fa69f110d
Mike Frysinger
2005-04-17
Subject
import fakeidentd module started by Thomas Lundquist
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include/applets.h +3 -0include/usage.h +7 -0networking/Config.in +7 -0networking/Makefile.in +1 -0networking/fakeidentd.c +441 -0
include/applets.h+3 -0
| @@ -185,6 +185,9 @@ | |
| #ifdef CONFIG_EXPR | |
| APPLET(expr, expr_main, _BB_DIR_USR_BIN, _BB_SUID_NEVER) | |
| #endif | |
| + | #ifdef CONFIG_FAKEIDENTD |
| + | APPLET(fakeidentd, fakeidentd_main, _BB_DIR_USR_SBIN, _BB_SUID_NEVER) |
| + | #endif |
| #ifdef CONFIG_FALSE | |
| APPLET(false, false_main, _BB_DIR_BIN, _BB_SUID_NEVER) | |
| #endif | |
include/usage.h+7 -0
| @@ -575,6 +575,13 @@ | |
| "\\( and \\) or null; if \\( and \\) are not used, they return the number \n" \ | |
| "of characters matched or 0." | |
| + | #define fakeidentd_trivial_usage \ |
| + | "[-b ip] [STRING]" |
| + | #define fakeidentd_full_usage \ |
| + | "Returns a set string to auth requests\n\n"\ |
| + | "\t-b\tBind to ip address\n"\ |
| + | "\tSTRING\tThe ident answer string (default is nobody)" |
| + | |
| #define false_trivial_usage \ | |
| "" | |
| #define false_full_usage \ | |
networking/Config.in+7 -0
| @@ -18,6 +18,13 @@ config CONFIG_ARPING | |
| help | |
| Ping hosts by ARP packets | |
| + | config CONFIG_FAKEIDENTD |
| + | bool "fakeidentd" |
| + | default n |
| + | help |
| + | fakeidentd listens to the ident port and returns a set fake |
| + | value whatever it gets. |
| + | |
| config CONFIG_FTPGET | |
| bool "ftpget" | |
| default n | |
networking/Makefile.in+1 -0
| @@ -24,6 +24,7 @@ endif | |
| srcdir=$(top_srcdir)/networking | |
| NETWORKING-y:= | |
| NETWORKING-$(CONFIG_ARPING) += arping.o | |
| + | NETWORKING-$(CONFIG_FAKEIDENTD) += fakeidentd.o |
| NETWORKING-$(CONFIG_FTPGET) += ftpgetput.o | |
| NETWORKING-$(CONFIG_FTPPUT) += ftpgetput.o | |
| NETWORKING-$(CONFIG_HOSTNAME) += hostname.o | |
networking/fakeidentd.c+441 -0
| @@ -0,0 +1,441 @@ | |
| + | /* vi: set sw=4 ts=4: */ |
| + | /* |
| + | * A fake identd server |
| + | * |
| + | * Adapted to busybox by Thomas Lundquist <[email protected]> |
| + | * Original Author: Tomi Ollila <[email protected]> |
| + | * http://www.guru-group.fi/~too/sw/ |
| + | * |
| + | * This program 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 2 of the License, or |
| + | * (at your option) any later version. |
| + | * |
| + | * This program 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 this program; if not, write to the Free Software |
| + | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| + | * |
| + | */ |
| + | |
| + | #include <unistd.h> |
| + | #include <stdio.h> |
| + | #include <stdlib.h> |
| + | #include <stdarg.h> |
| + | #include <string.h> |
| + | #include <fcntl.h> |
| + | #include <signal.h> |
| + | #include <sys/syslog.h> |
| + | |
| + | #include <pwd.h> |
| + | #include <netdb.h> |
| + | |
| + | #include <sys/syslog.h> |
| + | #include <sys/types.h> |
| + | #include <sys/time.h> |
| + | #include <time.h> |
| + | #include <sys/socket.h> |
| + | #include <netinet/in.h> |
| + | #include <errno.h> |
| + | #include <arpa/inet.h> |
| + | #include <sys/uio.h> |
| + | |
| + | #include "busybox.h" |
| + | |
| + | #define IDENT_PORT 113 |
| + | #define MAXCONNS 20 |
| + | #define MAXIDLETIME 45 |
| + | |
| + | static const char ident_substr[] = " : USERID : UNIX : "; |
| + | static const int ident_substr_len = sizeof(ident_substr) - 1; |
| + | #define PIDFILE "/var/run/identd.pid" |
| + | |
| + | /* |
| + | * We have to track the 'first connection socket' so that we |
| + | * don't go around closing file descriptors for non-clients. |
