Re: [squid-users] Issues with ssl-bump in 3.HEAD

From: Mike <>
Date: Thu, 12 Jun 2014 16:16:19 -0500

On 6/12/2014 2:46 PM, Guy Helmer wrote:
> On Jun 12, 2014, at 2:25 PM, Mike <> wrote:
>> On 6/12/2014 2:06 PM, Guy Helmer wrote:
>>> On Jun 12, 2014, at 1:01 PM, Mike <> wrote:
>>>> I have been racking my brain trying to get this working and each time,it refuses to connect to secure sites. In the end we need a working squid proxy for SSL connections within the company network which will serve over 1000 users (thus the larger 8MB cert cache size). We already have theinsecure HTTP proxy working fine (thus the use of port 3129 below).
>>>> Since it will be SSL based, I know it needs https_port (not http_port), ssl-bump, and intercept (required by ssl-bump). The https_port and ssl-bump documentation also mentioned the preference for sslflags (which may or may not be working in 3.HEAD) and cipher.
>>>> OS is Scientific Linux 6.5 (based on CentOS) fully up to date with yum. Server is quad core 3.4GHz, 8GB DDR3 with no other uses (like web server, etc).
>>>> SELinux has been set to permissive mode so it only reports, doesn't block the needed connections (although I also tested with it disabled and made no difference).
>>>> [root_at_localhost ~]# sestatus
>>>> SELinux status: enabled
>>>> SELinuxfs mount: /selinux
>>>> Current mode: permissive
>>>> Mode from config file: permissive
>>>> Policy version: 24
>>>> Policy from config file: targeted
>>>> Essential squid.conf lines (I have tested it with and without the "sslflags", does not impact it working or not working):
>>>> https_port 3129 intercept ssl-bump connection-auth=off generate-host-certificates=on dynamic_cert_mem_cache_size=8MB cert=/etc/squid/ssl/squid.pem key=/etc/squid/ssl/squid.key sslflags=DELAYED_AUTH cipher=ECDHE-RSA-RC4-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA:DHE-RSA-CAMELLIA128-SHA:AES128-SHA:RC4-SHA:HIGH:!aNULL:!MD5:!ADH
>>>> sslcrtd_program /usr/lib64/squid/ssl_crtd -s /var/lib/squid_ssl_db -M 8MB
>>>> sslcrtd_children 50 startup=5 idle=1
>>>> ssl_bump server-first all
>>>> ssl_bump none localhost
>>>> Local certs have been created and self signed, and the .der cert has been imported into the test browser (Firefox 30.0).
>>>> Squid info (includes the needed '--enable-ssl' '--enable-ssl-crtd' '--with-openssl'):
>>>> [root_at_localhost ~]# squid -v
>>>> Squid Cache: Version 3.HEAD-20140127-r13248
>>>> Service Name: squid
>>>> configure options: '--build=x86_64-redhat-linux-gnu' '--host=x86_64-redhat-linux-gnu' '--target=x86_64-redhat-linux-gnu' '--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' '--includedir=/usr/include' '--libdir=/usr/lib64' '--libexecdir=/usr/libexec' '--sharedstatedir=/var/lib' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--exec_prefix=/usr' '--libexecdir=/usr/lib64/squid' '--localstatedir=/var' '--datadir=/usr/share/squid' '--sysconfdir=/etc/squid' '--with-logdir=$(localstatedir)/log/squid' '--with-pidfile=$(localstatedir)/run/' '--disable-dependency-tracking' '--enable-eui' '--enable-follow-x-forwarded-for' '--enable-auth' '--enable-auth-basic=DB,LDAP,NCSA,NIS,PAM,POP3,RADIUS,SASL,SMB,getpwnam' '--enable-auth-ntlm=smb_lm,fake' '--enable-auth-digest=file,LDAP,eDirectory' '--enable-auth-negotiate=kerberos,wrapper' '--enable-external-acl-helpers=wbinfo_group,kerber!
>> os_ldap_
>> group,AD_group' '--enable-cache-digests' '--enable-cachemgr-hostname=localhost' '--enable-delay-pools' '--enable-epoll' '--enable-icap-client' '--enable-ident-lookups' '--enable-linux-netfilter' '--enable-removal-policies=heap,lru' '--enable-snmp' '--enable-ssl' '--enable-ssl-crtd' '--enable-storeio=aufs,diskd,ufs,rock' '--enable-wccpv2' '--enable-esi' '--with-aio' '--with-default-user=squid' '--with-filedescriptors=16384' '--with-dl' '--with-openssl' '--with-pthreads' '--disable-arch-native' 'build_alias=x86_64-redhat-linux-gnu' 'host_alias=x86_64-redhat-linux-gnu' 'target_alias=x86_64-redhat-linux-gnu' 'CFLAGS=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' 'CXXFLAGS=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC' 'PKG_CONFIG_PATH=/usr/lib64/pkgconfig:/usr/share/pkgconfig'
