Important Note: The method of validating certificates in my question below is incorrect, and will result in both false positives and false negatives. See my answer for the correct method.
I'm in the process of testing a tool I wrote to test all of the certificates in our environment, and I've run into an issue where OpenSSL doesn't seem to recognize a particular GoDaddy root certificate.
The error text:
$ openssl verify -CAfile bundle.txt cert.txt
cert.txt: C = US, ST = Arizona, L = Scottsdale, O = "GoDaddy.com, Inc.", CN = Go Daddy Root Certificate Authority - G2
error 2 at 2 depth lookup:unable to get issuer certificate
But that certificate is definitely in both /etc/pki/tls/certs/ca-bundle.crt and ca-bundle.trusted.crt. I've manually verified that the Issuer and Subject keys in the x509v3 extensions match up back to KeyID D2:C4:B0:D2:91:D4:4C:11:71:B3:61:CB:3D:A1:FE:DD:A8:6A:D4:E3 in the trusted bundles.
Am I missing something?
Certificate details:
Certificate:
Issuer: C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., OU=http://certs.godaddy.com/repository/, CN=Go Daddy Secure Certificate Authority - G2
X509v3 Subject Key Identifier:
28:3C:0E:1A:82:3E:7F:22:A6:DD:22:8C:45:78:BF:F6:40:47:4F:8A
X509v3 Authority Key Identifier:
keyid:40:C2:BD:27:8E:CC:34:83:30:A2:33:D7:FB:6C:B3:F0:B4:2C:80:CE
Bundle1:
Subject: C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., OU=http://certs.godaddy.com/repository/, CN=Go Daddy Secure Certificate Authority - G2
Issuer: C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., CN=Go Daddy Root Certificate Authority - G2
X509v3 Subject Key Identifier:
40:C2:BD:27:8E:CC:34:83:30:A2:33:D7:FB:6C:B3:F0:B4:2C:80:CE
X509v3 Authority Key Identifier:
keyid:3A:9A:85:07:10:67:28:B6:EF:F6:BD:05:41:6E:20:C1:94:DA:0F:DE
Bundle2:
Subject: C=US, ST=Arizona, L=Scottsdale, O=GoDaddy.com, Inc., CN=Go Daddy Root Certificate Authority - G2
Issuer: C=US, O=The Go Daddy Group, Inc., OU=Go Daddy Class 2 Certification Authority
X509v3 Subject Key Identifier:
3A:9A:85:07:10:67:28:B6:EF:F6:BD:05:41:6E:20:C1:94:DA:0F:DE
X509v3 Authority Key Identifier:
keyid:D2:C4:B0:D2:91:D4:4C:11:71:B3:61:CB:3D:A1:FE:DD:A8:6A:D4:E3
Trusted:
Subject: C=US, O=The Go Daddy Group, Inc., OU=Go Daddy Class 2 Certification Authority
X509v3 Subject Key Identifier:
D2:C4:B0:D2:91:D4:4C:11:71:B3:61:CB:3D:A1:FE:DD:A8:6A:D4:E3
X509v3 Authority Key Identifier:
keyid:D2:C4:B0:D2:91:D4:4C:11:71:B3:61:CB:3D:A1:FE:DD:A8:6A:D4:E3
DirName:/C=US/O=The Go Daddy Group, Inc./OU=Go Daddy Class 2 Certification Authority
serial:00
Edit
To add to the WTFery in play, opening a connection to the server in question using openssl s_client shows the certificate verifying just fine.
$ openssl s_client -servername www.foo.com -connect www.foo.com:443
Certificate chain
0 s:/OU=Domain Control Validated/CN=*.foo.com
i:/C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./OU=http://certs.godaddy.com/repository//CN=Go Daddy Secure Certificate Authority - G2
1 s:/C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./OU=http://certs.godaddy.com/repository//CN=Go Daddy Secure Certificate Authority - G2
i:/C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./CN=Go Daddy Root Certificate Authority - G2
2 s:/C=US/ST=Arizona/L=Scottsdale/O=GoDaddy.com, Inc./CN=Go Daddy Root Certificate Authority - G2
i:/C=US/O=The Go Daddy Group, Inc./OU=Go Daddy Class 2 Certification Authority
...yadda yadda yadda...