| + | * |
| + | * descriptor setup normally |
| + | * 0 = server socket |
| + | * 1 = syslog fd (hopefully -- otherwise this won't work) |
| + | * 2 = connection socket after detached from tty. standard error before that |
| + | * 3 - 2 + MAXCONNS = rest connection sockets |
| + | * |
| + | * To try to make sure that syslog fd is what is "requested", the that fd |
| + | * is closed before openlog() call. It can only severely fail if fd 0 |
| + | * is initially closed. |
| + | */ |
| + | #define FCS 2 |
| + | |
| + | /* |
| + | * FD of the connection is always the index of the connection structure |
| + | * in `conns' array + FCS |
| + | */ |
| + | struct { |
| + | char buf[20]; |
| + | int len; |
| + | time_t lasttime; |
| + | } conns[MAXCONNS]; |
| + | |
| + | /* When using global variables, bind those at least to a structure. */ |
| + | struct { |
| + | const char *identuser; |
| + | fd_set readfds; |
| + | int conncnt; |
| + | } G; |
| + | |
| + | /* |
| + | * Prototypes |
| + | */ |
| + | static void reply(int s, char *buf); |
| + | static void replyError(int s, char *buf); |
| + | |
| + | static const char *nobodystr = "nobody"; /* this needs to be declared like this */ |
| + | static char *bind_ip_address = "0.0.0.0"; |
| + | |
| + | static inline void movefd(int from, int to) |
| + | { |
| + | if (from != to) { |
| + | dup2(from, to); |
| + | close(from); |
| + | } |
| + | } |
| + | |
| + | static void inetbind(void) |
| + | { |
| + | int s, port; |
| + | struct sockaddr_in addr; |
| + | int len = sizeof(addr); |
| + | int one = 1; |
| + | struct servent *se; |
| + | |
| + | if ((se = getservbyname("identd", "tcp")) == NULL) |
| + | port = IDENT_PORT; |
| + | else |
| + | port = se->s_port; |
| + | |
| + | if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) |
| + | bb_perror_msg_and_die("Cannot create server socket"); |
| + | |
| + | setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); |
| + | |
| + | memset(&addr, 0, sizeof(addr)); |
| + | addr.sin_addr.s_addr = inet_addr(bind_ip_address); |
| + | addr.sin_family = AF_INET; |
| + | addr.sin_port = htons(port); |
| + | |
| + | if (bind(s, (struct sockaddr *)&addr, len) < 0) |
| + | bb_perror_msg_and_die("Cannot bind() port %i", IDENT_PORT); |
| + | |
| + | if (listen(s, 5) < 0) |
| + | bb_perror_msg_and_die("Cannot listen() on port %i", IDENT_PORT); |
| + | |
| + | movefd(s, 0); |
| + | } |
| + | |
| + | static void delpidfile(void) |
| + | { |
| + | /* |
| + | * Usually nobody has no write/delete access to directory /var/run/ |
| + | * therefore if file cannot be deleted, it is truncated |
| + | */ |
| + | if (unlink(PIDFILE) < 0) |
| + | close(open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644)); |
| + | } |
| + | |
| + | static void handlexitsigs(int signum) |
| + | { |
| + | delpidfile(); |
| + | exit(0); |
| + | } |
| + | |
| + | /* May succeed. If not, won't care. */ |
| + | static void writepid(uid_t nobody, uid_t nogrp) |
| + | { |
| + | char buf[24]; |
| + | int fd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0664); |
| + | |
| + | if (fd < 0) |
| + | return; |
| + | |
| + | snprintf(buf, 23, "%d\n", getpid()); |
| + | write(fd, buf, strlen(buf)); |
| + | fchown(fd, nobody, nogrp); |
| + | close(fd); |
| + | |
| + | /* should this handle ILL, ... (see signal(7)) */ |
| + | signal(SIGTERM, handlexitsigs); |
| + | signal(SIGINT, handlexitsigs); |
| + | signal(SIGQUIT, handlexitsigs); |
| + | } |
| + | |
| + | /* return 0 as parent, 1 as child */ |
| + | static int godaemon(void) |
| + | { |
| + | uid_t nobody, nogrp; |
| + | struct passwd *pw; |
| + | |
| + | switch (fork()) { |
| + | case -1: |
