Re: libssh 0.9.7 and 0.10.5 were released

[Jakub Jelen <jjelen@xxxxxxxxxx>]

On 5/8/23 19:52, Jakub Jelen wrote:
> On 5/8/23 04:05, Orion Poplawski wrote:
> > On 5/4/23 06:23, Jakub Jelen wrote:
> > > Hello,
> > >
> > > the libssh team released libssh 0.9.7 and 0.10.5, fixing previously 
> > > announced security issues CVE-2023-1667 and CVE-2023-2283:
> > >
> > > https://www.libssh.org/2023/05/04/libssh-0-10-5-and-libssh-0-9-7-security-releases/
> >
> > We're seeing a test failure just on i686 on Fedora rawhide:
> >
> > 40/62 Test #40: torture_rekey ....................***Failed   23.34 sec
> > [==========] tests: Running 14 test(s).
> > OK: SSH-2.0-OpenSSH_9.0
> > [ RUN      ] torture_rekey_default
> > [       OK ] torture_rekey_default
> > [ RUN      ] torture_rekey_time
> > [       OK ] torture_rekey_time
> > [ RUN      ] torture_rekey_recv
> > [       OK ] torture_rekey_recv
> > [ RUN      ] torture_rekey_send
> > [       OK ] torture_rekey_send
> > [ RUN      ] torture_rekey_different_kex
> > [  ERROR   ] --- 0x20 != 0x40
> > [   LINE   ] --- 
> > /builddir/build/BUILD/libssh-0.10.5/tests/client/torture_rekey.c:522: 
> > error: Failure!
> > [  FAILED  ] torture_rekey_different_kex
> > [ RUN      ] torture_rekey_send_compression_delayed
> > [       OK ] torture_rekey_send_compression_delayed
> > [ RUN      ] torture_rekey_recv_compression_delayed
> > [       OK ] torture_rekey_recv_compression_delayed
> > [ RUN      ] torture_rekey_server_different_kex
> > OK: SSH-2.0-OpenSSH_9.0
> > [  ERROR   ] --- 0x20 != 0x40
> > [   LINE   ] --- 
> > /builddir/build/BUILD/libssh-0.10.5/tests/client/torture_rekey.c:597: 
> > error: Failure!
> > [  FAILED  ] torture_rekey_server_different_kex
> > [ RUN      ] torture_rekey_server_send
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_server_send
> > [ RUN      ] torture_rekey_guess_send
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_guess_send
> > [ RUN      ] torture_rekey_guess_wrong_send
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_guess_wrong_send
> > [ RUN      ] torture_rekey_server_recv
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_server_recv
> > [ RUN      ] torture_rekey_guess_recv
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_guess_recv
> > [ RUN      ] torture_rekey_guess_wrong_recv
> > OK: SSH-2.0-OpenSSH_9.0
> > [       OK ] torture_rekey_guess_wrong_recv
> > [==========] tests: 14 test(s) run.
> > [  PASSED  ] 12 test(s).
> > [  FAILED  ] tests: 2 test(s), listed below:
> > [  FAILED  ] torture_rekey_different_kex
> > [  FAILED  ] torture_rekey_server_different_kex
> >   2 FAILED TEST(S)
> >
> >
> > any idea what might be causing that?
>
>
> Hi,
> I was hoping I debugged all these issues while working on the release, 
> but it looks like there are still some timing/memory/architecture 
> variables.
>
> This error happens in case the rekey did not happen as expected 
> (unexpected size of digest size). I was bumping the amount of sent data 
> in [1] and [2] in both branches, which looked like solving the problem 
> in upstream tests. Other option might be adding some sleep between the 
> sending and processing the packets to make sure the server gets its 
> turn, but hard to say if this would help ... the packet processing and 
> rekey is asynchronous ... but there might better ways to do that.
>
> [1] 
> https://gitlab.com/libssh/libssh-mirror/-/commit/31a33fd2fd0fdad7c814748fdff75c7390c7f06e [0.9]
> [2] 
> https://gitlab.com/libssh/libssh-mirror/-/commit/dc1254d53e4fc6cbeb4797fc6ca1c9ed2c21f15c [0.10]
>
> Regards,

From my understanding, this is an issue of the OpenSSH in Rawhide. I 
can reliably reproduce it in mock and it goes away when I try the same 
code in Fedora 38 (regardless of architecture).

There are several patches in rawhide openssh that are missing from the 
F38 version so I will continue some investigation tomorrow.

Regards,
--
Jakub Jelen
Crypto Team, Security Engineering
Red Hat, Inc.