svn commit: r187882 - in stable/7/sys: . contrib/pf dev/cxgb kern

[Konstantin Belousov]

Author: kib
Date: Thu Jan 29 10:33:32 2009
New Revision: 187882
URL: http://svn.freebsd.org/changeset/base/187882

Log:
  MFC r186601:
  Clear the pointers to the file in the struct filedesc before file is closed
  in fdfree. Otherwise, sysctl_kern_proc_filedesc may dereference stale
  struct file * values.

Modified:
  stable/7/sys/   (props changed)
  stable/7/sys/contrib/pf/   (props changed)
  stable/7/sys/dev/cxgb/   (props changed)
  stable/7/sys/kern/kern_descrip.c

Modified: stable/7/sys/kern/kern_descrip.c
==============================================================================
--- stable/7/sys/kern/kern_descrip.c	Thu Jan 29 09:32:56 2009	(r187881)
+++ stable/7/sys/kern/kern_descrip.c	Thu Jan 29 10:33:32 2009	(r187882)
@@ -1733,14 +1733,16 @@ fdfree(struct thread *td)
 	FILEDESC_XUNLOCK(fdp);
 	if (i > 0)
 		return;
-	/*
-	 * We are the last reference to the structure, so we can
-	 * safely assume it will not change out from under us.
-	 */
+
 	fpp = fdp->fd_ofiles;
 	for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
-		if (*fpp)
-			(void) closef(*fpp, td);
+		if (*fpp) {
+			FILEDESC_XLOCK(fdp);
+			fp = *fpp;
+			*fpp = NULL;
+			FILEDESC_XUNLOCK(fdp);
+			(void) closef(fp, td);
+		}
 	}
 	FILEDESC_XLOCK(fdp);