| + | bb_perror_msg_and_die("Could not fork"); |
| + | |
| + | case 0: |
| + | pw = getpwnam(nobodystr); |
| + | if (pw == NULL) |
| + | bb_error_msg_and_die("Cannot find uid/gid of user '%s'", nobodystr); |
| + | nobody = pw->pw_uid; |
| + | nogrp = pw->pw_gid; |
| + | writepid(nobody, nogrp); |
| + | |
| + | close(0); |
| + | inetbind(); |
| + | if (setgid(nogrp)) bb_error_msg_and_die("Could not setgid()"); |
| + | if (setegid(nogrp)) bb_error_msg_and_die("Could not setegid()"); |
| + | if (setuid(nobody)) bb_error_msg_and_die("Could not setuid()"); |
| + | if (seteuid(nobody)) bb_error_msg_and_die("Could not seteuid()"); |
| + | close(1); |
| + | close(2); |
| + | |
| + | signal(SIGHUP, SIG_IGN); |
| + | signal(SIGPIPE, SIG_IGN); /* connection closed when writing (raises ???) */ |
| + | |
| + | setsid(); |
| + | |
| + | openlog(bb_applet_name, 0, LOG_DAEMON); |
| + | return 1; |
| + | } |
| + | |
| + | return 0; |
| + | } |
| + | |
| + | static void deleteConn(int s) |
| + | { |
| + | int i = s - FCS; |
| + | |
| + | close(s); |
| + | |
| + | G.conncnt--; |
| + | |
| + | /* |
| + | * Most of the time there is 0 connections. Most often that there |
| + | * is connections, there is just one connection. When this one connection |
| + | * closes, i == G.conncnt = 0 -> no copying. |
| + | * When there is more than one connection, the oldest connections closes |
| + | * earlier on average. When this happens, the code below starts copying |
| + | * the connection structure w/ highest index to the place which which is |
| + | * just deleted. This means that the connection structures are no longer |
| + | * in chronological order. I'd quess this means that when there is more |
| + | * than 1 connection, on average every other connection structure needs |
| + | * to be copied over the time all these connections are deleted. |
| + | */ |
| + | if (i != G.conncnt) { |
| + | memcpy(&conns[i], &conns[G.conncnt], sizeof(conns[0])); |
| + | movefd(G.conncnt + FCS, s); |
| + | } |
| + | |
| + | FD_CLR(G.conncnt + FCS, &G.readfds); |
| + | } |
| + | |
| + | static int closeOldest(void) |
| + | { |
| + | time_t min = conns[0].lasttime; |
| + | int idx = 0; |
| + | int i; |
| + | |
| + | for (i = 1; i < MAXCONNS; i++) |
| + | if (conns[i].lasttime < min) |
| + | idx = i; |
| + | |
| + | replyError(idx + FCS, "X-SERVER-TOO-BUSY"); |
| + | close(idx + FCS); |
| + | |
| + | return idx; |
| + | } |
| + | |
| + | static int checkInput(char *buf, int len, int l) |
| + | { |
| + | int i; |
| + | for (i = len; i < len + l; ++i) |
| + | if (buf[i] == '\n') |
| + | return 1; |
| + | return 0; |
| + | } |
| + | |
| + | int fakeidentd_main(int argc, char **argv) |
| + | { |
| + | int flag; |
| + | |
| + | memset(conns, 0, sizeof(conns)); |
| + | memset(&G, 0, sizeof(G)); |
| + | FD_ZERO(&G.readfds); |
| + | FD_SET(0, &G.readfds); |
| + | |
| + | /* handle -b <ip> parameter */ |
| + | while ((flag = getopt(argc, argv, "b:")) != EOF) { |
| + | switch (flag) { |
| + | case 'b': |
| + | bind_ip_address = optarg; |
| + | break; |
| + | default: |
| + | bb_show_usage(); |
| + | } |
| + | } |
| + | /* handle optional REPLY STRING */ |
| + | if (optind < argc) |
| + | G.identuser = argv[optind]; |
| + | else |
| + | G.identuser = nobodystr; |
| + | |
| + | /* daemonize and have the parent return */ |
| + | if (godaemon() == 0) |
| + | return 0; |
| + | |
| + | while (1) { |
| + | fd_set rfds = G.readfds; |
| + | struct timeval tv = { 15, 0 }; |
| + | int i; |
| + | int tim = time(NULL); |
| + | |
| + | select(G.conncnt + FCS, &rfds, NULL, NULL, G.conncnt? &tv: NULL); |
| + | |
| + | for (i = G.conncnt - 1; i >= 0; i--) { |
