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-rw-r--r--loginutils/login.c316
1 files changed, 131 insertions, 185 deletions
diff --git a/loginutils/login.c b/loginutils/login.c
index c05ec066a..19f865550 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -29,59 +29,59 @@
#ifdef CONFIG_FEATURE_UTMP
// import from utmp.c
-static void checkutmp(int picky);
-static void setutmp(const char *name, const char *line);
-/* Stuff global to this file */
static struct utmp utent;
+static void read_or_build_utent(int picky);
+static void write_utent(const char *username);
#endif
enum {
TIMEOUT = 60,
EMPTY_USERNAME_COUNT = 10,
USERNAME_SIZE = 32,
+ TTYNAME_SIZE = 32,
};
-static int check_nologin(int amroot);
+static void die_if_nologin_and_non_root(int amroot);
#if defined CONFIG_FEATURE_SECURETTY
-static int check_tty(const char *tty);
+static int check_securetty(void);
#else
-static inline int check_tty(const char *tty) { return 1; }
+static inline int check_securetty(void) { return 1; }
#endif
-static int is_my_tty(const char *tty);
-static int login_prompt(char *buf_name);
+static int is_my_tty(void);
+static void get_username_or_die(char *buf, int size_buf);
static void motd(void);
static void alarm_handler(int sig ATTRIBUTE_UNUSED)
{
- fprintf(stderr, "\r\nLogin timed out after %s seconds\r\n", TIMEOUT);
+ fprintf(stderr, "\r\nLogin timed out after %d seconds\r\n", TIMEOUT);
exit(EXIT_SUCCESS);
}
+static char full_tty[TTYNAME_SIZE];
+static char* short_tty = full_tty;
+
+
int login_main(int argc, char **argv)
{
- char tty[BUFSIZ];
- char full_tty[200];
char fromhost[512];
char username[USERNAME_SIZE];
const char *tmp;
int amroot;
int flag;
- int failed;
int count = 0;
- struct passwd *pw, pw_copy;
+ struct passwd *pw;
#ifdef CONFIG_WHEEL_GROUP
struct group *grp;
#endif
int opt_preserve = 0;
int opt_fflag = 0;
char *opt_host = 0;
- int alarmstarted = 0;
#ifdef CONFIG_SELINUX
security_context_t user_sid = NULL;
#endif
@@ -90,7 +90,6 @@ int login_main(int argc, char **argv)
amroot = (getuid() == 0);
signal(SIGALRM, alarm_handler);
alarm(TIMEOUT);
- alarmstarted = 1;
while ((flag = getopt(argc, argv, "f:h:p")) != EOF) {
switch (flag) {
@@ -105,10 +104,10 @@ int login_main(int argc, char **argv)
if (optarg != argv[optind-1])
bb_show_usage();
- if (!amroot) /* Auth bypass only if real UID is zero */
- bb_error_msg_and_die("-f permission denied");
+ if (!amroot) /* Auth bypass only if real UID is zero */
+ bb_error_msg_and_die("-f is for root only");
- safe_strncpy(username, optarg, USERNAME_SIZE);
+ safe_strncpy(username, optarg, sizeof(username));
opt_fflag = 1;
break;
case 'h':
@@ -118,113 +117,83 @@ int login_main(int argc, char **argv)
bb_show_usage();
}
}
-
if (optind < argc) /* user from command line (getty) */
- safe_strncpy(username, argv[optind], USERNAME_SIZE);
+ safe_strncpy(username, argv[optind], sizeof(username));
+ /* Let's find out and memorize our tty */
if (!isatty(0) || !isatty(1) || !isatty(2))
return EXIT_FAILURE; /* Must be a terminal */
-
-#ifdef CONFIG_FEATURE_UTMP
- checkutmp(!amroot);
-#endif
-
+ safe_strncpy(full_tty, "UNKNOWN", sizeof(full_tty));
tmp = ttyname(0);
- if (tmp && (strncmp(tmp, "/dev/", 5) == 0))
