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.NET CLR Injection: Modify IL Code during Run-time

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7 Aug 2014LGPL310 min read 592.9K   18.4K   352  
Modify methods' IL codes on runtime even if they have been JIT-compiled, supports release mode / x64 & x86, and variants of .NET versions, from 2.0 to 4.5.
#!/usr/local/bin/perl
#***************************************************************************
#                                  _   _ ____  _
#  Project                     ___| | | |  _ \| |
#                             / __| | | | |_) | |
#                            | (__| |_| |  _ <| |___
#                             \___|\___/|_| \_\_____|
#
# Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://curl.haxx.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
###########################################################################

# Yeah, I know, probably 1000 other persons already wrote a script like
# this, but I'll tell ya:

# THEY DON'T FIT ME :-)

# Get readme file as parameter:

if($ARGV[0] eq "-c") {
    $c=1;
    shift @ARGV;
}

my $README = $ARGV[0];

if($README eq "") {
    print "usage: mkreadme.pl [-c] <README> < manpage\n";
    exit;
}


push @out, "                                  _   _ ____  _\n";
push @out, "  Project                     ___| | | |  _ \\| |\n";
push @out, "                             / __| | | | |_) | |\n";
push @out, "                            | (__| |_| |  _ <| |___\n";
push @out, "                             \\___|\\___/|_| \\_\\_____|\n";

my $olen=0;
while (<STDIN>) {
    my $line = $_;

    # this should be removed:
    $line =~ s/(.|_)//g;

    if($line =~ /^([ \t]*\n|curl)/i) {
        # cut off headers and empty lines
        $wline++; # count number of cut off lines
        next;
    }

    my $text = $line;
    $text =~ s/^\s+//g; # cut off preceding...
    $text =~ s/\s+$//g; # and trailing whitespaces

    $tlen = length($text);

    if($wline && ($olen == $tlen)) {
        # if the previous line with contents was exactly as long as
        # this line, then we ignore the newlines!

        # We do this magic because a header may abort a paragraph at
        # any line, but we don't want that to be noticed in the output
        # here
        $wline=0;
    }
    $olen = $tlen;

    if($wline) {
        # we only make one empty line max
        $wline = 0;
        push @out, "\n";
    }
    push @out, $line;
}
push @out, "\n"; # just an extra newline

open(READ, "<$README") ||
    die "couldn't read the README infile $README";

while(<READ>) {
    push @out, $_;
}
close(READ);

# if compressed
if($c) {
    my @test = `gzip --version 2>&1`;
    if($test[0] =~ /gzip/) {
        open(GZIP, ">dumpit") ||
            die "can't create the dumpit file, try without -c";
        binmode GZIP;
        for(@out) {
            print GZIP $_;
            $gzip += length($_);
        }
        close(GZIP);

        system("gzip --best --no-name dumpit");

        open(GZIP, "<dumpit.gz") ||
             die "can't read the dumpit.gz file, try without -c";
        binmode GZIP;
        while(<GZIP>) {
            push @gzip, $_;
            $gzipped += length($_);
        }
        close(GZIP);

        unlink("dumpit.gz");
    }
    else {
        # no gzip, no compression!
        undef $c;
        print STDERR "MEEEP: Couldn't find gzip, disable compression\n";
    }
}

$now = localtime;
print <<HEAD
/*
 * NEVER EVER edit this manually, fix the mkhelp.pl script instead!
 * Generation time: $now
 */
#ifdef USE_MANUAL
#include "tool_hugehelp.h"
HEAD
    ;
if($c) {
    print <<HEAD
#include <zlib.h>
#include "memdebug.h" /* keep this as LAST include */
static const unsigned char hugehelpgz[] = {
  /* This mumbo-jumbo is the huge help text compressed with gzip.
     Thanks to this operation, the size of this data shrunk from $gzip
     to $gzipped bytes. You can disable the use of compressed help
     texts by NOT passing -c to the mkhelp.pl tool. */
HEAD
;
    my $c=0;
    print " ";
    for(@gzip) {
        my @all=split(//, $_);
        for(@all) {
            my $num=ord($_);
            printf(" 0x%02x,", 0+$num);
            if(++$c>11) {
                print "\n ";
                $c=0;
            }
        }
    }
    print "\n};\n";

    print <<EOF
#define BUF_SIZE 0x10000
static voidpf zalloc_func(voidpf opaque, unsigned int items, unsigned int size)
{
  (void) opaque;
  /* not a typo, keep it calloc() */
  return (voidpf) calloc(items, size);
}
static void zfree_func(voidpf opaque, voidpf ptr)
{
  (void) opaque;
  free(ptr);
}
/* Decompress and send to stdout a gzip-compressed buffer */
void hugehelp(void)
{
  unsigned char* buf;
  int status,headerlen;
  z_stream z;

  /* Make sure no gzip options are set */
  if (hugehelpgz[3] & 0xfe)
    return;

  headerlen = 10;
  memset(&z, 0, sizeof(z_stream));
  z.zalloc = (alloc_func)zalloc_func;
  z.zfree = (free_func)zfree_func;
  z.avail_in = (unsigned int)(sizeof(hugehelpgz) - headerlen);
  z.next_in = (unsigned char *)hugehelpgz + headerlen;

  if (inflateInit2(&z, -MAX_WBITS) != Z_OK)
    return;

  buf = malloc(BUF_SIZE);
  if (buf) {
    while(1) {
      z.avail_out = BUF_SIZE;
      z.next_out = buf;
      status = inflate(&z, Z_SYNC_FLUSH);
      if (status == Z_OK || status == Z_STREAM_END) {
        fwrite(buf, BUF_SIZE - z.avail_out, 1, stdout);
        if (status == Z_STREAM_END)
          break;
      }
      else
        break;    /* Error */
    }
    free(buf);
  }
  inflateEnd(&z);
}
EOF
    ;
foot();
exit;
}
else {
    print <<HEAD
void hugehelp(void)
{
   fputs(
HEAD
         ;
}

$outsize=0;
for(@out) {
    chop;

    $new = $_;

    $outsize += length($new)+1; # one for the newline

    $new =~ s/\\/\\\\/g;
    $new =~ s/\"/\\\"/g;

    # gcc 2.96 claims ISO C89 only is required to support 509 letter strings
    if($outsize > 500) {
        # terminate and make another fputs() call here
        print ", stdout);\n fputs(\n";
        $outsize=length($new)+1;
    }
    printf("\"%s\\n\"\n", $new);

}

print ", stdout) ;\n}\n";

foot();

sub foot {
  print <<FOOT
#endif /* USE_MANUAL */
FOOT
  ;
}

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License

This article, along with any associated source code and files, is licensed under The GNU Lesser General Public License (LGPLv3)


Written By
Team Leader
China China
Jerry is from China. He was captivated by computer programming since 13 years old when first time played with Q-Basic.



  • Windows / Linux & C++
  • iOS & Obj-C
  • .Net & C#
  • Flex/Flash & ActionScript
  • HTML / CSS / Javascript
  • Gaming Server programming / video, audio processing / image & graphics


Contact: vcer(at)qq.com
Chinese Blog: http://blog.csdn.net/wangjia184

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