Verify return code: 0 (ok)
The naming of the openssl verify flags can be a bit counter-intuitive, and none of the documentation I found does much to address that. As x539 touched on I was using the -CAfile option incorrectly, and additionally I was missing the -untrusted option to specify the intermediate certificates.
I've found that the reason that the validation passed for most certificates is that most CAs have begun including the root certificate in the CA bundle, and the -CAfile option essentially defines what should comprise the trusted portion of the chain, including the root certificate. It was in the case that the intermediate bundle did not contain the root that my initial, incorrect method of validation failed.
Now I was under the misconception that -untrusted implied something like "never use these certificates!", but is rather intended to specify a chain of non-trusted certificates that leads back to a root in the "trusted" -CAfile bundle.
So the correct way to validate a certificate by using its intermediate certificate[s] and a trusted root bundle is:
openssl verify -CAfile /etc/pki/tls/certs/ca-bundle.crt -untrusted bundle.crt certificate.crt
If you specify -CAfile openssl only checks the given file for issuers, which in your case probably only contains the intermediate Certificates.
Related
Below are three self-signed certificates I've made and verified with openssl verify:
Certificate #1:
X509v3 Basic Constraints:
CA:FALSE
X509v3 Key Usage:
Digital Signature, Key Encipherment
This self-signed certificate is not a CA, it's missing the "Certificate Sign" value, and it fails verification:
$ openssl verify -CAfile ca_false_cert.crt ca_false_cert.crt
error 20 at 0 depth lookup: unable to get local issuer certificate
error ca_false_cert.crt: verification failed
Certificate #2:
X509v3 Basic Constraints:
CA:FALSE
X509v3 Key Usage:
Digital Signature, Key Encipherment, Certificate Sign
This self-signed certificate is not a CA, it includes the "Certificate Sign" value, and it passes verification:
$ openssl verify -CAfile ca_false_sign_cert.crt ca_false_sign_cert.crt
ca_false_sign_cert.crt: OK
Certificate #3:
X509v3 Basic Constraints:
CA:TRUE
X509v3 Key Usage:
Digital Signature, Key Encipherment
This self-signed certificate is a CA, it's missing the "Certificate Sign" value, and it fails verification:
$ openssl verify -CAfile ca_true_sign_cert.crt ca_true_sign_cert.crt
error 20 at 0 depth lookup: unable to get local issuer certificate
error ca_true_sign_cert.crt: verification failed
My two questions are:
Is X509v3 Key Usage: Certificate Sign necessary for a self-signed certificate (or for CA certificates in general)?
Are non-CA (i.e. without X509v3 Basic Constraints: CA:TRUE, or with CA:FALSE) self-signed certificates even valid? Or does openssl verify overlook this?
Here is how I understand the flow.
version: '2'
services:
shop_ca:
image: hyperledger/fabric-ca
environment:
- FABRIC_CA_HOME=/etc/hyperledger/fabric-ca-server
- FABRIC_CA_SERVER_CA_NAME=shop_ca
- FABRIC_CA_SERVER_CA_CERTFILE=/etc/hyperledger/fabric-ca-server-config/ca-cert.pem
- FABRIC_CA_SERVER_CA_KEYFILE=/etc/hyperledger/fabric-ca-server-config/ca-key.pem
ports:
- "7054:7054"
command: sh -c 'fabric-ca-server start -b admin3:admin3'
volumes:
- ./conf.yaml:/etc/hyperledger/fabric-ca-server/fabric-ca-server-config.yaml
container_name: shop_ca
I passed my certfile and keyfile as options.
