In Symbian 0S V9, files copied to the PC in a Backup operation are designated in
the file backup_registration.xml. Once on the PC they are free for reading by
the user. They can also be tampered / replaced by other files with same name. Is
there a mechanism to ensure that tampered files are not transferred back to the
phone by the Restore operation?
The same question applies to all files stored on the memory card ("private" or
not), when the card is taken out of the phone and used with a card reader.
Thanks,
Hi Guillaume
The main document on connectivity is here:
http://www.symbian.com/developer/tech_papers/papers/cpp_programming_technique.asp#pc_connectivity
I believe the answer is slightly different depending on what is backed up.
If you are talking executable files, I understand that these are effectively
re-bundled into SIS files which cannot be modified on the PC without it
being detected. On uninstall these are unpackaged through the installer
Other files may be encrypted when sent to the PC, but this is dependent on
licensee discretion (whether they have implemented it)
The same answer is true on the memory card - you can modify the files at
will. However the internal drive of the phone store a hash of the files that
are installed onto MMC, and won't run executables that are tampered. If the
executable is dependent on another file that could be modified and is not
part of the original SIS, then like any application it should deal with the
possibility of corrupt data.
Hope that answers.
Regards
Hamish
"Guillaume" <[email protected]> wrote in message
news:Tdm3RhlgGHA.1956@extapps30...
> In Symbian 0S V9, files copied to the PC in a Backup operation are
designated in
> the file backup_registration.xml. Once on the PC they are free for reading
by
> the user. They can also be tampered / replaced by other files with same
name. Is
> there a mechanism to ensure that tampered files are not transferred back
to the
> phone by the Restore operation?
>
> The same question applies to all files stored on the memory card
("private" or
> not), when the card is taken out of the phone and used with a card reader.
>
> Thanks,
>
>
>
>
>
Hi Hamish,
Many thanks for the quick and full answer. I guess that in the sentence "On
uninstall these are unpackaged through the installer" you meant "On restore...".
Regards,
Guillaume
"Hamish Willee" <[email protected]> escribi� en el mensaje
news:k5CD8JugGHA.1956@extapps30...
> Hi Guillaume
>
> The main document on connectivity is here:
>
http://www.symbian.com/developer/tech_papers/papers/cpp_programming_technique.as
p#pc_connectivity
>
> I believe the answer is slightly different depending on what is backed up.
> If you are talking executable files, I understand that these are effectively
> re-bundled into SIS files which cannot be modified on the PC without it
> being detected. On uninstall these are unpackaged through the installer
> Other files may be encrypted when sent to the PC, but this is dependent on
> licensee discretion (whether they have implemented it)
>
> The same answer is true on the memory card - you can modify the files at
> will. However the internal drive of the phone store a hash of the files that
> are installed onto MMC, and won't run executables that are tampered. If the
> executable is dependent on another file that could be modified and is not
> part of the original SIS, then like any application it should deal with the
> possibility of corrupt data.
>
> Hope that answers.
>
> Regards
> Hamish
>
>
> "Guillaume" <[email protected]> wrote in message
> news:Tdm3RhlgGHA.1956@extapps30...[color=green]
> > In Symbian 0S V9, files copied to the PC in a Backup operation are
> designated in
> > the file backup_registration.xml. Once on the PC they are free for reading
> by
> > the user. They can also be tampered / replaced by other files with same
> name. Is
> > there a mechanism to ensure that tampered files are not transferred back
> to the
> > phone by the Restore operation?
> >
> > The same question applies to all files stored on the memory card
> ("private" or
> > not), when the card is taken out of the phone and used with a card reader.
> >
> > Thanks,
> >
> >
> >
> >
> >
>
>[/color]
Yes.
BTW, I'm confirming all that, but I'm fairly sure its correct.
"Guillaume" <[email protected]> wrote in message
news:mFjIKTugGHA.1896@extapps30...
> Hi Hamish,
>
> Many thanks for the quick and full answer. I guess that in the sentence
"On
> uninstall these are unpackaged through the installer" you meant "On
restore...".
