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Date:      Tue, 6 Feb 2018 22:38:19 +0000 (UTC)
From:      "Pedro F. Giffuni" <pfg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r328957 - in head/sys: fs/ext2fs ufs/ufs
Message-ID:  <201802062238.w16McJCM050435@repo.freebsd.org>
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Author: pfg
Date: Tue Feb  6 22:38:19 2018
New Revision: 328957
URL: https://svnweb.freebsd.org/changeset/base/328957

Log:
  {ext2|ufs}_readdir: Avoid setting negative ncookies.
  
  ncookies cannot be negative or the allocator will fail. This should only
  happen if a caller is very broken but we can still try to survive the
  event.
  
  We should probably also verify for uio_resid > MAXPHYS but in that case
  it is not clear that just clipping the ncookies value is an adequate
  response.
  
  MFC after:	2 weeks

Modified:
  head/sys/fs/ext2fs/ext2_lookup.c
  head/sys/ufs/ufs/ufs_vnops.c

Modified: head/sys/fs/ext2fs/ext2_lookup.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_lookup.c	Tue Feb  6 22:17:01 2018	(r328956)
+++ head/sys/fs/ext2fs/ext2_lookup.c	Tue Feb  6 22:38:19 2018	(r328957)
@@ -153,7 +153,10 @@ ext2_readdir(struct vop_readdir_args *ap)
 		return (EINVAL);
 	ip = VTOI(vp);
 	if (ap->a_ncookies != NULL) {
-		ncookies = uio->uio_resid;
+		if (uio->uio_resid < 0)
+			ncookies = 0;
+		else
+			ncookies = uio->uio_resid;
 		if (uio->uio_offset >= ip->i_size)
 			ncookies = 0;
 		else if (ip->i_size - uio->uio_offset < ncookies)

Modified: head/sys/ufs/ufs/ufs_vnops.c
==============================================================================
--- head/sys/ufs/ufs/ufs_vnops.c	Tue Feb  6 22:17:01 2018	(r328956)
+++ head/sys/ufs/ufs/ufs_vnops.c	Tue Feb  6 22:38:19 2018	(r328957)
@@ -2179,7 +2179,10 @@ ufs_readdir(ap)
 	if (ip->i_effnlink == 0)
 		return (0);
 	if (ap->a_ncookies != NULL) {
-		ncookies = uio->uio_resid;
+		if (uio->uio_resid < 0)
+			ncookies = 0;
+		else
+			ncookies = uio->uio_resid;
 		if (uio->uio_offset >= ip->i_size)
 			ncookies = 0;
 		else if (ip->i_size - uio->uio_offset < ncookies)

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