On 6/2/17 2:18 PM, Serge E. Hallyn wrote: > Quoting Matt Brown (matt@xxxxxxxxx): >> On 6/2/17 12:57 PM, Serge E. Hallyn wrote: >>> I'm not quite sure what you're asking for here. Let me offer a precise >>> strawman design. I'm sure there are problems with it, it's just a starting >>> point. >>> >>> system-wide whitelist (for now 'may_push_chars') is full by default. >>> >> >> So is may_push_chars just an alias for TIOCSTI? Or are there some >> potential whitelist members that would map to multiple ioctls? > > <shrug> I'm seeing it as only TIOCSTI right now. > >>> By default, nothing changes - you can use those on your own tty, need >>> CAP_SYS_ADMIN against init_user_ns otherwise. >>> >>> Introduce a new CAP_TTY_PRIVILEGED. >>> >> >> I'm fine with this. >> >>> When may_push_chars is removed from the whitelist, you lose the ability >>> to use TIOCSTI on a tty - even your own - if you do not have CAP_TTY_PRIVILEGED >>> against the tty's user_ns. >>> >> >> How do you propose storing/updating the whitelist? sysctl? >> >> If it is a sysctl, would each whitelist member have a sysctl? >> e.g.: kernel.ioctlwhitelist.may_push_chars = 1 >> >> Overall, I'm fine with this idea. > > That sounds reasonable. Or a securityfs file - I guess not everyone > has securityfs, but if it were to become part of YAMA then that would > work. > Yama doesn't depend on securityfs does it? What do other people think? Should this be an addition to YAMA or its own thing? Alan Cox: what do you think of the above ioctl whitelisting scheme? -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
