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asp.net-coretls1.2dotnet-httpclientubuntu-20.04.net-5

Cannot make work Net5 with Ubuntu 20.04 (OpenSSL connection problem)


I have migrated an application from NetCore 3.1 and Ubuntu 18.04 to Net5 and Ubuntu 20.04.

The application has begun failing when a HttpWebRequest object calls the GetResponse method.

I have found a notice from Microsoft warning about major changes in the behaviour, see

https://learn.microsoft.com/en-US/dotnet/core/compatibility/cryptography/5.0/default-cipher-suites-for-tls-on-linux

And a very interesting post (generic for Linux, not related with Net5) in https://medium.com/siberians-pro/how-to-use-tlsv1-on-ubuntu-20-04-133c2898ad7

But both are not working for me.

What I have tried until now:

  1. I have created a specific local openssl.cnf file, with this content
openssl_conf = openssl_init
    
[openssl_init]
ssl_conf = ssl_sect
    
[ssl_sect]
system_default = system_default_sect
    
[system_default_sect]
MinProtocol = TLSv1
CipherString = DEFAULT@SECLEVEL=1
  1. I have exported the variable OPENSSL_CONF pointing this file
export OPENSSL_CONF=/var/www/spider/openssl.cnf 
  1. I launch my code normally
dotnet Spider.dll
  1. And I get the exception
fail: Spider.Program[0]
      [19/12/2020 08:50:52.724]: Error getting response from https://www.boe.es/diario_boe/xml.php?id=BOE-S-20201216
      System.Net.WebException: The SSL connection could not be established, see inner exception.
       ---> System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.
       ---> System.Security.Authentication.AuthenticationException: Authentication failed, see inner exception.
       ---> Interop+OpenSsl+SslException: SSL Handshake failed with OpenSSL error - SSL_ERROR_SSL.
       ---> Interop+Crypto+OpenSslCryptographicException: error:14094410:SSL routines:ssl3_read_bytes:sslv3 alert handshake failure
         --- End of inner exception stack trace ---
         at Interop.OpenSsl.DoSslHandshake(SafeSslHandle context, ReadOnlySpan`1 input, Byte[]& sendBuf, Int32& sendCount)
         at System.Net.Security.SslStreamPal.HandshakeInternal(SafeFreeCredentials credential, SafeDeleteSslContext& context, ReadOnlySpan`1 inputBuffer, Byte[]& outputBuffer, SslAuthenticationOptions sslAuthenticationOptions)
         --- End of inner exception stack trace ---
         at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)
         at System.Net.Security.SslStream.ProcessAuthentication(Boolean isAsync, Boolean isApm, CancellationToken cancellationToken)
         at System.Net.Security.SslStream.AuthenticateAsClient(SslClientAuthenticationOptions sslClientAuthenticationOptions)
         at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
         --- End of inner exception stack trace ---
         at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
         at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.DecompressionHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
         at System.Net.Http.HttpMessageHandlerStage.Send(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.SocketsHttpHandler.Send(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpClientHandler.Send(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpMessageInvoker.Send(HttpRequestMessage request, CancellationToken cancellationToken)
         at System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, Boolean async, Boolean emitTelemetryStartStop, CancellationToken cancellationToken)
         at System.Net.Http.HttpClient.Send(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
         at System.Net.HttpWebRequest.SendRequest(Boolean async)
         at System.Net.HttpWebRequest.GetResponse()
         --- End of inner exception stack trace ---
         at System.Net.HttpWebRequest.GetResponse()
         at Common.Services.WebContent.GetXmlContent() in xxxxxxxxx/ContentService.cs:line 671

NOTICE: I have also tried

  1. Change the global openssl.cnf in /etc/ssl/openssl.cnf
  2. Test the same URL with curl -vvv. It works WITH NO change in openssl.cnf, and shows a correct TLSv1.2 negotiation (in my URL, to AES128-SHA256)
  3. Test the same URL with openssl s_client -connect host:port. Again, run with no problems.

