Update mysql_aes256.c

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** --> call aes256_decrypt_init (mysql_aes256.c:199)
 * --> call my_aes256_get_size (my_aes.c:256)
 * <-- exit my_aes256_get_size (my_aes.c:257)
** --> call aes256_decrypt (mysql_aes256.c:283)
  - 1st Argument:
    + type   : 0
    + data   : (null)
    + length : 32
  - data    : (null) (udf: mysql_aes256.c:299)
04:58:45 UTC - mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.

key_buffer_size=402653184
read_buffer_size=2097152
max_used_connections=1
max_threads=512
thread_count=1
connection_count=1
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 2496208 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x4e59f20
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 7f6d0247ae68 thread_stack 0x40000
/usr/local/mysql/bin/mysqld(my_print_stacktrace+0x2e)[0x757a4e]
/usr/local/mysql/bin/mysqld(handle_fatal_signal+0x41a)[0x64e16a]
/lib64/libpthread.so.0[0x32a5e0f7e0]
/lib64/libc.so.6[0x32a573382f]
/usr/local/mysql/lib/plugin/lib_mysqludf_aes256.so(aes256_decrypt+0x10d)[0x7f6d0247d597]
/usr/local/mysql/bin/mysqld(_ZN11udf_handler7val_strEP6StringS1_+0x70)[0x698980]
/usr/local/mysql/bin/mysqld(_ZN17Item_func_udf_str7val_strEP6String+0x14)[0x698a64]
/usr/local/mysql/bin/mysqld(_ZN4Item4sendEP8ProtocolP6String+0x3e)[0x657c1e]
/usr/local/mysql/bin/mysqld(_ZN8Protocol19send_result_set_rowEP4ListI4ItemE+0xaf)[0x50bccf]
/usr/local/mysql/bin/mysqld(_ZN11select_send9send_dataER4ListI4ItemE+0x71)[0x542d01]
/usr/local/mysql/bin/mysqld(_ZN4JOIN4execEv+0xe48)[0x59ece8]
/usr/local/mysql/bin/mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0x162)[0x5a0132]
/usr/local/mysql/bin/mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x174)[0x5a0b74]
/usr/local/mysql/bin/mysqld[0x563e24]
/usr/local/mysql/bin/mysqld(_Z21mysql_execute_commandP3THD+0x2e11)[0x569ed1]
/usr/local/mysql/bin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x189)[0x56b579]
/usr/local/mysql/bin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x11e3)[0x56ceb3]
/usr/local/mysql/bin/mysqld(_Z24do_handle_one_connectionP3THD+0x176)[0x5f8056]
/usr/local/mysql/bin/mysqld(handle_one_connection+0x4a)[0x5f80ba]
/lib64/libpthread.so.0[0x32a5e07aa1]
/lib64/libc.so.6(clone+0x6d)[0x32a56e8aad]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (7f6cf000e9a0): is an invalid pointer
Connection ID (thread ID): 1
Status: NOT_KILLED

The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.
161116 13:58:45 mysqld_safe Number of processes running now: 0
161116 13:58:45 mysqld_safe mysqld restarted
161116 13:58:45 InnoDB: The InnoDB memory heap is disabled
161116 13:58:45 InnoDB: Mutexes and rw_locks use GCC atomic builtins
161116 13:58:45 InnoDB: Compressed tables use zlib 1.2.3
161116 13:58:45 InnoDB: Initializing buffer pool, size = 1.0G
161116 13:58:45 InnoDB: Completed initialization of buffer pool
161116 13:58:45 InnoDB: highest supported file format is Barracuda.
161116 13:58:45  InnoDB: Waiting for the background threads to start
161116 13:58:46 InnoDB: 5.5.30 started; log sequence number 3334779858854
161116 13:58:46 [Note] Semi-sync replication initialized for transactions.
161116 13:58:46 [Note] Semi-sync replication enabled on the master.
161116 13:58:46 [Note] Recovering after a crash using /pub/var/log/kppdb0111ddv-bin
161116 13:58:46 [Note] Starting crash recovery...
161116 13:58:46 [Note] Crash recovery finished.
161116 13:58:46 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3306
161116 13:58:46 [Note]   - '0.0.0.0' resolves to '0.0.0.0';
161116 13:58:46 [Note] Server socket created on IP: '0.0.0.0'.
161116 13:58:46 [Warning] 'proxies_priv' entry '@ root@XXXXXXXXXXX' ignored in --skip-name-resolve mode.
161116 13:58:46 [Note] Event Scheduler: Loaded 0 events
161116 13:58:46 [Note] /usr/local/mysql/bin/mysqld: ready for connections.
Version: '5.5.30-log'  socket: '/pub/var/run/mysql.sock'  port: 3306  Source distribution

src/mysql_aes256.c

@@ -293,6 +293,11 @@ EXPORT_API char * aes256_decrypt (
 			"    + length : %ld\n",
 			args->arg_type[0], args->args[0], args->lengths[0]
 		);
+		// 암호화되지 않은 임의의 값(select AES256_DECRYPT(UNHEX('encrypted_hash_string'), '0123456789abcdef0123456789abcdef');)을 
+		// 넣으면(예제소스를 그대로 실행시) 
+		// MySQL 5.5.30 version에서 DB 정지되는 현상 발생 
+		// 파라미터 검증 후 잘못된 값으로 판단되면 null 리턴되도록 수정 (2016-11-16)
+		return null;
 	}
 
 #ifdef MY_AES256_DEBUG