>
> Regards,
> Guillaume
>
>
>
> "Hamish Willee" <[email protected]> escribi� en el mensaje
> news:k5CD8JugGHA.1956@extapps30...[color=green]
> > Hi Guillaume
> >
> > The main document on connectivity is here:
> >
>[/color]
http://www.symbian.com/developer/tech_papers/papers/cpp_programming_technique.as
> p#pc_connectivity[color=green]
> >
> > I believe the answer is slightly different depending on what is backed[/color]
up.[color=green]
> > If you are talking executable files, I understand that these are[/color]
effectively[color=green]
> > re-bundled into SIS files which cannot be modified on the PC without it
> > being detected. On uninstall these are unpackaged through the installer
> > Other files may be encrypted when sent to the PC, but this is dependent[/color]
on[color=green]
> > licensee discretion (whether they have implemented it)
> >
> > The same answer is true on the memory card - you can modify the files at
> > will. However the internal drive of the phone store a hash of the files[/color]
that[color=green]
> > are installed onto MMC, and won't run executables that are tampered. If[/color]
the[color=green]
> > executable is dependent on another file that could be modified and is[/color]
not[color=green]
> > part of the original SIS, then like any application it should deal with[/color]
the[color=green]
> > possibility of corrupt data.
> >
> > Hope that answers.
> >
> > Regards
> > Hamish
> >
> >
> > "Guillaume" <[email protected]> wrote in message
> > news:Tdm3RhlgGHA.1956@extapps30...[color=darkred]
> > > In Symbian 0S V9, files copied to the PC in a Backup operation are
> > designated in
> > > the file backup_registration.xml. Once on the PC they are free for[/color][/color]
reading[color=green]
> > by[color=darkred]
> > > the user. They can also be tampered / replaced by other files with[/color][/color]
same[color=green]
> > name. Is[color=darkred]
> > > there a mechanism to ensure that tampered files are not transferred[/color][/color]
back[color=green]
> > to the[color=darkred]
> > > phone by the Restore operation?
> > >
> > > The same question applies to all files stored on the memory card
> > ("private" or
> > > not), when the card is taken out of the phone and used with a card[/color][/color]
reader.[color=green][color=darkred]
> > >
> > > Thanks,
> > >
> > >
> > >
> > >
> > >
> >
> >[/color]
>
>[/color]
Just to be sure that my understanding is correct:
(a) The document "PC Connectivity: how-to write backup aware software for
Symbian OS" states that "On platform security-enabled Symbian OS phones,
installed applications are no longer backed up by default and now require the
consent of the application designer." This is supposed to protect binaries from
the sight of users.
(b) On the other hand, Symbian Signed test criteria PKG-05 states that
"Application can be installed to all available media drives". Does this not kill
the protection granted in (a)?
Regards,
Guillaume
"Hamish Willee" <[email protected]> escribi� en el mensaje
news:nI7SZUugGHA.2496@extapps30...
> Yes.
> BTW, I'm confirming all that, but I'm fairly sure its correct.
>
> "Guillaume" <[email protected]> wrote in message
> news:mFjIKTugGHA.1896@extapps30...[color=green]
> > Hi Hamish,
> >
> > Many thanks for the quick and full answer. I guess that in the sentence
> "On
> > uninstall these are unpackaged through the installer" you meant "On
> restore...".
> >
> > Regards,
> > Guillaume
> >
> >
> >
> > "Hamish Willee" <[email protected]> escribi� en el mensaje
> > news:k5CD8JugGHA.1956@extapps30...[color=darkred]
> > > Hi Guillaume
> > >
> > > The main document on connectivity is here:
> > >
> >[/color]
>[/color]
http://www.symbian.com/developer/tech_papers/papers/cpp_programming_technique.as[color=green]
> > p#pc_connectivity[color=darkred]
> > >
> > > I believe the answer is slightly different depending on what is backed[/color]
> up.[color=darkred]
> > > If you are talking executable files, I understand that these are[/color]
> effectively[color=darkred]
> > > re-bundled into SIS files which cannot be modified on the PC without it
> > > being detected. On uninstall these are unpackaged through the installer
> > > Other files may be encrypted when sent to the PC, but this is dependent[/color]
> on[color=darkred]
> > > licensee discretion (whether they have implemented it)
> > >
> > > The same answer is true on the memory card - you can modify the files at
> > > will. However the internal drive of the phone store a hash of the files[/color]
> that[color=darkred]
> > > are installed onto MMC, and won't run executables that are tampered. If[/color]
> the[color=darkred]
> > > executable is dependent on another file that could be modified and is[/color]
> not[color=darkred]
> > > part of the original SIS, then like any application it should deal with[/color]
> the[color=darkred]
> > > possibility of corrupt data.
