Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:__legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock... or we risk stealing final mntput from sync umount - raising mnt_countafter umount(2) has verified that victim is not busy, but before ithas set MNT_SYNC_UMOUNT; in that case __legitimize_mnt() doesn't seethat it's safe to quietly undo mnt_count increment and leaves droppingthe reference to caller, where it'll be a full-blown mntput().Check under mount_lock is needed; leaving the current one done beforetaking that makes no sense - it's nowhere near common enough to botherwith.
No PoCs from references.
- https://github.com/w4zu/Debian_security