Hi Stuart, Stuart Henderson wrote on Fri, Jan 20, 2023 at 08:50:48AM +0000: > On 2023/01/18 12:46, Theo de Raadt wrote:
>> But you should not start a sentence with also. >> Also you should not start a sentence with but. >> >> Not the best english. jmc can weight in perhaps. >> Jan Klemkow <j.klem...@wemelug.de> wrote: >>> .Pp >>> Even with sufficient file system permissions, >>> these devices can only be opened when the >>> -.Xr securelevel 7 >>> -is insecure or when the >>> .Va kern.allowkmem >>> .Xr sysctl 2 >>> variable is set. >>> +Also the >>> +.Xr securelevel 7 >>> +insecure is needed, to open the device writable. > This is all that's needed isn't it? > > Even with sufficient file system permissions, > these devices can only be opened when the > .Xr securelevel 7 > -is insecure or when the > -is insecure and the > .Va kern.allowkmem > .Xr sysctl 2 > variable is set. I believe that is not what we want to say: deraadt@ argues that - nobody should run with insecure securelevel, not even for offline debugging - and it is not needed for read access to /dev/mem (The discussion has in part drifted off list.) If we want a complete description (including the strongly discouraged way to get write access), the following floating diff is the best i'm aware of: Even with sufficient file system permissions, these devices can only be opened when the -.Xr securelevel 7 -is insecure or when the .Va kern.allowkmem .Xr sysctl 2 variable is set. +Write access additionally requires an insecure +.Xr securelevel 7 . If we want to discourage this even more, we could say something like this: .Pp Even with sufficient file system permissions, -these devices can only be opened when the +these devices can only be opened for reading and only when the -.Xr securelevel 7 -is insecure or when the .Va kern.allowkmem .Xr sysctl 2 variable is set. .Sh FILES That would make write behaviour undefined, such that it could be removed with no further documentation fuss once write access is indeed removed in the future. I would be fine with either direction. Yours, Ingo
