[PATCH 4.19 016/306] Revert "fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()"

From: Greg Kroah-Hartman
Date: Wed Nov 27 2019 - 15:55:37 EST


From: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>

commit 94b07b6f9e2e996afff7395de6b35f34f4cb10bf upstream.

This reverts commit 56e94ea132bb5c2c1d0b60a6aeb34dcb7d71a53d.

Commit 56e94ea132bb ("fs: ocfs2: fix possible null-pointer dereferences
in ocfs2_xa_prepare_entry()") introduces a regression that fail to
create directory with mount option user_xattr and acl. Actually the
reported NULL pointer dereference case can be correctly handled by
loc->xl_ops->xlo_add_entry(), so revert it.

Link: http://lkml.kernel.org/r/1573624916-83825-1-git-send-email-joseph.qi@xxxxxxxxxxxxxxxxx
Fixes: 56e94ea132bb ("fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()")
Signed-off-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Reported-by: Thomas Voegtle <tv@xxxxxxxx>
Acked-by: Changwei Ge <gechangwei@xxxxxxx>
Cc: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/ocfs2/xattr.c | 56 ++++++++++++++++++++++++++++++++-----------------------
1 file changed, 33 insertions(+), 23 deletions(-)

--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -1498,6 +1498,18 @@ static int ocfs2_xa_check_space(struct o
return loc->xl_ops->xlo_check_space(loc, xi);
}

+static void ocfs2_xa_add_entry(struct ocfs2_xa_loc *loc, u32 name_hash)
+{
+ loc->xl_ops->xlo_add_entry(loc, name_hash);
+ loc->xl_entry->xe_name_hash = cpu_to_le32(name_hash);
+ /*
+ * We can't leave the new entry's xe_name_offset at zero or
+ * add_namevalue() will go nuts. We set it to the size of our
+ * storage so that it can never be less than any other entry.
+ */
+ loc->xl_entry->xe_name_offset = cpu_to_le16(loc->xl_size);
+}
+
static void ocfs2_xa_add_namevalue(struct ocfs2_xa_loc *loc,
struct ocfs2_xattr_info *xi)
{
@@ -2129,31 +2141,29 @@ static int ocfs2_xa_prepare_entry(struct
if (rc)
goto out;

- if (!loc->xl_entry) {
- rc = -EINVAL;
- goto out;
- }
-
- if (ocfs2_xa_can_reuse_entry(loc, xi)) {
- orig_value_size = loc->xl_entry->xe_value_size;
- rc = ocfs2_xa_reuse_entry(loc, xi, ctxt);
- if (rc)
- goto out;
- goto alloc_value;
- }
+ if (loc->xl_entry) {
+ if (ocfs2_xa_can_reuse_entry(loc, xi)) {
+ orig_value_size = loc->xl_entry->xe_value_size;
+ rc = ocfs2_xa_reuse_entry(loc, xi, ctxt);
+ if (rc)
+ goto out;
+ goto alloc_value;
+ }

- if (!ocfs2_xattr_is_local(loc->xl_entry)) {
- orig_clusters = ocfs2_xa_value_clusters(loc);
- rc = ocfs2_xa_value_truncate(loc, 0, ctxt);
- if (rc) {
- mlog_errno(rc);
- ocfs2_xa_cleanup_value_truncate(loc,
- "overwriting",
- orig_clusters);
- goto out;
+ if (!ocfs2_xattr_is_local(loc->xl_entry)) {
+ orig_clusters = ocfs2_xa_value_clusters(loc);
+ rc = ocfs2_xa_value_truncate(loc, 0, ctxt);
+ if (rc) {
+ mlog_errno(rc);
+ ocfs2_xa_cleanup_value_truncate(loc,
+ "overwriting",
+ orig_clusters);
+ goto out;
+ }
}
- }
- ocfs2_xa_wipe_namevalue(loc);
+ ocfs2_xa_wipe_namevalue(loc);
+ } else
+ ocfs2_xa_add_entry(loc, name_hash);

/*
* If we get here, we have a blank entry. Fill it. We grow our