[squid-users] LEGACY_SERVER_CONNECT, ALLOW_UNSAFE_LEGACY_RENEGOTIATION does not work - SSL bump, OpenSSL 3
Alex Rousskov
rousskov at measurement-factory.com
Thu Dec 29 02:44:33 UTC 2022
Hi Amish,
Thank you for updating test results. I have a working theory:
Staring SslBump disregards parsed tcp_outgoing_options since commit
f233022. That commit message explains why tcp_outgoing_options should be
ignored when peeking at the server. The message does not explain why
_staring_ mode got penalized as well, but I suspect that Squid had only
one context to use for both modes, so staring mode had to follow the
peeking code lead...
You can test that theory by replacing "false" with "true" in
Security::ProxyOutgoingConfig.createClientContext(false) call inside
configDoConfigure(). Needless to say, doing so may break SslBump
peeking, but at least we will know that the theory is correct.
HTH,
Alex.
On 12/28/22 20:22, Amish wrote:
> Hi Alex,
>
> Thank you once again!
>
> See replies inline below.
>
> On 28/12/22 22:57, Alex Rousskov wrote:
>> Hi Amish,
>>
>> TLS options are used on _both_ sides, in various cases, but there
>> are still too many unknowns, and I cannot quickly answer all of your
>> questions at once. Sorry. I can only guide you one step at a time.
>>
>> * If you are sure that SSL_CTX_set_options() is not called when
>> talking to the origin server in your setup, then there is no need to
>> hard-code those options. Instead, we need to figure out why Squid does
>> not call SSL_CTX_set_options(). The best next step is to configure
>> your Squid with the following ssl_bump rules and check whether
>> SSL_CTX_set_options() is called for the Squid-server connection in
>> that case. Sharing access.log records to double check that the origin
>> server was contacted may be a good idea.
>>
>> ssl_bump stare all
>> ssl_bump bump all
>
> I have concluded that updateContextOptions() is not being called for
> squid to origin server as cache.log does not show any calls.
>
> Here is how I concluded it.
>
> $ cat /etc/squid/squid.conf
> debug_options 83,6
> ssl_bump stare all
> ssl_bump bump all
>
> tls_outgoing_options \
> cafile=/etc/ssl/cert.pem \
> cipher=ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS \
> options=0x40000
>
> http_port 3128 intercept
> http_port 8080 ssl-bump generate-host-certificates=on
> tls-cert=/etc/squid/ssl_cert/squid.pem
> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x4
> https_port 8081 intercept ssl-bump generate-host-certificates=on
> tls-cert=/etc/squid/ssl_cert/squid.pem
> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x4
>
>
> Note that I have kept different options. 0x40000 for
> tcp_outgoing_options and 0x4 for http(s)_port.
>
> $ systemctl reload squid
> $ curl --no-progress-meter -kx 127.0.0.1:8080
> 'https://www.jio.com/?foo=bar'
> $ tail -f /var/log/squid/cache.log |grep -i 'openssl\|parsed'
> 2022/12/29 06:13:04.182 kid1| 83,5| PeerOptions.cc(447) parseOptions:
> INFO: TLS parsedOptions(1)=4
> 2022/12/29 06:13:04.182 kid1| 83,5| PeerOptions.cc(643)
> updateContextOptions: set OpenSSL options for context=0x559210db6b20,
> parsedOptions=4
> 2022/12/29 06:13:04.182 kid1| 83,5| PeerOptions.cc(645)
> updateContextOptions: get OpenSSL options for context=0x559210db6b20,
> getOptions=1179652
>
> parsedOptions is 4 which squid picked up from http_port line.
>
> $ tail -f /var/log/squid/access.log
> 1672274753.787 1290 127.0.0.1 NONE_NONE/200 0 CONNECT www.jio.com:443
> local HIER_NONE/- -
> 1672274753.789 0 127.0.0.1 NONE_NONE/503 4343 GET
> https://www.jio.com/?foo=bar - HIER_NONE/- text/html
>
> SSL Bumping is working fine as squid is able to find full HTTPS URL
> including CGI parameters.
