• Re: Chromium and self-signed certificates

    From Richard Kettlewell@21:1/5 to bp@www.zefox.net on Wed Aug 14 15:27:46 2024
    <bp@www.zefox.net> writes:
    I'm trying to get chromium under RasPiOS to open an
    https connection to a private webserver that's using
    a self-signed certificate. Apache starts up without
    reporting any errors, chromium opens the page but
    reports only an http connection. All I'm aiming for
    at this point is encryption, not authentication.

    Looking at the page that opens and examining the
    certificate reports only one thing that looks like
    it might be an error. Under Certificate Basic Constraints
    the field value contains:

    Critical
    Is a Certification Authority
    Maximum number of intermediate CAs: unlimited

    Anybody got a link to a good description of how to
    troubleshoot this sort of problem? For example, where
    does chromium put its error logs?

    On the one hand that’s just a description of something it found in the certificate. On the other hand it’s the kind of thing that browsers don’t like so it’s a reasonable candidate for your first problem.

    Normally the error page when you try to visit an ill-configured https
    site can be persuaded to give you some kind of error indicator - you
    should check that before assuming that the unlimited path length is
    really the (only) issue.


    If it is the problem:

    pathLenConstraint is documented here:
    https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.9

    If that is indeed the issue then you need to go back to where the
    self-signed certificate was generated and regenerate it with a pathLenConstraint. How you do that depends on how you generated it.


    The bigger picture:

    No modern web browser is likely to accept a self-signed certificate
    without complaint (although the degree of moaning may vary), so getting
    past this issue may not improve matters as much as you hope.

    Personally I use LetsEncrypt even for purely ‘internal’ certificates; it
    is a lot less painful than either self-signed certificates (which means
    tedious browser warnings) or running my own private CA (which means
    deploying the root to all the clients on my network, and fitting in with browser requirements, which can be a moving target).

    --
    https://www.greenend.org.uk/rjk/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bp@www.zefox.net@21:1/5 to Richard Kettlewell on Thu Aug 15 16:51:38 2024
    Richard Kettlewell <invalid@invalid.invalid> wrote:
    <bp@www.zefox.net> writes:
    I'm trying to get chromium under RasPiOS to open an
    https connection to a private webserver that's using
    a self-signed certificate. Apache starts up without
    reporting any errors, chromium opens the page but
    reports only an http connection. All I'm aiming for
    at this point is encryption, not authentication.

    Looking at the page that opens and examining the
    certificate reports only one thing that looks like
    it might be an error. Under Certificate Basic Constraints
    the field value contains:

    Critical
    Is a Certification Authority
    Maximum number of intermediate CAs: unlimited

    Anybody got a link to a good description of how to
    troubleshoot this sort of problem? For example, where
    does chromium put its error logs?

    On the one hand that’s just a description of something it found in the certificate. On the other hand it’s the kind of thing that browsers don’t like so it’s a reasonable candidate for your first problem.

    Normally the error page when you try to visit an ill-configured https
    site can be persuaded to give you some kind of error indicator - you
    should check that before assuming that the unlimited path length is
    really the (only) issue.


    If it is the problem:

    pathLenConstraint is documented here:
    https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.9

    If that is indeed the issue then you need to go back to where the
    self-signed certificate was generated and regenerate it with a pathLenConstraint. How you do that depends on how you generated it.


    The bigger picture:

    No modern web browser is likely to accept a self-signed certificate
    without complaint (although the degree of moaning may vary), so getting
    past this issue may not improve matters as much as you hope.

    Personally I use LetsEncrypt even for purely ‘internal’ certificates; it is a lot less painful than either self-signed certificates (which means tedious browser warnings) or running my own private CA (which means
    deploying the root to all the clients on my network, and fitting in with browser requirements, which can be a moving target).


    It's very slowly dawning on me just how much I've bitten off here 8-(
    Your reply makes it clear that I didn't understand the relationship between
    a certificate and a CA-certificate, doubtless there's much more to learn.

    My original goal was to get gmail to accept mail from my private mail
    server. When that proved opaque it seemed easier to get ssl/tls working
    with apache as a sort of rehearsal as it appeared better-documented.
    A single host handles both mail and web service and I supposed that
    one ssl/tls installation would work for both. Even if true the learning
    curve is much steeper than expected.

    Thanks very much for enlightening replies!

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bp@www.zefox.net@21:1/5 to bp@www.zefox.net on Sat Aug 31 00:54:42 2024
    bp@www.zefox.net wrote:
    Richard Kettlewell <invalid@invalid.invalid> wrote:
    <bp@www.zefox.net> writes:
    I'm trying to get chromium under RasPiOS to open an
    https connection to a private webserver that's using
    a self-signed certificate. Apache starts up without
    reporting any errors, chromium opens the page but
    reports only an http connection. All I'm aiming for
    at this point is encryption, not authentication.

    Looking at the page that opens and examining the
    certificate reports only one thing that looks like
    it might be an error. Under Certificate Basic Constraints
    the field value contains:

    Critical
    Is a Certification Authority
    Maximum number of intermediate CAs: unlimited

    Anybody got a link to a good description of how to
    troubleshoot this sort of problem? For example, where
    does chromium put its error logs?

    On the one hand that’s just a description of something it found in the
    certificate. On the other hand it’s the kind of thing that browsers don’t
    like so it’s a reasonable candidate for your first problem.

    Normally the error page when you try to visit an ill-configured https
    site can be persuaded to give you some kind of error indicator - you
    should check that before assuming that the unlimited path length is
    really the (only) issue.


