Squid fatal error with SSL interception

mrtom · Aug 19, 2017, 12:22 PM

The transparent SSL proxy was working and I'm not sure when it stopped exactly but I cannot get it to work again. When I start the Squid service it stops immediately. If I disable SSL filtering Squid works just fine. To figure out what might be going on I ran "squid -k parse" to test the config and I get:

2017/08/19 07:53:43| Processing: adaptation_access service_avi_resp allow all
2017/08/19 07:53:43| Initializing https proxy context
2017/08/19 07:53:43| Initializing http_port 192.168.200.1:3128 SSL context
2017/08/19 07:53:43| Using certificate in /usr/local/etc/squid/serverkey.pem
2017/08/19 07:53:43| WARNING: X509_check_private_key() failed to verify signing cert
FATAL: No valid signing SSL certificate configured for HTTP_port 192.168.200.1:3128
Squid Cache (Version 3.5.26): Terminated abnormally.

I don't understand why it's trying to configure an SSL certificate for the HTTP port, shouldn't that only be needed for the HTTPS port? The configuration generated after enabling SSL interception is:

_# This file is automatically generated by pfSense

Do not edit manually !

http_port 192.168.200.1:3128 ssl-bump generate-host-certificates=on dynamic_cert_mem_cache_size=10MB cert=/usr/local/etc/squid/serverkey.pem capath=/usr/local/share/certs/ cipher=EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH+aRSA+RC4:EECDH:EDH+aRSA:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS tls-dh=prime256v1:/etc/dh-parameters.2048 options=NO_SSLv2,NO_SSLv3,NO_TLSv1,SINGLE_DH_USE,SINGLE_ECDH_USE

http_port 127.0.0.1:3128 intercept ssl-bump generate-host-certificates=on dynamic_cert_mem_cache_size=10MB cert=/usr/local/etc/squid/serverkey.pem capath=/usr/local/share/certs/ cipher=EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH+aRSA+RC4:EECDH:EDH+aRSA:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS tls-dh=prime256v1:/etc/dh-parameters.2048 options=NO_SSLv2,NO_SSLv3,NO_TLSv1,SINGLE_DH_USE,SINGLE_ECDH_USE

https_port 127.0.0.1:3129 intercept ssl-bump generate-host-certificates=on dynamic_cert_mem_cache_size=10MB cert=/usr/local/etc/squid/serverkey.pem capath=/usr/local/share/certs/ cipher=EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH+aRSA+RC4:EECDH:EDH+aRSA:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS tls-dh=prime256v1:/etc/dh-parameters.2048 options=NO_SSLv2,NO_SSLv3,NO_TLSv1,SINGLE_DH_USE,SINGLE_ECDH_USE

icp_port 0
digest_generation off
dns_v4_first off
pid_filename /var/run/squid/squid.pid
cache_effective_user squid
cache_effective_group proxy
error_default_language en
icon_directory /usr/local/etc/squid/icons
visible_hostname localhost
cache_mgr admin@localhost
access_log /var/squid/logs/access.log
cache_log /var/squid/logs/cache.log
cache_store_log none
netdb_filename /var/squid/logs/netdb.state
pinger_enable on
pinger_program /usr/local/libexec/squid/pinger
sslcrtd_program /usr/local/libexec/squid/ssl_crtd -s /var/squid/lib/ssl_db -M 4MB -b 2048
sslcrtd_children 5
sslproxy_capath /usr/local/share/certs/
sslproxy_options NO_SSLv2,NO_SSLv3,NO_TLSv1,SINGLE_DH_USE,SINGLE_ECDH_USE
sslproxy_cipher EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EECDH+aRSA+SHA256:EECDH+aRSA+RC4:EECDH:EDH+aRSA:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS

logfile_rotate 0
debug_options rotate=0
shutdown_lifetime 3 seconds

Allow local network(s) on interface(s)

acl localnet src 192.168.200.0/24
forwarded_for truncate
httpd_suppress_version_string on
uri_whitespace strip

acl dynamic urlpath_regex cgi-bin ?
cache deny dynamic

cache_mem 64 MB
maximum_object_size_in_memory 256 KB
memory_replacement_policy heap GDSF
cache_replacement_policy heap LFUDA
minimum_object_size 0 KB
maximum_object_size 4 MB
cache_dir ufs /var/squid/cache 100 16 256
offline_mode off
cache_swap_low 90
cache_swap_high 95
cache allow all

