#!/usr/bin/env perl
#
# Copyright (c) 2011 The OpenSSL Project.
#
# The script embeds fingerprint into ELF executable object, either
# application binary or shared library.

######################################################################
#
# ELF symbol table parser by <appro@openssl.org>. The table entries
# are extended with offset within executable file...
#
{ package ELF;
  use FileHandle;

    sub dup  { my %copy=map {$_} @_; return \%copy; }

    sub Load {
	my $class = shift;
	my $self  = {};
	my $FD    = FileHandle->new();	# autoclose

	bless $self,$class;

	sysopen($FD,shift,0) or die "$!";
	binmode($FD);

	#################################################
	# read and parse elf_ehdr.e_ident...
	#
	read($FD,my $elf,16) or die "$!";

	my %e_ident;
	@e_ident{magic,class,data,version,osabi,abiver,pad}=
		unpack("a4C*",$elf);

	$!=42;		# signal fipsld to revert to two-step link
	die "not ELF file" if ($e_ident{magic} ne chr(0177)."ELF");

	my $elf_bits   = $e_ident{class}*32;	# 32 or 64
	my $big_endian = $e_ident{data}-1;	# 0 or 1

	if ($elf_bits==64) {
	    if (!(((1<<31)<<1) && $big_endian==(unpack("L",pack("N",1))==1))) {
		die "ELF64 is supported only natively";
	    }
	}

	#################################################
	# read and parse remainder of elf_ehdr...
	#
	read($FD,my $elfhdr,64) or die "$!";

	my %elf_ehdr;
	@elf_ehdr{e_type,e_machine,e_version,
		e_entry,e_phoff,e_shoff,e_flags,e_ehsize,
		e_phentsize,e_phnum,e_shentsize,e_shnum,e_shstrndx} =
	$elf_bits==32 ?
		unpack($big_endian?"nnN5n6":"vvV5v6",$elfhdr)
	:	unpack("SSLQ3LS6",$elfhdr);

	# put aside e_machine in case one has to treat specific
	# platforms differently, see EM_ constants in elf.h for
	# assortment... 
	$self->{e_machine} = $elf_ehdr{e_machine};

	#################################################
	# read and parse elf_shdr table...
	#
	my ($i,$sz,$symtab_idx,$blob,$strings);

	seek($FD,$elf_ehdr{e_shoff},0) or die "$!";
	read($FD,$blob,$elf_ehdr{e_shentsize}*$elf_ehdr{e_shnum}) or die "$!";

	my @sections;
	my $elf_shdr_struct=($elf_bits==32?($big_endian?"N10":"V10"):"L2Q4L2Q2");
	for ($sz=$elf_ehdr{e_shentsize},$i=0;$i<length($blob);$i+=$sz) {
	    my %elf_shdr;

	    @elf_shdr{sh_name,sh_type,sh_flags,
			sh_addr,sh_offset,sh_size,
			sh_link,sh_info,sh_addalign,sh_entsize} =
		unpack($elf_shdr_struct,substr($blob,$i,$sz));

	    push(@sections,dup(%elf_shdr));

	    # note SHT_SYMTAB or SHT_DYNSYM for future reference
	    if ($elf_shdr{sh_type}==2 || $elf_shdr{sh_type}==11) {
		$symtab_idx = $#sections;
	    }
	}

	# read strings table and map section names...
	seek($FD,@sections[$elf_ehdr{e_shstrndx}]->{sh_offset},0)	or die "$!";
	read($FD,$strings,@sections[$elf_ehdr{e_shstrndx}]->{sh_size})	or die "$!";
	for (@sections) {
	    $_->{sh_name}=(split(chr(0),substr($strings,$_->{sh_name},64)))[0];
	}

	#################################################
	# read symbol strings table...
	#
	$i=@sections[$symtab_idx]->{sh_link};
	seek($FD,@sections[$i]->{sh_offset},0)		or die "$!";
	read($FD,$strings,@sections[$i]->{sh_size})	or die "$!";