| + | int s = i + FCS; |
| + | |
| + | if (FD_ISSET(s, &rfds)) { |
| + | char *buf = conns[i].buf; |
| + | unsigned int len = conns[i].len; |
| + | unsigned int l; |
| + | |
| + | if ((l = read(s, buf + len, sizeof(conns[0].buf) - len)) > 0) { |
| + | if (checkInput(buf, len, l)) { |
| + | reply(s, buf); |
| + | goto deleteconn; |
| + | } else if (len + l >= sizeof(conns[0].buf)) { |
| + | replyError(s, "X-INVALID-REQUEST"); |
| + | goto deleteconn; |
| + | } else { |
| + | conns[i].len += l; |
| + | } |
| + | } else { |
| + | goto deleteconn; |
| + | } |
| + | |
| + | conns[i].lasttime = tim; |
| + | continue; |
| + | |
| + | deleteconn: |
| + | deleteConn(s); |
| + | } else { |
| + | /* implement as time_after() in linux kernel sources ... */ |
| + | if (conns[i].lasttime + MAXIDLETIME <= tim) { |
| + | replyError(s, "X-TIMEOUT"); |
| + | deleteConn(s); |
| + | } |
| + | } |
| + | } |
| + | |
| + | if (FD_ISSET(0, &rfds)) { |
| + | int s = accept(0, NULL, 0); |
| + | |
| + | if (s < 0) { |
| + | if (errno != EINTR) /* EINTR */ |
| + | syslog(LOG_ERR, "accept: %s", strerror(errno)); |
| + | } else { |
| + | if (G.conncnt == MAXCONNS) |
| + | i = closeOldest(); |
| + | else |
| + | i = G.conncnt++; |
| + | |
| + | movefd(s, i + FCS); /* move if not already there */ |
| + | FD_SET(i + FCS, &G.readfds); |
| + | |
| + | conns[i].len = 0; |
| + | conns[i].lasttime = time(NULL); |
| + | } |
| + | } |
| + | } /* end of while(1) */ |
| + | |
| + | return 0; |
| + | } |
| + | |
| + | static int parseAddrs(char *ptr, char **myaddr, char **heraddr); |
| + | static void reply(int s, char *buf) |
| + | { |
| + | char *myaddr, *heraddr; |
| + | |
| + | myaddr = heraddr = NULL; |
| + | |
| + | if (parseAddrs(buf, &myaddr, &heraddr)) |
| + | replyError(s, "X-INVALID-REQUEST"); |
| + | else { |
| + | struct iovec iv[6]; |
| + | iv[0].iov_base = myaddr; iv[0].iov_len = strlen(myaddr); |
| + | iv[1].iov_base = ", "; iv[1].iov_len = 2; |
| + | iv[2].iov_base = heraddr; iv[2].iov_len = strlen(heraddr); |
| + | iv[3].iov_base = (void *)ident_substr; iv[3].iov_len = ident_substr_len; |
| + | iv[4].iov_base = (void *)G.identuser; iv[4].iov_len = strlen(G.identuser); |
| + | iv[5].iov_base = "\r\n"; iv[5].iov_len = 2; |
| + | writev(s, iv, 6); |
| + | } |
| + | } |
| + | |
| + | static void replyError(int s, char *buf) |
| + | { |
| + | struct iovec iv[3]; |
| + | iv[0].iov_base = "0, 0 : ERROR : "; iv[0].iov_len = 15; |
| + | iv[1].iov_base = buf; iv[1].iov_len = strlen(buf); |
| + | iv[2].iov_base = "\r\n"; iv[2].iov_len = 2; |
| + | writev(s, iv, 3); |
| + | } |
| + | |
| + | static int chmatch(char c, char *chars) |
| + | { |
| + | for (; *chars; chars++) |
| + | if (c == *chars) |
| + | return 1; |
| + | return 0; |
| + | } |
| + | |
| + | static int skipchars(char **p, char *chars) |
| + | { |
| + | while (chmatch(**p, chars)) |
| + | (*p)++; |
| + | if (**p == '\r' || **p == '\n') |
| + | return 0; |
| + | return 1; |
| + | } |
| + | |
| + | static int parseAddrs(char *ptr, char **myaddr, char **heraddr) |
| + | { |
| + | /* parse <port-on-server> , <port-on-client> */ |
| + | |
| + | if (!skipchars(&ptr, " \t")) |
| + | return -1; |
| + | |
| + | *myaddr = ptr; |
| + | |
| + | if (!skipchars(&ptr, "1234567890")) |
| + | return -1; |
| + | |
| + | if (!chmatch(*ptr, " \t,")) |
| + | return -1; |
| + | |
| + | *ptr++ = '\0'; |
| + | |
| + | if (!skipchars(&ptr, " \t,") ) |
| + | return -1; |
| + | |
| + | *heraddr = ptr; |
| + | |
| + | skipchars(&ptr, "1234567890"); |
| + | |
| + | if (!chmatch(*ptr, " \n\r")) |
| + | return -1; |
| + | |
| + | *ptr = '\0'; |
| + | |
| + | return 0; |
| + | } |