From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE8E4EB64DD for ; Sun, 16 Jul 2023 16:30:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229798AbjGPQaW (ORCPT ); Sun, 16 Jul 2023 12:30:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229461AbjGPQaW (ORCPT ); Sun, 16 Jul 2023 12:30:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A4DAE4B for ; Sun, 16 Jul 2023 09:30:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8990860D42 for ; Sun, 16 Jul 2023 16:30:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 69AEEC433C7; Sun, 16 Jul 2023 16:30:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689525019; bh=1KdjfWWTZ5cvYI0hAxKzKZQpfjCB2VhhDjb2RSf4lf8=; h=Subject:To:Cc:From:Date:From; b=ScoSIX1ku+BgSImKVxAfUYbFJf9kInKrws/Ha++XEU2pVCAVK1Z4lw1VD1YMRjNTA hN779inotfUlQGh6HBPw5xmFEbCrjS1/dbz883gTUfyql5LpXKubWSu2PIt4+kqZzT D8LsTwWSGqLi9CrwkcflBsPqipujbS+LBo4BtxX0= Subject: FAILED: patch "[PATCH] ovl: fix null pointer dereference in ovl_permission()" failed to apply to 6.1-stable tree To: chengzhihao1@huawei.com, amir73il@gmail.com, brauner@kernel.org, mszeredi@redhat.com, stable@vger.kernel.org Cc: From: Date: Sun, 16 Jul 2023 18:30:16 +0200 Message-ID: <2023071616-vastly-cognition-78ba@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 1a73f5b8f079fd42a544c1600beface50c63af7c # git commit -s git send-email --to '' --in-reply-to '2023071616-vastly-cognition-78ba@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 1a73f5b8f079 ("ovl: fix null pointer dereference in ovl_permission()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 1a73f5b8f079fd42a544c1600beface50c63af7c Mon Sep 17 00:00:00 2001 From: Zhihao Cheng Date: Tue, 16 May 2023 22:16:18 +0800 Subject: [PATCH] ovl: fix null pointer dereference in ovl_permission() Following process: P1 P2 path_lookupat link_path_walk inode_permission ovl_permission ovl_i_path_real(inode, &realpath) path->dentry = ovl_i_dentry_upper(inode) drop_cache __dentry_kill(ovl_dentry) iput(ovl_inode) ovl_destroy_inode(ovl_inode) dput(oi->__upperdentry) dentry_kill(upperdentry) dentry_unlink_inode upperdentry->d_inode = NULL realinode = d_inode(realpath.dentry) // return NULL inode_permission(realinode) inode->i_sb // NULL pointer dereference , will trigger an null pointer dereference at realinode: [ 335.664979] BUG: kernel NULL pointer dereference, address: 0000000000000002 [ 335.668032] CPU: 0 PID: 2592 Comm: ls Not tainted 6.3.0 [ 335.669956] RIP: 0010:inode_permission+0x33/0x2c0 [ 335.678939] Call Trace: [ 335.679165] [ 335.679371] ovl_permission+0xde/0x320 [ 335.679723] inode_permission+0x15e/0x2c0 [ 335.680090] link_path_walk+0x115/0x550 [ 335.680771] path_lookupat.isra.0+0xb2/0x200 [ 335.681170] filename_lookup+0xda/0x240 [ 335.681922] vfs_statx+0xa6/0x1f0 [ 335.682233] vfs_fstatat+0x7b/0xb0 Fetch a reproducer in [Link]. Use the helper ovl_i_path_realinode() to get realinode and then do non-nullptr checking. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217405 Fixes: 4b7791b2e958 ("ovl: handle idmappings in ovl_permission()") Cc: # v5.19 Signed-off-by: Zhihao Cheng Suggested-by: Christian Brauner Suggested-by: Amir Goldstein Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 541cf3717fc2..ca56b1328a2c 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -288,8 +288,8 @@ int ovl_permission(struct mnt_idmap *idmap, int err; /* Careful in RCU walk mode */ - ovl_i_path_real(inode, &realpath); - if (!realpath.dentry) { + realinode = ovl_i_path_real(inode, &realpath); + if (!realinode) { WARN_ON(!(mask & MAY_NOT_BLOCK)); return -ECHILD; } @@ -302,7 +302,6 @@ int ovl_permission(struct mnt_idmap *idmap, if (err) return err; - realinode = d_inode(realpath.dentry); old_cred = ovl_override_creds(inode->i_sb); if (!upperinode && !special_file(realinode->i_mode) && mask & MAY_WRITE) {