVALID == 0);
+
   for (i = 0; tests[i].name[0] != '\0'; i++) {
-    TEST_CHECK(CMC_GetKeyLength(tests[i].name) == tests[i].key_length);
+    algorithm = UTI_CmacNameToAlgorithm(tests[i].name);
+    TEST_CHECK(algorithm != 0);
+    TEST_CHECK(CMC_GetKeyLength(algorithm) == tests[i].key_length);
 
     DEBUG_LOG("testing %s", tests[i].name);
 
     for (j = 0; j <= 128; j++) {
       if (j == tests[i].key_length)
         continue;
-      TEST_CHECK(!CMC_CreateInstance(tests[i].name, tests[i].key, j));
+      TEST_CHECK(!CMC_CreateInstance(algorithm, tests[i].key, j));
     }
 
-    inst = CMC_CreateInstance(tests[i].name, tests[i].key, tests[i].key_length);
+    inst = CMC_CreateInstance(algorithm, tests[i].key, tests[i].key_length);
     TEST_CHECK(inst);
 
-    TEST_CHECK(!CMC_CreateInstance("nosuchcipher", tests[i].key, tests[i].key_length));
+    TEST_CHECK(!CMC_CreateInstance(0, tests[i].key, tests[i].key_length));
 
     for (j = 0; j <= sizeof (hash); j++) {
       memset(hash, 0, sizeof (hash));

util.c

@@ -927,6 +927,18 @@ UTI_FloatHostToNetwork(double x)
 
 /* ================================================== */
 
+CMC_Algorithm
+UTI_CmacNameToAlgorithm(const char *name)
+{
+  if (strcmp(name, "AES128") == 0)
+    return CMC_AES128;
+  else if (strcmp(name, "AES256") == 0)
+    return CMC_AES256;
+  return CMC_INVALID;
+}
+
+/* ================================================== */
+
 HSH_Algorithm
 UTI_HashNameToAlgorithm(const char *name)
 {

util.h

@@ -32,6 +32,7 @@
 #include "addressing.h"
 #include "ntp.h"
 #include "candm.h"
+#include "cmac.h"
 #include "hash.h"
 
 /* Zero a timespec */
@@ -165,6 +166,7 @@ extern void UTI_TimespecHostToNetwork(const struct timespec *src, Timespec *dest
 extern double UTI_FloatNetworkToHost(Float x);
 extern Float UTI_FloatHostToNetwork(double x);
 
+extern CMC_Algorithm UTI_CmacNameToAlgorithm(const char *name);
 extern HSH_Algorithm UTI_HashNameToAlgorithm(const char *name);
 
 /* Set FD_CLOEXEC on descriptor */