| 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: <20081016163041.GB12174@atrey.karlin.mff.cuni.cz> Date: Thu, 16 Oct 2008 18:30:41 +0200 From: Cyril Hrubis <metan@....cz> To: linux-kernel@...r.kernel.org Subject: race condition in umount/statfs Hi, I've found that when umount command calls umount2() the process stays in umount2() call till caches are flushed but entry in /etc/mtab is removed after umount returns from umount2(). When df is invoked in the meantime, it just returns statfs() for path from mtab, but as the filesystem is not mounted in kernel anymore, you get statistics for another filesystem instead (most likely /). Example: mount a usb flashdisk, copy some files there and then umount. Cache flush on my machines is about 10 seconds. As an fix I could call statfs() on parent directory and compare f_fsid, but the manual says its set to zero on NFS and some systems. -- metan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists