Messages in this thread | | | Date | Mon, 6 Feb 2006 20:55:00 +0000 | From | Russell King <> | Subject | Re: 8250 serial console fixes -- issue |
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On Mon, Feb 06, 2006 at 08:26:55PM +0000, Pavel Machek wrote: > Hi! > > > > The serial console driver has a host of issues > > > > > > [...] > > > > > > - [SECURITY] 'r' should require DCD to be asserted > > > before outputing characters. Otherwise we talk to > > > Hayes modem command mode. This allows a non-root > > > user to re-program the modem and is a major security > > > issue is people configure calling line identification > > > or encryption to restrict use of the serial console. > > > > How is this possible? A normal user can't produce arbitarily formatted > > kernel messages, and if they have access to /dev/ttyS they can do what > > ever they like with the port anyway. > > Maybe not *arbitrary* messages, but any user probably can fake enough > to > confuse modem. Name your process \nATD609123456\n and cause it to eat > all memory, or something like that. OOM killer will print name...
As I say, it's a problem which needs fixing elsewhere. What if the process was called:
\nSystem Halted\n
(which will fit in the kernel's process name.) Or maybe some escape sequence which reprograms your terminal.
As I say, this is a problem which needs solving by other means. Maybe flush_old_exec() should be a little more careful about what it copies, changing non-alphanumeric characters to '?' ?
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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