logging TLS SNI hostname

Arkadiusz Miśkiewicz

30 May 2016 30 May '16

8:29 a.m.

Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

-- Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

Show replies by date

Arkadiusz Miśkiewicz

17 Oct 17 Oct

8:41 a.m.

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...

Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP).

Thanks,

Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

KT Walrus

5:08 p.m.

...

On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...
Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP).

I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP.

Kevin

Arkadiusz Miśkiewicz

18 Oct 18 Oct

1:16 p.m.

On Monday 17 of October 2016, KT Walrus wrote:

...

...
On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...
Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP).

I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP.

It only needs to be carefuly implemented on dovecot side as TLS SNI hostname is information passed directly by client.

So some fqdn name validation would need to happen in case if client has malicious intents.

...

Kevin

-- Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

Aki Tuomi

20 Oct 20 Oct

12:44 p.m.

On 18.10.2016 14:16, Arkadiusz Miśkiewicz wrote:

...

On Monday 17 of October 2016, KT Walrus wrote:

...
...
On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...
Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN> Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP). I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP. It only needs to be carefuly implemented on dovecot side as TLS SNI hostname is information passed directly by client.

So some fqdn name validation would need to happen in case if client has malicious intents.

...
Kevin

Hi!

I wonder if this would be of any help? It provides %{local_name} passdb/userdb variable, you can use it for some logging too...

https://github.com/dovecot/core/commit/fe791e96fdf796f7d8997ee0515b163dc5edd...

Aki

Arkadiusz Miśkiewicz

2:41 p.m.

On Thursday 20 of October 2016, Aki Tuomi wrote:

...

On 18.10.2016 14:16, Arkadiusz Miśkiewicz wrote:

...
On Monday 17 of October 2016, KT Walrus wrote:

...
...
On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...
Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP).

I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP.

It only needs to be carefuly implemented on dovecot side as TLS SNI hostname is information passed directly by client.

So some fqdn name validation would need to happen in case if client has malicious intents.

...
Kevin

Hi!

I wonder if this would be of any help? It provides %{local_name} passdb/userdb variable, you can use it for some logging too...

https://github.com/dovecot/core/commit/fe791e96fdf796f7d8997ee0515b163dc5ed dd72

Should it work for such usage, too?

login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e local_name=%{local_name} %c session=<%{session}>

Because I'm not getting local_name logged at all (dovecot -a shows its there).

...

Aki

Thanks,

Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

Aki Tuomi

2:45 p.m.

On 20.10.2016 15:41, Arkadiusz Miśkiewicz wrote:

...

On Thursday 20 of October 2016, Aki Tuomi wrote:

...
On 18.10.2016 14:16, Arkadiusz Miśkiewicz wrote:

...
On Monday 17 of October 2016, KT Walrus wrote:

...
...
On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote:

...
Is there a way to log SNI hostname used in TLS session? Info is there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it to ssl_io->host.

Unfortunately I don't see it expanded to any variables ( http://wiki.dovecot.org/Variables ). Please consider this to be a feature request.

The goal is to be able to see which hostname client used like:

May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN> Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP). I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP. It only needs to be carefuly implemented on dovecot side as TLS SNI hostname is information passed directly by client.

So some fqdn name validation would need to happen in case if client has malicious intents.

...
Kevin Hi!

I wonder if this would be of any help? It provides %{local_name} passdb/userdb variable, you can use it for some logging too...

https://github.com/dovecot/core/commit/fe791e96fdf796f7d8997ee0515b163dc5ed dd72 Should it work for such usage, too?

login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e local_name=%{local_name} %c session=<%{session}>

Because I'm not getting local_name logged at all (dovecot -a shows its there).

...
Aki Thanks,

How did you try? With openssl you need to use openssl s_client -connect ... -servername something

Aki

Arkadiusz Miśkiewicz

2:52 p.m.

On Thursday 20 of October 2016, Aki Tuomi wrote:

...

On 20.10.2016 15:41, Arkadiusz Miśkiewicz wrote:

...
On Thursday 20 of October 2016, Aki Tuomi wrote:

...
On 18.10.2016 14:16, Arkadiusz Miśkiewicz wrote:

...
On Monday 17 of October 2016, KT Walrus wrote:

...
...
On Oct 17, 2016, at 2:41 AM, Arkadiusz Miśkiewicz arekm@maven.pl wrote:

On Monday 30 of May 2016, Arkadiusz Miśkiewicz wrote: > Is there a way to log SNI hostname used in TLS session? Info is > there in SSL_CTX_set_tlsext_servername_callback, dovecot copies it > to ssl_io->host. > > Unfortunately I don't see it expanded to any variables ( > http://wiki.dovecot.org/Variables ). Please consider this to be a > feature request. > > The goal is to be able to see which hostname client used like: > > May 30 08:21:19 xxx dovecot: pop3-login: Login: user=<abc>, > method=PLAIN, rip=1.1.1.1, lip=2.2.2.2, mpid=17135, TLS, > SNI=pop3.somehost.org, session=<hfS9Qwk03sBTBnrN>

Dear dovecot team, would be possible to add such variable ^^^^^ ?

That would be neat feature because server operator would know what hostname client uses to connect to server (which is really usefull in case of many hostnames pointing to single IP).

I’d love to be able to use this SNI domain name in the Dovecot IMAP proxy for use in the SQL password_query. This would allow the proxy to support multiple IMAP server domains each with their own set of users. And, it would save me money by using only the IP of the proxy for all the IMAP server domains instead of giving each domain a unique IP.