>
> But just to double check that SSL bumping is working fine, we try
> accessing Google:
>
> $ curl --no-progress-meter -kx 127.0.0.1:8080 'https://google.com/?foo=bar'
> $ tail -f /var/log/squid/access.log
> 1672274850.924 1120 127.0.0.1 NONE_NONE/200 0 CONNECT google.com:443
> local HIER_DIRECT/2404:6800:4009:81d::200e -
> 1672274851.000 75 127.0.0.1 TCP_MISS/301 1041 GET
> https://google.com/?foo=bar local HIER_DIRECT/2404:6800:4009:81d::200e
> text/html
>
> Google.com is accessed successfully and access.log also shows the same
> with full HTTPS URL.
>
> Now I reversed the options. Setting the options as 0x4 for
> tcp_outgoing_options and 0x40000 for http(s)_port.
>
> $ cat /etc/squid/squid.conf
> tls_outgoing_options \
> ...
> options=0x4
> ...
> http_port 8080 ssl-bump generate-host-certificates=on
> tls-cert=/etc/squid/ssl_cert/squid.pem
> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x40000
> https_port 8081 intercept ssl-bump generate-host-certificates=on
> tls-cert=/etc/squid/ssl_cert/squid.pem
> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x40000
>
> $ systemctl reload squid
> $ curl --no-progress-meter -kx 127.0.0.1:8080 https://www.jio.com/?foo=bar'
> $ tail -f /var/log/squid/cache.log |grep -i 'openssl\|parsed'
> 2022/12/29 06:29:30.106 kid1| 83,5| PeerOptions.cc(447) parseOptions:
> INFO: TLS parsedOptions(1)=262144
> 2022/12/29 06:29:30.106 kid1| 83,5| PeerOptions.cc(643)
> updateContextOptions: set OpenSSL options for context=0x559211c674e0,
> parsedOptions=262144
> 2022/12/29 06:29:30.106 kid1| 83,5| PeerOptions.cc(645)
> updateContextOptions: get OpenSSL options for context=0x559211c674e0,
> getOptions=1441792
>
> Note: 262144 is 0x40000 = SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION.
> And 1441792 is 0x160000 (i.e. 0x100000 = SSL_OP_ENABLE_MIDDLEBOX_COMPAT
> | 0x40000 | 0x20000 = SSL_OP_NO_COMPRESSION)
>
> $ tail -f /var/log/squid/access.log
> 1672275570.422 325 127.0.0.1 NONE_NONE/200 0 CONNECT www.jio.com:443
> local HIER_NONE/- -
> 1672275570.423 0 127.0.0.1 NONE_NONE/503 4343 GET
> https://www.jio.com/?foo=bar - HIER_NONE/- text/html
>
> So from above two squid.conf settings we can conclude that
> updateContextOptions() and hence SSL_CTX_set_options() is getting called
> only for client to squid side of the connection and not squid to origin
> side of the connection.
>
> Now we need to find, where the server side connection happens OR why
> updateContextOptions() is not called for squid to origin server
> connections.
>
> Any idea?
>
> Thanks and regards
>
> Amish
>
>>
>> * If you are not sure whether SSL_CTX_set_options() is called when
>> talking to the origin server in your setup, then hard-coding those
>> options may still be the best next step. If it fixes the problem, then
>> we will be able to resolve a few variables without the test in the
>> first bullet.
>>
>>
>> HTH,
>>
>> Alex.
>>
>>
>> On 12/28/22 11:49, Amish wrote:
>>> Hi Alex,
>>>
>>> On 28/12/22 21:31, Alex Rousskov wrote:
>>>> Hi Amish,
>>>>
>>>> Squid parsing code is tricky. tls_outgoing_options parsing code
>>>> is triply so. Even its authors misinterpret it!
