[Ovmsdev] OTA status check timeout / SSL problem?

[Michael Balzer]

Mark,

support for HTTPS will help but not be a 100% protection against MITM attacks.

Regarding code signing, I think we don't need the ESP32 chip level protection, the primary concern is malicious downloads / uploads.

So we could store the public key in the firmware instead and use that to verify all downloads & uploads. That way, anyone can create his/her own key pair to use
for personal builds.

Installing a firmware with another key would still be possible by flashing via USB or SD.

Regards,
Michael


Am 07.04.2018 um 08:03 schrieb Mark Webb-Johnson:
> Not at the moment.
>
> From my understanding, there are two ways to do this (not mutually exclusive):
>
>  1. Signed firmware
>
>     This is the most comprehensive way. It involved a public key stored on the OVMS module itself (burned into e-fuses), and a private key used to sign
>     binaries. The boot loader will then refuse to load any App who’s signature doesn’t match. Works with flash encryption as well.
>
>     The problem with this is it conflicts with the nature of open source. Once an ESP32 chip is put in that mode, it will only execute code signed with that
>     private key. We can’t make that public (without destroying the entire security).
>
>  2. HTTPS
>
>     This at least provides some protection. We can validate the SSL certificate of the server (api.openvehicles.com <http://api.openvehicles.com>) and protect
>     somewhat from man-in-the-middle attacks.
>
>     It doesn’t protect against other side-load attacks (such as SD CARD firmware load) - but those require physical access which is pretty much game over
>     anyway, right?
>
>
> I would like to do #2, and made allowance for that with ‘ota flash http’ leaving room for ‘ota flash https’. Just our http client library is pretty crappy at
> the moment, and it will take some effort to make it support https.
>
> Regards, Mark.
>
>> On 6 Apr 2018, at 10:57 PM, Tom Saxton <tom at idleloop.com <mailto:tom at idleloop.com>> wrote:
>>
>> I don’t have the full context for this discussion, but I’m wondering: is the OTA update mechanism protected against a man-in-the-middle attack?
>>  
>>      Tom
>>  
>> *From: *OvmsDev <ovmsdev-bounces at lists.openvehicles.com <mailto:ovmsdev-bounces at lists.openvehicles.com>> on behalf of Mark Webb-Johnson
>> <mark at webb-johnson.net <mailto:mark at webb-johnson.net>>
>> *Reply-To: *OVMS Developers <ovmsdev at lists.openvehicles.com <mailto:ovmsdev at lists.openvehicles.com>>
>> *Date: *Wednesday, April 4, 2018 at 11:51 PM
>> *To: *OVMS Developers <ovmsdev at lists.openvehicles.com <mailto:ovmsdev at lists.openvehicles.com>>
>> *Subject: *Re: [Ovmsdev] OTA status check timeout / SSL problem?
>>  
>> I think it was a fault on the api.openvehicles.com<http://api.openvehicles.com/> config - that shouldn’t be redirecting to https.
>>  
>> I fixed it, and it should be ok now.
>>  
>> Regards, Mark.
>>  
>>> On 5 Apr 2018, at 12:44 AM, Michael Balzer <dexter at expeedo.de<mailto:dexter at expeedo.de>> wrote:
>>>  
>>> Mark,
>>>
>>> the server check for an OTA update now fails every time, times out after 10 seconds.
>>>
>>> I think that's because the new server currently does a redirect from http to https also on the api.openvehicles.com<http://api.openvehicles.com/> host. Not
>>> sure why the module doesn't fail
>>> directly on that, maybe it tries to validate the certificate which also does not match.
>>>
>>> As the openvehicles server has frequent connectivity issues from here I've added a "nocheck" option to the ota status command and use that for the standard web
>>> status page. The OTA page still checks for the update.
>>>
>>> Regards,
>>> Michael
>>>
>>> -- 
>>> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
>>> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>>>
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>>  
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>
>
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-- 
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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