	#################################################
	# read and parse elf_sym table...
	#
	seek($FD,@sections[$symtab_idx]->{sh_offset},0)		or die "$!";
	read($FD,my $blob,@sections[$symtab_idx]->{sh_size})	or die "$!";

	for ($sz=@sections[$symtab_idx]->{sh_entsize},$i=0;$i<length($blob);$i+=$sz) {
	    my %elf_sym;

	    if ($elf_bits==32) {
		@elf_sym{st_name,st_value,st_size,st_info,st_other,st_shndx} =
			unpack($big_endian?"N3CCn":"V3CCv",substr($blob,$i,$sz));
	    } else {
		@elf_sym{st_name,st_info,st_other,st_shndx,st_value,st_size} =
			unpack("LCCSQQ",substr($blob,$i,$sz));
	    }

	    my $st_type = $elf_sym{st_info}&0xf;
	    my $st_bind = $elf_sym{st_info}>>4;
	    my $st_secn = $elf_sym{st_shndx};
	    my $name;
	    #                 (STT_OBJECT  || STT_FUNC)
	    if ($st_bind<3 && ($st_type==1 || $st_type==2)
	    	&& $st_secn <= $#sections 		# sane st_shndx
		&& @sections[$st_secn]->{sh_type}	# not SHN_UNDEF
		&& ($name=(split(chr(0),substr($strings,$elf_sym{st_name},128)))[0])
		) {
		# synthesize st_offset, ...
	    	$elf_sym{st_offset}  = $elf_sym{st_value}
				- @sections[$st_secn]->{sh_addr}
				+ @sections[$st_secn]->{sh_offset};
		$elf_sym{st_name}    = $name;
		$elf_sym{st_section} = @sections[$st_secn]->{sh_name};
		# ... and add to lookup table
		$self->{symbols}{$name} = dup(%elf_sym);
	    }
	}

	return $self;
    }

    sub Lookup {
	my $self = shift;
	my $name = shift;
	return $self->{symbols}{$name};
    }

    sub Traverse {
	my $self = shift;
	my $code = shift;

	if (ref($code) eq 'CODE') {
	    for (keys(%{$self->{symbols}})) { &$code($self->{symbols}{$_}); }
	}
    }
}

######################################################################
#
# SHA1 and HMAC in Perl by <appro@openssl.org>.
#
{ package SHA1;
  use integer;

    {
    ################################### SHA1 block code generator
    my @V = ('$A','$B','$C','$D','$E');
    my $i;

    sub XUpdate {
      my $ret;
	$ret="(\$T=\$W[($i-16)%16]^\$W[($i-14)%16]^\$W[($i-8)%16]^\$W[($i-3)%16],\n\t";
	if ((1<<31)<<1) {
	    $ret.="    \$W[$i%16]=((\$T<<1)|(\$T>>31))&0xffffffff)\n\t  ";
	} else {
	    $ret.="    \$W[$i%16]=(\$T<<1)|((\$T>>31)&1))\n\t  ";
	}
    }
    sub tail {
      my ($a,$b,$c,$d,$e)=@V;
      my $ret;
	if ((1<<31)<<1) {
	    $ret.="(($a<<5)|($a>>27));\n\t";
	    $ret.="$b=($b<<30)|($b>>2);	$e&=0xffffffff;	#$b&=0xffffffff;\n\t";
	} else {
	    $ret.="(($a<<5)|($a>>27)&0x1f);\n\t";
	    $ret.="$b=($b<<30)|($b>>2)&0x3fffffff;\n\t";
	}
      $ret;
    }
    sub BODY_00_15 {
	my ($a,$b,$c,$d,$e)=@V;
	"$e+=\$W[$i]+0x5a827999+((($c^$d)&$b)^$d)+".tail();
    }
    sub BODY_16_19 {
	my ($a,$b,$c,$d,$e)=@V;
	"$e+=".XUpdate()."+0x5a827999+((($c^$d)&$b)^$d)+".tail();
    }
    sub BODY_20_39 {
	my ($a,$b,$c,$d,$e)=@V;
	"$e+=".XUpdate()."+0x6ed9eba1+($b^$c^$d)+".tail();
    }
    sub BODY_40_59 {
	my ($a,$b,$c,$d,$e)=@V;
	"$e+=".XUpdate()."+0x8f1bbcdc+(($b&$c)|(($b|$c)&$d))+".tail();
    }
    sub BODY_60_79 {
	my ($a,$b,$c,$d,$e)=@V;
	"$e+=".XUpdate()."+0xca62c1d6+($b^$c^$d)+".tail();
    }

    my $sha1_impl =
    'sub block {
	my $self = @_[0];
	my @W    = unpack("N16",@_[1]);
	my ($A,$B,$C,$D,$E,$T) = @{$self->{H}};
	';

