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Padiofire
IMP
existierende Implementationen
Beispiel: FlipImg
package Net::IMP::HTTP::Example::FlipImg;
use base 'Net::IMP::HTTP::Request';
use fields (
'ignore', # irrelevant content
'image', # collected octets for image
);
use Net::IMP; # import IMP_ constants
use Net::IMP::Debug;
use Image::Magick;
use constant MAX_SIZE => 2**16;
sub RTYPES { (IMP_PASS,IMP_REPLACE) }
sub new_analyzer {
my ($factory,%args) = @_;
my $self = $factory->SUPER::new_analyzer(%args);
# request data do not matter
$self->run_callback([ IMP_PASS,0,IMP_MAXOFFSET ]);
return $self;
}
sub request_hdr {}
sub request_body {}
sub any_data {}
sub response_hdr {
my ($self,$hdr) = @_;
my $ignore;
# we only want selected image/ content types and not too big
my ($ct) = $hdr =~m{\nContent-type:[ \t]*([^\s;]+)}i;
my ($clen) = $hdr =~m{\nContent-length:[ \t]*(\d+)}i;
my ($code) = $hdr =~m{\AHTTP/1\.[01][ \t]+(\d+)};
...
...
if ( $code != 200 ) {
debug("will not rotate code=$code");
$ignore++;
} elsif ( ! $ct or $ct !~m{^image/(png|gif|jpeg)$} ) {
debug("will not rotate content type $ct");
$ignore++;
} elsif ( $clen and $clen > 2**16 ) {
debug("image is too big: $clen" );
$ignore++;
}
...
...
if ( $ignore ) {
$self->run_callback([ IMP_PASS,1,IMP_MAXOFFSET ]);
$self->{ignore} = 1;
return;
}
# pass header
$self->run_callback([ IMP_PASS,1,$self->offset(1) ]);
}
sub response_body {
my ($self,$data) = @_;
$self->{ignore} and return;
my $off = $self->offset(1);
if ( $data ne '' ) {
....
...
$self->{image} .= $data; # append to image
# replace with '' in caller to save memory there
# at the end we will replace eof with the flipped image
$self->run_callback([ IMP_REPLACE,1,$off,'' ]);
# with chunked encoding we don't get a length up front, so check now
if ( length($self->{image}) > MAX_SIZE ) {
debug("image too big");
$self->run_callback(
[ IMP_REPLACE,1,$off,$self->{image} ], # unchanged image
[ IMP_PASS,1,IMP_MAXOFFSET ]
);
$self->{ignore} = 1;
}
return;
...
...
}
# end of image reached, flip with Image::Magick
debug("flip image size=%d",length($self->{image}));
my $img = Image::Magick->new;
debug("failed to flip img: $@") if ! eval {
$img->BlobToImage($self->{image});
$img->Flip;
($self->{image}) = $img->ImageToBlob;
debug("replace with ".length($self->{image})." bytes");
1;
};
$self->run_callback(
[ IMP_REPLACE,1,$self->offset(1),$self->{image} ],
[ IMP_PASS,1,IMP_MAXOFFSET ],
);
}
http_proxy_imp --filter Example::FlipImg 127.0.0.1:8888
Beispiel: Deny per Content-Type
package Net::IMP::HTTP::Example::BlockContentType; use base 'Net::IMP::HTTP::Request'; use Net::IMP; # import IMP_ constants use Net::IMP::Debug;
sub validate_cfg {
my ($class,%cfg) = @_;
my @err;
for my $k (qw(whiterx blackrx)) {
my $rx = delete $cfg{$k} or next;
ref($rx) and next;
push @err,"$k is no valid regexp: $@" if ! eval { qr/$rx/ };
}
return (@err,$class->SUPER::validate_cfg(%cfg));
}
sub str2cfg {
my ($class,$str) = @_;
my %cfg = $class->SUPER::str2cfg($str);
for my $k (qw(whiterx blackrx)) {
next if ! $cfg{$k} or ref $cfg{$k};
$cfg{$k} = eval { qr/$cfg{$k}/ }
or die "invalid rx in $k: $@";
}
return %cfg;
}
http_proxy_imp \ --filter 'Example::BlockContentType=whiterx=^text/&blackrx=...' \ 127.0.0.1:1235
sub RTYPES { ( IMP_PASS, IMP_DENY ) }
sub new_analyzer {
my ($factory,%args) = @_;
my $self = $factory->SUPER::new_analyzer(%args);
# request data do not matter
$self->run_callback([ IMP_PASS,0,IMP_MAXOFFSET ]);
if ( ! $self->{factory_args}{whiterx}
&& ! $self->{factory_args}{blackrx} ) {
# nothing to analyze
$self->run_callback([ IMP_PASS,1,IMP_MAXOFFSET ]);
}
return $self;
}
sub request_hdr {}
sub request_body {}
sub response_body {}
sub any_data {}
sub response_hdr {
my ($self,$hdr) = @_;
# we only want selected image/ content types and not too big
my $ct = $hdr =~m{\nContent-type:[ \t]*([^\s;]+)}i && lc($1)
|| 'unknown/unknown';
my $reason;
...
...
if ( my $white = $self->{factory_args}{whiterx} ) {
if ( $ct =~ $white ) {
debug("allowed $ct because of white list");
goto pass;
} else {
debug("denied $ct because not in white list");
$reason = "denied $ct because not in white list";
goto deny;
}
}
...
...
if ( my $black = $self->{factory_args}{blackrx} ) {
if ( $ct =~ $black ) {
debug("denied $ct because in black list");
$reason = "denied $ct because in black list";
goto deny;
} else {
debug("allow $ct because not in black list");
goto pass;
}
}
...
...
pass:
$self->run_callback([ IMP_PASS,1,IMP_MAXOFFSET ]);
return;
deny:
$self->run_callback([ IMP_DENY,1,$reason ]);
return;
}
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