Messages in this thread | | | Date | Tue, 30 May 2017 22:52:45 +0100 | From | Alan Cox <> | Subject | Re: [kernel-hardening] Re: [PATCH v6 0/2] security: tty: make TIOCSTI ioctl require CAP_SYS_ADMIN |
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> > So tty stuff should under a tty capabilities. > > (last reply on this) > > Currently capabilities.7 says > > * employ the TIOCSTI ioctl(2) to insert characters into the input queue of a > terminal other than the caller's controlling terminal; > > for CAP_SYS_ADMIN. > > So you can create a new CAP_SYS_TIOCSSTI if you like, and offer a patch where > *both* CAP_SYS_ADMIN and CAP_SYS_ADMIN suffice. Again, see CAP_SYSLOG for a > prior example.
Even then it wouldn't be useful because the attacker can use every other interface in the tty layer, many of which you can't magic away behind a capability bit. And the applications would need changing to use the feature - at which point any theoretical broken apps can instead be fixed to use a pty/tty pair and actually fix the real problem.
Alan
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