It only needs to be carefuly implemented on dovecot side as TLS SNI hostname is information passed directly by client.

So some fqdn name validation would need to happen in case if client has malicious intents.

...
Kevin

Hi!

I wonder if this would be of any help? It provides %{local_name} passdb/userdb variable, you can use it for some logging too...

https://github.com/dovecot/core/commit/fe791e96fdf796f7d8997ee0515b163dc 5ed dd72

Should it work for such usage, too?

login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e local_name=%{local_name} %c session=<%{session}>

Because I'm not getting local_name logged at all (dovecot -a shows its there).

...
Aki

Thanks,

How did you try? With openssl you need to use openssl s_client -connect ... -servername something

Yes, using it. -servername is mandatory for TLS SNI to work.

I'm getting correct certificate (as shown by openssl s_client). Certificate that's configured with local_name, so TLS SNI works fine on client and dovecot side.

ps. I'm using 2.2.25 + above %{local_name} patch. Could some other patch be needed for this to work?

...

Aki

Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

Aki Tuomi

3:10 p.m.

On 20.10.2016 15:52, Arkadiusz Miśkiewicz wrote:

...

...
... -servername something

If you want to try out, try applying this patch...

...

From 066edb5e5c14a05c90e9ae63f0b76fcfd9c1149e Mon Sep 17 00:00:00 2001 From: Aki Tuomi Date: Thu, 20 Oct 2016 16:06:27 +0300 Subject: [PATCH] login-common: Include local_name in login_var_expand_table

This way it can be used in login_log_format --- src/login-common/client-common.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/login-common/client-common.c b/src/login-common/client-common.c index d0a9c52..5964ec9 100644 --- a/src/login-common/client-common.c +++ b/src/login-common/client-common.c @@ -507,6 +507,7 @@ static struct var_expand_table login_var_expand_empty_tab[] = { { '\0', NULL, "auth_username" }, { '\0', NULL, "auth_domain" }, { '\0', NULL, "listener" }, + { '\0', NULL, "local_name" }, { '\0', NULL, NULL } }; @@ -581,6 +582,7 @@ get_var_expand_table(struct client *client) tab[24].value = tab[21].value; } tab[25].value = client->listener_name; + tab[26].value = client->local_name == NULL ? "" : client->local_name; return tab; } -- 2.7.4

Arkadiusz Miśkiewicz

3:21 p.m.

On Thursday 20 of October 2016, Aki Tuomi wrote:

...

On 20.10.2016 15:52, Arkadiusz Miśkiewicz wrote:

...
...
... -servername something

If you want to try out, try applying this patch...

Works, thanks!

...

From 066edb5e5c14a05c90e9ae63f0b76fcfd9c1149e Mon Sep 17 00:00:00 2001 From: Aki Tuomi aki.tuomi@dovecot.fi Date: Thu, 20 Oct 2016 16:06:27 +0300 Subject: [PATCH] login-common: Include local_name in login_var_expand_table

This way it can be used in login_log_format

-- Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

Aki Tuomi

3:32 p.m.

On 20.10.2016 16:21, Arkadiusz Miśkiewicz wrote:

...

On Thursday 20 of October 2016, Aki Tuomi wrote:

...
On 20.10.2016 15:52, Arkadiusz Miśkiewicz wrote:

...
...
... -servername something If you want to try out, try applying this patch... Works, thanks!

...
From 066edb5e5c14a05c90e9ae63f0b76fcfd9c1149e Mon Sep 17 00:00:00 2001 From: Aki Tuomi aki.tuomi@dovecot.fi Date: Thu, 20 Oct 2016 16:06:27 +0300 Subject: [PATCH] login-common: Include local_name in login_var_expand_table

This way it can be used in login_log_format Thank you for testing.

Aki

Arkadiusz Miśkiewicz

8 Nov 8 Nov

3:08 p.m.

On Thursday 20 of October 2016, Arkadiusz Miśkiewicz wrote:

...

On Thursday 20 of October 2016, Aki Tuomi wrote:

...
On 20.10.2016 15:52, Arkadiusz Miśkiewicz wrote:

...
...
... -servername something

If you want to try out, try applying this patch...

Works, thanks!

But... it's easy to log fake things

Nov 8 15:04:01 mbox dovecot: pop3-login: Aborted login (no auth attempts in 1 secs): user=<>, rip=127.0.0.1, lip=127.0.0.1, local_name=whitehouse.gov, i_can=put_anything, here=etc, TLS, session=<26rEnMpAPMtb6rD0>

by using

openssl s_client -connect 127.0.0.1:110 -starttls pop3 -servername "whitehouse.gov, i_can=put_anything, here=etc"

so some escaping here would also be needed.

conf: login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e local_name=%{local_name} %c session=<%{session}>

...

...
From 066edb5e5c14a05c90e9ae63f0b76fcfd9c1149e Mon Sep 17 00:00:00 2001 From: Aki Tuomi aki.tuomi@dovecot.fi Date: Thu, 20 Oct 2016 16:06:27 +0300 Subject: [PATCH] login-common: Include local_name in login_var_expand_table

This way it can be used in login_log_format

-- Arkadiusz Miśkiewicz, arekm / ( maven.pl | pld-linux.org )

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11 comments

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participants (3)

Aki Tuomi
Arkadiusz Miśkiewicz
KT Walrus