#endif
int pty_master_fd;
+static char pty_name[FILENAME_MAX];
static int pty_stamped_utmp = 0;
static int pty_child_pid;
+static int pty_utmp_helper_pid, pty_utmp_helper_pipe;
static sig_atomic_t pty_child_dead;
#ifndef OMIT_UTMP
static struct utmp utmp_entry;
static void pty_size(void);
-static void setup_utmp(char *ttyname)
+static void setup_utmp(char *ttyname, char *location)
{
#ifndef OMIT_UTMP
#ifdef HAVE_LASTLOG
FILE *lastlog;
#endif
struct passwd *pw;
- char *location;
FILE *wtmp;
- if (!cfg.stamp_utmp)
- return;
-
pw = getpwuid(getuid());
- location = get_x_display();
memset(&utmp_entry, 0, sizeof(utmp_entry));
utmp_entry.ut_type = USER_PROCESS;
utmp_entry.ut_pid = getpid();
#ifndef OMIT_UTMP
FILE *wtmp;
- if (!cfg.stamp_utmp || !pty_stamped_utmp)
+ if (!pty_stamped_utmp)
return;
utmp_entry.ut_type = DEAD_PROCESS;
raise(signum);
}
-/*
- * Called to set up the pty.
- *
- * Returns an error message, or NULL on success.
- *
- * Also places the canonical host name into `realhost'. It must be
- * freed by the caller.
- */
-static char *pty_init(char *host, int port, char **realhost, int nodelay)
+static void pty_open_master(void)
{
- int slavefd;
- char name[FILENAME_MAX];
- pid_t pid, pgrp;
-
#ifdef BSD_PTYS
- {
- const char chars1[] = "pqrstuvwxyz";
- const char chars2[] = "0123456789abcdef";
- const char *p1, *p2;
- char master_name[20];
-
- for (p1 = chars1; *p1; p1++)
- for (p2 = chars2; *p2; p2++) {
- sprintf(master_name, "/dev/pty%c%c", *p1, *p2);
- pty_master_fd = open(master_name, O_RDWR);
- if (pty_master_fd >= 0) {
- if (geteuid() == 0 ||
- access(master_name, R_OK | W_OK) == 0)
- goto got_one;
- close(pty_master_fd);
- }
+ const char chars1[] = "pqrstuvwxyz";
+ const char chars2[] = "0123456789abcdef";
+ const char *p1, *p2;
+ char master_name[20];
+ struct group *gp;
+
+ for (p1 = chars1; *p1; p1++)
+ for (p2 = chars2; *p2; p2++) {
+ sprintf(master_name, "/dev/pty%c%c", *p1, *p2);
+ pty_master_fd = open(master_name, O_RDWR);
+ if (pty_master_fd >= 0) {
+ if (geteuid() == 0 ||
+ access(master_name, R_OK | W_OK) == 0)
+ goto got_one;
+ close(pty_master_fd);
}
+ }
- /* If we get here, we couldn't get a tty at all. */
- fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n");
- exit(1);
+ /* If we get here, we couldn't get a tty at all. */
+ fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n");
+ exit(1);
- got_one:
- strcpy(name, master_name);
- name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
- }
+ got_one:
+ strcpy(pty_name, master_name);
+ pty_name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
+
+ /* We need to chown/chmod the /dev/ttyXX device. */
+ gp = getgrnam("tty");
+ chown(pty_name, getuid(), gp ? gp->gr_gid : -1);
+ chmod(pty_name, 0600);
#else
pty_master_fd = open("/dev/ptmx", O_RDWR);
exit(1);
}
- name[FILENAME_MAX-1] = '\0';
- strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1);
+ pty_name[FILENAME_MAX-1] = '\0';
+ strncpy(pty_name, ptsname(pty_master_fd), FILENAME_MAX-1);
#endif
+}
- /*
- * Set the backspace character to be whichever of ^H and ^? is
- * specified by bksp_is_delete.
- */
- {
- struct termios attrs;
- tcgetattr(pty_master_fd, &attrs);
- attrs.c_cc[VERASE] = cfg.bksp_is_delete ? '\177' : '\010';
- tcsetattr(pty_master_fd, TCSANOW, &attrs);
+/*
+ * Pre-initialisation. This is here to get around the fact that GTK
+ * doesn't like being run in setuid/setgid programs (probably
+ * sensibly). So before we initialise GTK - and therefore before we
+ * even process the command line - we check to see if we're running
+ * set[ug]id. If so, we open our pty master _now_, chown it as
+ * necessary, and drop privileges. We can always close it again
+ * later. If we're potentially going to be doing utmp as well, we
+ * also fork off a utmp helper process and communicate with it by
+ * means of a pipe; the utmp helper will keep privileges in order
+ * to clean up utmp when we exit (i.e. when its end of our pipe
+ * closes).
+ */
+void pty_pre_init(void)
+{
+ pid_t pid;
+ int pipefd[2];
+
+ pty_master_fd = -1;
+
+ if (geteuid() != getuid() || getegid() != getgid()) {
+ pty_open_master();
}
+#ifndef OMIT_UTMP
/*
- * Trap as many fatal signals as we can in the hope of having
- * the best chance to clean up utmp before termination.
+ * Fork off the utmp helper.
*/
- signal(SIGHUP, fatal_sig_handler);
- signal(SIGINT, fatal_sig_handler);
- signal(SIGQUIT, fatal_sig_handler);
- signal(SIGILL, fatal_sig_handler);
- signal(SIGABRT, fatal_sig_handler);
- signal(SIGFPE, fatal_sig_handler);
- signal(SIGPIPE, fatal_sig_handler);
- signal(SIGALRM, fatal_sig_handler);
- signal(SIGTERM, fatal_sig_handler);
- signal(SIGSEGV, fatal_sig_handler);
- signal(SIGUSR1, fatal_sig_handler);
- signal(SIGUSR2, fatal_sig_handler);
+ if (pipe(pipefd) < 0) {
+ perror("pterm: pipe");
+ exit(1);
+ }
+ pid = fork();
+ if (pid < 0) {
+ perror("pterm: fork");
+ exit(1);
+ } else if (pid == 0) {
+ char display[128], buffer[128];
+ int dlen, ret;
+
+ close(pipefd[1]);
+ /*
+ * Now sit here until we receive a display name from the
+ * other end of the pipe, and then stamp utmp. Unstamp utmp
+ * again, and exit, when the pipe closes.
+ */
+
+ dlen = 0;
+ while (1) {
+
+ ret = read(pipefd[0], buffer, lenof(buffer));
+ if (ret <= 0) {
+ cleanup_utmp();
+ exit(0);
+ } else if (!pty_stamped_utmp) {
+ if (dlen < lenof(display))
+ memcpy(display+dlen, buffer,
+ min(ret, lenof(display)-dlen));
+ if (buffer[ret-1] == '\0') {
+ /*
+ * Now we have a display name. NUL-terminate
+ * it, and stamp utmp.
+ */
+ display[lenof(display)-1] = '\0';
+ /*
+ * Trap as many fatal signals as we can in the
+ * hope of having the best possible chance to
+ * clean up utmp before termination. We are
+ * unfortunately unprotected against SIGKILL,
+ * but that's life.
+ */
+ signal(SIGHUP, fatal_sig_handler);
+ signal(SIGINT, fatal_sig_handler);
+ signal(SIGQUIT, fatal_sig_handler);
+ signal(SIGILL, fatal_sig_handler);
+ signal(SIGABRT, fatal_sig_handler);
+ signal(SIGFPE, fatal_sig_handler);
+ signal(SIGPIPE, fatal_sig_handler);
+ signal(SIGALRM, fatal_sig_handler);
+ signal(SIGTERM, fatal_sig_handler);
+ signal(SIGSEGV, fatal_sig_handler);
+ signal(SIGUSR1, fatal_sig_handler);
+ signal(SIGUSR2, fatal_sig_handler);
#ifdef SIGBUS
- signal(SIGBUS, fatal_sig_handler);
+ signal(SIGBUS, fatal_sig_handler);
#endif
#ifdef SIGPOLL
- signal(SIGPOLL, fatal_sig_handler);
