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"

Include dependency graph for func_aes.c:

Go to the source code of this file.

Defines

#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 = AST_BUILDOPT_SUM, .support_level = AST_MODULE_SUPPORT_CORE, .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 <dvossel@digium.com>

Definition in file func_aes.c.


Define 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 186 of file func_aes.c.

static void __unreg_module ( void   )  [static]

Definition at line 186 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, LOG_WARNING, and tmp().

00089 {
00090    unsigned char curblock[AES_BLOCK_SIZE] = { 0, };
00091    char *tmp;
00092    char *tmpP;
00093    int data_len, encrypt;
00094    ast_aes_encrypt_key ecx;                        /*  AES 128 Encryption context */
00095    ast_aes_decrypt_key dcx;
00096 
00097    AST_DECLARE_APP_ARGS(args,
00098       AST_APP_ARG(key);
00099       AST_APP_ARG(data);
00100    );
00101 
00102    AST_STANDARD_APP_ARGS(args, data);
00103 
00104    if (ast_strlen_zero(args.data) || ast_strlen_zero(args.key)) {
00105       ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - missing argument!\n", cmd);
00106       return -1;
00107    }
00108 
00109    if (strlen(args.key) != AES_BLOCK_SIZE) {        /* key must be of 16 characters in length, 128 bits */
00110       ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - <key> parameter must be exactly 16 characters!\n", cmd);
00111       return -1;
00112    }
00113 
00114    ast_aes_set_encrypt_key((unsigned char *) args.key, &ecx);   /* encryption:  plaintext -> encryptedtext -> base64 */
00115    ast_aes_set_decrypt_key((unsigned char *) args.key, &dcx);   /* decryption:  base64 -> encryptedtext -> plaintext */
00116    tmp = ast_calloc(1, len);                     /* requires a tmp buffer for the base64 decode */
00117    if (!tmp) {
00118       ast_log(LOG_ERROR, "Unable to allocate memory for data\n");
00119       return -1;
00120    }
00121    tmpP = tmp;
00122    encrypt = strcmp("AES_DECRYPT", cmd);           /* -1 if encrypting, 0 if decrypting */
00123 
00124    if (encrypt) {                                  /* if decrypting first decode src to base64 */
00125       ast_copy_string(tmp, args.data, len);
00126       data_len = strlen(tmp);
00127    } else {
00128       data_len = ast_base64decode((unsigned char *) tmp, args.data, len);
00129    }
00130 
00131    if (data_len >= len) {                        /* make sure to not go over buffer len */
00132       ast_log(LOG_WARNING, "Syntax: %s(<keys>,<data>) - <data> exceeds buffer length.  Result may be truncated!\n", cmd);
00133       data_len = len - 1;
00134    }
00135 
00136    while (data_len > 0) {
00137       memset(curblock, 0, AES_BLOCK_SIZE);
00138       memcpy(curblock, tmpP, (data_len < AES_BLOCK_SIZE) ? data_len : AES_BLOCK_SIZE);
00139       if (encrypt) {
00140          ast_aes_encrypt(curblock, (unsigned char *) tmpP, &ecx);
00141       } else {
00142          ast_aes_decrypt(curblock, (unsigned char *) tmpP, &dcx);
00143       }
00144       tmpP += AES_BLOCK_SIZE;
00145       data_len -= AES_BLOCK_SIZE;
00146    }
00147 
00148    if (encrypt) {                            /* if encrypting encode result to base64 */
00149       ast_base64encode(buf, (unsigned char *) tmp, strlen(tmp), len);
00150    } else {
00151       memcpy(buf, tmp, len);
00152    }
00153    ast_free(tmp);
00154 
00155    return 0;
00156 }

static int load_module ( void   )  [static]

static int unload_module ( void   )  [static]

Definition at line 168 of file func_aes.c.

References ast_custom_function_unregister().


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 = AST_BUILDOPT_SUM, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, .nonoptreq = "res_crypto", } [static]

Definition at line 186 of file func_aes.c.

Initial value:

 {
   .name = "AES_DECRYPT",
   .read = aes_helper,
}

Definition at line 163 of file func_aes.c.

Initial value:

 {
   .name = "AES_ENCRYPT",
   .read = aes_helper,
}

Definition at line 158 of file func_aes.c.

Definition at line 186 of file func_aes.c.


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