Index should always be of the same file type as origin, except for
the case of a whiteout index. A whiteout index should only exist
if all lower aliases have been unlinked, which means that finding
a lower origin on lookup whose index is a whiteout should be treated
as a lookup error.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/namei.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 229a88ff335c..8aef2b304b2d 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -513,6 +513,7 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry,
goto out;
}
+ inode = d_inode(index);
if (d_is_negative(index)) {
if (upper && d_inode(origin)->i_nlink > 1) {
pr_warn_ratelimited("overlayfs: hard link with origin but no index (ino=%lu).\n",
@@ -522,11 +523,22 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry,
dput(index);
index = NULL;
- } else if (upper && d_inode(index) != d_inode(upper)) {
- inode = d_inode(index);
- pr_warn_ratelimited("overlayfs: wrong index found (index ino: %lu, upper ino: %lu).\n",
- d_inode(index)->i_ino,
- d_inode(upper)->i_ino);
+ } else if (upper && d_inode(upper) != inode) {
+ pr_warn_ratelimited("overlayfs: wrong index found (index=%pd2, ino=%lu, upper ino=%lu).\n",
+ index, inode->i_ino, d_inode(upper)->i_ino);
+ goto fail;
+ } else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) ||
+ ((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) {
+ /*
+ * Index should always be of the same file type as origin
+ * except for the case of a whiteout index. A whiteout
+ * index should only exist if all lower aliases have been
+ * unlinked, which means that finding a lower origin on lookup
+ * whose index is a whiteout should be treated as an error.
+ */
+ pr_warn_ratelimited("overlayfs: bad index found (index=%pd2, ftype=%x, origin ftype=%x).\n",
+ index, d_inode(index)->i_mode & S_IFMT,
+ d_inode(origin)->i_mode & S_IFMT);
goto fail;
}
--
2.7.4
--
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