Hi Brian,

I have been working with the Android Keystore and have some doubts, I
would be glad if you could answer some of them:

- Do you now why AID_SYSTEM is not given the permission to read
certificates (~GET)?

- And also why are the public certificates stored encrypted? This
prevents the system from displaying the contents of the certificates
to the user, other platforms only encrypt the private key.

- Browser and Email get the certificates from cacerts.bks to use in
SSL, Wi-Fi and VPN cannot use these CA certs in their authentication
process, the reverse case happens with Browser and Email, they cannot
use user-installed CA certs. Is there some reason for the keystores
not being unified?

Thanks,
Gustavo.

On May 11, 12:51 pm, Brian Carlstrom <[email protected]> wrote:
> On Wed, May 11, 2011 at 6:03 AM, patrick Immling 
> <[email protected]>wrote:
>
> > Is the android keystore pass-protected?
>
> yes, the UI enforces a 8 character minimum password. try it yourself.
>
> Can any application access the key from the keystore?
>
>
>
> there are UID based restrictions, so arbitrary apps cannot access arbitrary
> keys. some system services like VPN and WiFi have access to system keys
>
>
>
> > Is there any security associated with the access to keys on android?
>
> the same table that defines the UID access also limits which operations are
> restricted to what types of users.
> From frameworks/base/cmds/keystore/keystore.c:
>
> static struct user {
>     uid_t uid;
>     uid_t euid;
>     uint32_t perms;} users[] = {
>
>     {AID_SYSTEM,   ~0,         ~GET},
>     {AID_VPN,      AID_SYSTEM, GET},
>     {AID_WIFI,     AID_SYSTEM, GET},
>     {AID_ROOT,     AID_SYSTEM, GET},
>     {~0,           ~0,         TEST | GET | INSERT | DELETE | EXIST | SAW},
>
> };
>
> The whole file is only about 500 lines, I suggest just reading it over to
> get an idea of how it works.
>
> -bri

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