From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793802959; b=0E8kRmJ8G/AIfbNS1ALgXyV7kibklCOv1ec2LE9kpua625HgC9qMdwNfqU500beXOkTq hnasf3HcPxfjqSlSMmO9piHPAwCBNTfcPZopDQfC0UCmIC/Wy6kxKMnTBTX0LemWqxOjk LeKMrgjxCTFFi3FPJ6Ba5AdYhFHRCBADZHRA5E6MuV4FQF6Gf+VHKL4L+/a2VXPYmQjLR pucLgzxJS+tMQt9TAkBSOBHgBO7mTKgHOC3RPRgT+h0brYBgk9UunqSPTAjEX38qtEmI2 CPMHblZKRksAPu6aVkwdlUN51Kq5iZrfv5zgebo03H50Fa8VOMc+qBwj38YIg5iUiIA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793802959; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=65qHMhjiweC8L9ykBaliqBaerM38LXfKbqDLE+oktpc=; b=zyy5Li9GZsjft15h4h9Ee/Mv9/0Skyfm3HSai1uvhEQ4mE83RMtVp2O+Htq7IQRzABJu yKcIYkzDbw5NCXC7WTAKMidegQ1XJCKj4ERvukppyQCPd+LK6iwGa45MvpW0S31lNHZ8w iYSYknUq0jc0ZXpDVeHoWSLtRM3IG2LbaXnw0j9mx8PCIYbdPddomVxLPbEYwuPjQogTC 6OtarWKDOMTJ2vdNREKYO+JgxxPaCFfXXk6xksBu7OS3hfBhIBufo4xhQkTAXUiyehgS2 /T+HaRSljehwz4z17REVaqwU9DJZUxWXUKaO3s2OkirucsPHEb/pj1DL9zB6QZ66ggQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aKWMVMmy; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 20B2C606A32C for ; Wed, 4 Nov 2026 14:35:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=aKWMVMmy Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D1F31F00919; Wed, 4 Nov 2026 14:35:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793802958; bh=65qHMhjiweC8L9ykBaliqBaerM38LXfKbqDLE+oktpc=; h=Subject:To:Cc:From:Date; b=aKWMVMmySOrzZ8+YOBZSinxSvpMPgo5uTChDyqnurGzqDDlcaxbNCtm59oBYdEvwY 5JGkjbmK58JzI5ZtdZkQM8ywLLgn46R9gE7xV7Ujd4Tglr3XvdprOHxUAX+9zwPdkR yxS7QDLJGjaMWpqrt3aEFotiMYHpQYJCsH2KQXEc= Subject: FAILED: patch "[PATCH] ovl: check that the parents of volatile/dirty are dirs" failed to apply to 5.15-stable tree To: mason@kernel.org,amir73il@gmail.com,josef@toxicpanda.com Cc: From: Date: Wed, 04 Nov 2026 15:35:53 +0100 Message-ID: <2026110453-dock-echo-0d7a@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-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-5.15.y git checkout FETCH_HEAD git cherry-pick -x e34d2ef818e4c7676d8d8e1bf43e6a1ed39efb2a # git commit -s git send-email --to '' --in-reply-to '2026110453-dock-echo-0d7a@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e34d2ef818e4c7676d8d8e1bf43e6a1ed39efb2a Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 7 Oct 2026 10:15:11 +0000 Subject: [PATCH] ovl: check that the parents of volatile/dirty are dirs An unprivileged user crashes the kernel by mounting overlayfs with the volatile option. A dentry that serves as the parent of a lookup must be a directory. ovl_create_volatile_dirty() walks work/incompat/volatile/dirty by name, and ovl_lookup_or_create() returns an existing entry whatever its type. A file or a symlink that another task creates during the mount becomes the parent of the next lookup, which calls a NULL ->lookup. An unprivileged user mounted overlayfs with "volatile" in a user namespace while a second process created a symlink named work/incompat, and the mount task oopsed on a NULL ->lookup call. Fix this by returning -ENOTDIR from ovl_lookup_or_create() when the caller asked for a directory and the existing entry is a non-dir. Fixes: c86243b090bc ("ovl: provide a mount option "volatile"") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason Signed-off-by: Josef Bacik Signed-off-by: Amir Goldstein diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index bd0a3f9039d2..18f56d463572 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -621,16 +621,21 @@ cleanup_temp: static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, struct dentry *parent, - const char *name, umode_t mode) + const char *name, bool is_dir) { struct dentry *child; child = ovl_start_creating_upper(ofs, parent, &QSTR(name)); if (!IS_ERR(child)) { - if (!child->d_inode) + if (!child->d_inode) { child = ovl_create_real(ofs, parent, child, &QSTR(name), - OVL_CATTR(mode)); + OVL_CATTR(is_dir ? S_IFDIR : + S_IFREG)); + } else if (is_dir && !d_can_lookup(child)) { + end_creating(child); + child = ERR_PTR(-ENOTDIR); + } end_creating_keep(child); } dput(parent); @@ -652,7 +657,7 @@ static int ovl_create_volatile_dirty(struct ovl_fs *ofs) const char *const *name = volatile_path; for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { - d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); + d = ovl_lookup_or_create(ofs, d, *name, ctr > 1); if (IS_ERR(d)) return PTR_ERR(d); }