	$sha1_impl.='
	$A &= 0xffffffff;
	$B &= 0xffffffff;
	' if ((1<<31)<<1);

	for($i=0;$i<16;$i++){ $sha1_impl.=BODY_00_15(); unshift(@V,pop(@V)); }
	for(;$i<20;$i++)    { $sha1_impl.=BODY_16_19(); unshift(@V,pop(@V)); }
	for(;$i<40;$i++)    { $sha1_impl.=BODY_20_39(); unshift(@V,pop(@V)); }
	for(;$i<60;$i++)    { $sha1_impl.=BODY_40_59(); unshift(@V,pop(@V)); }
	for(;$i<80;$i++)    { $sha1_impl.=BODY_60_79(); unshift(@V,pop(@V)); }

	$sha1_impl.='
	$self->{H}[0]+=$A;	$self->{H}[1]+=$B;	$self->{H}[2]+=$C;
	$self->{H}[3]+=$D;	$self->{H}[4]+=$E;	}';

    #print $sha1_impl,"\n";
    eval($sha1_impl);		# generate code
    }

    sub Init {
	my $class = shift;	# multiple instances...
	my $self  = {};

	bless $self,$class;
	$self->{H} = [0x67452301,0xefcdab89,0x98badcfe,0x10325476,0xc3d2e1f0];
	$self->{N} = 0;
	return $self;
    }

    sub Update {
	my $self = shift;
	my $msg;

	foreach $msg (@_) {
	    my $len  = length($msg);
	    my $num  = length($self->{buf});
	    my $off  = 0;

	    $self->{N} += $len;

	    if (($num+$len)<64)
	    {	$self->{buf} .= $msg; next;	}
	    elsif ($num)
	    {	$self->{buf} .= substr($msg,0,($off=64-$num));
		$self->block($self->{buf});
	    }

	    while(($off+64) <= $len)
	    {	$self->block(substr($msg,$off,64));
		$off += 64;
	    }

	    $self->{buf} = substr($msg,$off);
	}
	return $self;
    }

    sub Final {
	my $self = shift;
	my $num  = length($self->{buf});

	$self->{buf} .= chr(0x80); $num++;
	if ($num>56)
	{   $self->{buf} .= chr(0)x(64-$num);
	    $self->block($self->{buf});
	    $self->{buf}=undef;
	    $num=0;
	}
	$self->{buf} .= chr(0)x(56-$num);
	$self->{buf} .= pack("N2",($self->{N}>>29)&0x7,$self->{N}<<3);
	$self->block($self->{buf});

	return pack("N*",@{$self->{H}});
    }

    sub Selftest {
	my $hash;

	$hash=SHA1->Init()->Update('abc')->Final();
	die "SHA1 test#1" if (unpack("H*",$hash) ne 'a9993e364706816aba3e25717850c26c9cd0d89d');

	$hash=SHA1->Init()->Update('abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq')->Final();
	die "SHA1 test#2" if (unpack("H*",$hash) ne '84983e441c3bd26ebaae4aa1f95129e5e54670f1');

	#$hash=SHA1->Init()->Update('a'x1000000)->Final();
	#die "SHA1 test#3" if (unpack("H*",$hash) ne '34aa973cd4c4daa4f61eeb2bdbad27316534016f');
    }
}

{ package HMAC;

    sub Init {
	my $class = shift;
	my $key   = shift;
	my $self  = {};

	bless $self,$class;

	if (length($key)>64) {
	    $key = SHA1->Init()->Update($key)->Final();
	}
	$key .= chr(0x00)x(64-length($key));

	my @ikey = map($_^=0x36,unpack("C*",$key));
	($self->{hash} = SHA1->Init())->Update(pack("C*",@ikey));
	 $self->{okey} = pack("C*",map($_^=0x36^0x5c,@ikey));

	return $self;
    }

    sub Update {
	my $self = shift;
	$self->{hash}->Update(@_);
	return $self;
    }

    sub Final {
	my $self  = shift;
	my $ihash = $self->{hash}->Final();
	return SHA1->Init()->Update($self->{okey},$ihash)->Final();
    }

    sub Selftest {
	my $hmac;

