[squid-users] Squid TPROXY issues with Google sites

Vieri rentorbuy at yahoo.com
Fri May 26 15:44:02 UTC 2017


Hi,

I'd like to block access to Google Mail but allow it to Google Drive. I also need to intercept Google Drive traffic (https) and scan its content via c-icap modules for threats (with clamav and other tools which would block potentially harmful files).

I've failed so far.

I added mail.google.com to a custom file named "denied.domains" and loaded as denied_domains ACL in Squid. I know that in TLS traffic there are only IP addresses, so I created the "server_name" ACL as seen below.

[...]
acl denied_domains dstdomain "/usr/local/share/proxy-settings/denied.domains"
http_access deny denied_domains !allowed_groups !allowed_ips
http_access deny CONNECT denied_domains !allowed_groups !allowed_ips
[...]
reply_header_access Alternate-Protocol deny all
acl AllowTroublesome ssl::server_name .google.com .gmail.com
acl DenyTroublesome ssl::server_name mail.google.com
http_access deny DenyTroublesome
ssl_bump peek all
ssl_bump splice AllowTroublesome
ssl_bump bump all

First of all, I was expecting that if a client tried to open https://mail.google.com, the connection would be blocked by Squid (DenyTroublesome ACL). It isn't. Why?

Second, I am unable to scan content since Squid is splicing all Google traffic. However, if I "bump AllowTroublesome", I can enter my username in https://accounts.google.com, but trying to access to the next step (user password) fails with an unreported error.

Any suggestions?

Vieri


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