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authorAmir Goldstein <amir73il@gmail.com>2017-10-24 12:24:11 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-02 09:54:47 +0100
commit29fd10fb041b08f225df85a514bd6e2e55d84316 (patch)
parent725b704522357dad35d46cd0a2b26418669fd06f (diff)
ovl: do not cleanup unsupported index entries
commit fa0096e3bad69ed6f34843fd7ae1c45ca987012a upstream. With index=on, ovl_indexdir_cleanup() tries to cleanup invalid index entries (e.g. bad index name). This behavior could result in cleaning of entries created by newer kernels and is therefore undesirable. Instead, abort mount if such entries are encountered. We still cleanup 'stale' entries and 'orphan' entries, both those cases can be a result of offline changes to lower and upper dirs. When encoutering an index entry of type directory or whiteout, kernel was supposed to fallback to read-only mount, but the fill_super() operation returns EROFS in this case instead of returning success with read-only mount flag, so mount fails when encoutering directory or whiteout index entries. Bless this behavior by returning -EINVAL on directory and whiteout index entries as we do for all unsupported index entries. Fixes: 61b674710cd9 ("ovl: do not cleanup directory and whiteout index..") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 8 insertions, 10 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index e2fc425da165..0223ef4acbe4 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -405,14 +405,13 @@ int ovl_verify_index(struct dentry *index, struct path *lowerstack,
* be treated as stale (i.e. after unlink of the overlay inode).
* We don't know the verification rules for directory and whiteout
* index entries, because they have not been implemented yet, so return
- * EROFS if those entries are found to avoid corrupting an index that
- * was created by a newer kernel.
+ * EINVAL if those entries are found to abort the mount to avoid
+ * corrupting an index that was created by a newer kernel.
- err = -EROFS;
+ err = -EINVAL;
if (d_is_dir(index) || ovl_is_whiteout(index))
goto fail;
- err = -EINVAL;
if (index->d_name.len < sizeof(struct ovl_fh)*2)
goto fail;
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 74f7ead442f0..3ff960372cb9 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -704,13 +704,12 @@ int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
err = ovl_verify_index(index, lowerstack, numlower);
- if (err) {
- if (err == -EROFS)
- break;
+ /* Cleanup stale and orphan index entries */
+ if (err && (err == -ESTALE || err == -ENOENT))
err = ovl_cleanup(dir, index);
- if (err)
- break;
- }
+ if (err)
+ break;
index = NULL;