threads / patch / 34353

patchsend-email: squelch warning from Net::SMTP::SSL

Subject: [PATCH] send-email: squelch warning from Net::SMTP::SSL

## tl;dr

7 messages between Jul 5, 2013 and Jul 29, 2013. Diffs are folded; open one to read it.

replies: 6people: 5as markdown or json

Ramkumar Ramachandra· Jul 5, 2013, 10:18 UTC · lore

Due to a recent change in the Net::SMTP::SSL module, send-email emits the following ugly warning everytime a email is sent via SSL:

*******************************************************************
 Using the default of SSL_verify_mode of SSL_VERIFY_NONE for client
 is deprecated! Please set SSL_verify_mode to SSL_VERIFY_PEER
 together with SSL_ca_file|SSL_ca_path for verification.
 If you really don't want to verify the certificate and keep the
 connection open to Man-In-The-Middle attacks please set
 SSL_verify_mode explicitly to SSL_VERIFY_NONE in your application.
*******************************************************************

Fix this by explicitly specifying SSL_verify_mode => SSL_VERIFY_NONE in Net::SMTP::SSL->start_SSL().

Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 git-send-email.perl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
Show changes to git-send-email.perl +3 −1
diff --git a/git-send-email.perl b/git-send-email.perl
index ecbf56f..758100d 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -1193,10 +1193,12 @@ X-Mailer: git-send-email $gitversion
 						 Debug => $debug_net_smtp);
 			if ($smtp_encryption eq 'tls' && $smtp) {
 				require Net::SMTP::SSL;
+				use IO::Socket::SSL qw(SSL_VERIFY_NONE);
 				$smtp->command('STARTTLS');
 				$smtp->response();
 				if ($smtp->code == 220) {
-					$smtp = Net::SMTP::SSL->start_SSL($smtp)
+					$smtp = Net::SMTP::SSL->start_SSL($smtp,
+									  SSL_verify_mode => SSL_VERIFY_NONE)
 						or die "STARTTLS failed! ".$smtp->message;
 					$smtp_encryption = '';
 					# Send EHLO again to receive fresh

-- 
1.8.3.2.722.g3244e19.dirty
John Keeping· Jul 5, 2013, 10:45 UTC · re: Ramkumar Ramachandra · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

On Fri, Jul 05, 2013 at 03:48:31PM +0530, Ramkumar Ramachandra wrote:
Show 14 quoted lines
> Due to a recent change in the Net::SMTP::SSL module, send-email emits
> the following ugly warning everytime a email is sent via SSL:
> 
> *******************************************************************
>  Using the default of SSL_verify_mode of SSL_VERIFY_NONE for client
>  is deprecated! Please set SSL_verify_mode to SSL_VERIFY_PEER
>  together with SSL_ca_file|SSL_ca_path for verification.
>  If you really don't want to verify the certificate and keep the
>  connection open to Man-In-The-Middle attacks please set
>  SSL_verify_mode explicitly to SSL_VERIFY_NONE in your application.
> *******************************************************************
> 
> Fix this by explicitly specifying SSL_verify_mode => SSL_VERIFY_NONE in
> Net::SMTP::SSL->start_SSL().

I don't think this is really "fix", it's more plastering over the problem. As the message from OpenSSL says, specifying this means that we're explicitly saying that we don't want to check the server certificate which loses half of the security of SSL.

I'd rather leave this as it is (complete with the big scary error message) and eventually fix it properly by letting the user specify the ca_file or ca_path. Perhaps we can even set a sensible default, although I expect this needs to be platform-specific.

Ramkumar Ramachandra· Jul 5, 2013, 10:52 UTC · re: John Keeping · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

John Keeping wrote:
> I don't think this is really "fix", it's more plastering over the
> problem.

It defaulted to SSL_VERIFY_NONE before Net::SMTP::SSL was updated, and the behavior hasn't changed now. The new version simply asks us to be explicit about SSL_VERIFY_NONE, so we are aware about it.

> I'd rather leave this as it is (complete with the big scary error
> message) and eventually fix it properly by letting the user specify the
> ca_file or ca_path.  Perhaps we can even set a sensible default,
> although I expect this needs to be platform-specific.

Nothing scary about it: it eats up real estate, and that is annoying. I personally couldn't care less about ca_file, since all my emails are to public mailing lists anyway. Work on specifying a proper ca_file as a follow-up, if you so desire.

Matthieu Moy· Jul 5, 2013, 11:31 UTC · re: Ramkumar Ramachandra · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

Ramkumar Ramachandra <artagnon@gmail.com> writes:
Show 7 quoted lines
> John Keeping wrote:
>> I don't think this is really "fix", it's more plastering over the
>> problem.
>
> It defaulted to SSL_VERIFY_NONE before Net::SMTP::SSL was updated, and
> the behavior hasn't changed now.  The new version simply asks us to be
> explicit about SSL_VERIFY_NONE, so we are aware about it.

