Wed Jan 8 2020 09:50:12

Asterisk developer's documentation


func_aes.c File Reference

AES encryption/decryption dialplan functions. More...

#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/pbx.h"
#include "asterisk/app.h"
#include "asterisk/crypto.h"

Go to the source code of this file.

Macros

#define AES_BLOCK_SIZE   16
 

Functions

static void __reg_module (void)
 
static void __unreg_module (void)
 
static int aes_helper (struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
 
static int load_module (void)
 
static int unload_module (void)
 

Variables

static struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "AES dialplan functions" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "ac1f6a56484a8820659555499174e588" , .load = load_module, .unload = unload_module, .nonoptreq = "res_crypto", }
 
static struct ast_custom_function aes_decrypt_function
 
static struct ast_custom_function aes_encrypt_function
 
static struct ast_module_infoast_module_info = &__mod_info
 

Detailed Description

AES encryption/decryption dialplan functions.

Author
David Vossel dvoss.nosp@m.el@d.nosp@m.igium.nosp@m..com

Definition in file func_aes.c.

Macro Definition Documentation

#define AES_BLOCK_SIZE   16

Definition at line 39 of file func_aes.c.

Referenced by aes_helper().

Function Documentation

static void __reg_module ( void  )
static

Definition at line 185 of file func_aes.c.

static void __unreg_module ( void  )
static

Definition at line 185 of file func_aes.c.

static int aes_helper ( struct ast_channel chan,
const char *  cmd,
char *  data,
char *  buf,
size_t  len 
)
static

Definition at line 87 of file func_aes.c.

References AES_BLOCK_SIZE, args, ast_aes_decrypt(), ast_aes_encrypt(), ast_aes_set_decrypt_key(), ast_aes_set_encrypt_key(), AST_APP_ARG, ast_base64decode(), ast_base64encode(), ast_calloc, ast_copy_string(), AST_DECLARE_APP_ARGS, ast_free, ast_log(), AST_STANDARD_APP_ARGS, ast_strlen_zero(), LOG_ERROR, and LOG_WARNING.

