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> The EEPROM (SEEPROM) on these NICS is used to contain the startup > configuration bits and the IEEE Station Address. This must be a > unique number that is assigned so that there is no other such > number in (preferably) the world, and certainly in the LAN. > If you let a user write to this area, you will allow the user > to destroy the connectivity on a LAN. > > If you provide an ioctl() to write new SEEPROM contents, it had > better be disabled in code that user's (any, including root) > can execute because, if caught, your company may lose it's IEEE > Station Addresses and never again be allowed to configure Ethernet > Controllers. I think you overstate the seriousness here - it's not unheard of for manufacturers to ship hardware with duplicate MAC addresses - a trivial search on Google turns up Cisco as one offender: http://www.cisco.com/warp/public/770/7.html > > Because of this, there is no such thing as 'unused eeprom space' in > the Ethernet Controllers. Be careful about putting this weapon in > the hands of the 'public'. All you need is for one Linux Machine > on a LAN to end up with the same IEEE Station Address as another > on that LAN and connectivity to everything on that segment will > stop. You do this once at an important site and Linux will get a > very black eye. Worse than GE? http://www.gefanuc.com/support/plc/m030202.htm Being able to permanently fix a screwed up card that duplicated another card on my LAN would be nice, imo. Of course, this assumes that IEEE Station Address == MAC address. -- Ryan Anderson sometimes Pug Majere - 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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