Re: HMAC error - help pls

["Oliver Stöneberg" <oliverst@xxxxxxxxx>]

Hey,

maybe the log message should contain the number of the session, so
it's easier to figure the context.

Greetings
Oliver

> Hi,
>
> I have inspected the code path, there is no possibility for "decrypting
> 16 bytes" message to show up twice in a row. Are you using several
> sessions ? If so, could you try again but with only one client ? I'm not
> yet sure it's not a libssh problem so I prefer we investigate.
>
> Kr,
>
> Aris
>
> Le 7/06/11 13:22, jeetu.golani@xxxxxxxxx a écrit :
> > Hi Aris,
> >
> > Thanks for replying.
> >
> > Unfortunately I copy pasted only this part of the log, will reproduce
> > the error and paste the entire log.
> >
> > As for an estimation on the amount of data, gauging that the packet
> > number above is 36519 and while most packets seemed to have a length
> > of 32bytes, I did see some packets with a length of 668bytes too
> > (about 10%).....am guessing approx 35 Megabytes of data.
> >
> > For the ssh client I am using a standard openssh client, the server is
> > my own and creates a socket where an X client connects etc.
> >
> > Sincerely need your help. Thanks and sorry for the trouble.
> >
> > Bye for now
> >
> > On Tue, Jun 7, 2011 at 4:08 PM, Aris Adamantiadis <aris@xxxxxxxxxxxx> wrote:
> >> Hi Jeetu,
> >>
> >> I did not have much time to read your email completely, but it seems in
> >> first impression that server/client is sending garbage. Could you attach
> >> the first hundreds lines of debugging output, especially the key exchange ?
> >> Also, do you have an estimation of the number of bytes that have been
> >> transmitted before the failure ? (i.e. does it approach gigabytes ?)
> >>
> >> Thanks,
> >>
> >> Aris
> >>
> >> Le 7/06/11 12:00, jeetu.golani@xxxxxxxxx a écrit :
> >>> Hi guys,
> >>>
> >>> In continuation with my efforts to put together a libssh based server,
> >>> I have had significant success and can say it is very impressive to
> >>> see the effort you guys have put in the libssh library, thank you :)
> >>>
> >>> I could sincerely use some help though. All in all my server is
> >>> behaving much more robust than it ever has. I have been testing with
> >>> multiple X client applications being forwarded simultaneously and all
> >>> in all it runs well. I had some previous issues I had mailed this list
> >>> about (subject: multithreaded server issues) but an init of the buffer
> >>> seems to have helped.
> >>>
> >>> I have noticed some behaviour I do not understand. Below is what the
> >>> libssh log says when set to SSH_LOG_PACKET
> >>>
> >>> With multiple applications, after extensive use of the applications
> >>> (for e.g. xeyes and xclock running) I have noticed that after sometime
> >>> the applications are unable to refresh their window - there is no
> >>> crash most of these times and if left alone maybe clock may eventually
> >>> refresh part of the window etc. xeyes stops showing it's eyes moving
> >>> around but still seems to be running - ssh client connected seems to
> >>> show some activity too.
> >>>
> >>> The libssh log seems to suggest that there is packet corruption at
> >>> this point. Two things stand out from the below log:
> >>>
> >>> I]
> >>>
> >>> [3] Decrypting 16 bytes
> >>> [3] Packet size decrypted: 2754678753 (0xa4310fe1)
> >>> [1] Error : read_packet(): Packet len too high(2754678753 a4310fe1)
> >>>
> >>> II]
> >>> [3] Decrypting 96 bytes
> >>> [1] Error : HMAC error
> >>>
> >>> Pls note this log is an excerpt of a long log taken once the strange
> >>> behaviour has manifested.
> >>>
> >>> What is a HMAC error? can someone pls shed light on what could be
> >>> causing the above?
> >>>
> >>> Thanks,
> >>> Jeetu
> >>>
> >>>
> >>> [3] Type 94
> >>> [3] Dispatching handler for packet type 94
> >>> [2] Channel receiving 32 bytes data in 0 (local win=72640 remote win=2095160)
> >>> [1] placing 32 bytes into channel buffer (stderr=0)
> >>> [2] Channel windows are now (local win=72608 remote win=2095160)
> >>> [3] Decrypting 16 bytes
> >>> [3] Packet size decrypted: 60 (0x3c)
> >>> [3] Read a 60 bytes packet
> >>> [3] Decrypting 48 bytes
> >>> [3] 18 bytes padding, 59 bytes left in buffer
> >>> [3] After padding, 41 bytes left in buffer
> >>> [3] Final size 41
> >>> [3] Type 94
> >>> [3] Dispatching handler for packet type 94
> >>> [2] Channel receiving 32 bytes data in 0 (local win=72608 remote win=2095160)
> >>> [1] placing 32 bytes into channel buffer (stderr=0)
> >>> [2] Channel windows are now (local win=72576 remote win=2095160)
> >>> [3] Decrypting 16 bytes
> >>> [3] Decrypting 16 bytes
> >>> [3] Packet size decrypted: 2754678753 (0xa4310fe1)
> >>> [1] Error : read_packet(): Packet len too high(2754678753 a4310fe1)
> >>> [3] Packet size decrypted: 92 (0x5c)
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 96 bytes
> >>> [1] Error : HMAC error
> >>> [3] Writing on the wire a packet having 1993 bytes before
> >>> [3] 1993 bytes after comp + 18 padding bytes = 2012 bytes packet
> >>> [3] Encrypting packet with seq num: 36518, len: 2016
> >>> [3] Enabling POLLOUT for socket
> >>> [1] channel_write wrote 1984 bytes
> >>> [3] Writing on the wire a packet having 17 bytes before
> >>> [3] 17 bytes after comp + 10 padding bytes = 28 bytes packet
> >>> [3] Encrypting packet with seq num: 36519, len: 32
> >>> [3] Enabling POLLOUT for socket
> >>> [1] channel_write wrote 8 bytes
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 176 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 256 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 336 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 416 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 496 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 576 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 656 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 736 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 816 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 896 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 976 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 1056 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 1136 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 1216 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 1296 bytes
> >>> [1] Error : HMAC error
> >>> [3] Read a 92 bytes packet
> >>> [3] Decrypting 1376 bytes
> >>> [1] Error : HMAC error
> >>> [3] Writing on the wire a packet having 8605 bytes before
> >>> [3] 8605 bytes after comp + 14 padding bytes = 8620 bytes packet
> >>> [3] Encrypting packet with seq num: 885, len: 8624
> >>> [3] Enabling POLLOUT for socket
> >>> [1] channel_write wrote 8596 bytes
> >>> [3] Writing on the wire a packet having 8605 bytes before
> >>> [3] 8605 bytes after comp + 14 padding bytes = 8620 bytes packet
> >>> [3] Encrypting packet with seq num: 886, len: 8624
> >>> [3] Enabling POLLOUT for socket
> >>> [1] channel_write wrote 8596 bytes
> >>> [3] Decrypting 16 bytes
> >>> [3] Packet size decrypted: 3661937450 (0xda44bb2a)
> >>> [1] Error : read_packet(): Packet len too high(3661937450 da44bb2a)
> >>>
> >>
> >
>