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-rw-r--r--toys/login.c125
1 files changed, 40 insertions, 85 deletions
diff --git a/toys/login.c b/toys/login.c
index ac04adbe..c2c9ba38 100644
--- a/toys/login.c
+++ b/toys/login.c
@@ -30,7 +30,7 @@ config LOGIN
#define HOSTNAME_SIZE 32
DEFINE_GLOBALS(
- char * hostname;
+ char *hostname;
)
#define TT this.login
@@ -40,7 +40,7 @@ static void login_timeout_handler(int sig __attribute__((unused)))
exit(0);
}
-static const char *forbid[] = {
+static char *forbid[] = {
"BASH_ENV",
"ENV",
"HOME",
@@ -57,30 +57,16 @@ static const char *forbid[] = {
NULL
};
-// Unset dangerous environment variables.
-void sanitize_env()
-{
- const char **p = forbid;
- do {
- unsetenv(*p);
- p++;
- } while (*p);
-}
-
int verify_password(char * pwd)
{
- char * pass;
+ char *pass;
- if (read_password(toybuf, sizeof(toybuf), "Password: "))
- return 1;
- if (!pwd)
- return 1;
- if (pwd[0] == '!' || pwd[0] == '*')
- return 1;
+ if (read_password(toybuf, sizeof(toybuf), "Password: ")) return 1;
+ if (!pwd) return 1;
+ if (pwd[0] == '!' || pwd[0] == '*') return 1;
pass = crypt(toybuf, pwd);
- if (pass != NULL && strcmp(pass, pwd)==0)
- return 0;
+ if (pass && !strcmp(pass, pwd)) return 0;
return 1;
}
@@ -90,8 +76,7 @@ void read_user(char * buff, int size)
char hostname[HOSTNAME_SIZE+1];
int i = 0;
hostname[HOSTNAME_SIZE] = 0;
- if(!gethostname(hostname, HOSTNAME_SIZE))
- fputs(hostname, stdout);
+ if(!gethostname(hostname, HOSTNAME_SIZE)) fputs(hostname, stdout);
fputs(" login: ", stdout);
fflush(stdout);
@@ -106,10 +91,7 @@ void read_user(char * buff, int size)
if(!fgets(&buff[1], HOSTNAME_SIZE-1, stdin))
_exit(1);
- while(i<HOSTNAME_SIZE-1 && isgraph(buff[i]))
- {
- i++;
- }
+ while(i<HOSTNAME_SIZE-1 && isgraph(buff[i])) i++;
buff[i] = 0;
}
@@ -117,15 +99,12 @@ void handle_nologin(void)
{
int fd = open("/etc/nologin", O_RDONLY);
int size;
- if (fd == -1)
- return;
+ if (fd == -1) return;
size = readall(fd, toybuf,sizeof(toybuf)-1);
toybuf[size] = 0;
- if (!size)
- puts("System closed for routine maintenance\n");
- else
- puts(toybuf);
+ if (!size) puts("System closed for routine maintenance\n");
+ else puts(toybuf);
close(fd);
fflush(stdout);
@@ -136,8 +115,7 @@ void handle_motd(void)
{
int fd = open("/etc/motd", O_RDONLY);
int size;
- if (fd == -1)
- return;
+ if (fd == -1) return;
size = readall(fd, toybuf,sizeof(toybuf)-1);
toybuf[size] = 0;
@@ -149,12 +127,9 @@ void handle_motd(void)
int change_identity(const struct passwd *pwd)
{
- if (initgroups(pwd->pw_name,pwd->pw_gid))
- return 1;
- if (setgid(pwd->pw_uid))
- return 1;
- if (setuid(pwd->pw_uid))
- return 1;
+ if (initgroups(pwd->pw_name,pwd->pw_gid)) return 1;
+ if (setgid(pwd->pw_uid)) return 1;
+ if (setuid(pwd->pw_uid)) return 1;
return 0;
}
@@ -162,10 +137,8 @@ int change_identity(const struct passwd *pwd)
void spawn_shell(const char *shell)
{
const char * exec_name = strrchr(shell,'/');
- if (exec_name)
- exec_name++;
- else
- exec_name = shell;
+ if (exec_name) exec_name++;
+ else exec_name = shell;
snprintf(toybuf,sizeof(toybuf)-1, "-%s", shell);
execl(shell, toybuf, NULL);
@@ -174,20 +147,18 @@ void spawn_shell(const char *shell)
void setup_environment(const struct passwd *pwd, int clear_env)
{
- if (chdir(pwd->pw_dir))
- printf("can't chdir to home directory: %s\n", pwd->pw_dir);