> > >
> > > Hope that answers.
> > >
> > > Regards
> > > Hamish
> > >
> > >
> > > "Guillaume" <[email protected]> wrote in message
> > > news:Tdm3RhlgGHA.1956@extapps30...
> > > > In Symbian 0S V9, files copied to the PC in a Backup operation are
> > > designated in
> > > > the file backup_registration.xml. Once on the PC they are free for[/color]
> reading[color=darkred]
> > > by
> > > > the user. They can also be tampered / replaced by other files with[/color]
> same[color=darkred]
> > > name. Is
> > > > there a mechanism to ensure that tampered files are not transferred[/color]
> back[color=darkred]
> > > to the
> > > > phone by the Restore operation?
> > > >
> > > > The same question applies to all files stored on the memory card
> > > ("private" or
> > > > not), when the card is taken out of the phone and used with a card[/color]
> reader.[color=darkred]
> > > >
> > > > Thanks,
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> >
> >[/color]
>
>[/color]
Hi Guillaume
Firstly, let me confirm what I put in my previous message (verified by
connectivity team).
Responses to the other bits below.
Regards
H
"Guillaume" <[email protected]> wrote in message
news:IaosVSwgGHA.1896@extapps30...
> Just to be sure that my understanding is correct:
>
> (a) The document "PC Connectivity: how-to write backup aware software for
> Symbian OS" states that "On platform security-enabled Symbian OS phones,
> installed applications are no longer backed up by default and now require
the
> consent of the application designer." This is supposed to protect binaries
from
> the sight of users.
>
> (b) On the other hand, Symbian Signed test criteria PKG-05 states that
> "Application can be installed to all available media drives". Does this
not kill
> the protection granted in (a)?
Not really
I'd say that this bit "This is supposed to protect binaries from the sight
of users." is badly worded. "It is to give the developer choice on whether
the files are trusted to be backed up to PC."
Symbian signed mandates that the user should be allowed to install the
application where they like - that includes on the MMC card. If a file is of
such great importance that it should never be visible off the phone you
would store it on C drive in the private directory and get a waiver.
>
> Regards,
> Guillaume
>
>
>
>
> "Hamish Willee" <[email protected]> escribi� en el mensaje
> news:nI7SZUugGHA.2496@extapps30...[color=green]
> > Yes.
> > BTW, I'm confirming all that, but I'm fairly sure its correct.
> >
> > "Guillaume" <[email protected]> wrote in message
> > news:mFjIKTugGHA.1896@extapps30...[color=darkred]
> > > Hi Hamish,
> > >
> > > Many thanks for the quick and full answer. I guess that in the[/color][/color]
sentence[color=green]
> > "On[color=darkred]
> > > uninstall these are unpackaged through the installer" you meant "On
> > restore...".
> > >
> > > Regards,
> > > Guillaume
> > >
> > >
> > >
> > > "Hamish Willee" <[email protected]> escribi� en el mensaje
> > > news:k5CD8JugGHA.1956@extapps30...
> > > > Hi Guillaume
> > > >
> > > > The main document on connectivity is here:
> > > >
> > >
> >[/color]
>[/color]
http://www.symbian.com/developer/tech_papers/papers/cpp_programming_technique.as[color=green][color=darkred]
> > > p#pc_connectivity
> > > >
> > > > I believe the answer is slightly different depending on what is[/color][/color]
backed[color=green]
> > up.[color=darkred]
> > > > If you are talking executable files, I understand that these are
> > effectively
> > > > re-bundled into SIS files which cannot be modified on the PC without[/color][/color]
it[color=green][color=darkred]
> > > > being detected. On uninstall these are unpackaged through the[/color][/color]
installer[color=green][color=darkred]
> > > > Other files may be encrypted when sent to the PC, but this is[/color][/color]
dependent[color=green]
> > on[color=darkred]
> > > > licensee discretion (whether they have implemented it)
> > > >
> > > > The same answer is true on the memory card - you can modify the[/color][/color]
files at[color=green][color=darkred]
> > > > will. However the internal drive of the phone store a hash of the[/color][/color]
files[color=green]
> > that[color=darkred]
> > > > are installed onto MMC, and won't run executables that are tampered.[/color][/color]
If[color=green]
> > the[color=darkred]
> > > > executable is dependent on another file that could be modified and[/color][/color]
is[color=green]
> > not[color=darkred]
> > > > part of the original SIS, then like any application it should deal[/color][/color]
with[color=green]
> > the[color=darkred]
> > > > possibility of corrupt data.