When the fabric-ca-server starts, what it should do is create ca-cert and ca-key pem files in /etc/hyperledger/fabric-ca-server folder. then use the /etc/hyperledger/fabric-ca-server/fabric-ca-server-config.yaml config file to generate the final certificate(path must be /etc/hyperledger/fabric-ca-server-config/ca-cert.pem) that will be used to issue other certificates.
What I don't understand is this generated certificate /etc/hyperledger/fabric-ca-server-config/ca-cert.pem is self-signed. Question is why? I think what it does is makes csr request to /etc/hyperledger/fabric-ca-server/ca-cert.pem and this ca-cert.pem issues another ca-cert.pem. This question happened on my mind because when I use openssl and print the final generated ca-cert certificate, issuer and subject are both the same. I think issuer has to be /etc/hyperledger/fabric-ca-server/ca-cert.pem and subject must be /etc/hyperledger/fabric-ca-server-config/ca-cert.pem. but both issuer and subject are /etc/hyperledger/fabric-ca-server-config/ca-cert.pem. Why?
The top root certificate for any Certificate Authority is always self-signed (check out the Verisign cert at the bottom of this post) ... that's why you explicitly trust root certificates.
Fabric CA allows you to either specify an existing root key pair or if the specified files do not exist it generates them for you. (if the cert file exists but a matching private key cannot be found you'll get an error and fabric-ca-server will not start).
When fabric-ca-server generates its own self-signed keypair, it actually generates the private key in the msp/keystore folder but it will store the self-signed X509 cert in the file specified via FABRIC_CA_SERVER_CA_CERTFILE if specified else it will use the location in fabric-ca-server-config.yaml. Note that if you use the FABRIC_CA_SERVER_CA_CERTFILE override, the value is not updated in the config file (perhaps this is causing some confusion).
Verisign Primary
Garis-MBP:tmp gsingh$ openssl x509 -noout -text -in verisign.pem
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
18:da:d1:9e:26:7d:e8:bb:4a:21:58:cd:cc:6b:3b:4a
Signature Algorithm: sha1WithRSAEncryption
Issuer: C=US, O=VeriSign, Inc., OU=VeriSign Trust Network, OU=(c) 2006 VeriSign, Inc. - For authorized use only, CN=VeriSign Class 3 Public Primary Certification Authority - G5
Validity