>>>>
>>>> I assume you have removed multiple tls_outgoing_options directives
>>>> from your configuration before testing. If you have not, please
>>>> merge those directives into one and retest. You should still see
>>>> multiple parsing paths, in part, due to (unfortunate)
>>>> Security::PeerOptions implementation and, in part, due to Squid
>>>> parsing default options before Squid parses your actual
>>>> configuration files.
>>>>
>>> Yes I had combined all tls_outgoing_options in to a single directive
>>> (but in multiple lines ending with a backslash \). It can be seen in
>>> the grep command in my previous email.
>>>
>>> But wait, I have found something.
>>>
>>> And I have a doubt that parsedOptions work only for client to squid
>>> side of the connection and does not work for squid to server side of
>>> the connection.
>>>
>>> What I did is changed my "http(s)_port" directives to include
>>> options=0x4. These directives control options for the client to squid
>>> side of TLS connection.
>>>
>>> $ grep 'ssl-bump' /etc/squid/squid.conf
>>> http_port 8080 ssl-bump generate-host-certificates=on
>>> tls-cert=/etc/squid/ssl_cert/squid.pem
>>> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x4
>>> https_port 8081 intercept ssl-bump generate-host-certificates=on
>>> tls-cert=/etc/squid/ssl_cert/squid.pem
>>> tls-dh=/etc/squid/ssl_cert/dhparam.pem options=0x4
>>>
>>> Now lets reproduce the issue:
>>> $ curl --no-progress-meter -kx 127.0.0.1:8080 https://www.jio.com
>>> |grep 'TLS\|SSL'
>>> <pre>[No Error] (TLS code:
>>> SQUID_TLS_ERR_CONNECT+TLS_LIB_ERR=A000152+TLS_IO_ERR=1)</pre>
>>> <p>Failed to establish a secure connection: error:0A000152:SSL
>>> routines::unsafe legacy renegotiation disabled</p>
>>>
>>> Lets see what cache.log has to say:
>>>
>>> $ tail -f /var/log/squid/cache.log |grep -i 'openssl\|parsed'
>>> 2022/12/28 21:52:56.532 kid1| 83,5| PeerOptions.cc(447) parseOptions:
>>> INFO: TLS parsedOptions(1)=4
>>> 2022/12/28 21:52:56.532 kid1| 83,5| PeerOptions.cc(643)
>>> updateContextOptions: set OpenSSL options for context=0x559075043e30,
>>> parsedOptions=4
>>> 2022/12/28 21:52:56.532 kid1| 83,5| PeerOptions.cc(645)
>>> updateContextOptions: get OpenSSL options for context=0x559075043e30,
>>> getOptions=1179652
>>>
>>> Bingo!! As we can see, parsedOptions is now set to 4!
>>>
>>> And it is also confirmed by ssl_get_options() - 1179652 = 0x120004
>>> (4 means the option is accepted by OpenSSL too)
>>>
>>> But this also means that updateContextOptions() is called ONLY FOR
>>> client to squid side (curl to squid) and it is not called for squid
>>> to server (jio.com in this case) side.
>>>
>>> The reason being that we do not see updateContextOptions() being
>>> called twice for a request. But only once. And that is why request
>>> still fails with the negotiation error.
>>>
>>> So where exactly is the call for squid to server side being made?
>>>
>>>> If merging directives does not deliver custom options to
>>>> SSL_CTX_set_options(), then let's attack this from the other end:
>>>> Supply the right options to each SSL_CTX_set_options() call:
>>>>
>>>> const Security::ParsedOptions forcedParsedOptions = 0x4 | 0x40000;
>>>> SSL_CTX_set_options(ctx.get(), forcedParsedOptions);
>>>>
>>>> Does the above temporary hack fix the problem in your test?
>>>
>>>
>>> I will try this tomorrow (its late night here).
>>>
>>> But I think I will have to set this somewhere else and NOT in
>>> PeerOptions.cc. Because above code appears to be for client to squid
>>> side.