- safe_strncpy(tty, tmp + 5, sizeof(tty));
- else if (tmp && *tmp == '/')
- safe_strncpy(tty, tmp, sizeof(tty));
- else
- safe_strncpy(tty, "UNKNOWN", sizeof(tty));
+ if (tmp) {
+ safe_strncpy(full_tty, tmp, sizeof(full_tty));
+ if (strncmp(full_tty, "/dev/", 5) == 0)
+ short_tty = full_tty + 5;
+ }
-#ifdef CONFIG_FEATURE_UTMP
- if (amroot)
- memset(utent.ut_host, 0, sizeof(utent.ut_host));
-#endif
+ if (ENABLE_FEATURE_UTMP) {
+ read_or_build_utent(!amroot);
+ if (amroot)
+ memset(utent.ut_host, 0, sizeof(utent.ut_host));
+ }
if (opt_host) {
-#ifdef CONFIG_FEATURE_UTMP
- safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
-#endif
+ if (ENABLE_FEATURE_UTMP)
+ safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s' from "
- "`%.200s'", tty, opt_host);
+ "`%.200s'", short_tty, opt_host);
}
else
- snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s'", tty);
+ snprintf(fromhost, sizeof(fromhost)-1, " on `%.100s'", short_tty);
bb_setpgrp;
openlog(bb_applet_name, LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
while (1) {
- failed = 0;
-
if (!username[0])
- if (!login_prompt(username))
- return EXIT_FAILURE;
-
- if (!alarmstarted && (TIMEOUT > 0)) {
- alarm(TIMEOUT);
- alarmstarted = 1;
- }
+ get_username_or_die(username, sizeof(username));
pw = getpwnam(username);
if (!pw) {
- pw_copy.pw_name = "UNKNOWN";
- pw_copy.pw_passwd = "!";
- opt_fflag = 0;
- failed = 1;
- } else
- pw_copy = *pw;
-
- pw = &pw_copy;
+ safe_strncpy(username, "UNKNOWN", sizeof(username));
+ goto auth_failed;
+ }
- if ((pw->pw_passwd[0] == '!') || (pw->pw_passwd[0] == '*'))
- failed = 1;
+ if (pw->pw_passwd[0] == '!' || pw->pw_passwd[0] == '*')
+ goto auth_failed;
- if (opt_fflag) {
- opt_fflag = 0;
- goto auth_ok;
- }
+ if (opt_fflag)
+ break; /* -f USER: success without asking passwd */
- if (!failed && (pw->pw_uid == 0) && (!check_tty(tty)))
- failed = 1;
+ if (pw->pw_uid == 0 && !check_securetty())
+ goto auth_failed;
/* Don't check the password if password entry is empty (!) */
if (!pw->pw_passwd[0])
- goto auth_ok;
+ break;
/* authorization takes place here */
if (correct_password(pw))
- goto auth_ok;
-
- failed = 1;
-
-auth_ok:
- if (!failed)
- break;
+ break;
+auth_failed:
+ opt_fflag = 0;
bb_do_delay(FAIL_DELAY);
puts("Login incorrect");
- username[0] = 0;
if (++count == 3) {
- syslog(LOG_WARNING, "invalid password for `%s'%s", pw->pw_name, fromhost);
+ syslog(LOG_WARNING, "invalid password for `%s'%s",
+ username, fromhost);
return EXIT_FAILURE;
}
+ username[0] = '\0';
}
alarm(0);
- if (check_nologin(pw->pw_uid == 0))
- return EXIT_FAILURE;
-
-#ifdef CONFIG_FEATURE_UTMP
- setutmp(username, tty);
-#endif
+ die_if_nologin_and_non_root(pw->pw_uid == 0);
- if (*tty != '/')
- snprintf(full_tty, sizeof(full_tty)-1, "/dev/%s", tty);
- else
- safe_strncpy(full_tty, tty, sizeof(full_tty)-1);
+ if (ENABLE_FEATURE_UTMP)
+ write_utent(username);
#ifdef CONFIG_SELINUX
if (is_selinux_enabled()) {
@@ -249,7 +218,7 @@ auth_ok:
}
}
#endif
- if (!is_my_tty(full_tty))
+ if (!is_my_tty())
syslog(LOG_ERR, "unable to determine TTY name, got %s", full_tty);
/* Try these, but don't complain if they fail
@@ -300,96 +269,91 @@ auth_ok:
}