Add any of your own refresh_pattern entries above these.

refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern -i (/cgi-bin/|?) 0 0% 0
refresh_pattern . 0 20% 4320

#Remote proxies

Setup some default acls

ACLs all, manager, localhost, and to_localhost are predefined.

acl allsrc src all
acl safeports port 21 70 80 210 280 443 488 563 591 631 777 901 3128 3129 1025-65535
acl sslports port 443 563

acl purge method PURGE
acl connect method CONNECT

Define protocols used for redirects

acl HTTP proto HTTP
acl HTTPS proto HTTPS

SslBump Peek and Splice

http://wiki.squid-cache.org/Features/SslPeekAndSplice

http://wiki.squid-cache.org/ConfigExamples/Intercept/SslBumpExplicit

Match against the current step during ssl_bump evaluation [fast]

Never matches and should not be used outside the ssl_bump context.

At each SslBump step, Squid evaluates ssl_bump directives to find

the next bumping action (e.g., peek or splice). Valid SslBump step

values and the corresponding ssl_bump evaluation moments are:

# SslBump1: After getting TCP-level and HTTP CONNECT info.
# SslBump2: After getting TLS Client Hello info.
# SslBump3: After getting TLS Server Hello info.

These ACLs exist even when 'SSL/MITM Mode' is set to 'Custom' so that

they can be used there for custom configuration.

acl step1 at_step SslBump1
acl step2 at_step SslBump2
acl step3 at_step SslBump3
acl allowed_subnets src 192.168.1.0/24
acl whitelist dstdom_regex -i "/var/squid/acl/whitelist.acl"
http_access allow manager localhost

http_access deny manager
http_access allow purge localhost
http_access deny purge
http_access deny !safeports
http_access deny CONNECT !sslports

Always allow localhost connections

http_access allow localhost

request_body_max_size 0 KB
delay_pools 1
delay_class 1 2
delay_parameters 1 -1/-1 -1/-1
delay_initial_bucket_level 100
delay_access 1 allow allsrc

Reverse Proxy settings

Package Integration

url_rewrite_program /usr/local/bin/squidGuard -c /usr/local/etc/squidGuard/squidGuard.conf
url_rewrite_bypass off
url_rewrite_children 16 startup=8 idle=4 concurrency=0

Custom options before auth

access_log syslog:local8.info;

Always allow access to whitelist domains

http_access allow whitelist
acl sglog url_regex -i sgr=ACCESSDENIED
http_access deny sglog
ssl_bump peek step1
ssl_bump splice whitelist
ssl_bump bump all

Setup allowed ACLs

Allow local network(s) on interface(s)

http_access allow allowed_subnets
http_access allow localnet

Default block all to be sure

http_access deny allsrc

icap_enable on
icap_send_client_ip on
icap_send_client_username on
icap_client_username_encode off
icap_client_username_header X-Authenticated-User
icap_preview_enable on
icap_preview_size 1024

icap_service service_avi_req reqmod_precache icap://127.0.0.1:1344/squid_clamav bypass=off
adaptation_access service_avi_req allow all
icap_service service_avi_resp respmod_precache icap://127.0.0.1:1344/squid_clamav bypass=on
adaptation_access service_avi_resp allow all_

doktornotor · Aug 27, 2017, 7:58 PM

Noone read the GUI descriptions these days? Sigh…

Stop ticking that checkbox or configure a valid CA certificate created in Cert. Manager.