+ if (chdir(pwd->pw_dir)) printf("bad home dir: %s\n", pwd->pw_dir);
- if (clear_env)
- {
+ if (clear_env) {
const char * term = getenv("TERM");
clearenv();
if (term) setenv("TERM", term, 1);
}
- setenv("USER", pwd->pw_name, 1);
- setenv("LOGNAME", pwd->pw_name, 1);
- setenv("HOME", pwd->pw_dir, 1);
- setenv("SHELL", pwd->pw_shell, 1);
+ setenv("USER", pwd->pw_name, 1);
+ setenv("LOGNAME", pwd->pw_name, 1);
+ setenv("HOME", pwd->pw_dir, 1);
+ setenv("SHELL", pwd->pw_shell, 1);
}
void login_main(void)
@@ -195,25 +166,23 @@ void login_main(void)
int f_flag = (toys.optflags & 4) >> 2;
int p_flag = (toys.optflags & 2) >> 1;
int h_flag = toys.optflags & 1;
- char username[USER_NAME_MAX_SIZE+1];
+ char username[USER_NAME_MAX_SIZE+1], *pass = NULL, **ss;
struct passwd * pwd = NULL;
struct spwd * spwd = NULL;
- char *pass = NULL;
int auth_fail_cnt = 0;
if (f_flag && toys.optc != 1)
error_exit("-f requires username");
- if (geteuid() != 0 )
- error_exit("Cannot possibly work without effective root");
+ if (geteuid()) error_exit("not root");
- if (!isatty(0) || !isatty(1) || !isatty(2))
- error_exit("Not connected to a tty");
+ if (!isatty(0) || !isatty(1) || !isatty(2)) error_exit("no tty");
openlog("login", LOG_PID | LOG_CONS, LOG_AUTH);
signal(SIGALRM, login_timeout_handler);
alarm(LOGIN_TIMEOUT);
- sanitize_env();
+
+ for (ss = forbid; *ss; ss++) unsetenv(*ss);
while (1) {
tcflush(0, TCIFLUSH);
@@ -223,47 +192,37 @@ void login_main(void)
strncpy(username, toys.optargs[0], USER_NAME_MAX_SIZE);
else {
read_user(username, USER_NAME_MAX_SIZE+1);
- if (username[0] == 0)
- continue;
+ if (username[0] == 0) continue;
}
pwd = getpwnam(username);
- if (!pwd)
- goto query_pass; // Non-existing user
+ if (!pwd) goto query_pass; // Non-existing user
if (pwd->pw_passwd[0] == '!' || pwd->pw_passwd[0] == '*')
goto query_pass; // Locked account
- if (f_flag)
- break; // Pre-authenticated
+ if (f_flag) break; // Pre-authenticated
- if (pwd->pw_passwd[0] == '\0')
- break; // Password-less account
+ if (!pwd->pw_passwd[0]) break; // Password-less account
pass = pwd->pw_passwd;
if (pwd->pw_passwd[0] == 'x') {
spwd = getspnam (username);
- if (spwd)
- pass = spwd->sp_pwdp;
+ if (spwd) pass = spwd->sp_pwdp;
}
- query_pass:
- if (!verify_password(pass))
- break;
+query_pass:
+ if (!verify_password(pass)) break;
f_flag = 0;
syslog(LOG_WARNING, "invalid password for '%s' on %s %s %s", username,
- ttyname(0),
- (h_flag)?"from":"",
- (h_flag)?TT.hostname:"");
+ ttyname(0), (h_flag)?"from":"", (h_flag)?TT.hostname:"");
sleep(LOGIN_FAIL_TIMEOUT);
puts("Login incorrect");
if (++auth_fail_cnt == 3)
- {
error_exit("Maximum number of tries exceeded (%d)\n", auth_fail_cnt);
- }
username[0] = 0;
pwd = NULL;
@@ -272,20 +231,16 @@ void login_main(void)
alarm(0);
- if (pwd->pw_uid)
- handle_nologin();
+ if (pwd->pw_uid) handle_nologin();
- if (change_identity(pwd))
- error_exit("Failed to change identity");
+ if (change_identity(pwd)) error_exit("Failed to change identity");
setup_environment(pwd, !p_flag);
handle_motd();
syslog(LOG_INFO, "%s logged in on %s %s %s", pwd->pw_name,
- ttyname(0),
- (h_flag)?"from":"",
- (h_flag)?TT.hostname:"");
+ ttyname(0), (h_flag)?"from":"", (h_flag)?TT.hostname:"");
spawn_shell(pwd->pw_shell);
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 00:30:39 +0000