svn commit: r358192 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Fri Feb 21 01:44:31 2020
New Revision: 358192
URL: https://svnweb.freebsd.org/changeset/base/358192

Log:
  vfs: stop duplicating vnode work in audit during path lookup
  
  Duplicating the work was putting an avoidable requirement that the filedesc
  lock is held across the entire operation (otherwise by the time audit reads
  vnode pointers another thread in the same process can chdir somewhere else,
  making audit log things using different vnode than the one which will be
  used for actual lookup).
  
  Do the obvious thing and pass down vnodes which will be used.

Modified:
  head/sys/kern/vfs_lookup.c

Modified: head/sys/kern/vfs_lookup.c
==============================================================================
--- head/sys/kern/vfs_lookup.c	Fri Feb 21 01:40:49 2020	(r358191)
+++ head/sys/kern/vfs_lookup.c	Fri Feb 21 01:44:31 2020	(r358192)
@@ -403,14 +403,6 @@ namei(struct nameidata *ndp)
 	ndp->ni_rootdir = fdp->fd_rdir;
 	ndp->ni_topdir = fdp->fd_jdir;
 
-	/*
-	 * If we are auditing the kernel pathname, save the user pathname.
-	 */
-	if (cnp->cn_flags & AUDITVNODE1)
-		AUDIT_ARG_UPATH1(td, ndp->ni_dirfd, cnp->cn_pnbuf);
-	if (cnp->cn_flags & AUDITVNODE2)
-		AUDIT_ARG_UPATH2(td, ndp->ni_dirfd, cnp->cn_pnbuf);
-
 	startdir_used = 0;
 	dp = NULL;
 	cnp->cn_nameptr = cnp->cn_pnbuf;
@@ -505,6 +497,13 @@ namei(struct nameidata *ndp)
 			ndp->ni_lcf |= NI_LCF_LATCH;
 	}
 	FILEDESC_SUNLOCK(fdp);
+	/*
+	 * If we are auditing the kernel pathname, save the user pathname.
+	 */
+	if (cnp->cn_flags & AUDITVNODE1)
+		AUDIT_ARG_UPATH1_VP(td, ndp->ni_rootdir, dp, cnp->cn_pnbuf);
+	if (cnp->cn_flags & AUDITVNODE2)
+		AUDIT_ARG_UPATH2_VP(td, ndp->ni_rootdir, dp, cnp->cn_pnbuf);
 	if (ndp->ni_startdir != NULL && !startdir_used)
 		vrele(ndp->ni_startdir);
 	if (error != 0) {