flash-ota: add AES-support for culfw-devices

[hmcfgusb] / hm.c

diff --git a/hm.c b/hm.c
new file mode 100644 (file)
index 0000000..818081f
--- /dev/null
+++ b/hm.c
@@ -0,0 +1,114 @@
+/* HomeMatic protocol-functions
+ *
+ * Copyright (c) 2014-15 Michael Gernoth <michael@gernoth.net>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <string.h>
+#include <strings.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include "aes.h"
+#include "hexdump.h"
+#include "hm.h"
+
+static int debug = 0;
+
+uint8_t* hm_sign(uint8_t *key, uint8_t *challenge, uint8_t *m_frame, uint8_t *exp_auth, uint8_t *resp)
+{
+       uint8_t signkey[16];
+       WORD ks[60];
+       struct timeval tv;
+       int i;
+
+       printf("AES-request with challenge: %02x%02x%02x%02x%02x%02x\n",
+                       challenge[0], challenge[1], challenge[2],
+                       challenge[3], challenge[4], challenge[5]);
+
+       /*
+        * Build signing key by XORing the first 6 bytes of
+        * the key with the challenge.
+        */
+       memcpy(signkey, key, sizeof(signkey));
+       for (i = 0; i < 6; i++) {
+               signkey[i] ^= challenge[i];
+       }
+       aes_key_setup(signkey, ks, 128);
+
+       /*
+        * Generate payload for first encryption.
+        */
+       gettimeofday(&tv, NULL);
+       resp[0] = tv.tv_sec >> 24 & 0xff;
+       resp[1] = tv.tv_sec >> 16 & 0xff;
+       resp[2] = tv.tv_sec >> 8 & 0xff;
+       resp[3] = tv.tv_sec & 0xff;
+       resp[4] = tv.tv_usec >> 8 & 0xff;
+       resp[5] = tv.tv_usec & 0xff;
+       memcpy(&(resp[6]), &(m_frame[MSGID]), 10);
+
+       if (debug)
+               hexdump(resp, 16, "P   > ");
+
+       aes_encrypt(resp, resp, ks, 128);
+
+       if (debug)
+               hexdump(resp, 16, "Pe  > ");
+
+       /*
+        * Device has to answer with the first 4 bytes of the
+        * encrypted payload to authenticate, so pass them to
+        * the caller.
+        */
+
+       if (exp_auth) {
+               memcpy(exp_auth, resp, 4);
+       }
+
+       /*
+        * XOR parameters of the m_frame to the payload.
+        */
+       for (i = 0; i < PAYLOADLEN(m_frame) - 1; i++) {
+               if (i == 16) {
+                       break;
+               }
+
+               resp[i] ^= m_frame[PAYLOAD + 1+ i];
+       }
+
+       if (debug)
+               hexdump(resp, 16, "Pe^ > ");
+
+       /*
+        * Encrypt payload again
+        */
+       aes_encrypt(resp, resp, ks, 128);
+
+       if (debug)
+               hexdump(resp, 16, "Pe^e> ");
+
+       return resp;
+}