From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Tue, 22 Jan 2013 17:05:49 +0000 (-0800)
Subject: Fix zpl_revalidate() NULL deref
X-Git-Url: https://git.camperquake.de/gitweb.cgi?a=commitdiff_plain;h=09a661e960df49f1256ba4c5ae15f6956d27df84;p=zfs.git

Fix zpl_revalidate() NULL deref

In zpl_revalidate() it's possible for the nameidata to be NULL
for kernels which still accept the parameter.  In particular,
lookup_one_len() calls d_revalidate() with a NULL nameidata.

Resolve the issue by checking for a NULL nameidata in which case
just set the flags to 0.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1226
---

diff --git a/module/zfs/zpl_inode.c b/module/zfs/zpl_inode.c
index 0f6f3a4..e406288 100644
--- a/module/zfs/zpl_inode.c
+++ b/module/zfs/zpl_inode.c
@@ -396,7 +396,7 @@ static int
 #ifdef HAVE_D_REVALIDATE_NAMEIDATA
 zpl_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-	unsigned int flags = nd->flags;
+	unsigned int flags = (nd ? nd->flags : 0);
 #else
 zpl_revalidate(struct dentry *dentry, unsigned int flags)
 {