-static int login_prompt(char *buf_name)
+static void get_username_or_die(char *buf, int size_buf)
{
- char buf[1024];
- char *sp, *ep;
- int i;
-
- for (i=0; i<EMPTY_USERNAME_COUNT; i++) {
- print_login_prompt();
-
- if (!fgets(buf, sizeof(buf)-1, stdin))
- return 0;
-
- if (!strchr(buf, '\n'))
- return 0;
-
- for (sp = buf; isspace(*sp); sp++) { }
- for (ep = sp; isgraph(*ep); ep++) { }
-
- *ep = '\0';
- safe_strncpy(buf_name, sp, USERNAME_SIZE);
- if (buf_name[0])
- return 1;
- }
- return 0;
+ int c, cntdown;
+ cntdown = EMPTY_USERNAME_COUNT;
+prompt:
+ /* skip whitespace */
+ print_login_prompt();
+ do {
+ c = getchar();
+ if (c == EOF) exit(1);
+ if (c == '\n') {
+ if (!--cntdown) exit(1);
+ goto prompt;
+ }
+ } while (isspace(c));
+
+ *buf++ = c;
+ if (!fgets(buf, size_buf-2, stdin))
+ exit(1);
+ if (!strchr(buf, '\n'))
+ exit(1);
+ while (isgraph(*buf)) buf++;
+ *buf = '\0';
}
-static int check_nologin(int amroot)
+static void die_if_nologin_and_non_root(int amroot)
{
- if (access(bb_path_nologin_file, F_OK) == 0) {
- FILE *fp;
- int c;
-
- fp = fopen(bb_path_nologin_file, "r");
- if (fp) {
- while ((c = getc(fp)) != EOF)
- putchar((c=='\n') ? '\r' : c);
+ FILE *fp;
+ int c;
- fflush(stdout);
- fclose(fp);
- } else {
- puts("\r\nSystem closed for routine maintenance.\r");
- }
- if (!amroot)
- return 1;
+ if (access(bb_path_nologin_file, F_OK))
+ return;
- puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
- }
- return 0;
+ fp = fopen(bb_path_nologin_file, "r");
+ if (fp) {
+ while ((c = getc(fp)) != EOF)
+ putchar((c=='\n') ? '\r' : c);
+ fflush(stdout);
+ fclose(fp);
+ } else
+ puts("\r\nSystem closed for routine maintenance\r");
+ if (!amroot)
+ exit(1);
+ puts("\r\n[Disconnect bypassed -- root login allowed.]\r");
}
#ifdef CONFIG_FEATURE_SECURETTY
-static int check_tty(const char *tty)
+static int check_securetty(void)
{
FILE *fp;
int i;
char buf[BUFSIZ];
fp = fopen(bb_path_securetty_file, "r");
- if (fp) {
- while (fgets(buf, sizeof(buf)-1, fp)) {
- for(i = strlen(buf)-1; i>=0; --i) {
- if (!isspace(buf[i]))
- break;
- }
- buf[++i] = '\0';
- if ((buf[0]=='\0') || (buf[0]=='#'))
- continue;
-
- if (strcmp(buf, tty)== 0) {
- fclose(fp);
- return 1;
- }
+ if (!fp) {
+ /* A missing securetty file is not an error. */
+ return 1;
+ }
+ while (fgets(buf, sizeof(buf)-1, fp)) {
+ for(i = strlen(buf)-1; i>=0; --i) {
+ if (!isspace(buf[i]))
+ break;
+ }
+ buf[++i] = '\0';
+ if ((buf[0]=='\0') || (buf[0]=='#'))
+ continue;
+ if (strcmp(buf, short_tty) == 0) {
+ fclose(fp);
+ return 1;
}
- fclose(fp);
- return 0;
}
- /* A missing securetty file is not an error. */
- return 1;
+ fclose(fp);
+ return 0;
}
#endif
/* returns 1 if true */
-static int is_my_tty(const char *tty)
+static int is_my_tty(void)
{
struct stat by_name, by_fd;
- if (stat(tty, &by_name) || fstat(0, &by_fd))
+ if (stat(full_tty, &by_name) || fstat(0, &by_fd))
return 0;
if (by_name.st_rdev != by_fd.st_rdev)
@@ -414,15 +378,10 @@ static void motd(void)
#ifdef CONFIG_FEATURE_UTMP
-// vv Taken from tinylogin utmp.c vv
-
-#define NO_UTENT \
- "No utmp entry. You must exec \"login\" from the lowest level \"sh\""
-#define NO_TTY \
- "Unable to determine your tty name."
