sendmail broken by libssl in current

[Julian Elischer]

On 3/11/15 12:14 AM, Xin Li wrote:
>
> On 3/10/15 23:57, Julian Elischer wrote:
>> [sorry for reposting but the original copy I got back had been truncated]
>>
>> libssl has a new "feature"
>> implemented by:
>> crypto/openssl/ssl/t1_lib.c
>>
>>      672         /* Add padding to workaround bugs in F5 terminators.
>>      673          * See https://tools.ietf.org/html/draft-agl-tls-padding-03
>>      674          *
>>      675          * NB: because this code works out the length of all
>> existing
>>      676          * extensions it MUST always appear last.
>>      677          */
>>      678         //if (s->options & SSL_OP_TLSEXT_PADDING)
>>
>> unfortunatly this makes sendmail incompatible with various email servers
>> around the world,
>> including (apparently (ironically (*))) Ironport email gateways.
>> It fails in TLS handshake.
> I hate workarounds of workarounds :(
>
> How about this?
>
> %%%
> Index: contrib/sendmail/src/readcf.c
> ===================================================================
> --- contrib/sendmail/src/readcf.c       (revision 279857)
> +++ contrib/sendmail/src/readcf.c       (working copy)
> @@ -116,7 +116,7 @@ readcf(cfname, safe, e)
>
>   #if STARTTLS
>          Srv_SSL_Options = SSL_OP_ALL;
> -       Clt_SSL_Options = SSL_OP_ALL
> +       Clt_SSL_Options = SSL_OP_ALL & ~SSL_OP_TLSEXT_PADDING
>   #ifdef SSL_OP_NO_SSLv2
>                  | SSL_OP_NO_SSLv2
>   #endif
> %%%

that's certainly better.. MY change was to just prove where the 
problem was after reading a bit on the web.
The trouble is that that may break mail servers behind F5 appliances.
One wonders if one could only turn it off for every second attempt on 
a retry after a failed attempt.
or some other way of not breaking  the F5 appliances...

I found I could not talk to my child's school (department of 
education) and my bank, over a period of just a week..
I will look to see if I start picking up new failures now (and see how 
many F5 appliances there are :-).


> Cheers,
>