From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DB0713921DD; Fri, 28 Aug 2026 11:00:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787914844; cv=none; b=TbReTJA/VwLS8Ez5IGl31c8ZYzJBdm9cgF2l2FoSY+pAsOM1Zf0s9OCgoKHSw8frUeo6WxYC+M7tynmGkOoVc+ecVzY/Xbalw+WyJbT5/C9H9aUHLb4LKql8gaGO3qZ9z0/kU/lugtAxVA/C1re4vdIgnyPgavB/L+Dam4yFtUo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787914844; c=relaxed/simple; bh=/qhUprrDNLX/tJneZQd+Poo4n0a3K1dWxMXFQZHDfSs=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rjhlZocQVcPhSLp3N4/bJ6ct+bkmipQ/qtlKOvxB7Sek/U80ZKQuk9nPrKtKbNcCY/eTrDgSNvIKniLYUoMtchPy77PSPEyTMpYk1M6jGX4YfOXpQAaJMpI5Q/QU/U5b0EFtib6Xn+fkYQ8e487piAFfW5od6mKphu8CM9NTKpw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=erL7lPk3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="erL7lPk3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88B6A1F000E9; Fri, 28 Aug 2026 11:00:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787914842; bh=Eb1BvKKwTtbIY42JRUlbCa0/eJ/kSVwzFFKhEii/Y4k=; h=Date:From:To:Subject:References:In-Reply-To; b=erL7lPk30gNdLuGbtgQEDUIJdyTFOoXD4zT8bjrO/8SUl/gU7/+ASWfPfKDMejgzx ZFRtdHQUmkqRff9WVfJAUet/44zEzCyx1V4naln+tmcYUoOB7RWpoUkotfbHSgqbbU xg4tnXsLWXZQxn/xlXo1xmoT9qh6gYpePUC+0tSc= Date: Fri, 28 Aug 2026 12:59:00 +0200 From: Greg KH To: Gao Xiang , cve@kernel.org, linux-kernel@vger.kernel.org, linux-cve-announce@vger.kernel.org Subject: Re: CVE-2026-80697: erofs: ensure valid f_path for page cache sharing Message-ID: <2026082849-janitor-stonework-71c9@gregkh> References: <2026082805-CVE-2026-80697-4e8a@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Aug 28, 2026 at 03:49:05PM +0800, Gao Xiang wrote: > Hi Greg, > > On Fri, Aug 28, 2026 at 08:53:20AM +0200, Greg Kroah-Hartman wrote: > > From: Greg Kroah-Hartman > > > > Description > > =========== > > > > In the Linux kernel, the following vulnerability has been resolved: > > > > erofs: ensure valid f_path for page cache sharing > > > > Previously, backing files for page cache sharing were set up with > > f_path left as NULL (only f_inode was valid). It worked, but a recent > > mincore fix relies on f_path.mnt and crashes (found by "erofs/028" on > > 7.2-rc4): > > > > BUG: kernel NULL pointer dereference, address: 0000000000000018 > > #PF: supervisor read access in kernel mode > > #PF: error_code(0x0000) - not-present page > > PGD 0 P4D 0 > > Oops: Oops: 0000 [#1] SMP PTI > > CPU: 3 UID: 0 PID: 675528 Comm: fincore Not tainted 7.2.0-rc4-00002-g[]-dirty #1 PREEMPT(lazy) > > Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014 > > RIP: 0010:__do_sys_mincore+0xc0/0x2c0 > > ... > > > > Specify valid paths using valid disconnected dentries together with > > erofs_ishare_mnt instead of leaving f_path empty, so they are more > > like real backing files in a pseudo filesystem and standard > > backing_file_open() can be used directly. > > > > The Linux kernel CVE team has assigned CVE-2026-80697 to this issue. > > > > > > Affected and fixed versions > > =========================== > > > > Issue introduced in 7.1.4 with commit 04ba248d02d9eaa3d9077b00a6134caa75fa3e90 and fixed in 7.1.8 with commit 3879657c4ffd81b9a42cf575fc6cb60201032587 > > Issue introduced in 5.15.217 with commit 7368bec565bac3e536cd43579dbde1e715e6ba61 > > Issue introduced in 6.1.184 with commit b2f3d94ea310bea9d36d53e9d9b3f45e86c1d893 > > Issue introduced in 6.6.145 with commit 744b23aa430d52f5c8e4dbff7d71496d6643bed2 > > Issue introduced in 6.12.96 with commit 8344bdf0629457e532797b42d9d2bbf2a2900bbf > > Issue introduced in 6.18.39 with commit 5c942ad7df75925ee166e7f0fb36892d8dde376b > > I don't think that is correct, although commit e187bc02f8fa > ("mm: do file ownership checks with the proper mount idmap") directly > causes this issue, the entire page cache sharing feature was introduced > in Linux 7.0. Yes, but it was backported to all of the above stable kernels as well, which is why they are listed that way. > There is not any codebase below Linux 7.0 so it's possible to fix > 5.15/6.1/6.6/6.12/6.18 in any case. The affected versions are only > Linux 7.0+. Even though e187bc02f8fa ("mm: do file ownership checks with the proper mount idmap") was backported to those older trees? thanks, greg k-h