Not Before: Nov 8 00:00:00 2006 GMT
Not After : Jul 16 23:59:59 2036 GMT
Subject: C=US, O=VeriSign, Inc., OU=VeriSign Trust Network, OU=(c) 2006 VeriSign, Inc. - For authorized use only, CN=VeriSign Class 3 Public Primary Certification Authority - G5
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:af:24:08:08:29:7a:35:9e:60:0c:aa:e7:4b:3b:
4e:dc:7c:bc:3c:45:1c:bb:2b:e0:fe:29:02:f9:57:
08:a3:64:85:15:27:f5:f1:ad:c8:31:89:5d:22:e8:
2a:aa:a6:42:b3:8f:f8:b9:55:b7:b1:b7:4b:b3:fe:
8f:7e:07:57:ec:ef:43:db:66:62:15:61:cf:60:0d:
a4:d8:de:f8:e0:c3:62:08:3d:54:13:eb:49:ca:59:
54:85:26:e5:2b:8f:1b:9f:eb:f5:a1:91:c2:33:49:
d8:43:63:6a:52:4b:d2:8f:e8:70:51:4d:d1:89:69:
7b:c7:70:f6:b3:dc:12:74:db:7b:5d:4b:56:d3:96:
bf:15:77:a1:b0:f4:a2:25:f2:af:1c:92:67:18:e5:
f4:06:04:ef:90:b9:e4:00:e4:dd:3a:b5:19:ff:02:
ba:f4:3c:ee:e0:8b:eb:37:8b:ec:f4:d7:ac:f2:f6:
f0:3d:af:dd:75:91:33:19:1d:1c:40:cb:74:24:19:
21:93:d9:14:fe:ac:2a:52:c7:8f:d5:04:49:e4:8d:
63:47:88:3c:69:83:cb:fe:47:bd:2b:7e:4f:c5:95:
ae:0e:9d:d4:d1:43:c0:67:73:e3:14:08:7e:e5:3f:
9f:73:b8:33:0a:cf:5d:3f:34:87:96:8a:ee:53:e8:
25:15
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Basic Constraints: critical
CA:TRUE
X509v3 Key Usage: critical
Certificate Sign, CRL Sign
1.3.6.1.5.5.7.1.12:
0_.].[0Y0W0U..image/gif0!0.0...+..............k...j.H.,{..0%.#http://logo.verisign.com/vslogo.gif
X509v3 Subject Key Identifier:
7F:D3:65:A7:C2:DD:EC:BB:F0:30:09:F3:43:39:FA:02:AF:33:31:33
Signature Algorithm: sha1WithRSAEncryption
93:24:4a:30:5f:62:cf:d8:1a:98:2f:3d:ea:dc:99:2d:bd:77:
f6:a5:79:22:38:ec:c4:a7:a0:78:12:ad:62:0e:45:70:64:c5:
e7:97:66:2d:98:09:7e:5f:af:d6:cc:28:65:f2:01:aa:08:1a:
47:de:f9:f9:7c:92:5a:08:69:20:0d:d9:3e:6d:6e:3c:0d:6e:
d8:e6:06:91:40:18:b9:f8:c1:ed:df:db:41:aa:e0:96:20:c9:
cd:64:15:38:81:c9:94:ee:a2:84:29:0b:13:6f:8e:db:0c:dd:
25:02:db:a4:8b:19:44:d2:41:7a:05:69:4a:58:4f:60:ca:7e:
82:6a:0b:02:aa:25:17:39:b5:db:7f:e7:84:65:2a:95:8a:bd:
86:de:5e:81:16:83:2d:10:cc:de:fd:a8:82:2a:6d:28:1f:0d:
0b:c4:e5:e7:1a:26:19:e1:f4:11:6f:10:b5:95:fc:e7:42:05:
32:db:ce:9d:51:5e:28:b6:9e:85:d3:5b:ef:a5:7d:45:40:72:
8e:b7:0e:6b:0e:06:fb:33:35:48:71:b8:9d:27:8b:c4:65:5f:
0d:86:76:9c:44:7a:f6:95:5c:f6:5d:32:08:33:a4:54:b6:18:
3f:68:5c:f2:42:4a:85:38:54:83:5f:d1:e8:2c:f2:ac:11:d6:
a8:ed:63:6a
I have two extremely similar self signed certificates, generated via two different methods.