> > > >
> > > > Hope that answers.
> > > >
> > > > Regards
> > > > Hamish
> > > >
> > > >
> > > > "Guillaume" <[email protected]> wrote in message
> > > > news:Tdm3RhlgGHA.1956@extapps30...
> > > > > In Symbian 0S V9, files copied to the PC in a Backup operation are
> > > > designated in
> > > > > the file backup_registration.xml. Once on the PC they are free for
> > reading
> > > > by
> > > > > the user. They can also be tampered / replaced by other files with
> > same
> > > > name. Is
> > > > > there a mechanism to ensure that tampered files are not[/color][/color]
transferred[color=green]
> > back[color=darkred]
> > > > to the
> > > > > phone by the Restore operation?
> > > > >
> > > > > The same question applies to all files stored on the memory card
> > > > ("private" or
> > > > > not), when the card is taken out of the phone and used with a card
> > reader.
> > > > >
> > > > > Thanks,
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >[/color]
>
>[/color]
Hi Hamish,
Thank you for the pointer. Here is another related question (sorry if the answer
is in the book, which I do not have with me yet, or elsewhere in this ng): how
easy is it to extract files from Symbian Signed SIS files? Are these files
encrypted or just signed?
Regards,
Guillaume
"Hamish Willee" <[email protected]> escribi� en el mensaje
news:dqU6caThGHA.2592@extapps30...
> Hi Guillaume
>
> Can I also recommend the excellent coverage of this subject in Chapter 4 of
> the PlatSec book (particularly pp.69-74) which provides a superb exposition
> of this very subject written by someone in the security team 😊
>
> Regards
> H
>
>
Hi Guillaume
If its a SIS file, ie pre Symbian OS v9 you can extract the files using
unsis on www.symbian.com/developer/. So very easy indeed.
If its a SISX file (ie v9 and later) there is an internal tool called
dumpsis for this. Its available only to DevKit licensees. The internal
format isn't published.
So to answer your question, the files are not encrypted are not in any way
protected from extraction by others.
Regards
H
"Guillaume" <[email protected]> wrote in message
news:Om8V29hhGHA.1368@extapps30...
> Hi Hamish,
>
> Thank you for the pointer. Here is another related question (sorry if the
answer
> is in the book, which I do not have with me yet, or elsewhere in this ng):
how
> easy is it to extract files from Symbian Signed SIS files? Are these files
> encrypted or just signed?
>
> Regards,
> Guillaume
>
>
>
>
> "Hamish Willee" <[email protected]> escribi� en el mensaje
> news:dqU6caThGHA.2592@extapps30...[color=green]
> > Hi Guillaume
> >
> > Can I also recommend the excellent coverage of this subject in Chapter 4[/color]
of[color=green]
> > the PlatSec book (particularly pp.69-74) which provides a superb[/color]
exposition[color=green]
> > of this very subject written by someone in the security team 😊
> >
> > Regards
> > H
> >
> >
>
>
>
>[/color]
Hamish Willee wrote:
> Hi Guillaume
>
> If its a SIS file, ie pre Symbian OS v9 you can extract the files using
> unsis on www.symbian.com/developer/. So very easy indeed.
> If its a SISX file (ie v9 and later) there is an internal tool called
> dumpsis for this. Its available only to DevKit licensees. The internal
> format isn't published.
Gulliame the SISX format will be published soon on the
Symbian.com/developer site 😊
>
> So to answer your question, the files are not encrypted are not in any way
> protected from extraction by others.
>
In fact any digital signature is some sort of encrypted digest of the
content it signs of course 😊
So you can read them, but if you change them the signature proves this,
while you cannot attach another signature, becasue the signatory who
originaly issued it has done so with their private key.
> Regards
> H
>
>
>
> "Guillaume" <[email protected]> wrote in message
> news:Om8V29hhGHA.1368@extapps30...
>[color=green]
>>Hi Hamish,
>>
>>Thank you for the pointer. Here is another related question (sorry if the
>
> answer
>
>>is in the book, which I do not have with me yet, or elsewhere in this ng):
>
> how
>
>>easy is it to extract files from Symbian Signed SIS files? Are these files
>>encrypted or just signed?
>>
>>Regards,
>>Guillaume[/color]