1 /* pam_securetty module */
3 #define SECURETTY_FILE "/etc/securetty"
4 #define TTY_PREFIX "/dev/"
7 * by Elliot Lee <sopwith@redhat.com>, Red Hat Software.
9 * This code shamelessly ripped from the pam_rootok module.
10 * Slight modifications AGM. 1996/12/3
11 * $FreeBSD: src/contrib/libpam/modules/pam_securetty/pam_securetty.c,v 1.3.2.2 2001/06/11 15:28:27 markm Exp $
18 #include <sys/types.h>
29 * here, we make a definition for the externally accessible function
30 * in this file (this definition is required for static a module
31 * but strongly encouraged generally) it is used to instruct the
32 * modules include file to define the function prototypes.
37 #include <security/pam_modules.h>
41 static void _pam_log(int err, const char *format, ...)
45 va_start(args, format);
46 openlog("PAM-securetty", LOG_CONS|LOG_PID, LOG_AUTH);
47 vsyslog(err, format, args);
52 /* argument parsing */
54 #define PAM_DEBUG_ARG 0x0001
56 static int _pam_parse(int argc, const char **argv)
60 /* step through arguments */
61 for (ctrl=0; argc-- > 0; ++argv) {
65 if (!strcmp(*argv,"debug"))
66 ctrl |= PAM_DEBUG_ARG;
68 _pam_log(LOG_ERR,"pam_parse: unknown option; %s",*argv);
75 /* --- authentication management functions (only) --- */
78 int pam_sm_authenticate(pam_handle_t *pamh,int flags,int argc
81 int retval = PAM_AUTH_ERR;
84 char ttyfileline[256];
85 struct stat ttyfileinfo;
86 struct passwd *user_pwd;
90 /* parse the arguments */
91 ctrl = _pam_parse(argc, argv);
93 retval = pam_get_user(pamh, &username, NULL);
94 if (retval != PAM_SUCCESS || username == NULL) {
95 if (ctrl & PAM_DEBUG_ARG) {
96 _pam_log(LOG_WARNING, "cannot determine username");
98 return (retval == PAM_CONV_AGAIN
99 ? PAM_INCOMPLETE:PAM_SERVICE_ERR);
102 retval = pam_get_item(pamh, PAM_TTY, (const void **)&uttyname);
103 if (retval != PAM_SUCCESS || uttyname == NULL) {
104 if (ctrl & PAM_DEBUG_ARG) {
105 _pam_log(LOG_WARNING, "cannot determine user's tty");
107 return PAM_SERVICE_ERR;
110 /* The PAM_TTY item may be prefixed with "/dev/" - skip that */
111 if (strncmp(TTY_PREFIX, uttyname, sizeof(TTY_PREFIX)-1) == 0)
112 uttyname += sizeof(TTY_PREFIX)-1;
114 user_pwd = getpwnam(username);
115 if (user_pwd == NULL) {
117 } else if (user_pwd->pw_uid != 0) { /* If the user is not root,
118 securetty's does not apply
123 if (stat(SECURETTY_FILE, &ttyfileinfo)) {
124 _pam_log(LOG_NOTICE, "Couldn't open " SECURETTY_FILE);
125 return PAM_SUCCESS; /* for compatibility with old securetty handling,
126 this needs to succeed. But we still log the
130 if ((ttyfileinfo.st_mode & S_IWOTH)
131 || !S_ISREG(ttyfileinfo.st_mode)) {
132 /* If the file is world writable or is not a
133 normal file, return error */
134 _pam_log(LOG_ERR, SECURETTY_FILE
135 " is either world writable or not a normal file");
139 ttyfile = fopen(SECURETTY_FILE,"r");
140 if(ttyfile == NULL) { /* Check that we opened it successfully */
142 "Error opening " SECURETTY_FILE);
143 return PAM_SERVICE_ERR;
145 /* There should be no more errors from here on */
147 /* This loop assumes that PAM_SUCCESS == 0
148 and PAM_AUTH_ERR != 0 */
149 while((fgets(ttyfileline,sizeof(ttyfileline)-1, ttyfile) != NULL)
151 if(ttyfileline[strlen(ttyfileline) - 1] == '\n')
152 ttyfileline[strlen(ttyfileline) - 1] = '\0';
153 retval = strcmp(ttyfileline,uttyname);
157 if (ctrl & PAM_DEBUG_ARG)
158 _pam_log(LOG_WARNING, "access denied: tty '%s' is not secure !",
160 retval = PAM_AUTH_ERR;
162 if ((retval == PAM_SUCCESS) && (ctrl & PAM_DEBUG_ARG))
163 _pam_log(LOG_DEBUG, "access allowed for '%s' on '%s'",
169 int pam_sm_setcred(pam_handle_t *pamh,int flags,int argc
178 /* static module data */
180 struct pam_module _pam_securetty_modstruct = {
192 /* end of module definition */