To test them I have:
Added an entry in my hosts file for local.mydomain.com
Set up an nginx server to listen on that domain on port 443 with the certificate under test plus associated private key (I then switch the cert and restart nginx to compare)
Connected to nginx with openssl s_client -connect local.mydomain.com -CAfile /path/to/the/ca/cert.pem
One certificate fails:
CONNECTED(00000003)
depth=0 CN = local.mydomain.com
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 CN = local.mydomain.com
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/CN=local.mydomain.com
i:/CN=local.mydomain.com
---
One certificate succeeds:
CONNECTED(00000003)
depth=0 CN = local.mydomain.com
verify return:1
---
Certificate chain
0 s:/CN = local.mydomain.com
i:/CN = local.mydomain.com
---
I compare the details of the certificates with openssl x509 -in /path/to/the/ca/cert.pem -text -noout
The failing cert:
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
47:dc:02:c7:11:fc:8e:96:45:22:aa:6b:23:79:32:ca
Signature Algorithm: sha256WithRSAEncryption
Issuer: CN=local.mydomain.com
Validity
Not Before: Nov 18 11:55:31 2016 GMT
Not After : Nov 18 12:15:31 2017 GMT
Subject: CN=local.mydomain.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
<stuff>
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Key Usage: critical
Digital Signature, Key Encipherment
X509v3 Extended Key Usage:
TLS Web Client Authentication, TLS Web Server Authentication
X509v3 Subject Alternative Name:
DNS:local.mydomain.com
X509v3 Subject Key Identifier:
6D:4F:AF:E4:60:23:72:E5:83:27:91:7D:1D:5F:E9:7C:D9:B6:00:2A
Signature Algorithm: sha256WithRSAEncryption
<stuff>
The working cert:
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
9b:6b:3d:a3:b9:a3:a4:b4
Signature Algorithm: sha256WithRSAEncryption
Issuer: CN=local.mydomain.com
Validity
Not Before: Nov 19 13:27:30 2016 GMT
Not After : Nov 19 13:27:30 2017 GMT
Subject: CN=local.mydomain.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
<stuff>
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Subject Key Identifier:
03:E7:DA:AA:2E:CC:23:ED:C5:07:3D:E1:33:86:F5:22:D4:76:EB:CB
X509v3 Authority Key Identifier:
keyid:03:E7:DA:AA:2E:CC:23:ED:C5:07:3D:E1:33:86:F5:22:D4:76:EB:CB
X509v3 Basic Constraints:
CA:TRUE
Signature Algorithm: sha256WithRSAEncryption
57<stuff>
Looking at this the most obvious difference is that the working cert has CA:TRUE under X509v3 Basic Constraints. However, from reading around the web I was under the impression that self signed certs weren't meant to be CAs, in particular this says they normally won't be:
https://security.stackexchange.com/questions/44340/basic-self-signed-certificate-questions
The answer there says that being self-signed there is no CA involved. But maybe openssl requires self signed certs to have that set anyway?
From my own experiments I can confirm what you see. My explanation of the behavior is that a self signed certificate is still a certificate which is signed by the issuer, even if the issuer's certificate is the certificate itself. But only CA certificates can be used to sign certificates, i.e. that's exactly the constraint CA:true allows. This means that a self-signed certificate needs also to be a CA certificate with the constraint CA:true.
RFC5280 says:
So, if your certificate does not have CA:TRUE flag, this certificate may not be used to verify the signature on any certificate, including itself. OpenSSL correctly follows the RFC.
It is incorrect to think that a certificate belongs to one of two types, either "CA certificate" or "end-entity certificate". A certificate with CA:TRUE can be used for authenticating the entity. This is exactly what you do when you authenticate with a self-signed certificate. It can also be a certificate with CA:TRUE, signed by someone else.
I have a newly purchased GeoTrust domain certificate and a matching CA file and would like to verify with openssl.
openssl verify -verbose -purpose any
-CAfile /full/path/sub.domain.com-geotrust.crt /full/path/sub.domain.com.crt
From this page: https://secure.marumoto.us/motowiki/tiki-index.php?page=Verify+a+Certificate+Chain
The issuer of each certificate in the chain should match the subject of the next certificate in the chain. For example the issuer of myserver.mydomain.com.cert should match the subject of myintermediate_ca.cert, and the issuer of myintermediate_ca.cert should match the subject of myroot_ca.cert. You can use the following command to view a certificate in .pem or base64 format.
From
openssl x509 -text -in sub.domain.crt and
openssl x509 -text -in sub.domain-geotrust.crt (CA root file)
sub.domain.com
Subject: OU=GT44865949,
OU=See www.geotrust.com/resources/cps (c)15,
OU=Domain Control Validated - QuickSSL(R),
CN=sub.domain.com
Issuer:
commonName = GeoTrust DV SSL CA - G4
organizationalUnitName = Domain Validated SSL
organizationName = GeoTrust Inc.
countryName = US
Intermediate:
Subject:
commonName = GeoTrust DV SSL CA - G4
organizationalUnitName = Domain Validated SSL
organizationName = GeoTrust Inc.
