lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <8222b5dd-5ee5-4ee6-9763-d1c21b9804db@huawei.com> Date: Mon, 30 Dec 2024 16:21:00 +0800 From: Baokun Li <libaokun1@...wei.com> To: Greg KH <gregkh@...uxfoundation.org> CC: <linux-cve-announce@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Jan Kara <jack@...e.com>, Theodore Ts'o <tytso@....edu>, "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>, Yang Erkun <yangerkun@...wei.com> Subject: Re: CVE-2024-50191: ext4: don't set SB_RDONLY after filesystem errors On 2024/12/30 15:54, Greg KH wrote: > On Mon, Dec 30, 2024 at 03:27:45PM +0800, Baokun Li wrote: >>> Description >>> =========== >>> >>> In the Linux kernel, the following vulnerability has been resolved: >>> >>> ext4: don't set SB_RDONLY after filesystem errors >>> >>> When the filesystem is mounted with errors=remount-ro, we were setting >>> SB_RDONLY flag to stop all filesystem modifications. We knew this misses >>> proper locking (sb->s_umount) and does not go through proper filesystem >>> remount procedure but it has been the way this worked since early ext2 >>> days and it was good enough for catastrophic situation damage >>> mitigation. Recently, syzbot has found a way (see link) to trigger >>> warnings in filesystem freezing because the code got confused by >>> SB_RDONLY changing under its hands. Since these days we set >>> EXT4_FLAGS_SHUTDOWN on the superblock which is enough to stop all >>> filesystem modifications, modifying SB_RDONLY shouldn't be needed. So >>> stop doing that. >>> >>> The Linux kernel CVE team has assigned CVE-2024-50191 to this issue. >>> >>> >>> Affected and fixed versions >>> =========================== >>> >>> Fixed in 5.15.168 with commit fbb177bc1d64 >>> Fixed in 6.1.113 with commit 4061e07f040a >> Since 6.1 and 5.15 don't have backport >> commit 95257987a638 ("ext4: drop EXT4_MF_FS_ABORTED flag"), >> we won't set the EXT4_FLAGS_SHUTDOWN bit in ext4_handle_error() yet. So >> here these two commits cause us to repeatedly get the following printout: >> >> [ 42.993195] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993351] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993483] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993597] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993638] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993718] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993866] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993874] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.993874] EXT4-fs error (device sda) in __ext4_new_inode:1089: Journal >> has aborted >> [ 42.994059] EXT4-fs error (device sda): ext4_journal_check_start:83: comm >> fsstress: Detected aborted journal >> [ 42.999893] EXT4-fs: 58002 callbacks suppressed >> [ 42.999895] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000110] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000274] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000421] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000569] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000701] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.000869] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.001094] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.001229] EXT4-fs (sda): Remounting filesystem read-only >> [ 43.001365] EXT4-fs (sda): Remounting filesystem read-only >> >> Perhaps we should revert both commits. > Maybe, if so, please send the needed info to the stable list with the > backports that have been tested. cve@...nel.org isn't the place for > this :) I replied to this thread on lore, which automatically CC's cve@...nel.org. We don't use these two versions, we just happened to find the issue. If you feel that reporting issue is bothering you, then I won't do it.🙂 Regards, Baokun
Powered by blists - more mailing lists