While the Third party server connects to C2DM Google Server, I think there is SSL or TLS Connection in between. if so, where do i get the certificate that will be used in between for handshaking?
You can extract this certificate from Google C2DM server with the following command:
openssl s_client -connect android.apis.google.com:443
I assume it is signed by a certifying authority that you can verify.
Related
I've to enable both server and client certificates. My plan is to use Let's encrypt for server and OpenSSL for the client certificate. The reason is that Let's encrypt only provide server certificates. I know that some commercial providers like DigiCert or GlobalSign provide both server and client certificates but that is not the option.
I haven't tried yet but I guess CA doesn't necessarily have to be the same for both certificates. Can anyone suggest a better idea?
If you use OpenSSL you will either have to establish a trusted internal CA or else use self-signed certificates, and ensure that whichever you use is trusted by the server(s). In the end it's cheaper to pay an external CA, then you don't have to overcome any trust issues.
I wouldn't say that Let's Encrypt only issues server certificates. There is no difference between a server certificate and a client certificate. However their authentication method requires a web server.
I have an application running on Centos7 that needs to connect to a remote host over HTTPS. However, it is unable to verify the certificate and fails. Also, if I try to download a file from the server using wget, I get the below error:
[root#foo:~]# wget https://10.65.127.9/index.html
--2017-05-22 09:03:01-- https://10.65.127.9/index.html
Connecting to 10.65.127.9:443... connected.
ERROR: cannot verify 10.65.127.9's certificate, issued by ‘/CN=us6877vnxe7827’:
Unable to locally verify the issuer's authority.
To connect to 10.65.127.9 insecurely, use `--no-check-certificate'.
So I get the certificate from the host:
openssl s_client -connect 10.65.127.9:443 <<<'' | openssl x509 -out /etc/pki/ca-trust/source/anchors/mycert.pem
And execute the following to process it:
update-ca-trust extract
This however results in the same issue.. If I run:
openssl s_client -connect 10.65.127.9:443 -showcerts -debug
I do get some errors and various messages:
depth=0 CN = us6877vnxe7827
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 CN = us6877vnxe7827
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/CN=us6877vnxe7827
i:/CN=us6877vnxe7827
Server certificate
subject=/CN=us6877vnxe7827
issuer=/CN=us6877vnxe7827
---
No client certificate CA names sent
---
Verify return code: 21 (unable to verify the first certificate)
Any ideas what I may be missing? If any further info helps, please let me know.
For wget you need to provide the certificate authority (CA) certificate(s) that signed the https server certificate. If you have those CA certificates - add them under --ca-certificate=file or --ca-directory=directory options
If you don't have them and you want to skip https server certificate verification (unsecure and can be dangerous) then use --no-check-certificate option.
I had the same problem with Jenkins trying to connect to our GitLab server.
The server does have a valid official certificate in our case, but Java didn't except it.
You are right about downloading the certificate.
However, the application you are mentioning is probably running inside a Java Virtual Machine (as a lot of applications are).
So from the point that you downloaded the certificate to a PEM file, you may have to add it to the VM's trusted certificates instead.
This article describes how to do that. Hope it helps.
I am developing a client/server application with TLS. My idea is to use a certificate on the client so it is authenticated by the server. Also another certificate on the server so the client is also able to authenticate that it is connecting to the right server.
I want first to test and use openssl s_server and openssl s_client to validate the proposal.
Until now I have created a CA private key on the server, I have created a root certificate. With the root certificate I have signed two CSR, so I get one certificate for the server and one certificate for the client.
I also have installed the client certificate + root certificate on the client, and the server certificate + root certificate on the server.
I want now to try to establish a connection between openssl s_server and openssl s_client and verify that they get both authenticated mutually, but I cannot wrap my mind with the documentation on how to do it. Any help or any guide on that?
Once I have that set up, the next step is to test the own developed client against that server, and our own developed server against the s_client. Can we use that for testing?
Thanks
It looks like you are trying to set up a root of trust with (1) s_client and s_server for testing; and (2) programmatically within your code using OpenSSL.
To ensure openssl s_client (or openssl s_server) uses your root, use the following options:
-CAfile option to specify the root
-cert option for the certificate to use
-key option for the private key of the certificate
See the docs on s_client(1) and s_server(1) for details.
To do the same programmatically on the client, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate to specify the client certificate
SSL_CTX_use_PrivateKey to load the private key for the client certificate
To do the same programmatically on the server, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate_chain_file to specify the server certificate
SSL_CTX_use_PrivateKey to load the private key for the server certificate
SSL_CTX_set_client_CA_list to tell the client to send its client certificate
If you don't want to use the parameters for every connection (i.e. the common context), then set it for each SSL connection with, for example, SSL_use_certificate and SSL_use_PrivateKey.
A lot goes on with SSL_CTX_set_client_CA_list. It (1) loads the CA's to the server uses to verify a client, (2) it causes the server to send a list of CAs it accepts when verifing a client, and (3) it triggers the ClientCertificate message at the client if the client has a certificate that satisfies the server's accepted CAs list.
Also see the docs on SSL_CTX_load_verify_locations(3), SSL_CTX_use_certificate(3), SSL_CTX_set_client_CA_list and friends.
The easiest certificate and key format to use is PEM. PEM is the one that uses, for example, ----- BEGIN CERTIFICATE -----. For the server certificate, be sure the file is a concatenation of the server's certificate and any intermediates needed by the client to build the chain.
