Move __cleanup into mprotect'ed page to prevent unintentional modifications

similar to the atexit handlers. Idea and help deraadt@, ok deraadt@

4 files changed, 12 insertions, 11 deletions

diff --git a/lib/libc/stdio/findfp.c b/lib/libc/stdio/findfp.c
index 0702efad985..3aa66965367 100644
--- a/lib/libc/stdio/findfp.c
+++ b/lib/libc/stdio/findfp.c
@@ -35,7 +35,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: findfp.c,v 1.2 1996/08/19 08:32:36 tholo Exp $";
+static char rcsid[] = "$OpenBSD: findfp.c,v 1.3 2002/09/14 22:03:14 dhartmei Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
@@ -141,9 +141,10 @@ f_prealloc()
 }
 
 /*
- * exit() calls _cleanup() through *__cleanup, set whenever we
- * open or buffer a file.  This chicanery is done so that programs
- * that do not use stdio need not link it all in.
+ * exit() and abort() call _cleanup() through the callback registered
+ * with __atexit_register_cleanup(), set whenever we open or buffer a
+ * file. This chicanery is done so that programs that do not use stdio
+ * need not link it all in.
  *
  * The name `_cleanup' is, alas, fairly well known outside stdio.
  */
@@ -161,6 +162,6 @@ void
 __sinit()
 {
 	/* make sure we clean up on exit */
-	__cleanup = _cleanup;		/* conservative */
+	__atexit_register_cleanup(_cleanup); /* conservative */
 	__sdidinit = 1;
 }
diff --git a/lib/libc/stdio/local.h b/lib/libc/stdio/local.h
index 70d5c564471..05060408f82 100644
--- a/lib/libc/stdio/local.h
+++ b/lib/libc/stdio/local.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: local.h,v 1.4 2002/02/17 19:42:23 millert Exp $	*/
+/*	$OpenBSD: local.h,v 1.5 2002/09/14 22:03:14 dhartmei Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -50,13 +50,13 @@ fpos_t	__sseek(void *, fpos_t, int);
 int	__sclose(void *);
 void	__sinit(void);
 void	_cleanup(void);
-void	(*__cleanup)(void);
 void	__smakebuf(FILE *);
 int	__swhatbuf(FILE *, size_t *, int *);
 int	_fwalk(int (*)(FILE *));
 int	__swsetup(FILE *);
 int	__sflags(const char *, int *);
 
+extern void __atexit_register_cleanup(void (*)());
 extern int __sdidinit;
 
 /*
diff --git a/lib/libc/stdio/makebuf.c b/lib/libc/stdio/makebuf.c
index 4ebc3e93362..da9b86ca4ce 100644
--- a/lib/libc/stdio/makebuf.c
+++ b/lib/libc/stdio/makebuf.c
@@ -35,7 +35,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: makebuf.c,v 1.3 1998/11/25 05:18:49 millert Exp $";
+static char rcsid[] = "$OpenBSD: makebuf.c,v 1.4 2002/09/14 22:03:14 dhartmei Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/types.h>
@@ -73,7 +73,7 @@ __smakebuf(fp)
 		fp->_bf._size = 1;
 		return;
 	}
-	__cleanup = _cleanup;
+	__atexit_register_cleanup(_cleanup);
 	flags |= __SMBF;
 	fp->_bf._base = fp->_p = p;
 	fp->_bf._size = size;
diff --git a/lib/libc/stdio/setvbuf.c b/lib/libc/stdio/setvbuf.c
index 65501fce9d9..0c6fd8d1623 100644
--- a/lib/libc/stdio/setvbuf.c
+++ b/lib/libc/stdio/setvbuf.c
@@ -35,7 +35,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.3 2001/07/09 06:57:44 deraadt Exp $";
+static char rcsid[] = "$OpenBSD: setvbuf.c,v 1.4 2002/09/14 22:03:14 dhartmei Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <stdio.h>
@@ -155,7 +155,7 @@ nbf:
 		/* begin/continue reading, or stay in intermediate state */
 		fp->_w = 0;
 	}
-	__cleanup = _cleanup;
+	__atexit_register_cleanup(_cleanup);
 
 	return (ret);
 }