1 files changed, 109 insertions, 0 deletions
diff --git a/gnu/libexec/uucp/libunix/uid.c b/gnu/libexec/uucp/libunix/uid.c
new file mode 100644
index 0000000..b93e2a9
--- /dev/null
+++ b/gnu/libexec/uucp/libunix/uid.c
@@ -0,0 +1,109 @@
+/* uid.c
+   Switch back and forth between UUCP and user permissions.
+
+   Copyright (C) 1992, 1995 Ian Lance Taylor
+
+   This file is part of the Taylor UUCP package.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+   The author of the program may be contacted at ian@airs.com or
+   c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
+   */
+
+#include "uucp.h"
+
+#include "uudefs.h"
+#include "sysdep.h"
+
+#include <errno.h>
+
+/* Switch to permissions of the invoking user.  */
+
+boolean
+fsuser_perms (pieuid)
+     uid_t *pieuid;
+{
+  uid_t ieuid, iuid;
+
+  ieuid = geteuid ();
+  iuid = getuid ();
+  if (pieuid != NULL)
+    *pieuid = ieuid;
+
+#if HAVE_SETREUID
+  /* Swap the effective user id and the real user id.  We can then
+     swap them back again when we want to return to the uucp user's
+     permissions.  */
+  if (setreuid (ieuid, iuid) < 0)
+    {
+      ulog (LOG_ERROR, "setreuid (%ld, %ld): %s",
+	    (long) ieuid, (long) iuid, strerror (errno));
+      return FALSE;
+    }
+#else /* ! HAVE_SETREUID */
+#if HAVE_SAVED_SETUID
+  /* Set the effective user id to the real user id.  Since the
+     effective user id is saved (it's the saved setuid) we will able
+     to set back to it later.  If the real user id is root we will not
+     be able to switch back and forth, so don't even try.  */
+  if (iuid != 0)
+    {
+      if (setuid (iuid) < 0)
+	{
+	  ulog (LOG_ERROR, "setuid (%ld): %s", (long) iuid, strerror (errno));
+	  return FALSE;
+	}
+    }
+#else /* ! HAVE_SAVED_SETUID */
+  /* There's no way to switch between real permissions and effective
+     permissions.  Just try to open the file with the uucp
+     permissions.  */
+#endif /* ! HAVE_SAVED_SETUID */
+#endif /* ! HAVE_SETREUID */
+
+  return TRUE;
+}
+
+/* Restore the uucp permissions.  */
+
+/*ARGSUSED*/
+boolean
+fsuucp_perms (ieuid)
+     long ieuid;
+{
+#if HAVE_SETREUID
+  /* Swap effective and real user id's back to what they were.  */
+  if (! fsuser_perms ((uid_t *) NULL))
+    return FALSE;
+#else /* ! HAVE_SETREUID */
+#if HAVE_SAVED_SETUID
+  /* Set ourselves back to our original effective user id.  */
+  if (setuid ((uid_t) ieuid) < 0)
+    {
+      ulog (LOG_ERROR, "setuid (%ld): %s", (long) ieuid, strerror (errno));
+      /* Is this error message helpful or confusing?  */
+      if (errno == EPERM)
+	ulog (LOG_ERROR,
+	      "Probably HAVE_SAVED_SETUID in policy.h should be set to 0");
+      return FALSE;
+    }
+#else /* ! HAVE_SAVED_SETUID */
+  /* We didn't switch, no need to switch back.  */
+#endif /* ! HAVE_SAVED_SETUID */
+#endif /* ! HAVE_SETREUID */
+
+  return TRUE;
+}