| 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
| ||
|
Date: Sun, 29 Apr 2007 20:59:11 +0200 From: utz lehmann <lkml123@...4n2c.de> To: Miklos Szeredi <miklos@...redi.hu>, LKML <linux-kernel@...r.kernel.org> Subject: unprivileged mount problems: device permissions ignored, mount sharing Hello I tried the unprivileged mount v5 patches with 2.6.21.1. I made some experiments with normal filesystems (ext3, xfs, iso9660). I removed the FS_SAFE checks for that. Mounting and umounting as unprivileged user (user1) works, e.g. (/mnt/user1 is a mount owned by user1) [user1@...v ~]$ mmount -t xfs /dev/mapper/vg00-test /mnt/user1 But the device permissions are ignored. The unprivileged user can mount the block device even there are no permissions to access it: brw------- 1 root root 253, 5 Apr 29 18:32 /dev/mapper/vg00-test And there is another problem with sharing the device (superblock?). If user1 mount a device readonly: [user1@...v ~]$ mmount -r -t xfs /dev/mapper/vg00-test /mnt/user1 Than root cannot mount the device rw: [root@...v ~]# mount /dev/mapper/vg00-test /mnt/test/ mount: /dev/mapper/vg00-test already mounted or /mnt/test/ busy Mounting ro works and than remounting rw work. But than /mnt/user1 is rw too. This can DoS e.g. the automounter mounting /dev/mapper/vg00-test rw. utz - 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