+ signal(SIGPOLL, fatal_sig_handler);
#endif
#ifdef SIGPROF
- signal(SIGPROF, fatal_sig_handler);
+ signal(SIGPROF, fatal_sig_handler);
#endif
#ifdef SIGSYS
- signal(SIGSYS, fatal_sig_handler);
+ signal(SIGSYS, fatal_sig_handler);
#endif
#ifdef SIGTRAP
- signal(SIGTRAP, fatal_sig_handler);
+ signal(SIGTRAP, fatal_sig_handler);
#endif
#ifdef SIGVTALRM
- signal(SIGVTALRM, fatal_sig_handler);
+ signal(SIGVTALRM, fatal_sig_handler);
#endif
#ifdef SIGXCPU
- signal(SIGXCPU, fatal_sig_handler);
+ signal(SIGXCPU, fatal_sig_handler);
#endif
#ifdef SIGXFSZ
- signal(SIGXFSZ, fatal_sig_handler);
+ signal(SIGXFSZ, fatal_sig_handler);
#endif
#ifdef SIGIO
- signal(SIGIO, fatal_sig_handler);
+ signal(SIGIO, fatal_sig_handler);
+#endif
+ /* Also clean up utmp on normal exit. */
+ atexit(cleanup_utmp);
+ setup_utmp(pty_name, display);
+ }
+ }
+ }
+ } else {
+ close(pipefd[0]);
+ pty_utmp_helper_pid = pid;
+ pty_utmp_helper_pipe = pipefd[1];
+ }
#endif
- /* Also clean up utmp on normal exit. */
- atexit(cleanup_utmp);
- setup_utmp(name);
+
+ /* Drop privs. */
+ {
+ int gid = getgid(), uid = getuid();
+#ifndef HAVE_NO_SETRESUID
+ int setresgid(gid_t, gid_t, gid_t);
+ int setresuid(uid_t, uid_t, uid_t);
+ setresgid(gid, gid, gid);
+ setresuid(uid, uid, uid);
+#else
+ setgid(getgid());
+ setuid(getuid());
+#endif
+ }
+}
+
+/*
+ * Called to set up the pty.
+ *
+ * Returns an error message, or NULL on success.
+ *
+ * Also places the canonical host name into `realhost'. It must be
+ * freed by the caller.
+ */
+static char *pty_init(char *host, int port, char **realhost, int nodelay)
+{
+ int slavefd;
+ pid_t pid, pgrp;
+
+ if (pty_master_fd < 0)
+ pty_open_master();
+
+ /*
+ * Set the backspace character to be whichever of ^H and ^? is
+ * specified by bksp_is_delete.
+ */
+ {
+ struct termios attrs;
+ tcgetattr(pty_master_fd, &attrs);
+ attrs.c_cc[VERASE] = cfg.bksp_is_delete ? '\177' : '\010';
+ tcsetattr(pty_master_fd, TCSANOW, &attrs);
+ }
+
+ /*
+ * Stamp utmp (that is, tell the utmp helper process to do so),
+ * or not.
+ */
+ if (!cfg.stamp_utmp)
+ close(pty_utmp_helper_pipe); /* just let the child process die */
+ else {
+ char *location = get_x_display();
+ int len = strlen(location)+1, pos = 0; /* +1 to include NUL */
+ while (pos < len) {
+ int ret = write(pty_utmp_helper_pipe, location+pos, len - pos);
+ if (ret < 0) {
+ perror("pterm: writing to utmp helper process");
+ close(pty_utmp_helper_pipe); /* arrgh, just give up */
+ break;
+ }
+ pos += ret;
+ }
+ }
/*
* Fork and execute the command.
* We are the child.
*/
- slavefd = open(name, O_RDWR);
+ slavefd = open(pty_name, O_RDWR);
if (slavefd < 0) {
perror("slave pty: open");
exit(1);
}
-#ifdef BSD_PTYS
- /* We need to chown/chmod the /dev/ttyXX device. */
- {
- struct group *gp = getgrnam("tty");
- fchown(slavefd, getuid(), gp ? gp->gr_gid : -1);
- fchmod(slavefd, 0600);
- }
-#endif
-
close(pty_master_fd);
close(0);
close(1);
pgrp = getpid();
tcsetpgrp(slavefd, pgrp);
setpgrp();
- close(open(name, O_WRONLY, 0));
+ close(open(pty_name, O_WRONLY, 0));
setpgrp();
- /* In case we were setgid-utmp or setuid-root, drop privs. */
- setgid(getgid());
- setuid(getuid());
/* Close everything _else_, for tidiness. */
for (i = 3; i < 1024; i++)
close(i);
~mdw / sgt / putty / commitdiff