Re: [PATCH] diffie-hellman-group-exchange-sha256

[Yanis Kurganov <yanis.kurganov@xxxxxxxxx>]

Hi Jon!
Do you have a log file from dropbear or/and libssh server?

2015-01-26 4:12 GMT+03:00 Jon Simons <jon@xxxxxxxxxxxxx>:

> Hi Yanis,
>
> On 1/23/15, 5:40 AM, Yanis Kurganov wrote:
>
>> It's a final version with modern SSH_MSG_KEY_DH_GEX_REQUEST.
>> Some clients (for example, Tera Term) use only this message.
>>
>
> In my local testing with this patch, it seems that this breaks the initial
> key exchange for dropbear clients.
>
> Steps to reproduce:
>
>  1. build libssh WITH_SERVER and tests:
>
>       cd build && cmake -DWITH_TESTING=ON -DWITH_SERVER=ON ..
>
>  2. build a dropbear client with these options enabled in options.h, and
>     ensure that the 'dbclient' binary is in your PATH:
>
>       #define DROPBEAR_BLOWFISH
>
>       #define DROPBEAR_SHA2_256_HMAC
>       #define DROPBEAR_SHA2_512_HMAC
>
>  3. now run the 'pkd_hello' test:
>
>     cd build/tests/pkd
>
>     # all combinations with 1 iteration:
>     ./pkd_hello -i1
>
>     # just one single verbose dropbear pass (exhibits the regression):
>     ./pkd_hello -i1 -t torture_pkd_dropbear_rsa_default -v -v -v -v
>
> Attached is a patch which adds passes for the new group exchange algorithms
> to 'pkd', but the patch is not needed to demonstrate the dropbear interop
> bug.
>
>
> -Jon
>
>