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login: cleanup work by Walter Harms. No logic changes.

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This commit is contained in:
Denis Vlasenko 2009-02-02 00:15:00 +00:00
parent 73121c3c8c
commit 4eff8efa59
1 changed files with 56 additions and 46 deletions
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102
loginutils/login.c
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@ -165,6 +165,56 @@ static int check_securetty(void)
static ALWAYS_INLINE int check_securetty(void) { return 1; }
#endif
#if ENABLE_SELINUX
static void initselinux(char *username, char *full_tty,
security_context_t *user_sid)
{
security_context_t old_tty_sid, new_tty_sid;
if (!is_selinux_enabled())
return;
if (get_default_context(username, NULL, user_sid)) {
bb_error_msg_and_die("cannot get SID for %s", username);
}
if (getfilecon(full_tty, &old_tty_sid) < 0) {
bb_perror_msg_and_die("getfilecon(%s) failed", full_tty);
}
if (security_compute_relabel(user_sid, old_tty_sid,
SECCLASS_CHR_FILE, &new_tty_sid) != 0) {
bb_perror_msg_and_die("security_change_sid(%s) failed", full_tty);
}
if (setfilecon(full_tty, new_tty_sid) != 0) {
bb_perror_msg_and_die("chsid(%s, %s) failed", full_tty, new_tty_sid);
}
}
#endif
#if ENABLE_LOGIN_SCRIPTS
static void run_login_script(struct passwd *pw, char *full_tty)
{
char *t_argv[2];
t_argv[0] = getenv("LOGIN_PRE_SUID_SCRIPT");
if (t_argv[0]) {
t_argv[1] = NULL;
xsetenv("LOGIN_TTY", full_tty);
xsetenv("LOGIN_USER", pw->pw_name);
xsetenv("LOGIN_UID", utoa(pw->pw_uid));
xsetenv("LOGIN_GID", utoa(pw->pw_gid));
xsetenv("LOGIN_SHELL", pw->pw_shell);
spawn_and_wait(t_argv); /* NOMMU-friendly */
unsetenv("LOGIN_TTY");
unsetenv("LOGIN_USER");
unsetenv("LOGIN_UID");
unsetenv("LOGIN_GID");
unsetenv("LOGIN_SHELL");
}
}
#else
void run_login_script(struct passwd *pw, char *full_tty);
#endif
static void get_username_or_die(char *buf, int size_buf)
{
int c, cntdown;
@ -285,8 +335,7 @@ int login_main(int argc UNUSED_PARAM, char **argv)
read_or_build_utent(&utent, run_by_root);
if (opt & LOGIN_OPT_h) {
if (ENABLE_FEATURE_UTMP)
safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
USE_FEATURE_UTMP(safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));)
fromhost = xasprintf(" on '%s' from '%s'", short_tty, opt_host);
} else {
fromhost = xasprintf(" on '%s'", short_tty);
@ -410,54 +459,16 @@ int login_main(int argc UNUSED_PARAM, char **argv)
write_utent(&utent, username);
#if ENABLE_SELINUX
if (is_selinux_enabled()) {
security_context_t old_tty_sid, new_tty_sid;
USE_SELINUX(initselinux(username, full_tty, &user_sid));
if (get_default_context(username, NULL, &user_sid)) {
bb_error_msg_and_die("cannot get SID for %s",
username);
}
if (getfilecon(full_tty, &old_tty_sid) < 0) {
bb_perror_msg_and_die("getfilecon(%s) failed",
full_tty);
}
if (security_compute_relabel(user_sid, old_tty_sid,
SECCLASS_CHR_FILE, &new_tty_sid) != 0) {
bb_perror_msg_and_die("security_change_sid(%s) failed",
full_tty);
}
if (setfilecon(full_tty, new_tty_sid) != 0) {
bb_perror_msg_and_die("chsid(%s, %s) failed",
full_tty, new_tty_sid);
}
}
#endif
/* Try these, but don't complain if they fail.
* _f_chown is safe wrt race t=ttyname(0);...;chown(t); */
fchown(0, pw->pw_uid, pw->pw_gid);
fchmod(0, 0600);
/* We trust environment only if we run by root */
if (ENABLE_LOGIN_SCRIPTS && run_by_root) {
char *t_argv[2];
t_argv[0] = getenv("LOGIN_PRE_SUID_SCRIPT");
if (t_argv[0]) {
t_argv[1] = NULL;
xsetenv("LOGIN_TTY", full_tty);
xsetenv("LOGIN_USER", pw->pw_name);
xsetenv("LOGIN_UID", utoa(pw->pw_uid));
xsetenv("LOGIN_GID", utoa(pw->pw_gid));
xsetenv("LOGIN_SHELL", pw->pw_shell);
spawn_and_wait(t_argv); /* NOMMU-friendly */
unsetenv("LOGIN_TTY" );
unsetenv("LOGIN_USER" );
unsetenv("LOGIN_UID" );
unsetenv("LOGIN_GID" );
unsetenv("LOGIN_SHELL");
}
}
if (ENABLE_LOGIN_SCRIPTS && run_by_root)
run_login_script(pw, full_tty);
change_identity(pw);
tmp = pw->pw_shell;
@ -470,11 +481,10 @@ int login_main(int argc UNUSED_PARAM, char **argv)
if (pw->pw_uid == 0)
syslog(LOG_INFO, "root login%s", fromhost);
#if ENABLE_SELINUX
/* well, a simple setexeccon() here would do the job as well,
* but let's play the game for now */
set_current_security_context(user_sid);
#endif
USE_SELINUX(set_current_security_context(user_sid);)
// util-linux login also does:
// /* start new session */