>>>> In the end testing with only the SSL proxy set to this server via port3129, it tries loading the secure website for 2-3 minutes and then timesout. Checking "top", it shows squid running at 12.1g VIRT, 2.0g RES, 54.5% of MEM (server has 8GB) and using 100% of CPU2. The ../squid/access.log and cache_access.log shows no new entries at all. We had to disable thecache.log (cache_log /dev/null) as it continuously recorded everything and quickly took up all the space on the 80GB hard drive.
>>>> So the question is what is going wrong that it is refusing to let ANY secure site load and how can we get this resolved?
>>>> We greatly appreciate any help on this.
>>>> Mike
>>> If I understand correctly, you are attempting to use port 3129 as a forward proxy. If so, you shouldn’t need the “intercept” option on 3129, and you should change it to http_port since squid will be directly receiving HTTP “CONNECT” requests, not SSL connections.
>>> Regards,
>>> Guy
>> Guy,
>> According to it says:
>> https_port: The socket address where Squid will listen for client requests made over TLS or SSL connections.
> Correct, but if you are configuring your browser to use this proxy for HTTPS, the browser will start its connection to the specified port with HTTP, not SSL -- the browser will initially send a plaintext "CONNECT xxx:443 HTTP/1.1” command, and then the browser will start using SSL. The plaintext HTTP command needs to be received at an http_port on the squid proxy, not https_port.
>> ssl-bump - blah blah "Requires tproxy or intercept.”
> Yes, because browsers can not be configured to do an SSL connection to the proxy - as I mention above, if you are configuring the browser, then the browser starts its HTTPS requests with a plaintext HTTP command before shifting to SSL. The only purpose for the https_port configuration parameter is to setup a port for a “transparent” interception proxy (in which the browser is NOT configured to talk to the proxy, but instead the proxy intercepts TCP connections).
>> I have tried it all 3 ways, both with and without those 2 modes, and at least with "intercept", it seems that squid is doing something by the i/o and squid activity, although the logs remain empty.
>> Also according to the same documentation, since this will be SSL proxy (not standard insecure HTTP proxy), "https_port" is required. Initially I did try it with "http_port" but it tries to treat CONNECT requests like a normal insecure http request causing sslcrtd to constantly crash, taking squid down with it. At least with "https_port 3129 intercept ssl-bump..." it doesn't crash and is the only time it shows i/o and squid activity, thus my request to the squid-users group.
>> Thank you,
>> Mike
> If you are configuring your browser to use the proxy for SSL, you will need to use http_port with ssl-bump enabled. It does not make it a “standard insecure HTTP proxy” but enables forward proxy of HTTPS traffic. I would suggest that you install wireshark and capture the browser’s traffic to the proxy to verify how this works.
> If squid then has trouble with the ssl_crtd helpers, that is another issue that requires resolution. The fact that squid does not crash when you are using https_port likely indicates that squid and your browser have a failure to communicate, and that is masking your ssl_crtd issue.
> Hope this helps,
> Guy

Based on your mention (changing it to http_port), it will not work since
it IMMEDIATELY crashes the sslcrtd helpers every single time (100% of
the time within half a second of each request), and after 4 crashes in a
short timeframe, it also stops the squid service and browser times out.
I've already explored that avenue and the fix as mentioned by people on
previous squid-user emails, and other websites with a working ssl-bump
is using "https_port intercept ssl-bump...".
So any other way to get this working either with http_port but stopping
the ssl_crtd crashing immediately, or via https_port?

Received on Thu Jun 12 2014 - 21:16:25 MDT

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