[Shr-Devel] Security features of SHR

Carsten Haitzler (The Rasterman) raster at rasterman.com
Fri May 28 15:00:52 CEST 2010

On Fri, 28 May 2010 17:19:53 +0500 Shaz <shazalive at gmail.com> said:

> On Fri, May 28, 2010 at 5:13 PM, Christ van Willegen
> <cvwillegen at gmail.com> wrote:
> > On Fri, May 28, 2010 at 2:09 PM, Shaz <shazalive at gmail.com> wrote:
> >> On Fri, May 28, 2010 at 10:54 AM, Christ van Willegen
> >> <cvwillegen at gmail.com> wrote:
> >>> On Fri, May 28, 2010 at 2:06 AM, Carsten Haitzler <raster at rasterman.com>
> >>> wrote:
> >>>> On Fri, 28 May 2010 05:00:50 +0500 Shaz <shazalive at gmail.com> said:
> >>>>
> >>>>> > For a default "real user", if there's any chance that there may be
> >>>>> > multiple users on the system, the system should probably just ask,
> >>>>> > e.g., when getting the initial user password.
> >>>>>
> >>>>> We can't expect a smartphone or a mobile or a handheld to have
> >>>>> multiple users. Can we?
> >>>>
> >>>> i'd say you can.
> >>>
> >>> /me nods in agreement
> >>
> >> Can you guys suggest a usecase?
> >
> > My spouse lending my phone, so that she has access to her own
> > database, messages (and even SIM if we should choose to exchange it).
> > Lending the phone to another person (that's what PIN2 is for, AFAIK).
> Still not satisfied because sharing phones is very unusual.

people often enough say: "my phone battery is dead - can i use yours? i'll use
my sim card so you don't have to pay". and you lend them your phone. you'd like
the user logged in to be tied to the sim card in this case, so new sim card ==
create new empty user for it.

another case - corporate use. companies want to make their employees do more
outside the office - this means being mobile. this also means you have, these
days, a company phone AND a private phone often enough. the company wants their
specific apps and customisations isolated on their phones. not mixed up with
tonnes of other junk/malware/games you install on your private phone. as such
this separationg is possible via users on a single devce, so in the long term
when in "work mode" you simply switch to the work user id - it has no access to
private files, contacts, apps etc. and vice-versa. of course i am assuming 3rd
party apps are installed in the user homedir as the user id - unless they are
specific system services.

i can come up with more examples (and yes you could find ways of doing these
without user id's but as such a privilege separation enforced by a kernel makes
simple sense here in so many ways, and re-cycles existing concepts unix has
had for decades that are still useful and applicable).

------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    raster at rasterman.com

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