countryName = US
Issuer:
commonName = GeoTrust Global CA
organizationName = GeoTrust Inc.
countryName = US
Root:
Subject:
commonName = GeoTrust Global CA
organizationName = GeoTrust Inc.
countryName = US
Issuer:
organizationalUnitName = Equifax Secure Certificate Authority
organizationName = Equifax
countryName = US
It appears my Issuer and Subject fields are matching up properly but I am getting the following error with openssl:
error 20 at 0 depth lookup:unable to get local issuer certificate
/full/path/sub.domain.com.crt: /OU=GT44865949/OU=See www.geotrust.com/resources/cps (c)15/OU=Domain Control Validated - QuickSSL(R)/CN=sub.domain.com
error 20 at 0 depth lookup:unable to get local issuer certificate
I'd like to use this and a similar GeoTrust certificate at a different subdomain to do two-way SSL authentication at a restful web url but the certs won't verify with 'openssl verify' against the CA files issued with them. Any suggestions much appreciated.
As per discussion, it is a matter of allowing openssl to see the entire validation chain: with both GeoTrust CA intermediates and the root.
openssl should be run with CADir parameter containing all the 3 CAs in PEM format. The actual root for GeoTrust can either be extracted from your favourite browser, or here: filedropper.com/geotrustglobalca.
When you configure your actual server, just make sure that you send the intermediates on the Server Hello, some sites don't do that and break clients that do not have the intermediates cached.
Following on from RomanK's answer, you can get the GeoTrust Global CA from their root certificate store. They have a number of primary/universal/global certificates listed there, so make sure to get the right one for your intermediate certificate.
As per the chain display, the root certificate is not self signed . Its shows its issued by Equifax. Openssl will continue giving the error "local issuer certificate not found" till it gets a self signed root certificate. When it comes across a root self signed then it's able to verify the certificate chain as complete.
I have a certificate (for example this one) saved in a local file. Using openssl from the command line, how can I display the entire chain from this certificate to a root CA? I tried:
openssl verify -verbose -purpose sslserver -CApath /etc/ssl/certs InCommonServerCA.txt
and got this confusing output that only seems to show the leaf certificate:
InCommonServerCA.txt: C = US, O = Internet2, OU = InCommon, CN = InCommon Server CA
error 26 at 0 depth lookup:unsupported certificate purpose
OK
Any ideas?
For local certificates you can see the subject and direct issuer using:
openssl x509 -noout -subject -issuer -in test.crt
subject= /C=US/ST=Utah/L=SLC/O=My Organization/CN=my.server.com
issuer= /C=BE/O=GlobalSign nv-sa/CN=GlobalSign Organization Validation CA - SHA256 - G2
But that doesn't indicate if the certificate includes any intermediate certificates or the full chain of trust. The verify command you listed will fail if your system cannot validate the chain (example: you are missing an intermediate certificate or the root is not trusted), showing an error message like:
error 20 at 0 depth lookup:unable to get local issuer certificate
If you want to verify each entry in the file, you can use this script to show the chain of trust for a local certificate:
~ % ssl_chain.sh google.crt
0: subject= /C=US/ST=California/L=Mountain View/O=Google Inc/CN=www.google.com
issuer= /C=US/O=Google Inc/CN=Google Internet Authority G2
1: subject= /C=US/O=Google Inc/CN=Google Internet Authority G2
issuer= /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
2: subject= /C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
issuer= /C=US/O=Equifax/OU=Equifax Secure Certificate Authority
google.crt: OK
If you want to verify the chain and purpose, your openssl command is correct. The "OK" indicates the chain verifies. The error indicates there is an issue with that certificate being used for an sslserver purpose. It looks like your certificate is a CA cert, not a leaf cert.
What kind of chain info are you trying to display? You could look at the subject and issuer fields to show chaining. The verify command you used above proves that the one cert signed the other cert.