/*
* return human readable permission string. Never returns NULL.
*/
-char *cmd_perms_itohuman(unsigned int perms)
+static char *cmd_perms_itohuman(unsigned int perms)
{
char *msg = para_malloc(5 * sizeof(char));
/*
* compute status bar string. Never returns NULL
*/
-char *get_sb_string(struct misc_meta_data *nmmd)
+static char *get_sb_string(struct misc_meta_data *nmmd)
{
char *base, *ret;
long long unsigned secs = 0, rsecs = 0, percent = 0;
}
perms = cmd_perms_itohuman(cmd->perms);
ret = send_va_buffer(fd,
- "NAME\n\t%s - %s\n"
- "SYNOPSIS\n\t para_client %s\n"
- "DESCRIPTION\n%s\n"
- "HANDLER\n"
- "This command is handled by %s.\n\n"
- "PERMISSIONS\n"
- "Needed privileges for %s: %s\n",
+ "%s - %s\n\n"
+ "handler: %s\n"
+ "permissions: %s\n"
+ "usage: %s\n\n"
+ "%s\n",
argv[1],
cmd->description,
- cmd->synopsis,
- cmd->help,
handler,
- argv[1],
- perms
+ perms,
+ cmd->usage,
+ cmd->help
);
free(perms);
free(handler);
return get_cmd_ptr(buf, NULL);
}
-long int para_rand(long unsigned max)
+static long int para_rand(long unsigned max)
{
return (long int) ((max + 0.0) * (random() / (RAND_MAX + 1.0)));
}
RC4(&rc4_send_key, len, indata, outdata);
}
+/**
+ * perform user authentication and execute a command
+ *
+ * \param fd the file descriptor to send output to
+ * \param addr socket address info of peer
+ *
+ * \return EXIT_SUCCESS or EXIT_FAILURE
+ *
+ * Whenever para_server accepts an incoming tcp connection on
+ * the port it listens on, it forks and the resulting child
+ * calls this function.
+ *
+ * An RSA-based challenge/response is used to authenticate
+ * the peer. It that authentication succeeds, a random RC4
+ * session key is generated and sent back to the peer,
+ * encrypted with its RSA public key. From this point on,
+ * all transfers are crypted with this session key.
+ *
+ * Next it is checked if the peer supplied a valid server
+ * command or a command for the audio file selector currently
+ * in use. If yes, and if the user has sufficient
+ * permissions to execute that command, the function calls
+ * the corresponding command handler which does argument
+ * checking and further processing.
+ *
+ * In order to cope with a DOS attacks, a timeout is set up
+ * which terminates the function if the connection was not
+ * authenticated when the timeout expires.
+ *
+ * \sa alarm(2), rc4(3), crypt.c, crypt.h
+ */
int handle_connect(int fd, struct sockaddr_in *addr)
{
int numbytes, ret, argc, use_rc4 = 0;