The "automatic" login feature is described as follows:
The USER environment variable holds the name of the person telnetting in.
This is the username of the person on the client machine. The traditional
behaviour is to execute login(1) with this username first, meaning that
login(1) will prompt for the password only. If login fails, login(1) will
retry, but now prompt for the username before prompting for the password.
This feature got broken by how the environment got scrubbed. Before the
change in r69825 we removed variables that we deemed dangerous. Starting
with r69825 we only keep those variable we know to be safe.
The USER environment variable fell through the cracks. It suddenly got
scrubbed (i.e. removed from the environment) while still being checked
for. It also got explicitly removed from the environment to handle the
failed login case.
The fix is to obtain the value of the USER environment variable before
we scrub the environment and used the "cached" in subsequent checks.
This guarantees that the environment does not contain the USER variable
in the end, while still being able to implement "automatic" login.
Obtained from: Juniper Networks, Inc.
Just like rlogind, there is no need to change the ownership of the
terminal during shutdown anymore. Also don't call logwtmp, because the
login(1)/PAM is responsible for doing this. Also use SHUT_RDWR instead
of 2.
Some time ago I got some reports MPSAFE TTY broke telnetd(8). Even
though it turned out to be a different problem within the TTY code, I
spotted a small issue with telnetd(8). Instead of allocating PTY's using
openpty(3) or posix_openpt(2), it used its own PTY allocation routine.
This means that telnetd(8) still uses /dev/ptyXX-style devices.
I've also increased the size of line[]. Even though 16 should be enough,
we already use 13 bytes ("/dev/pts/999", including '\0'). 32 bytes gives
us a little more freedom.
Also enable -DSTREAMSPTY. Otherwise telnetd(8) strips the PTY's pathname
to the latest slash instead of just removing "/dev/" (e.g. /dev/pts/0 ->
0, instead of pts/0).
Reviewed by: rink
can then end up not properly clearing wtmp/utmp entries.
PR: bin/37934
Submitted by: Sandeep Kumar <skumar@juniper.net>
Reviewed by: markm
MFC after: 2 weeks
signal handlers. In this case, use _exit(2) instead, following
the call to shutdown(2).
This fixes rare telnetd hangs.
PR: misc/33672
Submitted by: Umesh Krishnaswamy <umesh@juniper.net>
MFC after: 1 month
1) ANSIfy.
2) Clean up ifdefs so that
a) ones that never/always apply are appropriately either
fully removed, or just the #if junk is removed.
b) change #if defined(FOO) for appropiate values of FOO.
(currently AUTHENTICATION and ENCRYPTION)
3) WARNS=2 fixing
4) GC other unused stuff
This code can now be unifdef(1)ed to make non-crypto telnet.
