/* -- unixpw.c -- */ #ifdef __linux__ /* some conflict with _XOPEN_SOURCE */ extern int grantpt(int); extern int unlockpt(int); extern char *ptsname(int); extern char *crypt(const char*, const char *); #endif #include "x11vnc.h" #include "scan.h" #include "cleanup.h" #include "xinerama.h" #include #if LIBVNCSERVER_HAVE_FORK #if LIBVNCSERVER_HAVE_SYS_WAIT_H && LIBVNCSERVER_HAVE_WAITPID #define UNIXPW_SU #endif #endif #if LIBVNCSERVER_HAVE_PWD_H && LIBVNCSERVER_HAVE_GETPWNAM #if LIBVNCSERVER_HAVE_CRYPT || LIBVNCSERVER_HAVE_LIBCRYPT #define UNIXPW_CRYPT #endif #endif #if LIBVNCSERVER_HAVE_SYS_IOCTL_H #include #endif #if LIBVNCSERVER_HAVE_TERMIOS_H #include #endif #if LIBVNCSERVER_HAVE_SYS_STROPTS_H #include #endif #if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) #define IS_BSD #endif void unixpw_screen(int init); void unixpw_keystroke(rfbBool down, rfbKeySym keysym, int init); void unixpw_accept(char *user); void unixpw_deny(void); int su_verify(char *user, char *pass); int crypt_verify(char *user, char *pass); static int white(void); static int text_x(void); static int text_y(void); static void set_db(void); static void unixpw_verify(char *user, char *pass); int unixpw_in_progress = 0; time_t unixpw_last_try_time = 0; rfbClientPtr unixpw_client = NULL; static int in_login = 0, in_passwd = 0, tries = 0; static int char_row = 0, char_col = 0; static int char_x = 0, char_y = 0, char_w = 8, char_h = 16; static int db = 0; static int white(void) { static unsigned long black_pix = 0, white_pix = 1, set = 0; if (depth <= 8 && ! set) { X_LOCK; black_pix = BlackPixel(dpy, scr); white_pix = WhitePixel(dpy, scr); X_UNLOCK; set = 1; } if (depth <= 8) { return (int) white_pix; } else if (depth < 24) { return 0xffff; } else { return 0xffffff; } } static int text_x(void) { return char_x + char_col * char_w; } static int text_y(void) { return char_y + char_row * char_h; } void unixpw_screen(int init) { if (unixpw_nis) { #ifndef UNIXPW_CRYPT rfbLog("-unixpw_nis is not supported on this OS/machine\n"); clean_up_exit(1); #endif } else { #ifndef UNIXPW_SU rfbLog("-unixpw is not supported on this OS/machine\n"); clean_up_exit(1); #endif } if (init) { int x, y; char log[] = "login: "; zero_fb(0, 0, dpy_x, dpy_y); x = nfix(dpy_x / 2 - strlen(log) * char_w, dpy_x); y = dpy_y / 4; rfbDrawString(screen, &default8x16Font, x, y, log, white()); char_x = x; char_y = y; char_col = strlen(log); char_row = 0; } mark_rect_as_modified(0, 0, dpy_x, dpy_y, 0); } #ifdef MAXPATHLEN static char slave_str[MAXPATHLEN]; #else static char slave_str[4096]; #endif static int used_get_pty_ptmx = 0; char *get_pty_ptmx(int *fd_p) { char *slave; int fd = -1, i, ndevs = 4, tmp; char *devs[] = { "/dev/ptmx", "/dev/ptm/clone", "/dev/ptc", "/dev/ptmx_bsd" }; *fd_p = -1; #if LIBVNCSERVER_HAVE_GRANTPT for (i=0; i < ndevs; i++) { #ifdef O_NOCTTY fd = open(devs[i], O_RDWR|O_NOCTTY); #else fd = open(devs[i], O_RDWR); #endif if (fd >= 0) { break; } } if (fd < 0) { rfbLogPerror("open /dev/ptmx"); return NULL; } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCPKT) tmp = 0; ioctl(fd, TIOCPKT, (char *) &tmp); #endif if (grantpt(fd) != 0) { rfbLogPerror("grantpt"); close(fd); return