From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
commit 48bd024b8a40d73ad6b086de2615738da0c7004f upstream.
In preparation for more permission checking, override credentials for
directory operations on the underlying filesystems.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@xxxxxxxxxxx>
---
fs/overlayfs/readdir.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 11b7941c5dbc..db9132a020de 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -735,8 +735,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
struct ovl_dir_file *od = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct ovl_cache_entry *p;
+ const struct cred *old_cred;
int err;
+ old_cred = ovl_override_creds(dentry->d_sb);
if (!ctx->pos)
ovl_dir_reset(file);
@@ -750,17 +752,20 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
(ovl_same_sb(dentry->d_sb) &&
(ovl_is_impure_dir(file) ||
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {
- return ovl_iterate_real(file, ctx);
+ err = ovl_iterate_real(file, ctx);
+ } else {
+ err = iterate_dir(od->realfile, ctx);
}
- return iterate_dir(od->realfile, ctx);
+ goto out;
}
if (!od->cache) {
struct ovl_dir_cache *cache;
cache = ovl_cache_get(dentry);
+ err = PTR_ERR(cache);
if (IS_ERR(cache))
- return PTR_ERR(cache);
+ goto out;
od->cache = cache;
ovl_seek_cursor(od, ctx->pos);
@@ -772,7 +777,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
if (!p->ino) {
err = ovl_cache_update_ino(&file->f_path, p);
if (err)
- return err;
+ goto out;
}
if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
break;
@@ -780,7 +785,10 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
od->cursor = p->l_node.next;
ctx->pos++;
}
- return 0;
+ err = 0;
+out:
+ revert_creds(old_cred);
+ return err;
}
static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
--
2.43.0
