I'm on a corporate laptop dual booted with Ubuntu and Windows. Whenever I try to install things like Caddy, Docker Desktop, or really any application it turns into a whole thing and I can't install them. I'm also new to Linux so I don't understand the seemingly arbitrary strings of numbers and letters that represent files(?) in Ubuntu.
I've attempted to clear my caches, re-install certificates, use gpt instead of apt-key (apparently it's deprecated but still defaults to it?), etc. When I try to run 'apt update', any non-standard applications are ignored and I get errors back.
Edit: Here's the error I get for step one, doing an apt-get update
Ign:2 https://download.docker.com/linux/ubuntu jammy InRelease
Ign:2 https://download.docker.com/linux/ubuntu jammy InRelease
Err:2 https://download.docker.com/linux/ubuntu jammy InRelease
Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 146.112.250.208 443]
Fetched 2,054 kB in 8s (267 kB/s)
Reading package lists... Done
W: Failed to fetch https://download.docker.com/linux/ubuntu/dists/jammy/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 146.112.250.208 443]
W: Some index files failed to download. They have been ignored, or old ones used instead.
openssl s_client -connect download.docker.com:443 response:
CONNECTED(00000003)
depth=2 C = US, ST = California, L = San Francisco, O = Cisco, CN = Cisco Umbrella Primary SubCA
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=1 O = Cisco, CN = Cisco Umbrella Secondary SubCA nyc-SG
verify return:1
depth=0 C = US, ST = California, L = San Francisco, O = "Cisco Systems, Inc.", CN = download.docker.com
verify return:1
---
Certificate chain
0 s:C = US, ST = California, L = San Francisco, O = "Cisco Systems, Inc.", CN = download.docker.com
i:O = Cisco, CN = Cisco Umbrella Secondary SubCA nyc-SG
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Jun 16 11:33:13 2024 GMT; NotAfter: Jun 21 11:33:13 2024 GMT
1 s:O = Cisco, CN = Cisco Umbrella Secondary SubCA nyc-SG
i:C = US, ST = California, L = San Francisco, O = Cisco, CN = Cisco Umbrella Primary SubCA
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: Jun 16 19:01:12 2024 GMT; NotAfter: Jun 27 19:01:12 2024 GMT
2 s:C = US, ST = California, L = San Francisco, O = Cisco, CN = Cisco Umbrella Primary SubCA
i:O = Cisco, CN = Cisco Umbrella Root CA
a:PKEY: rsaEncryption, 2048 (bit); sigalg: RSA-SHA256
v:NotBefore: May 14 18:21:48 2024 GMT; NotAfter: May 14 18:21:48 2029 GMT
---
Server certificate
-----BEGIN CERTIFICATE-----
[SERVER CERTIFICATE REMOVED]
-----END CERTIFICATE-----
subject=C = US, ST = California, L = San Francisco, O = "Cisco Systems, Inc.", CN = download.docker.com
issuer=O = Cisco, CN = Cisco Umbrella Secondary SubCA nyc-SG
---
No client certificate CA names sent
Peer signing digest: SHA256
Peer signature type: RSA-PSS
Server Temp Key: X25519, 253 bits
---
SSL handshake has read 3724 bytes and written 401 bytes
Verification error: unable to get local issuer certificate
---
New, TLSv1.3, Cipher is TLS_AES_256_GCM_SHA384
Server public key is 2048 bit
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 20 (unable to get local issuer certificate)
---
---
Post-Handshake New Session Ticket arrived:
SSL-Session:
Protocol : TLSv1.3
Cipher : TLS_AES_256_GCM_SHA384
Session-ID: [SESSION-ID-REMOVED]
Session-ID-ctx:
Resumption PSK: [PSK-REMOVED]
PSK identity: None
PSK identity hint: None
SRP username: None
TLS session ticket lifetime hint: 7200 (seconds)
TLS session ticket:
[TLS-SESSION-TICKET-REMOVED]
Start Time: 1718807630
Timeout : 7200 (sec)
Verify return code: 20 (unable to get local issuer certificate)
Extended master secret: no
Max Early Data: 0
---
read R BLOCK
---
Post-Handshake New Session Ticket arrived:
SSL-Session:
Protocol : TLSv1.3
Cipher : TLS_AES_256_GCM_SHA384
Session-ID: [SESSION-ID-REMOVED]
Session-ID-ctx:
Resumption PSK: [PSK-REMOVED]
PSK identity: None
PSK identity hint: None
SRP username: None
TLS session ticket lifetime hint: 7200 (seconds)
TLS session ticket:
[TLS-SESSION-TICKET-REMOVED]
Start Time: 1718807630
Timeout : 7200 (sec)
Verify return code: 20 (unable to get local issuer certificate)
Extended master secret: no
Max Early Data: 0
---
read R BLOCK