89 {
90  unsigned char curblock[AES_BLOCK_SIZE] = { 0, };
91  char *tmp;
92  char *tmpP;
93  int data_len, encrypt;
94  ast_aes_encrypt_key ecx; /* AES 128 Encryption context */
96 
98  AST_APP_ARG(key);
99  AST_APP_ARG(data);
100  );
101 
103 
104  if (ast_strlen_zero(args.data) || ast_strlen_zero(args.key)) {
105  ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - missing argument!\n", cmd);
106  return -1;
107  }
108 
109  if (strlen(args.key) != AES_BLOCK_SIZE) { /* key must be of 16 characters in length, 128 bits */
110  ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - <key> parameter must be exactly 16 characters!\n", cmd);
111  return -1;
112  }
113 
114  ast_aes_set_encrypt_key((unsigned char *) args.key, &ecx); /* encryption: plaintext -> encryptedtext -> base64 */
115  ast_aes_set_decrypt_key((unsigned char *) args.key, &dcx); /* decryption: base64 -> encryptedtext -> plaintext */
116  tmp = ast_calloc(1, len); /* requires a tmp buffer for the base64 decode */
117  if (!tmp) {
118  ast_log(LOG_ERROR, "Unable to allocate memory for data\n");
119  return -1;
120  }
121  tmpP = tmp;
122  encrypt = strcmp("AES_DECRYPT", cmd); /* -1 if encrypting, 0 if decrypting */
123 
124  if (encrypt) { /* if decrypting first decode src to base64 */
125  ast_copy_string(tmp, args.data, len);
126  data_len = strlen(tmp);
127  } else {
128  data_len = ast_base64decode((unsigned char *) tmp, args.data, len);
129  }
130 
131  if (data_len >= len) { /* make sure to not go over buffer len */
132  ast_log(LOG_WARNING, "Syntax: %s(<keys>,<data>) - <data> exceeds buffer length. Result may be truncated!\n", cmd);
133  data_len = len - 1;
134  }
135 
136  while (data_len > 0) {
137  memset(curblock, 0, AES_BLOCK_SIZE);
138  memcpy(curblock, tmpP, (data_len < AES_BLOCK_SIZE) ? data_len : AES_BLOCK_SIZE);
139  if (encrypt) {
140  ast_aes_encrypt(curblock, (unsigned char *) tmpP, &ecx);
141  } else {
142  ast_aes_decrypt(curblock, (unsigned char *) tmpP, &dcx);
143  }
144  tmpP += AES_BLOCK_SIZE;
145  data_len -= AES_BLOCK_SIZE;
146  }
147 
148  if (encrypt) { /* if encrypting encode result to base64 */
149  ast_base64encode(buf, (unsigned char *) tmp, strlen(tmp), len);
150  } else {
151  memcpy(buf, tmp, len);
152  }
153  ast_free(tmp);
154 
155  return 0;
156 }
int ast_aes_set_encrypt_key(const unsigned char *key, ast_aes_encrypt_key *ctx)
Set an encryption key.
Definition: res_crypto.c:461
#define LOG_WARNING
Definition: logger.h:144
#define AST_DECLARE_APP_ARGS(name, arglist)
Declare a structure to hold an application&#39;s arguments.
Definition: app.h:572
#define AES_BLOCK_SIZE
Definition: func_aes.c:39
void ast_aes_decrypt(const unsigned char *in, unsigned char *out, const ast_aes_decrypt_key *ctx)
AES decrypt data.
Definition: res_crypto.c:476
AES_KEY ast_aes_encrypt_key
Definition: crypto.h:35
int ast_base64decode(unsigned char *dst, const char *src, int max)
Decode data from base64.
Definition: utils.c:279
void ast_aes_encrypt(const unsigned char *in, unsigned char *out, const ast_aes_encrypt_key *ctx)
AES encrypt data.
Definition: res_crypto.c:471
static force_inline int attribute_pure ast_strlen_zero(const char *s)
Definition: strings.h:63
#define LOG_ERROR
Definition: logger.h:155
int ast_base64encode(char *dst, const unsigned char *src, int srclen, int max)
Encode data in base64.
Definition: utils.c:357
static struct @350 args
int ast_aes_set_decrypt_key(const unsigned char *key, ast_aes_decrypt_key *ctx)
Set a decryption key.
Definition: res_crypto.c:466
static int len(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t buflen)
void ast_log(int level, const char *file, int line, const char *function, const char *fmt,...)
Used for sending a log message This is the standard logger function. Probably the only way you will i...
Definition: logger.c:1207
#define ast_free(a)
Definition: astmm.h:97
AES_KEY ast_aes_decrypt_key
Definition: crypto.h:36
#define ast_calloc(a, b)
Definition: astmm.h:82
void ast_copy_string(char *dst, const char *src, size_t size)
Size-limited null-terminating string copy.
Definition: strings.h:223
#define AST_APP_ARG(name)
Define an application argument.
Definition: app.h:555
#define AST_STANDARD_APP_ARGS(args, parse)
Performs the &#39;standard&#39; argument separation process for an application.
Definition: app.h:604
static int load_module ( void  )
static

Definition at line 174 of file func_aes.c.

References ast_custom_function_register, AST_MODULE_LOAD_DECLINE, and AST_MODULE_LOAD_SUCCESS.

175 {
179 }
static struct ast_custom_function aes_decrypt_function
Definition: func_aes.c:163
static struct ast_custom_function aes_encrypt_function
Definition: func_aes.c:158
#define ast_custom_function_register(acf)
Register a custom function.
Definition: pbx.h:1164
static int unload_module ( void  )
static

Definition at line 168 of file func_aes.c.

References ast_custom_function_unregister().

169 {
172 }
int ast_custom_function_unregister(struct ast_custom_function *acf)
Unregister a custom function.
Definition: pbx.c:3814
static struct ast_custom_function aes_decrypt_function
Definition: func_aes.c:163
static struct ast_custom_function aes_encrypt_function
Definition: func_aes.c:158

Variable Documentation

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_DEFAULT , .description = "AES dialplan functions" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = "ac1f6a56484a8820659555499174e588" , .load = load_module, .unload = unload_module, .nonoptreq = "res_crypto", }
static

Definition at line 185 of file func_aes.c.

struct ast_custom_function aes_decrypt_function
static
Initial value:
= {
.name = "AES_DECRYPT",
.read = aes_helper,
}
static int aes_helper(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
Definition: func_aes.c:87

Definition at line 163 of file func_aes.c.

struct ast_custom_function aes_encrypt_function
static
Initial value:
= {
.name = "AES_ENCRYPT",
.read = aes_helper,
}
static int aes_helper(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
Definition: func_aes.c:87

Definition at line 158 of file func_aes.c.

Definition at line 185 of file func_aes.c.