/home security problem

[Andy Koppe]

On 4 September 2010 11:07, Corinna Vinschen wrote:
> On Sep  4 10:32, Andy Koppe wrote:
>> On 4 September 2010 09:35, Andy Koppe wrote:
>> >> On, second thoughts, the 'rename bogus home dir aside' bit won't work
>> >> for ordinary users, because they don't have the right to do so. So
>> >> perhaps have the 'SOMEONE ELSE OWNS YOUR HOME!' warning only?
>> >
>> > Hmm, no, that's not good enough either. I've got my Cygwin home set to
>> > my Windows home directory (C:\Users\Andy), and that's actually owned
>> > by the SYSTEM account.
>>
>> How about something like this (the elif refers to 'if [ ! -d "${HOME}" ]'):
>>
>> --- profile.orig        2010-09-04 10:01:27.885800000 +0100
>> +++ profile     2010-09-04 10:21:28.328200000 +0100
>> @@ -72,6 +72,8 @@
>>
>>                 echo "Setting HOME to ${HOME}."
>>         fi
>> +elif [ ! -O "$HOME" -a  `/usr/bin/dirname "$HOME"` = /home ]; then
>> +        echo "WARNING: Your home directory at $HOME is owned by someone else!"
>>  fi
>>
>> Unfortunately that does incur a fork when the SYSTEM-owned Windows
>> user directory is used as the Cygwin home, but not for the default
>> case where the Cygwin home is in /home.
>
> You could do that without fork:
>
>  elif [ ! -O "$HOME" -a "${HOME#/home/}" != "${HOME}" ]

Nice. (Also, I hadn't considered that process substitution is done
before arguments are passed to test.)

Andy