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 = ASTERISK_GPL_KEY , .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 191 of file func_aes.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 191 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 92 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, and LOG_WARNING.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 191 of file func_aes.c.

load_module()

static int load_module ( void  )

static

Definition at line 179 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 173 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 = ASTERISK_GPL_KEY , .buildopt_sum = AST_BUILDOPT_SUM, .support_level = AST_MODULE_SUPPORT_CORE, .load = load_module, .unload = unload_module, .requires = "res_crypto", }

static

Definition at line 191 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 168 of file func_aes.c.

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

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 163 of file func_aes.c.

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

Referenced by load_module(), and unload_module().

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 191 of file func_aes.c.