r21267: the first 4 bytes in each encrypted attribute is the crc32

checksum over the remaining bytes

metze

diff --git a/source/torture/rpc/dssync.c b/source/torture/rpc/dssync.c
index 063b37c6177e8f94f7da99967c0a966a0386cc8f..0f07c51516502a92925eeb602eadd1d325bba261 100644 (file)
--- a/source/torture/rpc/dssync.c
+++ b/source/torture/rpc/dssync.c
@@ -345,6 +345,11 @@ static DATA_BLOB decrypt_blob(TALLOC_CTX *mem_ctx,
        DATA_BLOB enc_key;
 
        DATA_BLOB dec_buffer;
+
+       uint32_t crc32_given;
+       uint32_t crc32_calc;
+       DATA_BLOB checked_buffer;
+
        DATA_BLOB plain_buffer;
 
        /*
@@ -382,6 +387,26 @@ static DATA_BLOB decrypt_blob(TALLOC_CTX *mem_ctx,
        }
        arcfour_crypt_blob(dec_buffer.data, dec_buffer.length, &enc_key);
 
+       /* 
+        * the first 4 byte are the crc32 checksum
+        * of the remaining bytes
+        */
+       if (dec_buffer.length < 4) {
+               return data_blob_const(NULL, 0);
+       }
+
+       crc32_given = IVAL(dec_buffer.data, 0);
+       crc32_calc = crc32_calc_buffer(dec_buffer.data + 4 , dec_buffer.length - 4);
+       if (crc32_given != crc32_calc) {
+               DEBUG(0,("CRC32: given[0x%08X] calc[0x%08X]\n",
+                     crc32_given, crc32_calc));
+               return data_blob_const(NULL, 0);
+       }
+       checked_buffer = data_blob_talloc(mem_ctx, dec_buffer.data + 4, dec_buffer.length - 4);
+       if (!checked_buffer.data) {
+               return data_blob_const(NULL, 0);
+       }
+
        /*
         * some attributes seem to be in a usable form after this decryption
         * (supplementalCredentials, priorValue, currentValue, trustAuthOutgoing,
@@ -393,18 +418,14 @@ static DATA_BLOB decrypt_blob(TALLOC_CTX *mem_ctx,
         * dBCSPwd, unicodePwd, ntPwdHistory, lmPwdHistory
         *
         * it's the sam_rid_crypt() function, as the value is constant,
-        * so it doesn't depend on sessionkeys. But for the unicodePwd attribute
-        * which contains the nthash has 20 bytes at this point.
-        * 
-        * the first 4 byte are unknown yet, but the last 16 byte are the
-        * rid crypted hash.
+        * so it doesn't depend on sessionkeys.
         */
        if (rcrypt) {
-               plain_buffer = data_blob_talloc(mem_ctx, dec_buffer.data, dec_buffer.length);
+               plain_buffer = data_blob_talloc(mem_ctx, checked_buffer.data, checked_buffer.length);
                if (!plain_buffer.data) {
                        return data_blob_const(NULL, 0);
                }
-               if (plain_buffer.length < 20) {
+               if (plain_buffer.length < 16) {
                        return data_blob_const(NULL, 0);
                }
                /*
@@ -414,9 +435,9 @@ static DATA_BLOB decrypt_blob(TALLOC_CTX *mem_ctx,
                 *       for each hash, but here we assume the rid des key is shifted
                 *       by one for each 8 byte block.
                 */
-               sam_rid_crypt_len(rid, dec_buffer.length - 4, dec_buffer.data + 4, plain_buffer.data + 4, 0);
+               sam_rid_crypt_len(rid, checked_buffer.length, checked_buffer.data, plain_buffer.data, 0);
        } else {
-               plain_buffer = dec_buffer;
+               plain_buffer = checked_buffer;
        }
 
        return plain_buffer;