UPDATE: I have created a simple test code. This code runs without problems in Net5 in Mac, and in a docker container but fails with the previous error in Ubuntu 20.04

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Net.Security;
using System.Threading.Tasks;

namespace BugSSL
{
    class Program
    {
        static void Main(string[] args)
        {
            Curl("https://www.boe.es/diario_boe/xml.php?id=BOE-S-20201216");
        }

        static void Curl(string url)
        {
            HttpWebRequest request;
            HttpWebResponse response;

            ServicePointManager.SecurityProtocol = SecurityProtocolType.SystemDefault;

            try
            {
                Console.WriteLine("START-------------------------------------------------");
                Console.WriteLine($"Getting URL ${url}");
                request = WebRequest.CreateHttp(url);
                request.Method = "GET";
                
                request.AllowAutoRedirect = true;
                request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
                request.Headers.Add(HttpRequestHeader.UserAgent, "SSLBugTest/0.0.0");
                using (response = (HttpWebResponse)request.GetResponse())
                {
                    Console.WriteLine($"Response status: {response.StatusCode} {response.StatusDescription}");
                    Console.WriteLine("Response headers");
                    foreach(string header in response.Headers)
                    {
                        Console.WriteLine($"    {header}: {response.GetResponseHeader(header)}");
                    }
                    Console.WriteLine($"Content-Type: {response.ContentType}");
                    Console.WriteLine($"Content-Length: {response.ContentLength}");
                }

                Console.WriteLine("END---------------------------------------------------");

            }
            catch (Exception e)
            {
                TextWriter stderr = Console.Error;
                stderr.WriteLine($"Error processing {url}. Error: {e.Message}");
                stderr.WriteLine(e.StackTrace);
                while(e.InnerException!=null)
                {
                    e = e.InnerException;
                    Console.WriteLine($"Inner exception: {e.Message}");
                    stderr.WriteLine(e.StackTrace);
                }
            }

        }
    }
}

UPDATE1: I have found this issue in github, but it has been closed without diagnostic or solution https://github.com/dotnet/runtime/issues/44191

UPDATE2: I suspected the problem was that Net5 was not using the configured CipherStrings, and I created a test to use all internally configured. THIS DID NOT WORK, but, maybe, the code can help for further diagnose


        static async Task Curl2(string url)
        {
            List<TlsCipherSuite> cipherSuites;
            SslClientAuthenticationOptions sslOptions;
            SocketsHttpHandler socketHttpHandler;
            HttpResponseMessage response;

            Console.WriteLine("START-------------------------------------------------");
            Console.WriteLine("Using HttpClient and custom socket (custom SslOptions)");

            cipherSuites = new List<TlsCipherSuite>();
            foreach (TlsCipherSuite cipherSuite in (TlsCipherSuite[]) Enum.GetValues(typeof(TlsCipherSuite)))
            {
                cipherSuites.Add(cipherSuite);
            }

            sslOptions = new SslClientAuthenticationOptions();
            //sslOptions = new SslClientAuthenticationOptions
            //{
            //    CipherSuitesPolicy = new CipherSuitesPolicy(cipherSuites)
            //};
            try
            {
                sslOptions = new SslClientAuthenticationOptions();
                socketHttpHandler = new SocketsHttpHandler
                {
                    SslOptions = sslOptions
                };
                var httpClient = new HttpClient(socketHttpHandler, true);
                using (response = await httpClient.GetAsync(url))
                {
                    Console.WriteLine($"Response status: {response.StatusCode}");
                    Console.WriteLine("Response headers");
                    foreach (KeyValuePair<string, IEnumerable<string>> header in response.Headers)
                    {
                        Console.Write($"    {header.Key}: ");
                        foreach (string value in header.Value)
                        {
                            Console.Write($"{value} ");
                        }
                        Console.WriteLine("");
                    }
                }
            }
            catch (Exception e)
            {
                TextWriter stderr = Console.Error;
                stderr.WriteLine($"Error processing {url}. Error: {e.Message}");
                stderr.WriteLine(e.StackTrace);
                while (e.InnerException != null)
                {
                    e = e.InnerException;
                    Console.WriteLine($"Inner exception: {e.Message}");
                    stderr.WriteLine(e.StackTrace);
                }
            }

            Console.WriteLine("END---------------------------------------------------");


        }
    

Solution

  • The bug in https://github.com/dotnet/runtime/issues/46271 is solved.

