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Diffstat (limited to 'daemon.h')
| -rw-r--r-- | daemon.h | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/daemon.h b/daemon.h new file mode 100644 index 0000000..afe1a27 --- /dev/null +++ b/daemon.h @@ -0,0 +1,173 @@ +/* + * uAnytun + * + * uAnytun is a tiny implementation of SATP. Unlike Anytun which is a full + * featured implementation uAnytun has no support for multiple connections + * or synchronisation. It is a small single threaded implementation intended + * to act as a client on small platforms. + * The secure anycast tunneling protocol (satp) defines a protocol used + * for communication between any combination of unicast and anycast + * tunnel endpoints. It has less protocol overhead than IPSec in Tunnel + * mode and allows tunneling of every ETHER TYPE protocol (e.g. + * ethernet, ip, arp ...). satp directly includes cryptography and + * message authentication based on the methodes used by SRTP. It is + * intended to deliver a generic, scaleable and secure solution for + * tunneling and relaying of packets of any protocol. + * + * + * Copyright (C) 2007-2008 Christian Pointner <equinox@anytun.org> + * + * This file is part of uAnytun. + * + * uAnytun is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * any later version. + * + * uAnytun is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with uAnytun. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef _DAEMON_H_ +#define _DAEMON_H_ + +#include <poll.h> +#include <fcntl.h> +#include <pwd.h> +#include <grp.h> +#include <sys/wait.h> +#include <sys/stat.h> +#include <unistd.h> + +struct priv_info_struct { + struct passwd* pw_; + struct group* gr_; +}; +typedef struct priv_info_struct priv_info_t; + +int priv_init(priv_info_t* priv, const char* username, const char* groupname) +{ + if(!priv) + return -1; + + priv->pw_ = NULL; + priv->gr_ = NULL; + + priv->pw_ = getpwnam(username); + if(!priv->pw_) { + log_printf(ERROR, "unkown user %s", username); + return -1; + } + + if(groupname) + priv->gr_ = getgrnam(groupname); + else + priv->gr_ = getgrgid(priv->pw_->pw_gid); + + if(!priv->gr_) { + log_printf(ERROR, "unkown group %s", groupname); + return -1; + } + + return 0; +} + +int priv_drop(priv_info_t* priv) +{ + if(!priv || !priv->pw_ || !priv->gr_) { + log_printf(ERROR, "privileges not initialized properly"); + return -1; + } + + if(setgid(priv->gr_->gr_gid)) { + log_printf(ERROR, "setgid('%s') failed: %s", priv->gr_->gr_name, strerror(errno)); + return -1; + } + + gid_t gr_list[1]; + gr_list[0] = priv->gr_->gr_gid; + if(setgroups (1, gr_list)) { + log_printf(ERROR, "setgroups(['%s']) failed: %s", priv->gr_->gr_name, strerror(errno)); + return -1; + } + + if(setuid(priv->pw_->pw_uid)) { + log_printf(ERROR, "setuid('%s') failed: %s", priv->pw_->pw_name, strerror(errno)); + return -1; + } + + log_printf(NOTICE, "dropped privileges to %s:%s", priv->pw_->pw_name, priv->gr_->gr_name); + return 0; +} + + +int do_chroot(const char* chrootdir) +{ + if(getuid() != 0) { + log_printf(ERROR, "this programm has to be run as root in order to run in a chroot"); + return -1; + } + + if(chroot(chrootdir)) { + log_printf(ERROR, "can't chroot to %s: %s", chrootdir, strerror(errno)); + return -1; + } + log_printf(NOTICE, "we are in chroot jail (%s) now", chrootdir); + if(chdir("/")) { + log_printf(ERROR, "can't change to /: %s", strerror(errno)); + return -1; + } +} + +void daemonize() +{ + pid_t pid; + + pid = fork(); + if(pid < 0) { + log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno)); + exit(-1); + } + if(pid) exit(0); + + umask(0); + + if(setsid() < 0) { + log_printf(ERROR, "daemonizing failed at setsid(): %s, exitting", strerror(errno)); + exit(-1); + } + + pid = fork(); + if(pid < 0) { + log_printf(ERROR, "daemonizing failed at fork(): %s, exitting", strerror(errno)); + exit(-1); + } + if(pid) exit(0); + + if ((chdir("/")) < 0) { + log_printf(ERROR, "daemonizing failed at chdir(): %s, exitting", strerror(errno)); + exit(-1); + } + + int fd; + for (fd=0;fd<=2;fd++) // close all file descriptors + close(fd); + fd = open("/dev/null",O_RDWR); // stdin + if(fd == -1) + log_printf(WARNING, "can't open stdin (chroot and no link to /dev/null?)"); + else { + if(dup(fd) == -1) // stdout + log_printf(WARNING, "can't open stdout"); + if(dup(fd) == -1) // stderr + log_printf(WARNING, "can't open stderr"); + } + umask(027); +} + +#endif + |