Messages in this thread | | | Subject | Re: [PATCH] make TIOCSTI ioctl require CAP_SYS_ADMIN | From | Matt Brown <> | Date | Wed, 19 Apr 2017 20:08:02 -0400 |
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On 04/19/2017 07:18 AM, James Morris wrote: > On Tue, 18 Apr 2017, Matt Brown wrote: > >> This patch reproduces GRKERNSEC_HARDEN_TTY functionality from the grsecurity >> project in-kernel. > > It seems like an ugly hack to an ugly feature (CAP_SYS_ADMIN barely makes > sense here), and rather than sprinkling these types of things throughout > the kernel, I wonder if it might be better to implement it via LSM, in the > YAMA module. > >
CAP_SYS_ADMIN is already used in the TIOCSTI TTY code to allow character insertion into TTYs other than the caller's controlling terminal. This is done because different TTYs indicate a security boundary that should only be able to be crossed by a privileged process. This patch would merely extend this security boundary protection to include unprivileged processes from utilizing a common TTY to step across a security boundary.
> > - James >
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