    The problem was in the /etc/ssl/openssl.cnf. This openssl.cnf works (check CipherString and CipherSuites at the end of the file)

    #
    # OpenSSL example configuration file.
    # This is mostly being used for generation of certificate requests.
    #
    
    # Note that you can include other files from the main configuration
    # file using the .include directive.
    #.include filename
    
    # This definition stops the following lines choking if HOME isn't
    # defined.
    HOME            = .
    
    openssl_conf = openssl_init
    
    
    # Extra OBJECT IDENTIFIER info:
    #oid_file       = $ENV::HOME/.oid
    oid_section     = new_oids
    
    # To use this configuration file with the "-extfile" option of the
    # "openssl x509" utility, name here the section containing the
    # X.509v3 extensions to use:
    # extensions        =
    # (Alternatively, use a configuration file that has only
    # X.509v3 extensions in its main [= default] section.)
    
    [ new_oids ]
    
    # We can add new OIDs in here for use by 'ca', 'req' and 'ts'.
    # Add a simple OID like this:
    # testoid1=1.2.3.4
    # Or use config file substitution like this:
    # testoid2=${testoid1}.5.6
    
    # Policies used by the TSA examples.
    tsa_policy1 = 1.2.3.4.1
    tsa_policy2 = 1.2.3.4.5.6
    tsa_policy3 = 1.2.3.4.5.7
    
    ####################################################################
    [ ca ]
    default_ca  = CA_default        # The default ca section
    
    ####################################################################
    [ CA_default ]
    
    dir     = ./demoCA      # Where everything is kept
    certs       = $dir/certs        # Where the issued certs are kept
    crl_dir     = $dir/crl      # Where the issued crl are kept
    database    = $dir/index.txt    # database index file.
    #unique_subject = no            # Set to 'no' to allow creation of
                        # several certs with same subject.
    new_certs_dir   = $dir/newcerts     # default place for new certs.
    
    certificate = $dir/cacert.pem   # The CA certificate
    serial      = $dir/serial       # The current serial number
    crlnumber   = $dir/crlnumber    # the current crl number
                        # must be commented out to leave a V1 CRL
    crl     = $dir/crl.pem      # The current CRL
    private_key = $dir/private/cakey.pem# The private key
    
    x509_extensions = usr_cert      # The extensions to add to the cert
    
    # Comment out the following two lines for the "traditional"
    # (and highly broken) format.
    name_opt    = ca_default        # Subject Name options
    cert_opt    = ca_default        # Certificate field options
    
    # Extension copying option: use with caution.
    # copy_extensions = copy
    
    # Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
    # so this is commented out by default to leave a V1 CRL.
    # crlnumber must also be commented out to leave a V1 CRL.
    # crl_extensions    = crl_ext
    
    default_days    = 365           # how long to certify for
    default_crl_days= 30            # how long before next CRL
    default_md  = default       # use public key default MD
    preserve    = no            # keep passed DN ordering
    
    # A few difference way of specifying how similar the request should look
    # For type CA, the listed attributes must be the same, and the optional
    # and supplied fields are just that :-)
    policy      = policy_match
    
    # For the CA policy
    [ policy_match ]
    countryName     = match
    stateOrProvinceName = match
    organizationName    = match
    organizationalUnitName  = optional
    commonName      = supplied
    emailAddress        = optional
    
    # For the 'anything' policy
    # At this point in time, you must list all acceptable 'object'
    # types.
    [ policy_anything ]
    countryName     = optional
    stateOrProvinceName = optional
    localityName        = optional
    organizationName    = optional
    organizationalUnitName  = optional
    commonName      = supplied
    emailAddress        = optional
    
    ####################################################################
    [ req ]
    default_bits        = 2048
    default_keyfile     = privkey.pem
    distinguished_name  = req_distinguished_name
    attributes      = req_attributes
    x509_extensions = v3_ca # The extensions to add to the self signed cert
    
    # Passwords for private keys if not present they will be prompted for
    # input_password = secret
    # output_password = secret
    
