From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CEDB1C36; Mon, 7 Apr 2025 17:15:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744046132; cv=none; b=ZcHjYoO4HGkZxeMSUEcvbobduSODYvxGXgYtDXrietWbPs+lt2RnVfwwRmyk9CwwQegVTOCQTSHZzmPJdWN7Bmt4BvEJ8V8/1ExPL2Ceirp07IvqJbj2uDCcW2guKzT/TwNcPhk2Sh3gvCVHNDduQVHnD8r5rR8frw+ihBRGLh4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744046132; c=relaxed/simple; bh=njTr8RbcFgdvmq7pMd62rzNVCZwMFJrNvhEZS3Hn1pM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bLTJbYj6C4M2VJ3XqDqlGAROMQ/hoH7tucdwGWN7TMenLOv5A+ZbEP44lggXe0bvMsqMXtTxFpxbIPrtHW7KBtx0nOqzG51hbK7bpUXkv2H0oB3X03YaQ8Zo4InXULbaobehkCelR8OP67Bappd5UZL9YAmDvFq/k6iETEdhGyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E07sSCSA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="E07sSCSA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AF5DC4CEDD; Mon, 7 Apr 2025 17:15:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744046131; bh=njTr8RbcFgdvmq7pMd62rzNVCZwMFJrNvhEZS3Hn1pM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=E07sSCSAHmYy+HGr343lvKCdv4oMSfWMIniSAvNNlu7zZ7O0aGtRR9NV5Yzb/3Rrt LnRRws/fegpkMeO1wL+Dk3n5Gx7w2u7MFN+oiBYgUXe0KCohZNZaLw+8dNWN3e58qR G5fMXaRR0dSmHtl9vwQzzSqSwZy3YKqdpq5E7w5xv+hMN9kInoUHYIXE2iUwttJADy mY2Ip3+yt8+pVvvqF8shaxuIL9KETesDEo6w/toRNVEoX8iwfrERLU8hxOP35MOoo0 6KqosoILviXo1SdpYKMd6kanmUNiKaeuo+OHFuVsX8xO+I6G2XWp9z3/4RQndZdvpz ZgLrWjUnymSRA== Date: Mon, 7 Apr 2025 19:15:26 +0200 From: Christian Brauner To: Cengiz Can , Attila Szasz Cc: Greg KH , Salvatore Bonaccorso , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, lvc-patches@linuxtesting.org, dutyrok@altlinux.org, syzbot+5f3a973ed3dfb85a6683@syzkaller.appspotmail.com, stable@vger.kernel.org, Alexander Viro Subject: Re: [PATCH] hfs/hfsplus: fix slab-out-of-bounds in hfs_bnode_read_key Message-ID: <20250407-kumpel-klirren-ad0db3c77321@brauner> References: <20241019191303.24048-1-kovalev@altlinux.org> <2025032402-jam-immovable-2d57@gregkh> <7qi6est65ekz4kjktvmsbmywpo5n2kla2m3whbvq4dsckdcyst@e646jwjazvqh> <2025032404-important-average-9346@gregkh> <20250407-biegung-furor-e7313ca9d712@brauner> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250407-biegung-furor-e7313ca9d712@brauner> On Mon, Apr 07, 2025 at 12:59:18PM +0200, Christian Brauner wrote: > On Sun, Apr 06, 2025 at 07:07:57PM +0300, Cengiz Can wrote: > > On 24-03-25 11:53:51, Greg KH wrote: > > > On Mon, Mar 24, 2025 at 09:43:18PM +0300, Cengiz Can wrote: > > > > In the meantime, can we get this fix applied? > > > > > > Please work with the filesystem maintainers to do so. > > > > Hello Christian, hello Alexander > > > > Can you help us with this? > > > > Thanks in advance! > > Filesystem bugs due to corrupt images are not considered a CVE for any > filesystem that is only mountable by CAP_SYS_ADMIN in the initial user > namespace. That includes delegated mounting. > > Now, quoting from [1]: > > "So, for the record, the Linux kernel in general only allows mounts for > those with CAP_SYS_ADMIN, however, it is true that desktop and even > server environments allow regular non-privileged users to mount and > automount filesystems. > > In particular, both the latest Ubuntu Desktop and Server versions come > with default polkit rules that allow users with an active local session > to create loop devices and mount a range of block filesystems commonly > found on USB flash drives with udisks2. Inspecting > /usr/share/polkit-1/actions/org.freedesktop.UDisks2.policy shows:" > > So what this saying is: > > A distribution is shipping tooling that allows unprivileged users to mount > arbitrary filesystems including hpfsplus. Or to rephrase this: A > distribution is allowing unprivileged users to mount orphaned > filesystems. Congratulations on the brave decision to play Russian > Roulette with a fully-loaded gun. > > The VFS doesn't allow mounting arbitrary filesystems by unprivileged > users. Every FS_REQUIRES_DEV filesystem requires global CAP_SYS_ADMIN > privileged at which point you can also do sudo rm -rf --no-preserve-root / > or a million other destructive things. > > The blogpost is aware that the VFS maintainers don't accept CVEs like > this. Yet a CVE was still filed against the upstream kernel. IOW, > someone abused the fact that a distro chose to allow mounting arbitrary > filesystems including orphaned ones by unprivileged user as an argument > to gain a kernel CVE. > > Revoke that CVE against the upstream kernel. This is a CVE against a > distro. There's zero reason for us to hurry with any fix. Before that gets misinterpreted: This is not intended to either implicitly or explicitly imply that patch pickup is dependend on the revocation of this CVE. Since this isn't a valid CVE there's no reason to hurry-up merging this into mainline within the next 24 hours. It'll get there whenever the next fixes pr is ready. > > [1]: https://ssd-disclosure.com/ssd-advisory-linux-kernel-hfsplus-slab-out-of-bounds-write/