>>>
>>> And I need to add forcedParsedOptions to the code which connects
>>> squid to server. But where?
>>>
>>> Thank you,
>>>
>>> Amish.
>>>
>>>
>>>> Thank you,
>>>>
>>>> Alex.
>>>>
>>>> On 12/28/22 02:32, Amish wrote:
>>>>> Hi Alex,
>>>>>
>>>>> Thanks again for your reply.
>>>>>
>>>>> To find answers to your questions, I added few debugs() lines to
>>>>> PeerOptions.cc.
>>>>>
>>>>> The diff file (patch) is attached.
>>>>>
>>>>> It prints parsedOptions and options retrieved from SSL context and
>>>>> session objects at several stages.
>>>>>
>>>>> Here is tls_outgoing_options setting:
>>>>>
>>>>> $ grep tls_outgoing_options /etc/squid/squid.conf
>>>>> tls_outgoing_options \
>>>>> cafile=/etc/ssl/cert.pem \
>>>>> cipher=ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS \
>>>>> options=0x4
>>>>>
>>>>>
>>>>> Here is what squid logs on reload i.e. on parsing the squid.conf
>>>>>
>>>>> $ systemctl reload squid
>>>>> $ tail -f /var/log/squid/cache.log |grep -i 'openssl\|parsed'
>>>>> 2022/12/28 12:19:30.596 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:30.598 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:30.723 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=4
>>>>> 2022/12/28 12:19:30.729 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:30.729 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:32.147 kid1| 83,5| PeerOptions.cc(447)
>>>>> parseOptions: INFO: TLS parsedOptions(1)=0
>>>>> 2022/12/28 12:19:32.147 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:33.524 kid1| 83,5| PeerOptions.cc(447)
>>>>> parseOptions: INFO: TLS parsedOptions(1)=0
>>>>> 2022/12/28 12:19:33.532 kid1| 83,5| PeerOptions.cc(547)
>>>>> parseOptions: INFO: TLS parsedOptions(3)=0
>>>>> 2022/12/28 12:19:33.695 kid1| 83,5| PeerOptions.cc(447)
>>>>> parseOptions: INFO: TLS parsedOptions(1)=0
>>>>> 2022/12/28 12:19:33.695 kid1| 83,5| PeerOptions.cc(643)
>>>>> updateContextOptions: set OpenSSL options for
>>>>> context=0x562a5387fe30, parsedOptions=0
>>>>> 2022/12/28 12:19:33.695 kid1| 83,5| PeerOptions.cc(645)
>>>>> updateContextOptions: get OpenSSL options for
>>>>> context=0x562a5387fe30, getOptions=1179648
>>>>
>>>>> 2022/12/28 12:19:33.708 kid1| 83,5| PeerOptions.cc(447)
>>>>> parseOptions: INFO: TLS parsedOptions(1)=0
>>>>> 2022/12/28 12:19:33.708 kid1| 83,5| PeerOptions.cc(643)
>>>>> updateContextOptions: set OpenSSL options for
>>>>> context=0x562a53e6e740, parsedOptions=0
>>>>> 2022/12/28 12:19:33.708 kid1| 83,5| PeerOptions.cc(645)
>>>>> updateContextOptions: get OpenSSL options for
>>>>> context=0x562a53e6e740, getOptions=1179648
>>>>>
>>>>> It seems that squid parses the options multiple times and only once
>>>>> it gets the value as 4. Rest are parsed as 0.
>>>>>
>>>>> The value of 1179648 (0x120000) corresponds to
>>>>> SSL_OP_NO_COMPRESSION (0x20000) and SSL_OP_ENABLE_MIDDLEBOX_COMPAT.
