update: fix dkim extraction from TXT records for some domains

[vishal-android-freak]

Weirdly for some TXT record answers, the TXT record string has a \\" before the DKIM prefix because of which an empty string was returned. This tries to remove the escape characters and correctly read the DKIM record

[vishal-android-freak]

The changes are completed and ready for review now :)

[wolveix]

@vishal-android-freak thanks for the contribution! I'll give this a look over :) Do you have a domain that you can provide that exhibits the problematic behaviour before your changes, please?

[vishal-android-freak]

Yes, it is my company's domain itself - https://rudrasecure.com

The extracted TXT record has a \\"v1= at the start and \\; at the end of the DKIM part

[wolveix]

@vishal-android-freak what DKIM selector does your domain use? I'm not currently seeing a DKIM record with our default list :D

[vishal-android-freak]

Ah yes, I pass the dkimSelector as default

[wolveix]

@vishal-android-freak yep, and which selector do you provide? Could you provide me with the scan command you're running? E.g. ./dss scan yourdomain.tld --dkimSelector x

[vishal-android-freak]

This is what I am running

dss scan --dkimSelector default rudrasecure.com

[wolveix]

Thanks!

[wolveix]

@vishal-android-freak after inspecting your domain directly, it seems that this is actually a misconfiguration issue. Here's the raw dig output from our globalcyberalliance.org domain:

~
❯ dig gca._domainkey.globalcyberalliance.org txt

; <<>> DiG 9.10.6 <<>> gca._domainkey.globalcyberalliance.org txt
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 36909
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;gca._domainkey.globalcyberalliance.org.        IN TXT

;; ANSWER SECTION:
gca._domainkey.globalcyberalliance.org. 300 IN TXT "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCqPnV7+e5SuK77YHtzO815h/qofRr/ZCnCzER9CnHQX3HXfmVrhWoCMG6p4HpWVN1uZhsuqMdeOtwzh4DCvlb2D7BDoQAbTUdb9tEZ1sY4pOqUgYfjVLmJXztN8HfLj2fbqvOZEnUPNNHb4RGouSFUBpLsTMTCodIfF/xSZfGNZQIDAQAB"

And here's the raw dig output from your domain:

~
❯ dig default._domainkey.rudrasecure.com txt    

; <<>> DiG 9.10.6 <<>> default._domainkey.rudrasecure.com txt
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5449
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;default._domainkey.rudrasecure.com. IN TXT

;; ANSWER SECTION:
default._domainkey.rudrasecure.com. 3483 IN TXT "\"v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAypzx5jyJoi0C8heUJfP8M8CIWKTtJCAv6fRTqJ8+9XE9Skv4ultwE7Pyp+Fe7r4waq0bgjdpQe+uRRzi2qyXrhhbKXYOlk0ZtCNH4SN0aL5Y5Ldn2tlvdhnBH7kiLfd2g8bzjTWd0mv8jkopO647f9GAdx0fTnAZ0AySrrtEX46RNX/nlblzHJDJjPetrC5/" "C\" m3yfpQ+2qNp3lSXFtdtIH4uP+v0Jr13307L/zYEl0uwxNAv8DCugTZcos39p9qRkKKqjiOT9iy8rphkxTZw3RPrPoVbp9ZKaiHoBJxx1+c4D4wLd8Ingh/q3mFJ99q5BVsBmr5RKlFjRLdOSD2tswIDAQAB\\;"

Your record itself contains backslashes. I'm assuming when you added the DNS record to your provider, you left the quotes intact, and then your DNS provider automatically escaped them when creating the record.