Merge tag 'ovl-update-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:

 - Fix a regression introduced in the last cycle

 - Fix a use-after-free in the AIO path

 - Fix a bogus warning reported by syzbot

* tag 'ovl-update-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix filattr copy-up failure
  ovl: fix warning in ovl_create_real()
  ovl: fix use after free in struct ovl_aio_req

1 files changed, 14 insertions, 2 deletions

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index ac461a499882..fa125feed0ff 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -17,6 +17,7 @@
 
 struct ovl_aio_req {
 	struct kiocb iocb;
+	refcount_t ref;
 	struct kiocb *orig_iocb;
 	struct fd fd;
 };
@@ -252,6 +253,14 @@ static rwf_t ovl_iocb_to_rwf(int ifl)
 	return flags;
 }
 
+static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
+{
+	if (refcount_dec_and_test(&aio_req->ref)) {
+		fdput(aio_req->fd);
+		kmem_cache_free(ovl_aio_request_cachep, aio_req);
+	}
+}
+
 static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
 {
 	struct kiocb *iocb = &aio_req->iocb;
@@ -268,8 +277,7 @@ static void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
 	}
 
 	orig_iocb->ki_pos = iocb->ki_pos;
-	fdput(aio_req->fd);
-	kmem_cache_free(ovl_aio_request_cachep, aio_req);
+	ovl_aio_put(aio_req);
 }
 
 static void ovl_aio_rw_complete(struct kiocb *iocb, long res)
@@ -319,7 +327,9 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 		aio_req->orig_iocb = iocb;
 		kiocb_clone(&aio_req->iocb, iocb, real.file);
 		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
+		refcount_set(&aio_req->ref, 2);
 		ret = vfs_iocb_iter_read(real.file, &aio_req->iocb, iter);
+		ovl_aio_put(aio_req);
 		if (ret != -EIOCBQUEUED)
 			ovl_aio_cleanup_handler(aio_req);
 	}
@@ -390,7 +400,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 		kiocb_clone(&aio_req->iocb, iocb, real.file);
 		aio_req->iocb.ki_flags = ifl;
 		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
+		refcount_set(&aio_req->ref, 2);
 		ret = vfs_iocb_iter_write(real.file, &aio_req->iocb, iter);
+		ovl_aio_put(aio_req);
 		if (ret != -EIOCBQUEUED)
 			ovl_aio_cleanup_handler(aio_req);
 	}