Messages in this thread |  | | | Date | Fri, 03 Feb 2006 12:28:46 +1030 | | From | Glen Turner <> | | Subject | Re: 8250 serial console fixes -- issue |
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Hi Alan,
The serial console driver has a host of issues
- end of line should be CR LF, not LF CR
- 'r' option for CTS/RTS flow control assumes CTS is asserted when DSR is not asserted. This is wrong as lots of modems float control lines when off. No control signals are defined is DSR is unasserted.
- [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.
- 'r' option has insanely slow CTS timeout. So if a terminal server is inactive the kernel can take 30 minutes to boot as each character write to the serial console requires a CTS timeout.
All of these have been reported to me multiple times (I'm maintainer of the Remote-Serial-Console-HOWTO).
I occassionally clean up and repost a patch I wrote years ago which never gets integrated (although it ships in the patchset of a number of kernels from supercomputer vendors). I'm happy to clean it up again if there's a hope of integration.
See <http://www.aarnet.edu.au/~gdt/patch/console/serial-console.patch> for the most recent attempt.
Thanks so much, Glen
-- Glen Turner Tel: (08) 8303 3936 or +61 8 8303 3936 Australia's Academic & Research Network www.aarnet.edu.au - 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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