Introduction

Recently, I got an error with PayPal Ruby SDK, but the solution is that there is no Japanese information even if I search Google, and English is hardly hit, so make a note. It seems to have happened in the last few days.

SSL_connect returned=1 errno=0 state=error: certificate verify failed (unable to get local issuer certificate)

1. Cause

The cause is on the PayPal side. PayPal Ruby SDK Gem has packaged the SSL certificate internally, and this certificate was recently removed. I don't know why PayPal made it so that the certificate goes into the Gem, but you can fix it by hacking the SDK.

2. Solution

You can fix it by adding the PEM that is still expired to the certificate inside the SDK and restarting the Rails server.

3. Solution procedure

(1) Download PEM

Download the PEM announced by PayPal in the reference article. I used the DigiCert High Assurance EV Root CA, but I think any one is fine.

Where to get DigiCert High Assurance EV Root CA

Download here: https://www.digicert.com/digicert-root-certificates.htm

Download the DigiCert High Assurance EV Root CA PEM from here.

スクリーンショット 2020-08-04 午後10.29.53.png

(2) Search for the location of paypal.crt in the SDK

For Mac and Unix, use the find command to find it. For Rails apps, look under the application's root directory. In the Production environment, if you don't know where Ruby is, you can use sudo to search all from / (find / -name paypal.crt -print).

Since my server is AWS, I searched under ~ / as follows.

`rails_root`


[ec2-user@awsome_server ~]$ find ./ -name paypal.crt -print 2>/dev/null
./.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/paypal-sdk-rest-1.7.4/data/paypal.crt

(3) Add PEM to paypal.crt

Check the contents of the downloaded PEM file.

`Local Mac terminal`


$ cat DigiCertHighAssuranceEVRootCA.crt.pem
-----BEGIN CERTIFICATE-----
MIIDxTCCAq2gAwIBAgIQAqxcJmoLQJuPC3nyrkYldzANBgkqhkiG9w0BAQUFADBs
MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3
d3cuZGlnaWNlcnQuY29tMSswKQYDVQQDEyJEaWdpQ2VydCBIaWdoIEFzc3VyYW5j
ZSBFViBSb290IENBMB4XDTA2MTExMDAwMDAwMFoXDTMxMTExMDAwMDAwMFowbDEL

Omitted on the way

Yzi9RKR/5CYrCsSXaQ3pjOLAEFe4yHYSkVXySGnYvCoCWw9E1CAx2/S6cCZdkGCe
vEsXCS+0yx5DaMkHJ8HSXPfqIbloEpw8nL+e/IBcm2PN7EeqJSdnoDfzAIJ9VNep
+OkuE6N36B9K
-----END CERTIFICATE-----

Edit paypal.crt found by find. The following lines 172 to 196 are the added parts. I just added it to the bottom, but note that it requires ====== and is separated by the exact name (DigiCert High Assurance EV Root CA).

`Run on rails server`


[ec2-user@awsome_server ~]$ sudo vi paypal.crt

    168 CEHwxWsKzH4PIRnN5GfcX6kb5sroc50i2JhucwNhkcV8sEVAbkSdjbCxlnRhLQ2pRdKkkirWmnWX
    169 bj9T/UWZYB2oK0z5XqcJ2HUw19JlYD1n1khVdWk/kfVIC0dpImmClr7JyDiGSnoscxlIaU5rfGW/
    170 D/xwzoiQ
    171 -----END CERTIFICATE-----
    172 DigiCert High Assurance EV Root CA
    173 =======================================================
    174 -----BEGIN CERTIFICATE-----
    175 MIIDxTCCAq2gAwIBAgIQAqxcJmoLQJuPC3nyrkYldzANBgkqhkiG9w0BAQUFADBs
    176 MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3
    177 d3cuZGlnaWNlcnQuY29tMSswKQYDVQQDEyJEaWdpQ2VydCBIaWdoIEFzc3VyYW5j
    178 ZSBFViBSb290IENBMB4XDTA2MTExMDAwMDAwMFoXDTMxMTExMDAwMDAwMFowbDEL
    179 MAkGA1UEBhMCVVMxFTATBgNVBAoTDERpZ2lDZXJ0IEluYzEZMBcGA1UECxMQd3d3
    180 LmRpZ2ljZXJ0LmNvbTErMCkGA1UEAxMiRGlnaUNlcnQgSGlnaCBBc3N1cmFuY2Ug

Omitted on the way

    191 eM7b41N5cdblIZQB2lWHmiRk9opmzN6cN82oNLFpmyPInngiK3BD41VHMWEZ71jF
    192 hS9OMPagMRYjyOfiZRYzy78aG6A9+MpeizGLYAiJLQwGXFK3xPkKmNEVX58Svnw2
    193 Yzi9RKR/5CYrCsSXaQ3pjOLAEFe4yHYSkVXySGnYvCoCWw9E1CAx2/S6cCZdkGCe
    194 vEsXCS+0yx5DaMkHJ8HSXPfqIbloEpw8nL+e/IBcm2PN7EeqJSdnoDfzAIJ9VNep
    195 +OkuE6N36B9K
    196 -----END CERTIFICATE-----

(4) Restart Rails server

It depends on the environment, but in my case I can restart with systemctl on AWS, so run it.

`AWS`


[ec2-user@awsome_server ~]$ sudo systemctl restart rails

Now the SSL error disappears and you can make API calls normally.

[RAILS] How to resolve SSL_connect error in PayPal Ruby SDK