Still no luck, and getting clueless… :-/

Let's Encrypt have a live test server: https://valid-isrgrootx1.letsencrypt.org/

Here's a simple test script to access that server:

(function(){
    HTTP.request({
      url: "https://valid-isrgrootx1.letsencrypt.org/",
      always: function() { JSON.print(this); }
    });
})();

Just copy this into the editor and evaluate.

After commenting out the DST certificate from the TLS source, the http request terminates with an SSL error (-3) with installed…
But the access works immediately after reinstalling the old DST root certificate. There is no DST reference in the chain of that server…


I found another ESP32 project -- not using WolfSSL but the esp-idf SSL & MQTT lib --; apparently all they needed to do was to add the very same self-signed ISRG X1 certificate I added:

So: why would WolfSSL not use the supplied ISRG certificate? Why would it use the DST cert without DST being present as an issuer?

The ISRG certificate is the only one having…

  signed using      : RSA with SHA-256
  RSA key size      : 4096 bits

But that would surely be supported by WolfSSL, wouldn't it?

I'm running out of ideas, and this really isn't my primary area. Any help is appreciated.

Regards,
Michael


Am 28.09.21 um 19:15 schrieb Stephen Casner:
Michael,

Certainly within our code as it stands there is not any mechanism to
tell the WolfSSL code to adjust its certificate validation procedure.
The browser certificate substitution that you hypothesize is not clear
to me.  I would expect the validation to simply follow the chain.

                                                        -- Steve

On Tue, 28 Sep 2021, Michael Balzer wrote:


More info:

All my browsers already have a builtin ISRG X1 certificate signed by ISRG
only, that's the new version:

https://crt.sh/?id=9314791

My server still sends the ISRG X1 certificate cross signed / issued by DST
Root CA X3. That's the chain it got from Let's Encrypt (via certbot) on the
last renewal (last month!):

https://crt.sh/?id=3958242236

Without the DST root cert, WolfSSL then fails validating the DST signed X1
root certificate (I assume): https://www.wolfssl.com/docs/wolfssl-manual/ch7/

My servers will continue sending that chain including the outdated root cert
probably until the next renewal, so it's possible having added the new X1 root
certificate didn't solve the issue.

The browsers seem to know how to substitute the DST signed certificate by the
builtin self-signed (?). Is there a similar option in WolfSSL, and do we need
to enable that?

Steve, can you confirm this, do you know a solution?

Regards,
Michael


Am 28.09.21 um 15:34 schrieb Michael Balzer:

I've tried adding the intermediate cert ("R3") and then also my site
certificate, that didn't help.

Only adding the DST cert again fixes the connection.

Any ideas?


OVMS# tls trust list
...
ISRG Root X1 length 1939 bytes
1939 byte certificate: ISRG Root X1
  cert. version     : 3
  serial number     : 82:10:CF:B0:D2:40:E3:59:44:63:E0:BB:63:82:8B:00
  issuer name       : C=US, O=Internet Security Research Group, CN=ISRG Root
X1
  subject name      : C=US, O=Internet Security Research Group, CN=ISRG Root
X1
  issued  on        : 2015-06-04 11:04:38
  expires on        : 2035-06-04 11:04:38
  signed using      : RSA with SHA-256
  RSA key size      : 4096 bits
  basic constraints : CA=true
  key usage         : Key Cert Sign, CRL Sign
...
dexter length 1972 bytes
1972 byte certificate: dexter
  cert. version     : 3
  serial number     : 04:55:1D:F4:27:A3:7D:E9:E4:A8:5C:37:F6:A1:61:87:3C:E5
  issuer name       : C=US, O=Let's Encrypt, CN=R3
  subject name      : CN=dexter.shopdriver.de
  issued  on        : 2021-08-07 05:47:57
  expires on        : 2021-11-05 05:47:55
  signed using      : RSA with SHA-256
  RSA key size      : 2048 bits
  basic constraints : CA=false
  subject alt name  : dexter.shopdriver.de, dexters-web.de,
ovms.dexters-web.de, www.dexter.shopdriver.de, www.dexters-web.de
  key usage         : Digital Signature, Key Encipherment
  ext key usage     : TLS Web Server Authentication, TLS Web Client
Authentication
...
r3 length 1826 bytes
1826 byte certificate: r3
  cert. version     : 3
  serial number     : 91:2B:08:4A:CF:0C:18:A7:53:F6:D6:2E:25:A7:5F:5A
  issuer name       : C=US, O=Internet Security Research Group, CN=ISRG Root
X1
  subject name      : C=US, O=Let's Encrypt, CN=R3
  issued  on        : 2020-09-04 00:00:00
  expires on        : 2025-09-15 16:00:00
  signed using      : RSA with SHA-256
  RSA key size      : 2048 bits
  basic constraints : CA=true, max_pathlen=0
  key usage         : Digital Signature, Key Cert Sign, CRL Sign
  ext key usage     : TLS Web Client Authentication, TLS Web Server
Authentication



Am 28.09.21 um 15:07 schrieb Michael Balzer:

We would need to bypass / shortcut the "eap" test phase.

But I agree, "master" is stable, I haven't had any issues or reports, so I
think we could do that. The FreeRTOS timer issue I'm working on only
affects very specific conditions, so not necessary to wait for that.

Should we remove the expiring DST certificate in that release then?

...uh oh: just tried removing the DST certificate: the module cannot
connect to my server anymore...!?

I (490213) ovms-server-v2: Connection is ovms.dexters-web.de:6870 TEST1
I (490213) ovms-server-v2: Status: Connecting...
V (490723) ovms-server-v2: OvmsServerV2MongooseCallback(MG_EV_CONNECT=-3)
W (490723) ovms-server-v2: Connection failed
E (490723) ovms-server-v2: Status: Error: Connection failed
V (490723) ovms-server-v2: OvmsServerV2MongooseCallback(MG_EV_CLOSE)
I (490723) ovms-server-v2: Status: Disconnected




Am 28.09.21 um 14:32 schrieb Mark Webb-Johnson:

Shall we release a full update? The last 3.2?

What we have now in master seems stable.

Mark


On 28 Sep 2021, at 5:39 PM, Michael Balzer <dexter@expeedo.de> wrote:

 Everyone,

the DST root certificate we include (DST Root CA X3) expires on
September 30, i.e. in two days.

OVMS# tls trust list
DST Root CA X3 length 1200 bytes
1200 byte certificate: DST Root CA X3
  cert. version     : 3
  serial number     : 44:AF:B0:80:D6:A3:27:BA:89:30:39:86:2E:F8:40:6B
  issuer name       : O=Digital Signature Trust Co., CN=DST Root CA X3
  subject name      : O=Digital Signature Trust Co., CN=DST Root CA X3
  issued  on        : 2000-09-30 21:12:19
*  expires on        : 2021-09-30 14:01:15*
  signed using      : RSA with SHA1
  RSA key size      : 2048 bits
  basic constraints : CA=true
  key usage         : Key Cert Sign, CRL Sign

AFAICT, this root certificate is currently used by the OVMS to
validate Let's Encrypt certificates.

  *
https://letsencrypt.org/docs/dst-root-ca-x3-expiration-september-2021/
  * https://letsencrypt.org/docs/certificate-compatibility/

Unfortunately, we missed adding the followup LE root certificate "ISRG
Root X1" in time.

I've just added that certificate to our builtin certificate
repository, but it's too late now to roll out a "main" update in time
(isn't it?).

So, to prevent losing TLS connectivity with LE servers, users need to
manually add the ISRG Root X1 certificate to their TLS repositories.

I've added a section on this to our user manual:

  * https://docs.openvehicles.com/en/latest/userguide/ssltls.html

If users contact you, point them to that page.

We probably should also remove the expired DST root certificate after
September 30.

Regards,
Michael

--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
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Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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-- 
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26