    If it is the problem:

    pathLenConstraint is documented here:
    https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.9

    If that is indeed the issue then you need to go back to where the
    self-signed certificate was generated and regenerate it with a
    pathLenConstraint. How you do that depends on how you generated it.


    The bigger picture:

    No modern web browser is likely to accept a self-signed certificate
    without complaint (although the degree of moaning may vary), so getting
    past this issue may not improve matters as much as you hope.

    Personally I use LetsEncrypt even for purely ‘internal’ certificates; it >> is a lot less painful than either self-signed certificates (which means
    tedious browser warnings) or running my own private CA (which means
    deploying the root to all the clients on my network, and fitting in with
    browser requirements, which can be a moving target).


    It's very slowly dawning on me just how much I've bitten off here 8-(
    Your reply makes it clear that I didn't understand the relationship between
    a certificate and a CA-certificate, doubtless there's much more to learn.

    My original goal was to get gmail to accept mail from my private mail
    server. When that proved opaque it seemed easier to get ssl/tls working
    with apache as a sort of rehearsal as it appeared better-documented.
    A single host handles both mail and web service and I supposed that
    one ssl/tls installation would work for both. Even if true the learning
    curve is much steeper than expected.

    Perhaps a little progress has been made. I've generated a new host.crt
    and host.key pair and gotten apache to accept them. When I try to open
    an https connection chromium reports it's not secure, clicking on the
    not secure icon in the url bar lets me see the certificate details, with
    an "export" button at the bottom.

    Clicking "export" brings up a file save dialog open to Documents and
    clicking "save" saves it in ~/Documents under the FQDN of the host.

    Opening Settings > Privacy and Security > Security > Manage Certificates
    opens opens a page with an Authorities tab. That opens an Import button, clicking Import opens ~/Documents. Perhaps significantly, the default
    view doesn't recognize the file, viewing All Files lets me see the
    certificate. Selecting the certificate file and clicking open brings
    up a dialog box with checkmarks trusting websites, email users and
    software makers. Clicking the identifying websites box and clicking OK
    adds a new certificate to the authorities list, named not for the host
    but for the organization name. That the file wasn't recognized as a
    certificate seems suspicious to me.

    At this point closing the old tabs and opening a new one to the server
    again reports a failure, to wit:
    pelorus.zefox.org normally uses encryption to protect your information. When Chromium tried to connect to pelorus.zefox.org this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be
    pelorus.zefox.org, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Chromium stopped the connection before any data was exchanged.




    Clicking on the "not secure" icon again lets
    me see the certificate details. The Subject field contains

    emailAddress = bp@www.zefox.net
    CN = pelorus.zefox.org
    OU = pelorus.zefox.org
    O = zefox networks
    L = davis
    ST = ca
    C = us
    I gather the CN has to be the FQDN for the server, and it is.

    The Issuer field appears the same:
    emailAddress = bp@www.zefox.net
    CN = pelorus.zefox.org
    OU = pelorus.zefox.org
    O = zefox networks
    L = davis
    ST = ca
    C = us
    Could the identical OU and CN fields be troublesome? I'd think not...

    The Certificate Basic Constraints field contains
    Critical
    Is a Certification Authority
    Maximum number of intermediate CAs: unlimited
    but it isn't obviously a problem, as this is a standalone certificate
    with a trust chain length of either zero or one, depending on how one
    counts.

    The command to generate the self-signed certificate and key pair was
    openssl req -new -x509 -days 365 -sha3-512 -keyout host.key -out host.crt
    based on instructions from
    https://docs.freebsd.org/en/books/handbook/security/ combined with some
    private correspondence suggesting it worked correctly.

    The reference to "scrambled credentials" implies a syntax error, some
    kind of credential checker would be a useful tool at this point.

    Thanks to all for writing!

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Kettlewell@21:1/5 to bp@www.zefox.net on Sat Aug 31 10:22:37 2024
    <bp@www.zefox.net> writes:
    The reference to "scrambled credentials" implies a syntax error, some
    kind of credential checker would be a useful tool at this point.

    I see nothing about “scrambled credentials” above. If the browser got as far as displaying the certificate subject then it is certainly
    syntactically well-formed, your browser just doesn’t like the contents.

    You will probably need at least a subjectAltName extension containing
    the DNS name of your server. This has been a cabforum.org requirement
    for real certificates for a long time and I don’t know of any reason it wouldn’t apply to self-signed certificates too.

    --
    https://www.greenend.org.uk/rjk/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bp@www.zefox.net@21:1/5 to Lawrence D'Oliveiro on Sat Sep 7 01:39:00 2024
    Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
    On Sun, 1 Sep 2024 22:49:42 -0000 (UTC), bp wrote:

    Are the certificates and keys the same between SSH and TLS?

    The basic encryption algorithms may be the same, but the usage is a little different. SSH has no concept of “certificates”, only of “host keys” versus “user keys”. Each key is of course actually a key pair, consisting of a public key (freely redistributable, but recipients need to be sure
    they get them from a trusted source) and a corresponding private key
    (never to be disclosed to anybody else).

    There is a file in your SSH client config called “known_hosts”, which contains the public host keys of all the hosts you’ve previously connected to; this is used to guard against somebody trying to impersonate any of
    those hosts when you next try to connect.

    I was confusing host keys and server certificates. One more puzzle down.

    Your scripts seem to work on both FreeBSD and RasPiOS. Now to see if
    I can stumble through making them work between _between_ FreeBSD and
    RasPiOS. One obvious question is setting the "listen_addr" in the
    try_server script. Can it be set to "any" or a range by IP or FQEN?
    A list would be fine, I have only eight addresses total.

    Thank you!

    bob prohaska

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)