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Folks-
Not only is this bug appearing on many different
platforms, but the fix I proposed earlier (and the
subsequent jgilbert fix) doesn't work on some of
them with v1.30 (ppc-linux in particular).
I've written a perl script to cause the bug to occur,
and identify just how many characters your system needs
to trigger it. Can you try running it and see if you
have the bug and post your results here? I've also
sent this to Dave Robins to see if he can figure this
but out once and for all.
Attached is my output.
Thanks
-Craig
#!/usr/bin/perl
use strict;
use warnings;
use English;
use Data::Dumper;
# Set these for your remote host...
my $user = "user";
my $password = "password";
my $host = "machine";
# Time to wait for remote command to finish...
my $timeout=10; # Consider upping this if you change $high
# Remote command...
my $cmd = "cat";
# Print heading...
print "Net::SSH::Perl bug test...\n";
print "host=$host user=$user remoteCmd=$cmd\n";
# Set variables...
my $high=932779; # Maximum number of starting xmitChars
my $low=0;
my $i=$high;
my $delta=$high-$low;;
my $ssh;
# Main loop...
while($delta>1) {
undef($ssh);
print "xferChars=$i";
# setup SSH...
$ssh = newssh() ||
die "Can't create a new ssh, exiting...";
print '|'; # Indicates newssh worked...
$ssh->login($user,$password) ||
die "Can't login, exiting...";
print '-'; # Indicates successful login...
# Proper values of $i will trigger the bug...
my $stdin = '=' x $i;
# Run remote command...
my ($stdout, $stderr, $exit) = runcmd($ssh, $cmd, $stdin, $timeout);
# Check output...
if(defined($stdout)) {
if(length($stdout) != $i) {
die "Data mismatch, expected: $i chars, got: ",
length($stdout), "chars\n";
}
# Go back up...
$delta = $high-$i;
$low = $i;
$i += int($delta/2);
print "OK, back up to $i chars\n"
}else{
# Go down...
$delta = $i-$low;
$high = $i;
$i -= int($delta/2);
print "Error, down to $i chars\n\t$stderr\n";
next;
}
}
if ($i == $high) {
print "\nBug did not trigger with $high chars on this system.\n";
}else{
print "\nReport for remote host: $host...\n";
print "xferChars=$low works, xferChars=$high hangs on timeout=$timeout.\n";
}
print "exiting...\n";
sub newssh
{
my $ssh;
# Require the correct SSH package, based on OS...
if($OSNAME=~/^(MSWin32)/) {
require Net::SSH::W32Perl;
$ssh = Net::SSH::W32Perl->new( $host,
port => 22 ,
protocol => 2,
#debug => 999,
);
}else{
require Net::SSH::Perl;
$ssh = Net::SSH::Perl->new( $host,
port => 22 ,
protocol => 2,
#debug => 999,
);
}
return($ssh);
}
sub runcmd
{
my $ssh = shift || die "Missing ssh object";
my $cmd = shift || die "Missing cmd";
my $stdin = shift || die "Missing stdin";
my $timeout = shift || die "Missing timeout";
my ($stdout, $stderr, $exit);
eval {
local $SIG{'ALRM'} = sub {
die "alarm handler $timeout second timeout";
};
alarm($timeout);
($stdout, $stderr, $exit) = $ssh->cmd($cmd, $stdin);
alarm(0);
};
if($@) {
$stderr=$@;
$stderr=~s/( at |\n).*$/ /s;
}
return ($stdout, $stderr, $exit);
}
Here is my output:
Net::SSH::Perl bug test...
host=nwsgpb user=watchmrk remoteCmd=cat
xferChars=932779|-Error, down to 466390 chars
Received disconnect message: Corrupted MAC on input.
xferChars=466390|-Error, down to 233195 chars
Received disconnect message: Corrupted MAC on input.
xferChars=233195|-Error, down to 116598 chars
Received disconnect message: Corrupted MAC on input.
xferChars=116598|-Error, down to 58299 chars
Received disconnect message: Corrupted MAC on input.
xferChars=58299|-Error, down to 29150 chars
alarm handler 10 second timeout
xferChars=29150|-Error, down to 14575 chars
alarm handler 10 second timeout
xferChars=14575|-Error, down to 7288 chars
alarm handler 10 second timeout
xferChars=7288|-OK, back up to 10931 chars
xferChars=10931|-OK, back up to 12753 chars
xferChars=12753|-Error, down to 11842 chars
alarm handler 10 second timeout
xferChars=11842|-Error, down to 11387 chars
alarm handler 10 second timeout
xferChars=11387|-OK, back up to 11614 chars
xferChars=11614|-Error, down to 11501 chars
alarm handler 10 second timeout
xferChars=11501|-OK, back up to 11557 chars
xferChars=11557|-Error, down to 11529 chars
Received disconnect message: Corrupted MAC on input.
xferChars=11529|-OK, back up to 11543 chars
xferChars=11543|-Error, down to 11536 chars
Received disconnect message: Corrupted MAC on input.
xferChars=11536|-Error, down to 11533 chars
alarm handler 10 second timeout
xferChars=11533|-OK, back up to 11534 chars
xferChars=11534|-OK, back up to 11535 chars
xferChars=11535|-OK, back up to 11535 chars
Report for remote host: nwsgpb...
xferChars=11535 works, xferChars=11536 hangs on timeout=10.
exiting...
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