Merge v6.19.9linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 827554963a7c..13f1f3b52b04 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6542,6 +6542,25 @@ int btrfs_create_new_inode(struct btrfs_trans_handle *trans,
 	int ret;
 	bool xa_reserved = false;
 
+	if (!args->orphan && !args->subvol) {
+		/*
+		 * Before anything else, check if we can add the name to the
+		 * parent directory. We want to avoid a dir item overflow in
+		 * case we have an existing dir item due to existing name
+		 * hash collisions. We do this check here before we call
+		 * btrfs_add_link() down below so that we can avoid a
+		 * transaction abort (which could be exploited by malicious
+		 * users).
+		 *
+		 * For subvolumes we already do this in btrfs_mksubvol().
+		 */
+		ret = btrfs_check_dir_item_collision(BTRFS_I(dir)->root,
+						     btrfs_ino(BTRFS_I(dir)),
+						     name);
+		if (ret < 0)
+			return ret;
+	}
+
 	path = btrfs_alloc_path();
 	if (!path)
 		return -ENOMEM;