Having the server send all required certificates is standard practice for a problem known as the "which directory" problem. Its a well known problem in PKI, and its essentially the problem that clients don't know where to go to fetch missing intermediate certificates.
In general, you now know the functions that you need to use. Download a small server like nginx, and see how a production server uses them in practice. You could even use a SQL server like Postgres since it sets up a SSL/TLS server. Simply search the source files for SSL_CTX_load_verify_locations or SSL_load_verify_locations, and you will find the right place.
Though I don't recommend it, you could even look at s_client.c and s_server.c. They are located in <openssl dir>/apps. But the code can be difficult to read at times.
Generate two pairs of certificates/keys, one for the server and one for the client. Also create test.txt with any content.
To set up an SSL server that checks a client certificate, run the following command:
openssl s_server -cert server_cert.pem -key server_key.pem -WWW -port 12345 -CAfile client_cert.pem -verify_return_error -Verify 1
To test the server with client certificate, run the following command:
echo -e 'GET /test.txt HTTP/1.1\r\n\r\n' | openssl s_client -cert client_cert.pem -key client_key.pem -CAfile server_cert.pem -connect localhost:12345 -quiet
Alternatively you can use curl command:
curl -k --cert client_cert.pem --key client_key.pem https://localhost:12345/test.txt
I'm trying to create web application with client certificates, generated programmatically. My main problem is following: I've added generated .p12 keystore to my web browser, but it doesn't send certificate to the server.
How does browser understand which x509 certificate it should use? And is it possible to debug SSL in Chrome of Firefox?
SSL/TLS server sends Certificate Request message (see RFC 4346 for TLS 1.1 or others). In this message there is only certificate type and acceptable certificate authorities names, so server doesn't tell anything about particular certificate.
The possible reason is that your certificate of invalid type (i.e. DSA instead of RSA but key exchange algorithm depends on client RSA certificate), or server requests certificate of different certificate authority.
I am developing a client/server application with TLS. My idea is to use a certificate on the client so it is authenticated by the server. Also another certificate on the server so the client is also able to authenticate that it is connecting to the right server.
I want first to test and use openssl s_server and openssl s_client to validate the proposal.
Until now I have created a CA private key on the server, I have created a root certificate. With the root certificate I have signed two CSR, so I get one certificate for the server and one certificate for the client.
I also have installed the client certificate + root certificate on the client, and the server certificate + root certificate on the server.
I want now to try to establish a connection between openssl s_server and openssl s_client and verify that they get both authenticated mutually, but I cannot wrap my mind with the documentation on how to do it. Any help or any guide on that?
Once I have that set up, the next step is to test the own developed client against that server, and our own developed server against the s_client. Can we use that for testing?
Thanks
It looks like you are trying to set up a root of trust with (1) s_client and s_server for testing; and (2) programmatically within your code using OpenSSL.
To ensure openssl s_client (or openssl s_server) uses your root, use the following options:
-CAfile option to specify the root
-cert option for the certificate to use
-key option for the private key of the certificate
See the docs on s_client(1) and s_server(1) for details.
To do the same programmatically on the client, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate to specify the client certificate
SSL_CTX_use_PrivateKey to load the private key for the client certificate
To do the same programmatically on the server, you would use:
SSL_CTX_load_verify_locations to load the trusted root
SSL_CTX_use_certificate_chain_file to specify the server certificate
SSL_CTX_use_PrivateKey to load the private key for the server certificate
SSL_CTX_set_client_CA_list to tell the client to send its client certificate
If you don't want to use the parameters for every connection (i.e. the common context), then set it for each SSL connection with, for example, SSL_use_certificate and SSL_use_PrivateKey.
A lot goes on with SSL_CTX_set_client_CA_list. It (1) loads the CA's to the server uses to verify a client, (2) it causes the server to send a list of CAs it accepts when verifing a client, and (3) it triggers the ClientCertificate message at the client if the client has a certificate that satisfies the server's accepted CAs list.
Also see the docs on SSL_CTX_load_verify_locations(3), SSL_CTX_use_certificate(3), SSL_CTX_set_client_CA_list and friends.
The easiest certificate and key format to use is PEM. PEM is the one that uses, for example, ----- BEGIN CERTIFICATE -----. For the server certificate, be sure the file is a concatenation of the server's certificate and any intermediates needed by the client to build the chain.
Having the server send all required certificates is standard practice for a problem known as the "which directory" problem. Its a well known problem in PKI, and its essentially the problem that clients don't know where to go to fetch missing intermediate certificates.
In general, you now know the functions that you need to use. Download a small server like nginx, and see how a production server uses them in practice. You could even use a SQL server like Postgres since it sets up a SSL/TLS server. Simply search the source files for SSL_CTX_load_verify_locations or SSL_load_verify_locations, and you will find the right place.
Though I don't recommend it, you could even look at s_client.c and s_server.c. They are located in <openssl dir>/apps. But the code can be difficult to read at times.
Generate two pairs of certificates/keys, one for the server and one for the client. Also create test.txt with any content.
To set up an SSL server that checks a client certificate, run the following command:
openssl s_server -cert server_cert.pem -key server_key.pem -WWW -port 12345 -CAfile client_cert.pem -verify_return_error -Verify 1
To test the server with client certificate, run the following command:
echo -e 'GET /test.txt HTTP/1.1\r\n\r\n' | openssl s_client -cert client_cert.pem -key client_key.pem -CAfile server_cert.pem -connect localhost:12345 -quiet
Alternatively you can use curl command:
curl -k --cert client_cert.pem --key client_key.pem https://localhost:12345/test.txt