to do what they are supposed to: under some circumstances output data would
be truncated, or the buffer would not actually be flushed (possibly leading
to overflows when the caller assumes the operation succeeded). Change the
semantics so that these functions ensure they complete the operation before
returning.
Comment out diagnostic code enabled by '-D reports' which causes an
infinite recursion and an eventual crash.
Patch developed with assistance from ru and assar.
o Fixed `nfrontp' calculations in output_data(). If `remaining' is
initially zero, it was possible for `nfrontp' to be decremented.
Noticed by: dillon
o Replaced leaking writenet() with output_datalen():
: * writenet
: *
: * Just a handy little function to write a bit of raw data to the net.
: * It will force a transmit of the buffer if necessary
: *
: * arguments
: * ptr - A pointer to a character string to write
: * len - How many bytes to write
: */
: void
: writenet(ptr, len)
: register unsigned char *ptr;
: register int len;
: {
: /* flush buffer if no room for new data) */
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
: if ((&netobuf[BUFSIZ] - nfrontp) < len) {
: /* if this fails, don't worry, buffer is a little big */
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
: netflush();
: }
:
: memmove(nfrontp, ptr, len);
: nfrontp += len;
:
: } /* end of writenet */
What an irony! :-)
o Optimized output_datalen() a bit.
SRA does a Diffie-Hellmen exchange and then DES-encrypts the
authentication data. If the authentication is successful, it also
sets up a session key for DES encryption.
SRA was originally developed at Texas A&M University.
This code is probably export restricted (despite the fact that I
originally found it at a University in Germany).
SRA is not perfect. It is vulnerable to monkey-in-the-middle attacks
and does not use tremendously large DH constants (and thus an individual
exchange probably could be factored in a few days on modern CPU
horsepower). It does not, however, require any changes in user or
administrative behavior and foils session hijacking and sniffing.
The goal of this commit is that telnet and telnetd end up in the DES
distribution and that therefore an encrypted session telnet becomes
standard issue for FreeBSD.
This change changes the default handling of linemode so that older and/or
stupider telnet clients can still get wakeup characters like <ESC> and
<CTRL>D to work correctly multiple times on the same line, as in csh
"set filec" operations. It also causes CR and LF characters to be read by
apps in certain terminal modes consistently, as opposed to returning
CR sometimes and LF sometimes, which broke existing apps. The change
was shown to fix the problem demonstrated in the FreeBSD telnet client,
along with the telnet client in Solaris, SCO, Windows '95 & NT, DEC OSF,
NCSA, and others.
A similar change was incorporated in the non-crypto version of telnetd.
This resolves bin/771 and bin/1037.