"We" as "the Git developers", yes. But your change makes sure users are _not_ aware about it. There's a long history of software ignoring SSL certificates by default, I don't think we should cast in stone that we don't want SSL certificate verification.

-- 
Matthieu Moy
http://www-verimag.imag.fr/~moy/
Colin Guthrie· Jul 26, 2013, 09:29 UTC · re: Matthieu Moy · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

'Twas brillig, and Matthieu Moy at 05/07/13 12:31 did gyre and gimble:
Show 14 quoted lines
> Ramkumar Ramachandra <artagnon@gmail.com> writes:
> 
>> John Keeping wrote:
>>> I don't think this is really "fix", it's more plastering over the
>>> problem.
>>
>> It defaulted to SSL_VERIFY_NONE before Net::SMTP::SSL was updated, and
>> the behavior hasn't changed now.  The new version simply asks us to be
>> explicit about SSL_VERIFY_NONE, so we are aware about it.
> 
> "We" as "the Git developers", yes. But your change makes sure users are
> _not_ aware about it. There's a long history of software ignoring SSL
> certificates by default, I don't think we should cast in stone that we
> don't want SSL certificate verification.

For what it's worth, after upgrading here, I got this error at the server side:

Jul 26 10:15:41 foo.example.com postfix/smtpd[7736]: warning: TLS library problem: 7736:error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca:s3_pkt.c:1256:SSL alert number 48:

This is because my postfix doesn't have a ca bundle configured but all other mail clients have been fine before.

With the original patch here I could continue.

I'd really love to see an option to set this to none in the .gitconfig, but agree with the principle that it should be one by default and the setting should over ride that.

All the best
Col

PS I'm mainly posting this such that people searching the intertubes for the postfix error above and git-send-email will match at least this message and find the fix/workaround :)

-- 
Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited http://www.tribalogic.net/
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Junio C Hamano· Jul 29, 2013, 16:01 UTC · re: Colin Guthrie · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

Colin Guthrie <gmane@colin.guthr.ie> writes:
Show 14 quoted lines
> For what it's worth, after upgrading here, I got this error at the
> server side:
>
> Jul 26 10:15:41 foo.example.com postfix/smtpd[7736]: warning: TLS
> library problem: 7736:error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1
> alert unknown ca:s3_pkt.c:1256:SSL alert number 48:
>
>
> This is because my postfix doesn't have a ca bundle configured but all
> other mail clients have been fine before.
>
> With the original patch here I could continue.
>
> I'd really love to see an option to set this to none in the .gitconfig,

Isn't that what the final patch committed under Ram's name implements?

    sendemail.smtpsslcertpath::
           Path to ca-certificates (either a directory or a single file).
           Set it to an empty string to disable certificate verification.
or have we missed your use case?
> but agree with the principle that it should be one by default and the
> setting should over ride that.
Colin Guthrie· Jul 29, 2013, 17:12 UTC · re: Junio C Hamano · lore

Re: [PATCH] send-email: squelch warning from Net::SMTP::SSL

'Twas brillig, and Junio C Hamano at 29/07/13 17:01 did gyre and gimble:
Show 25 quoted lines
> Colin Guthrie <gmane@colin.guthr.ie> writes:
> 
>> For what it's worth, after upgrading here, I got this error at the
>> server side:
>>
>> Jul 26 10:15:41 foo.example.com postfix/smtpd[7736]: warning: TLS
>> library problem: 7736:error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1
>> alert unknown ca:s3_pkt.c:1256:SSL alert number 48:
>>
>>
>> This is because my postfix doesn't have a ca bundle configured but all
>> other mail clients have been fine before.
>>
>> With the original patch here I could continue.
>>
>> I'd really love to see an option to set this to none in the .gitconfig,
> 
> Isn't that what the final patch committed under Ram's name
> implements?
> 
>     sendemail.smtpsslcertpath::
>            Path to ca-certificates (either a directory or a single file).
>            Set it to an empty string to disable certificate verification.
> 
> or have we missed your use case?

Yeah that patch works fine if I set the certpath = "" in the config, and I even added that path to our packages.

I read the mailing list after following the google trail and replied to
that specific message without realising a more recent patch was
available and then didn't post a followup saying the final patch worked
- my bad!
Sorry about that, and thanks to everyone for the final patch :)
Col
-- 
Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited http://www.tribalogic.net/
Open Source:
  Mageia Contributor http://www.mageia.org/
  PulseAudio Hacker http://www.pulseaudio.org/
  Trac Hacker http://trac.edgewall.org/

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