>>>>> (0x100000)
>>>>>
>>>>>
>>>>> Now lets reproduce the issue:
>>>>>
>>>>> $ curl --no-progress-meter -kx 127.0.0.1:8080 https://www.jio.com
>>>>> |grep 'TLS\|SSL'
>>>>> <pre>[No Error] (TLS code:
>>>>> SQUID_TLS_ERR_CONNECT+TLS_LIB_ERR=A000152+TLS_IO_ERR=1)</pre>
>>>>> <p>Failed to establish a secure connection: error:0A000152:SSL
>>>>> routines::unsafe legacy renegotiation disabled</p>
>>>>>
>>>>> So, as we can see, we are still not able to access the site.
>>>>>
>>>>> Lets see what cache.log has to say.
>>>>>
>>>>> $ tail -f /var/log/squid/cache.log |grep -i 'openssl\|parsed'
>>>>> 2022/12/28 12:31:09.971 kid1| 83,5| PeerOptions.cc(447)
>>>>> parseOptions: INFO: TLS parsedOptions(1)=0
>>>>> 2022/12/28 12:31:09.971 kid1| 83,5| PeerOptions.cc(643)
>>>>> updateContextOptions: set OpenSSL options for
>>>>> context=0x562a53eb14e0, parsedOptions=0
>>>>> 2022/12/28 12:31:09.971 kid1| 83,5| PeerOptions.cc(645)
>>>>> updateContextOptions: get OpenSSL options for
>>>>> context=0x562a53eb14e0, getOptions=1179648
>>>>>
>>>>> Strangely parsedOptions was zero and not 4!
>>>>>
>>>>> Now we can answer your questions as below.
>>>>>
>>>>>
>>>>> On 27/12/22 21:52, Alex Rousskov wrote:
>>>>>> On 12/27/22 10:42, Amish wrote:
>>>>>>> On 26/12/22 21:31, Alex Rousskov wrote:
>>>>>>>> tls_outgoing_options options=0x4,0x40000
>>>>>>
>>>>>>> With numeric hex values, I do not see the ERROR on stderr.
>>>>>>
>>>>>>> But it still does not seem to be working as expected. Squid still
>>>>>>> does not open the page and gives same legacy negotiation error.
>>>>>>
>>>>>> There are still many unknowns (from my point of view), including:
>>>>>>
>>>>>> 1. Does OpenSSL accept the above options? You ask that question
>>>>>> below.
>>>>>
>>>>> Google search shows some projects using OpenSSL v3 where there is
>>>>> mention to use above option when a similar error occurred to them.
>>>>>
>>>>> But in our case, its clear that squid does not pass value 4 to SSL
>>>>> context, hence we do not know yet if OpenSSL accepts above options.
>>>>>
>>>>>
>>>>>> 2. Does Squid indeed stare at the server, as expected?
>>>>>> 3. Does Squid apply the accepted options when staring at the server?
>>>>>
>>>>> A comment for parseOptions() in PeerOptions.cc states this:
>>>>>
>>>>> /**
>>>>> * Pre-parse TLS options= parameter to be applied when the TLS
>>>>> objects created.
>>>>> * Options must not used in the case of peek or stare bump mode.
>>>>> */
>>>>> void Security::PeerOptions::parseOptions()
>>>>>
>>>>> So it appears that TLS options is NOT used for peek as well as
>>>>> stare. But why? I am not sure.
>>>>>
>>>>> How do I make squid use it for 'stare' atleast?
>>>>>
>>>>>
>>>>>> 4. Why does TLS negotiation fail despite those options applied,
>>>>>> especially since it succeeds with using openssl s_client
>>>>>
>>>>> It possibly fails because options are not applied by squid.
>>>>>
>>>>> So, where do I check next on why parsedOptions is still set to 0
>>>>> and why its not used for 'stare'?
>>>>>
>>>>> Thanks and regards,
>>>>>
>>>>> Amish.
>>>>>
>>> _______________________________________________
>>> squid-users mailing list
>>> squid-users at lists.squid-cache.org
>>> http://lists.squid-cache.org/listinfo/squid-users
>>
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