Summary of login.conf support changes:

o Incorporated BSDI code and enhancements, better logging for error
  checking (which has been shown to be a problem, and is therefore
  justified, imho); also some minor things we were missing, including
  better quad_t math, which checks for under/overflows.

o setusercontext() now allows user resource limit overrides, but
  does this AFTER dropping root privs, to restrict the user to
  droping hard limits and set soft limits within the kernel's
  allowed user limits.

o umask() only set once, and only if requested.

o add _secure_path(), and use in login.conf to guard against
  symlinks etc. and non-root owned or non-user owned files being
  used. Derived from BSDI contributed code.

o revamped authentication code to BSDI's latest api, which
  includes deleting authenticate() and adding auth_check()
  and a few other functions. This is still marked as depecated
  in BSDI, but is included for completeness. No other source
  in the tree uses this anyway, so it is now bracketed with
  #ifdef LOGIN_CAP_AUTH which is by default not defined. Only
  auth_checknologin() and auth_cat() are actually used in
  module login_auth.c.

o AUTH_NONE definition removed (collided with other includes
  in the tree). [bde]

o BSDI's login_getclass() now accepts a char *classname
  parameter rather than struct passwd *pwd. We now do likewise,
  but added login_getpwclass() for (sort of) backwards
  compatiblity, namely because we handle root as a special
  case for the default class. This will require quite a few
  changes elsewhere in the source tree.

o We no longer pretend to support rlim_t as a long type.

o Revised code formatting to be more bsd-ish style.

1 files changed, 72 insertions, 0 deletions

diff --git a/libutil/_secure_path.c b/libutil/_secure_path.c
new file mode 100644
index 0000000..38a974e
--- /dev/null
+++ b/libutil/_secure_path.c
@@ -0,0 +1,72 @@
+/*-
+ * Based on code copyright (c) 1995,1997 by
+ * Berkeley Software Design, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, is permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice immediately at the beginning of the file, without modification,
+ *    this list of conditions, and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. This work was done expressly for inclusion into FreeBSD.  Other use
+ *    is permitted provided this notation is included.
+ * 4. Absolutely no warranty of function or purpose is made by the authors.
+ * 5. Modifications may be freely made to this file providing the above
+ *    conditions are met.
+ *
+ *	$Id$
+ */
+
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <syslog.h>
+#include <errno.h>
+#include <libutil.h>
+
+/*
+ * Check for common security problems on a given path
+ * It must be:
+ * 1. A regular file, and exists
+ * 2. Owned and writaable only by root (or given owner)
+ * 3. Group ownership is given group or is non-group writable
+ *
+ * Returns:	-2 if file does not exist,
+ *		-1 if security test failure
+ *		0  otherwise
+ */
+
+int
+_secure_path(const char *path, uid_t uid, gid_t gid)
+{
+    int		r = -1;
+    struct stat	sb;
+    const char	*msg = NULL;
+
+    if (lstat(path, &sb) < 0) {
+	if (errno == ENOENT) /* special case */
+	    r = -2;  /* if it is just missing, skip the log entry */
+	else
+	    msg = "%s: cannot stat %s: %m";
+    }
+    else if (!S_ISREG(sb.st_mode))
+    	msg = "%s: %s is not a regular file";
+    else if (sb.st_mode & S_IWOTH)
+    	msg = "%s: %s is world writable";
+    else if (uid != -1 && sb.st_uid != uid) {
+    	if (uid == 0)
+    		msg = "%s: %s is not owned by root";
+    	else
+    		msg = "%s: %s is not owned by uid %d";
+    } else if (gid != -1 && sb.st_gid != gid && (sb.st_mode & S_IWGRP))
+    	msg = "%s: %s is group writeable by non-authorised groups";
+    else
+    	r = 0;
+    if (msg != NULL)
+	syslog(LOG_ERR, msg, "_secure_path", path, uid);
+    return r;
+}