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.

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)
struct ast_module *	AST_MODULE_SELF_SYM (void)
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, .requires = "res_crypto", }
static struct ast_custom_function	aes_decrypt_function
static struct ast_custom_function	aes_encrypt_function
static const struct ast_module_info *	ast_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

AES_BLOCK_SIZE

#define AES_BLOCK_SIZE   16

Definition at line 38 of file func_aes.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 185 of file func_aes.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 185 of file func_aes.c.

aes_helper()

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

static

Definition at line 86 of file func_aes.c.

{
    unsigned char curblock[AES_BLOCK_SIZE] = { 0, };
    char *tmp;
    char *tmpP;
    int data_len, encrypt;
    ast_aes_encrypt_key ecx;                        /*  AES 128 Encryption context */
    ast_aes_decrypt_key dcx;
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(key);
        AST_APP_ARG(data);
    );
 
    AST_STANDARD_APP_ARGS(args, data);
 
    if (ast_strlen_zero(args.data) || ast_strlen_zero(args.key)) {
        ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - missing argument!\n", cmd);
        return -1;
    }
 
    if (strlen(args.key) != AES_BLOCK_SIZE) {        /* key must be of 16 characters in length, 128 bits */
        ast_log(LOG_WARNING, "Syntax: %s(<key>,<data>) - <key> parameter must be exactly 16 characters!\n", cmd);
        return -1;
    }
 
    ast_aes_set_encrypt_key((unsigned char *) args.key, &ecx);   /* encryption:  plaintext -> encryptedtext -> base64 */
    ast_aes_set_decrypt_key((unsigned char *) args.key, &dcx);   /* decryption:  base64 -> encryptedtext -> plaintext */
    tmp = ast_calloc(1, len);                     /* requires a tmp buffer for the base64 decode */
    if (!tmp) {
        ast_log(LOG_ERROR, "Unable to allocate memory for data\n");
        return -1;
    }
    tmpP = tmp;
    encrypt = strcmp("AES_DECRYPT", cmd);           /* -1 if encrypting, 0 if decrypting */
 
    if (encrypt) {                                  /* if decrypting first decode src to base64 */
        ast_copy_string(tmp, args.data, len);
        data_len = strlen(tmp);
    } else {
        data_len = ast_base64decode((unsigned char *) tmp, args.data, len);
    }
 
    if (data_len >= len) {                        /* make sure to not go over buffer len */
        ast_log(LOG_WARNING, "Syntax: %s(<keys>,<data>) - <data> exceeds buffer length.  Result may be truncated!\n", cmd);
        data_len = len - 1;
    }
 
    while (data_len > 0) {
        memset(curblock, 0, AES_BLOCK_SIZE);
        memcpy(curblock, tmpP, (data_len < AES_BLOCK_SIZE) ? data_len : AES_BLOCK_SIZE);
        if (encrypt) {
            ast_aes_encrypt(curblock, (unsigned char *) tmpP, &ecx);
        } else {
            ast_aes_decrypt(curblock, (unsigned char *) tmpP, &dcx);
        }
        tmpP += AES_BLOCK_SIZE;
        data_len -= AES_BLOCK_SIZE;
    }
 
    if (encrypt) {                            /* if encrypting encode result to base64 */
        ast_base64encode(buf, (unsigned char *) tmp, tmpP - tmp, len);
    } else {
        memcpy(buf, tmp, len);
    }
    ast_free(tmp);
 
    return 0;
}

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(), buf, len(), LOG_ERROR, LOG_WARNING, and tmp().

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 185 of file func_aes.c.

load_module()

static int load_module ( void  )

static

Definition at line 173 of file func_aes.c.

{
    int res = ast_custom_function_register(&aes_decrypt_function);
    res |= ast_custom_function_register(&aes_encrypt_function);
    return res ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS;
}

References aes_decrypt_function, aes_encrypt_function, ast_custom_function_register, AST_MODULE_LOAD_DECLINE, and AST_MODULE_LOAD_SUCCESS.

unload_module()

static int unload_module ( void  )

static

Definition at line 167 of file func_aes.c.

{
    int res = ast_custom_function_unregister(&aes_decrypt_function);
    return res | ast_custom_function_unregister(&aes_encrypt_function);
}

References aes_decrypt_function, aes_encrypt_function, and ast_custom_function_unregister().

Variable Documentation

__mod_info

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, .requires = "res_crypto", }

static

Definition at line 185 of file func_aes.c.

aes_decrypt_function

struct ast_custom_function aes_decrypt_function

static

Initial value:

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

Definition at line 162 of file func_aes.c.

Referenced by load_module(), and unload_module().

aes_encrypt_function

struct ast_custom_function aes_encrypt_function

static

Initial value:

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

Definition at line 157 of file func_aes.c.

Referenced by load_module(), and unload_module().

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 185 of file func_aes.c.