	$hmac = HMAC->Init('0123456789:;<=>?@ABC')->Update('Sample #2')->Final();
	die "HMAC test" if (unpack("H*",$hmac) ne '0922d3405faa3d194f82a45830737d5cc6c75d24');
    }
}

######################################################################
#
# main()
#
my $legacy_mode;

if ($ARGV<0 || ($#ARGV>0 && !($legacy_mode=(@ARGV[0] =~ /^\-(dso|exe)$/)))) {
	print STDERR "usage: $0 [-dso|-exe] elfbinary\n";
	exit(1);
}

$exe = ELF->Load(@ARGV[$#ARGV]);

$FIPS_text_start	= $exe->Lookup("FIPS_text_start")		or die;
$FIPS_text_end		= $exe->Lookup("FIPS_text_end")			or die;
$FIPS_rodata_start	= $exe->Lookup("FIPS_rodata_start")		or die;
$FIPS_rodata_end	= $exe->Lookup("FIPS_rodata_end")		or die;
$FIPS_signature		= $exe->Lookup("FIPS_signature")		or die;

# new cross-compile support
$FIPS_text_startX	= $exe->Lookup("FIPS_text_startX");
$FIPS_text_endX		= $exe->Lookup("FIPS_text_endX");

if (!$legacy_mode) {
    if (!$FIPS_text_startX || !$FIPS_text_endX) {
	print STDERR "@ARGV[$#ARGV] is not cross-compiler aware.\n";
	exit(42);	# signal fipsld to revert to two-step link
    }

    $FINGERPRINT_ascii_value
			= $exe->Lookup("FINGERPRINT_ascii_value")	or die;

}
if ($FIPS_text_startX && $FIPS_text_endX) {
    $FIPS_text_start = $FIPS_text_startX;
    $FIPS_text_end   = $FIPS_text_endX;
}

sysopen(FD,@ARGV[$#ARGV],$legacy_mode?0:2) or die "$!";	# 2 is read/write
binmode(FD);

sub HMAC_Update {
  my ($hmac,$off,$len) = @_;
  my $blob;

    seek(FD,$off,0)	or die "$!";
    read(FD,$blob,$len)	or die "$!";
    $$hmac->Update($blob);
}

# fips/fips.c:FIPS_incore_fingerprint's Perl twin
#
sub FIPS_incore_fingerprint {
  my $p1  = $FIPS_text_start->{st_offset};
  my $p2  = $FIPS_text_end->{st_offset};
  my $p3  = $FIPS_rodata_start->{st_offset};
  my $p4  = $FIPS_rodata_end->{st_offset};
  my $sig = $FIPS_signature->{st_offset};
  my $ctx = HMAC->Init("etaonrishdlcupfm");

    # detect overlapping regions
    if ($p1<=$p3 && $p2>=$p3) {
	$p3 = $p1; $p4 = $p2>$p4?$p2:$p4; $p1 = 0; $p2 = 0;
    } elsif ($p3<=$p1 && $p4>=$p1) {
	$p3 = $p3; $p4 = $p2>$p4?$p2:$p4; $p1 = 0; $p2 = 0;
    }

    if ($p1) {
	HMAC_Update (\$ctx,$p1,$p2-$p1);
    }

    if ($sig>=$p3 && $sig<$p4) {
	# "punch" hole
	HMAC_Update(\$ctx,$p3,$sig-$p3);
	$p3 = $sig+20;
	HMAC_Update(\$ctx,$p3,$p4-$p3);
    } else {
	HMAC_Update(\$ctx,$p3,$p4-$p3);
    }

    return $ctx->Final();
}

$fingerprint = FIPS_incore_fingerprint();

if ($legacy_mode) {
    print unpack("H*",$fingerprint);
} else {
    seek(FD,$FINGERPRINT_ascii_value->{st_offset},0)	or die "$!";
    print FD unpack("H*",$fingerprint)			or die "$!";
}

close (FD);