NULL; } if (unlockpt(fd) != 0) { rfbLogPerror("unlockpt"); close(fd); return NULL; } slave = ptsname(fd); if (! slave) { rfbLogPerror("ptsname"); close(fd); return NULL; } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCFLUSH) ioctl(fd, TIOCFLUSH, (char *) 0); #endif strcpy(slave_str, slave); *fd_p = fd; return slave_str; #else return NULL; #endif /* GRANTPT */ } char *get_pty_loop(int *fd_p) { char master_str[16]; int fd = -1, i; char c; *fd_p = -1; /* for *BSD loop over /dev/ptyXY */ for (c = 'p'; c <= 'z'; c++) { for (i=0; i < 16; i++) { sprintf(master_str, "/dev/pty%c%x", c, i); #ifdef O_NOCTTY fd = open(master_str, O_RDWR|O_NOCTTY); #else fd = open(master_str, O_RDWR); #endif if (fd >= 0) { break; } } if (fd >= 0) { break; } } if (fd < 0) { return NULL; } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCFLUSH) ioctl(fd, TIOCFLUSH, (char *) 0); #endif sprintf(slave_str, "/dev/tty%c%x", c, i); *fd_p = fd; return slave_str; } char *get_pty(int *fd_p) { used_get_pty_ptmx = 0; if (getenv("BSD_PTY")) { return get_pty_loop(fd_p); } #ifdef IS_BSD return get_pty_loop(fd_p); #else #if LIBVNCSERVER_HAVE_GRANTPT used_get_pty_ptmx = 1; return get_pty_ptmx(fd_p); #else return get_pty_loop(fd_p); #endif #endif } void try_to_be_nobody(void) { #if LIBVNCSERVER_HAVE_PWD_H struct passwd *pw; pw = getpwnam("nobody"); if (pw) { #if LIBVNCSERVER_HAVE_SETUID setuid(pw->pw_uid); #endif #if LIBVNCSERVER_HAVE_SETEUID seteuid(pw->pw_uid); #endif #if LIBVNCSERVER_HAVE_SETGID setgid(pw->pw_gid); #endif #if LIBVNCSERVER_HAVE_SETEGID setegid(pw->pw_gid); #endif } #endif /* PWD_H */ } static int slave_fd = -1, alarm_fired = 0;; static void close_alarm (int sig) { if (slave_fd >= 0) { close(slave_fd); } alarm_fired = 1; if (0) sig = 0; /* compiler warning */ } static void kill_child (pid_t pid, int fd) { int status; slave_fd = -1; alarm_fired = 0; if (fd >= 0) { close(fd); } kill(pid, SIGTERM); waitpid(pid, &status, WNOHANG); } int crypt_verify(char *user, char *pass) { #ifndef UNIXPW_CRYPT return 0; #else struct passwd *pwd; char *realpw, *cr; int n; pwd = getpwnam(user); if (! pwd) { return 0; } realpw = pwd->pw_passwd; if (realpw == NULL || realpw[0] == '\0') { return 0; } n = strlen(pass); if (pass[n-1] == '\n') { pass[n-1] = '\0'; } cr = crypt(pass, realpw); if (cr == NULL) { return 0; } if (!strcmp(cr, realpw)) { return 1; } else { return 0; } #endif /* UNIXPW_CRYPT */ } int su_verify(char *user, char *pass) { #ifndef UNIXPW_SU return 0; #else int i, j, status, fd = -1, sfd, tfd; int slow_pw = 1; char *slave, *bin_true = NULL, *bin_su = NULL; pid_t pid, pidw; struct stat sbuf; static int first = 1; char instr[32], buf[10]; if (first) { set_db(); first = 0; } if (unixpw_list) { char *p, *q, *str = strdup(unixpw_list); int ok = 0; p = strtok(str, ","); while (p) { if ( (q = strchr(p, ':')) != NULL ) { *q = '\0'; /* get rid of options. */ } if (!strcmp(user, p) || !strcmp("*", p)) { ok = 1; break; } p = strtok(NULL, ","); } free(str); if (! ok) { return 0; } } #define SU_DEBUG 0 #if SU_DEBUG if (stat("/su", &sbuf) == 0) { bin_su = "/su"; /* Freesbie read-only-fs /bin/su not suid! */ #else if (0) { ; #endif } else if (stat("/bin/su", &sbuf) == 0) { bin_su = "/bin/su"; } else if (stat("/usr/bin/su", &sbuf) == 0) { bin_su = "/usr/bin/su"; } if (bin_su == NULL) { rfbLogPerror("existence /bin/su"); return 0; } if (stat("/bin/true", &sbuf) == 0) { bin_true = "/bin/true"; } if (stat("/usr/bin/true", &sbuf) == 0) { bin_true = "/usr/bin/true"; } if (bin_true == NULL) { rfbLogPerror("existence /bin/true"); return 0; } slave = get_pty(&fd); if (slave == NULL) { rfbLogPerror("get_pty failed."); return 0; } if (db) fprintf(stderr, "slave is: %s fd=%d\n", slave, fd); if (fd < 0) { rfbLogPerror("get_pty fd < 0"); return 0; } fcntl(fd, F_SETFD, 1); pid = fork(); if (pid < 0) { rfbLogPerror("fork"); close(fd); return 0; } if (pid == 0) { /* child */ int ttyfd; ttyfd = -1; /* compiler warning */ #if LIBVNCSERVER_HAVE_SETSID if (setsid() == -1) { perror("setsid"); exit(1); } #else if (setpgrp() == -1) { perror("setpgrp"); exit(1); } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCNOTTY) ttyfd = open("/dev/tty", O_RDWR); if (ttyfd >= 0) { (void) ioctl(ttyfd, TIOCNOTTY, (char *) 0); close(ttyfd); } #endif #endif /* SETSID */ close(0); close(1); close(2); sfd = open(slave, O_RDWR); if (sfd < 0) { exit(1); } /* streams options fixups, handle cases as they are found: */ #if defined(__hpux) #if LIBVNCSERVER_HAVE_SYS_STROPTS_H #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(I_PUSH) if (used_get_pty_ptmx) { ioctl(sfd, I_PUSH, "ptem"); ioctl(sfd, I_PUSH, "ldterm"); ioctl(sfd, I_PUSH, "ttcompat"); } #endif #endif #endif /* n.b. sfd will be 0 since we closed 0. so dup it to 1 and 2 */ if (fcntl(sfd, F_DUPFD, 1) == -1) { exit(1); } if (fcntl(sfd, F_DUPFD, 2) == -1) { exit(1); } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCSCTTY) ioctl(sfd, TIOCSCTTY, (char *) 0); #endif if (db > 2) { char nam[256]; unlink("/tmp/isatty"); tfd = open("/tmp/isatty", O_CREAT|O_WRONLY, 0600); if (isatty(sfd)) { close(tfd); sprintf(nam, "stty -a < %s > /tmp/isatty 2>&1", slave); system(nam); } else { write(tfd, "NOTTTY\n", 7); close(tfd); } } chdir("/"); try_to_be_nobody(); #if LIBVNCSERVER_HAVE_GETUID if (getuid() == 0 || geteuid() == 0) { exit(1); } #else exit(1); #endif set_env("LC_ALL", "C"); set_env("LANG", "C"); set_env("SHELL", "/bin/sh"); /* synchronize with parent: */ write(2, "C", 1); execlp(bin_su, bin_su, user, "-c", bin_true, (char *) NULL); exit(1); } /* parent */ if (db) fprintf(stderr, "pid: %d\n", pid); /* * set an alarm for blocking read() to close the master * (presumably terminating the child. SIGTERM too...) */ slave_fd = fd; alarm_fired = 0; signal(SIGALRM, close_alarm); alarm(10); /* synchronize with child: */ for (i=0; i<10; i++) { int n; buf[0] = '\0'; buf[1] = '\0'; n = read(fd, buf, 1); if (n < 0 && errno == EINTR) { continue; } else { break; } } if (db) { fprintf(stderr, "read from child: '%s'\n", buf); } alarm(0); signal(SIGALRM, SIG_DFL); if (alarm_fired) { kill_child(pid, fd); return 0; } #if LIBVNCSERVER_HAVE_SYS_IOCTL_H && defined(TIOCTRAP) { int control = 1; ioctl(fd, TIOCTRAP, &control); } #endif /* * In addition to checking exit code below, we watch for the * appearance of the string "Password:". BSD does not seem to * ask for a password trying to su to yourself. This is the * setting in /etc/pam.d/su: * auth sufficient pam_self.so * it may be commented out without problem. */ for (i=0; i<32; i++) { instr[i] = '\0'; } alarm_fired = 0; signal(SIGALRM, close_alarm); alarm(10); j = 0; for (i=0; i < (int) strlen("Password:"); i++) { char pstr[] = "password:"; int n; buf[0] = '\0'; buf[1] = '\0'; n = read(fd, buf, 1); if (n < 0 && errno == EINTR) { i--; continue; } if (db) fprintf(stderr, "%s", buf); if (db > 3 && n == 1 && buf[0] == ':') { char cmd[32]; usleep( 100 * 1000 ); fprintf(stderr, "\n\n"); sprintf(cmd, "ps wu %d", pid); system(cmd); sprintf(cmd, "stty -a < %s", slave); system(cmd); fprintf(stderr, "\n\n"); } if (n == 1) { if (isspace(buf[0])) { i--; continue; } instr[j++] = tolower(buf[0]); } if (n <= 0 || strstr(pstr, instr) != pstr) { if (db) { fprintf(stderr, "\"Password:\" did not appear: '%s'" " n=%d\n", instr, n); if (db > 3 && n == 1 && j < 32) { continue; } } alarm(0); signal(SIGALRM, SIG_DFL); kill_child(pid, fd); return 0; } } alarm(0); signal(SIGALRM, SIG_DFL); if (alarm_fired) { kill_child(pid, fd); return 0; } usleep(100 * 1000); if (slow_pw) { unsigned int k; for (k = 0; k < strlen(pass); k++) { write(fd, pass+k, 1); usleep(100 * 1000); } } else { write(fd, pass, strlen(pass)); } alarm_fired = 0; signal(SIGALRM, close_alarm); alarm(15); /* * try to drain the output, hopefully never as much as 4096 (motd?) * if we don't drain we may block at waitpid. If we close(fd), the * make cause child to die by signal. */ for (i = 0; i<4096; i++) { int n; buf[0] = '\0'; buf[1] = '\0'; n = read(fd, buf, 1); if (n < 0 && errno == EINTR) { continue; } if (db) fprintf(stderr, "%s", buf); if (n <= 0) { break; } } if (db) fprintf(stderr, "\n"); alarm(0); signal(SIGALRM, SIG_DFL); if (alarm_fired) { kill_child(pid, fd); return 0; } slave_fd = -1; pidw = waitpid(pid, &status, 0); close(fd); if (pid != pidw) { return 0; } if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { return 1; /* this is the only return of success. */ } else { return 0; } #endif /* UNIXPW_SU */ } static void unixpw_verify(char *user, char *pass) { int x, y; char li[] = "Login incorrect"; char log[] = "login: "; if (db) fprintf(stderr, "unixpw_verify: '%s' '%s'\n", user, db > 1 ? pass : "********"); rfbLog("unixpw_verify: %s\n", user); if (unixpw_nis) { if (crypt_verify(user, pass)) { unixpw_accept(user); return; } else { usleep(3000*1000); } } else { if (su_verify(user, pass)) { unixpw_accept(user); return; } } if (tries < 2) { char_row++; char_col = 0; x = text_x(); y = text_y(); rfbDrawString(screen, &default8x16Font, x, y, li, white()); char_row += 2; x = text_x(); y = text_y(); rfbDrawString(screen, &default8x16Font, x, y, log, white()); char_col = strlen(log); mark_rect_as_modified(0, 0, dpy_x, dpy_y, 0); unixpw_last_try_time = time(0); unixpw_keystroke(0, 0, 2); tries++; } else { unixpw_deny(); } } static void set_db(void) { if (getenv("DEBUG_UNIXPW")) { db = atoi(getenv("DEBUG_UNIXPW")); } } void unixpw_keystroke(rfbBool down, rfbKeySym keysym, int init) { int x, y, i, nmax = 100; static char user[100], pass[100]; static int u_cnt = 0, p_cnt = 0, first = 1; char keystr[100]; if (first) { set_db(); first = 0; } if (init) { in_login = 1; in_passwd = 0; if (init == 1) { tries = 0; } u_cnt = 0; p_cnt = 0; for (i=0; i 2) { fprintf(stderr, "%s / %s 0x%x %s\n", in_login ? "login":"pass ", down ? "down":"up ", keysym, keystr); } if (keysym == XK_Return || keysym == XK_Linefeed) { ; /* let "up" pass down below for Return case */ } else if (! down) { return; } if (in_login) { if (keysym == XK_BackSpace || keysym == XK_Delete) { if (u_cnt > 0) { user[u_cnt-1] = '\0'; x = text_x(); y = text_y(); zero_fb(x - char_w, y - char_h, x, y); mark_rect_as_modified(x - char_w, y - char_h, x, y, 0); char_col--; u_cnt--; } return; } if (keysym == XK_Return || keysym == XK_Linefeed) { char pw[] = "Password: "; if (down) { /* * require Up so the Return Up is not processed * by the normal session after login. */ return; } in_login = 0; in_passwd = 1; char_row++; char_col = 0; x = text_x(); y = text_y(); rfbDrawString(screen, &default8x16Font, x, y, pw, white()); char_col = strlen(pw); mark_rect_as_modified(0, 0, dpy_x, dpy_y, 0); return; } if (keysym <= ' ' || keysym >= 0x7f) { return; } if (u_cnt >= nmax - 1) { rfbLog("unixpw_deny: username too long\n"); for (i=0; i 0) { pass[p_cnt-1] = '\0'; p_cnt--; } return; } if (keysym == XK_Return || keysym == XK_Linefeed) { if (down) { /* * require Up so the Return Up is not processed * by the normal session after login. */ return; } in_login = 0; in_passwd = 0; pass[p_cnt++] = '\n'; unixpw_verify(user, pass); for (i=0; i= 0x7f) { return; } if (p_cnt >= nmax - 2) { rfbLog("unixpw_deny: password too long\n"); for (i=0; iclientData; rfbClientPtr cl = unixpw_client; int i; if (user) { if (cd->unixname) { free(cd->unixname); } cd->unixname = strdup(user); } if (! unixpw_list) { return; } str = strdup(unixpw_list); /* apply any per-user options. */ p = strtok(str, ","); while (p) { if ( (q = strchr(p, ':')) != NULL ) { *q = '\0'; /* get rid of options. */ } else { p = strtok(NULL, ","); continue; } if (user && !strcmp(user, p)) { opts = strdup(q+1); } if (!strcmp("*", p)) { opts_star = strdup(q+1); } p = strtok(NULL, ","); } free(str); for (i=0; i < 2; i++) { char *s = (i == 0) ? opts_star : opts; if (s == NULL) { continue; } p = strtok(s, "+"); while (p) { if (!strcmp(p, "viewonly")) { cl->viewOnly = TRUE; strncpy(cd->input, "-", CILEN); } else if (!strcmp(p, "fullaccess")) { cl->viewOnly = FALSE; strncpy(cd->input, "-", CILEN); } else if ((q = strstr(p, "input=")) == p) { q += strlen("input="); strncpy(cd->input, q, CILEN); } else if (!strcmp(p, "deny")) { cl->viewOnly = TRUE; unixpw_deny(); break; } p = strtok(NULL, "+"); } free(s); } } void unixpw_accept(char *user) { apply_opts(user); unixpw_in_progress = 0; unixpw_client = NULL; mark_rect_as_modified(0, 0, dpy_x, dpy_y, 0); } void unixpw_deny(void) { int x, y, i; char pd[] = "Permission denied."; char_row += 2; char_col = 0; x = char_x + char_col * char_w; y = char_y + char_row * char_h; rfbDrawString(screen, &default8x16Font, x, y, pd, white()); mark_rect_as_modified(0, 0, dpy_x, dpy_y, 0); for (i=0; i<5; i++) { rfbPE(-1); usleep(500 * 1000); } rfbCloseClient(unixpw_client); rfbClientConnectionGone(unixpw_client); rfbPE(-1); unixpw_in_progress = 0; unixpw_client = NULL; copy_screen(); }