    # This sets a mask for permitted string types. There are several options.
    # default: PrintableString, T61String, BMPString.
    # pkix   : PrintableString, BMPString (PKIX recommendation before 2004)
    # utf8only: only UTF8Strings (PKIX recommendation after 2004).
    # nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
    # MASK:XXXX a literal mask value.
    # WARNING: ancient versions of Netscape crash on BMPStrings or UTF8Strings.
    string_mask = utf8only
    
    # req_extensions = v3_req # The extensions to add to a certificate request
    
    [ req_distinguished_name ]
    countryName         = Country Name (2 letter code)
    countryName_default     = AU
    countryName_min         = 2
    countryName_max         = 2
    
    stateOrProvinceName     = State or Province Name (full name)
    stateOrProvinceName_default = Some-State
    
    localityName            = Locality Name (eg, city)
    
    0.organizationName      = Organization Name (eg, company)
    0.organizationName_default  = Internet Widgits Pty Ltd
    
    # we can do this but it is not needed normally :-)
    #1.organizationName     = Second Organization Name (eg, company)
    #1.organizationName_default = World Wide Web Pty Ltd
    
    organizationalUnitName      = Organizational Unit Name (eg, section)
    #organizationalUnitName_default =
    
    commonName          = Common Name (e.g. server FQDN or YOUR name)
    commonName_max          = 64
    
    emailAddress            = Email Address
    emailAddress_max        = 64
    
    # SET-ex3           = SET extension number 3
    
    [ req_attributes ]
    challengePassword       = A challenge password
    challengePassword_min       = 4
    challengePassword_max       = 20
    
    unstructuredName        = An optional company name
    
    [ usr_cert ]
    
    # These extensions are added when 'ca' signs a request.
    
    # This goes against PKIX guidelines but some CAs do it and some software
    # requires this to avoid interpreting an end user certificate as a CA.
    
    basicConstraints=CA:FALSE
    
    # Here are some examples of the usage of nsCertType. If it is omitted
    # the certificate can be used for anything *except* object signing.
    
    # This is OK for an SSL server.
    # nsCertType            = server
    
    # For an object signing certificate this would be used.
    # nsCertType = objsign
    
    # For normal client use this is typical
    # nsCertType = client, email
    
    # and for everything including object signing:
    # nsCertType = client, email, objsign
    
    # This is typical in keyUsage for a client certificate.
    # keyUsage = nonRepudiation, digitalSignature, keyEncipherment
    
    # This will be displayed in Netscape's comment listbox.
    nsComment           = "OpenSSL Generated Certificate"
    
    # PKIX recommendations harmless if included in all certificates.
    subjectKeyIdentifier=hash
    authorityKeyIdentifier=keyid,issuer
    
    # This stuff is for subjectAltName and issuerAltname.
    # Import the email address.
    # subjectAltName=email:copy
    # An alternative to produce certificates that aren't
    # deprecated according to PKIX.
    # subjectAltName=email:move
    
    # Copy subject details
    # issuerAltName=issuer:copy
    
    #nsCaRevocationUrl      = http://www.domain.dom/ca-crl.pem
    #nsBaseUrl
    #nsRevocationUrl
    #nsRenewalUrl
    #nsCaPolicyUrl
    #nsSslServerName
    
    # This is required for TSA certificates.
    # extendedKeyUsage = critical,timeStamping
    
    [ v3_req ]
    
    # Extensions to add to a certificate request
    
    basicConstraints = CA:FALSE
    keyUsage = nonRepudiation, digitalSignature, keyEncipherment
    
    [ v3_ca ]
    
    
    # Extensions for a typical CA
    
    
    # PKIX recommendation.
    
    subjectKeyIdentifier=hash
    
    authorityKeyIdentifier=keyid:always,issuer
    
    basicConstraints = critical,CA:true
    
    # Key usage: this is typical for a CA certificate. However since it will
    # prevent it being used as an test self-signed certificate it is best
    # left out by default.
    # keyUsage = cRLSign, keyCertSign
    
    # Some might want this also
    # nsCertType = sslCA, emailCA
    
    # Include email address in subject alt name: another PKIX recommendation
    # subjectAltName=email:copy
    # Copy issuer details
    # issuerAltName=issuer:copy
    
    # DER hex encoding of an extension: beware experts only!
    # obj=DER:02:03
    # Where 'obj' is a standard or added object
    # You can even override a supported extension:
    # basicConstraints= critical, DER:30:03:01:01:FF
    
