Re: Interop lsh and SSH-2.0-GitLab-SSHD

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>>> 0064: 73 68 2D 72 73 61 00 00 00 03 01 00 01 00 00 00 sh-rsa..........
>>> 0080: C1 00 E4 C5 6B 62 93 98 2F 7B 70 D2 89 B4 82 9E ....kb../{p.....
>> [...]
> Apologies for coming in late on this, but I noticed in the hex dump that the$

Hm!  My attempt looks like

1202    0   32 00 00 00 03 67 69 74  00 00 00 0e 73 73 68 2d  2····git····ssh-
1203   10   63 6f 6e 6e 65 63 74 69  6f 6e 00 00 00 09 70 75  connection····pu
1204   20   62 6c 69 63 6b 65 79 00  00 00 00 0c 72 73 61 2d  blickey·····rsa-
1205   30   73 68 61 32 2d 32 35 36  00 00 01 1d 00 00 00 07  sha2-256········
1206   40   73 73 68 2d 72 73 61 00  00 00 09 00 80 00 80 04  ssh-rsa·········
1207   50   00 00 00 01 00 00 01 01  00 aa 82 a6 3f 3b c6 bc  ·········ª·¦?;Ƽ
1208   60   cf 99 7b 58 3b 07 5e 01  80 e8 cc cc be f4 04 3d  Ï·{X;·^··èÌ̾ô·=
1209   70   1b 1a b3 40 3f 21 6e 50  ea e8 e2 42 05 b6 b8 5a  ··³@?!nPêèâB·¶¸Z

ie, modulus is 2Kbit long and exponent is 0x8000800400000001.  And I
see the abrupt disconnect.  pgut001@ has exponent 0x010001 and a
1536-bit modulus, and doesn't.  nisse@ wrote

> I've successfully tested interop with "SSH-2.0-OpenSSH_9.1
> FreeBSD-20230719", and I'm testing with a particular 3072-bit RSA
> key.  The only unusual thing with the key, as far as I can tell, is
> that the "e" value is a randomly selected 32-bit number, not just 17
> or 65537.

and is seeing the disconnect.

So it's not just modulus size, but I'm wondering if the gitlab code is
stupid enough to consider any exponent over 65537 as an error or some
such.

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