+/* vv Taken from tinylogin utmp.c vv */
/*
- * checkutmp - see if utmp file is correct for this process
+ * read_or_build_utent - see if utmp file is correct for this process
*
* System V is very picky about the contents of the utmp file
* and requires that a slot for the current process exist.
@@ -435,9 +394,8 @@ static void motd(void)
* command line flags.
*/
-static void checkutmp(int picky)
+static void read_or_build_utent(int picky)
{
- char *line;
struct utmp *ut;
pid_t pid = getpid();
@@ -446,53 +404,41 @@ static void checkutmp(int picky)
/* First, try to find a valid utmp entry for this process. */
while ((ut = getutent()))
if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0] &&
- (ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
+ (ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS))
break;
/* If there is one, just use it, otherwise create a new one. */
if (ut) {
utent = *ut;
} else {
- time_t t_tmp;
-
- if (picky) {
- puts(NO_UTENT);
- exit(1);
- }
- line = ttyname(0);
- if (!line) {
- puts(NO_TTY);
- exit(1);
- }
- if (strncmp(line, "/dev/", 5) == 0)
- line += 5;
+ if (picky)
+ bb_error_msg_and_die("no utmp entry found");
+
memset(&utent, 0, sizeof(utent));
utent.ut_type = LOGIN_PROCESS;
utent.ut_pid = pid;
- strncpy(utent.ut_line, line, sizeof(utent.ut_line));
- /* XXX - assumes /dev/tty?? */
- strncpy(utent.ut_id, utent.ut_line + 3, sizeof(utent.ut_id));
+ strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
+ /* This one is only 4 chars wide. Try to fit something
+ * remotely meaningful by skipping "tty"... */
+ strncpy(utent.ut_id, short_tty + 3, sizeof(utent.ut_id));
strncpy(utent.ut_user, "LOGIN", sizeof(utent.ut_user));
- t_tmp = (time_t)utent.ut_time;
- time(&t_tmp);
+ utent.ut_time = time(NULL);
}
}
/*
- * setutmp - put a USER_PROCESS entry in the utmp file
+ * write_utent - put a USER_PROCESS entry in the utmp file
*
- * setutmp changes the type of the current utmp entry to
+ * write_utent changes the type of the current utmp entry to
* USER_PROCESS. the wtmp file will be updated as well.
*/
-static void setutmp(const char *name, const char *line ATTRIBUTE_UNUSED)
+static void write_utent(const char *username)
{
- time_t t_tmp = (time_t)utent.ut_time;
-
utent.ut_type = USER_PROCESS;
- strncpy(utent.ut_user, name, sizeof(utent.ut_user));
- time(&t_tmp);
- /* other fields already filled in by checkutmp above */
+ strncpy(utent.ut_user, username, sizeof(utent.ut_user));
+ utent.ut_time = time(NULL);
+ /* other fields already filled in by read_or_build_utent above */
setutent();
pututline(&utent);
endutent();
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 08:26:50 +0000