    [ crl_ext ]
    
    # CRL extensions.
    # Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.
    
    # issuerAltName=issuer:copy
    authorityKeyIdentifier=keyid:always
    
    [ proxy_cert_ext ]
    # These extensions should be added when creating a proxy certificate
    
    # This goes against PKIX guidelines but some CAs do it and some software
    # requires this to avoid interpreting an end user certificate as a CA.
    
    basicConstraints=CA:FALSE
    
    # Here are some examples of the usage of nsCertType. If it is omitted
    # the certificate can be used for anything *except* object signing.
    
    # This is OK for an SSL server.
    # nsCertType            = server
    
    # For an object signing certificate this would be used.
    # nsCertType = objsign
    
    # For normal client use this is typical
    # nsCertType = client, email
    
    # and for everything including object signing:
    # nsCertType = client, email, objsign
    
    # This is typical in keyUsage for a client certificate.
    # keyUsage = nonRepudiation, digitalSignature, keyEncipherment
    
    # This will be displayed in Netscape's comment listbox.
    nsComment           = "OpenSSL Generated Certificate"
    
    # PKIX recommendations harmless if included in all certificates.
    subjectKeyIdentifier=hash
    authorityKeyIdentifier=keyid,issuer
    
    # This stuff is for subjectAltName and issuerAltname.
    # Import the email address.
    # subjectAltName=email:copy
    # An alternative to produce certificates that aren't
    # deprecated according to PKIX.
    # subjectAltName=email:move
    
    # Copy subject details
    # issuerAltName=issuer:copy
    
    #nsCaRevocationUrl      = http://www.domain.dom/ca-crl.pem
    #nsBaseUrl
    #nsRevocationUrl
    #nsRenewalUrl
    #nsCaPolicyUrl
    #nsSslServerName
    
    # This really needs to be in place for it to be a proxy certificate.
    proxyCertInfo=critical,language:id-ppl-anyLanguage,pathlen:3,policy:foo
    
    ####################################################################
    [ tsa ]
    
    default_tsa = tsa_config1   # the default TSA section
    
    [ tsa_config1 ]
    
    # These are used by the TSA reply generation only.
    dir     = ./demoCA      # TSA root directory
    serial      = $dir/tsaserial    # The current serial number (mandatory)
    crypto_device   = builtin       # OpenSSL engine to use for signing
    signer_cert = $dir/tsacert.pem  # The TSA signing certificate
                        # (optional)
    certs       = $dir/cacert.pem   # Certificate chain to include in reply
                        # (optional)
    signer_key  = $dir/private/tsakey.pem # The TSA private key (optional)
    signer_digest  = sha256         # Signing digest to use. (Optional)
    default_policy  = tsa_policy1       # Policy if request did not specify it
                        # (optional)
    other_policies  = tsa_policy2, tsa_policy3  # acceptable policies (optional)
    digests     = sha1, sha256, sha384, sha512  # Acceptable message digests (mandatory)
    accuracy    = secs:1, millisecs:500, microsecs:100  # (optional)
    clock_precision_digits  = 0 # number of digits after dot. (optional)
    ordering        = yes   # Is ordering defined for timestamps?
                    # (optional, default: no)
    tsa_name        = yes   # Must the TSA name be included in the reply?
                    # (optional, default: no)
    ess_cert_id_chain   = no    # Must the ESS cert id chain be included?
                    # (optional, default: no)
    ess_cert_id_alg     = sha1  # algorithm to compute certificate
                    # identifier (optional, default: sha1)
    
    [openssl_init]
    ssl_conf = ssl_config
    
    [ssl_config]
    system_default = tls_defaults
    
    [tls_defaults]
    CipherString = @SECLEVEL=2:kEECDH:kRSA:kEDH:kPSK:kDHEPSK:kECDHEPSK:-aDSS:-3DES:!DES:!RC4:!RC2:!IDEA:-SEED:!eNULL:!aNULL:!MD5:-SHA384:-CAMELLIA:-ARIA:-AESCCM8
    Ciphersuites = TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256:TLS_AES_128_CCM_SHA256
    MinProtocol = TLSv1.2