openssh bugs - Jul 2008 - [Bug 1486] New: Improperly used buffer during KEX

https://bugzilla.mindrot.org/show_bug.cgi?id=1486

           Summary: Improperly used buffer during KEX
    Classification: Unclassified
           Product: Portable OpenSSH
           Version: 5.0p1
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Miscellaneous
        AssignedTo: unassigned-bugs at mindrot.org
        ReportedBy: godji at 300penguins.org


In kex.c:kex_input_kexinit, when a packet with the other side's KEX
proposal is received, it is appended into a buffer that has not been
cleared first. This could lead to problems - in particular, if that
buffer already contains an old peer proposal, the new one will be
appended but the old one will be silently used instead.

The code is currently:

    ptr = packet_get_raw(&dlen);
    buffer_append(&kex->peer, ptr, dlen);

but should be:

    ptr = packet_get_raw(&dlen);
    buffer_clear(&kex->peer);
    buffer_append(&kex->peer, ptr, dlen);

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https://bugzilla.mindrot.org/show_bug.cgi?id=1486

Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |djm at mindrot.org
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID

--- Comment #1 from Damien Miller <djm at mindrot.org>  ---
input_kexinit calls the kex method on completion, which clears
kex->peer so your case cannot happen.

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https://bugzilla.mindrot.org/show_bug.cgi?id=1486

Damien Miller <djm at mindrot.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #2 from Damien Miller <djm at mindrot.org> 2011-01-24 12:33:33
EST ---
Move resolved bugs to CLOSED after 5.7 release

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