Improved local login detection

pam_usb/src/local.c

@@ -22,20 +22,26 @@
 #include "log.h"
 #include "conf.h"
 
-int		pusb_local_login(t_pusb_options *opts, const char *user)
+int		pusb_local_login(t_pusb_options *opts, const char *user,
+				 const char *from)
 {
-  char		*from;
   struct utmp	utsearch;
   struct utmp	*utent;
   int		i;
 
   log_debug("Checking whether the caller is local or not...\n");
-  from = ttyname(STDIN_FILENO);
-  if (!from)
-      return (1);
+  if (!from || !(*from))
+    {
+      from = ttyname(STDIN_FILENO);
+      if (!from)
+	{
+	  log_debug("Couldn't retrieve the tty name, aborting.\n");
+	  return (1);
+	}
+      if (!strncmp(from, "/dev/", strlen("/dev/")))
+	from += strlen("/dev/");
+    }
   log_debug("Authentication request from tty %s\n", from);
-  if (!strncmp(from, "/dev/", strlen("/dev/")))
-    from += strlen("/dev/");
   strncpy(utsearch.ut_line, from, sizeof(utsearch.ut_line));
   setutent();
   utent = getutline(&utsearch);

pam_usb/src/local.h

@@ -18,6 +18,7 @@
 #ifndef PUSB_LOCAL_H_
 # define PUSB_LOCAL_H_
 
-int	pusb_local_login(t_pusb_options *opts, const char *user);
+int	pusb_local_login(t_pusb_options *opts, const char *user,
+			 const char *tty);
 
 #endif /* !PUSB_LOCAL_H_ */

pam_usb/src/pam.c

@@ -32,6 +32,7 @@ int			pam_sm_authenticate(pam_handle_t *pamh, int flags,
   t_pusb_options	opts;
   const char		*service;
   const char		*user;
+  const char		*tty;
   char			*conf_file = PUSB_CONF_FILE;
   int			retval;
 
@@ -65,7 +66,10 @@ int			pam_sm_authenticate(pam_handle_t *pamh, int flags,
   log_info("pam_usb v.%s\n", PUSB_VERSION);
   log_info("Authentication request for user \"%s\" (%s)\n",
 	   user, service);
-  if (!pusb_local_login(&opts, user))
+
+  if (pam_get_item(pamh, PAM_TTY, (const void **)&tty) != PAM_SUCCESS)
+    tty = NULL;
+  if (!pusb_local_login(&opts, user, tty))
     {
       log_error("Access denied.\n");
       return (PAM_AUTH_ERR);

pam_usb/src/pusb_check.c

@@ -52,7 +52,7 @@ static int	pusb_check_perform_authentication(t_pusb_options *opts,
     }
   log_info("Authentication request for user \"%s\" (%s)\n",
 	   user, service);
-  if (!pusb_local_login(opts, user))
+  if (!pusb_local_login(opts, user, NULL))
     {
       log_error("Access denied.\n");
       return (0);