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Detect terminating chains

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- no RETURN Rules
- last rule is terminating

Signed-off-by: Tom Eastep <teastep@shorewall.net>
This commit is contained in:
Tom Eastep 2013-01-08 16:32:24 -08:00
parent 011dd2c901
commit 1fd3a6a522
1 changed files with 98 additions and 87 deletions
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185
Shorewall/Perl/Shorewall/Chains.pm
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@ -667,9 +667,7 @@ sub initialize( $$$ ) {
%isocodes = ();
%nfobjects = ();
%switches = ();
#
# Initialize this here so we can make it dynamic without moving the initialization
#
%terminating = ( ACCEPT => 1,
DROP => 1,
RETURN => 1,
@ -2854,6 +2852,7 @@ sub optimize_level4( $$ ) {
# The search continues until no short chains remain
# Chains with 'DONT_OPTIMIZE' are exempted from optimization
#
while ( $progress ) {
$progress = 0;
$passes++;
@ -2892,100 +2891,112 @@ sub optimize_level4( $$ ) {
delete_references $chainref;
$progress = 1;
}
} elsif ( $numrules == 1) {
my $firstrule = $chainref->{rules}[0];
#
# Chain has a single rule
#
if ( $firstrule ->{simple} ) {
#
# Easy case -- the rule is a simple jump
#
if ( $chainref->{builtin} ) {
#
# A built-in chain. If the target is a user chain without 'dont_move',
# we can copy its rules to the built-in
#
if ( conditionally_copy_rules $chainref, $firstrule->{target} ) {
#
# Target was a user chain -- rules moved
#
$progress = 1;
} else {
#
# Target was a built-in. Ignore this chain in follow-on passes
#
$chainref->{optflags} |= DONT_OPTIMIZE;
}
} elsif ( ( $firstrule->{target} || '' ) eq 'RETURN' ) {
#
# A chain with a single 'RETURN' rule -- get rid of it
#
delete_chain_and_references( $chainref );
} else {
#
# Replace all references to this chain with references to the target
#
replace_references $chainref, $firstrule->{target}, $firstrule->{targetopts};
$progress = 1;
}
} elsif ( $firstrule->{target} ) {
#
# Not so easy -- the rule contains matches
#
if ( $chainref->{builtin} || ! $globals{KLUDGEFREE} || $firstrule->{policy} ) {
#
# This case requires a new rule merging algorithm. Ignore this chain for
# now on.
#
$chainref->{optflags} |= DONT_OPTIMIZE;
} else {
#
# Replace references to this chain with the target and add the matches
#
$progress = 1 if replace_references1 $chainref, $firstrule;
}
}
} else {
#
# Chain has more than one rule. If the last rule is a simple jump, then delete
# all immediately preceding rules that have the same target
# The chain has rules -- determine if it is terminating
#
my $rulesref = $chainref->{rules};
my $lastref = $rulesref->[-1];
my $name = $chainref->{name};
my $lastref = $chainref->{rules}[-1];
if ( $lastref->{simple} && $lastref->{target} && ! $lastref->{targetopts} ) {
my $target = $lastref->{target};
my $count = 0;
my $rule = @$rulesref - 1;
unless ( $terminating{$name} ) {
$progress = 1 if $terminating{$name} = ( ( $terminating{$lastref->{target} || ''} ) || ( $lastref->{jump} || '' ) eq 'g' );
}
pop @$rulesref; #Pop the last simple rule
if ( $numrules == 1) {
#
# Chain has a single rule
#
my $firstrule = $lastref;
while ( @$rulesref ) {
my $rule1ref = $rulesref->[-1];
last unless ( $rule1ref->{target} || '' ) eq $target && ! $rule1ref->{targetopts};
trace ( $chainref, 'D', $rule, $rule1ref ) if $debug;
pop @$rulesref;
$progress = 1;
$count++;
$rule--;
}
if ( @$rulesref || ! $chainref->{builtin} || $target !~ /^(?:ACCEPT|DROP|REJECT)$/ ) {
push @$rulesref, $lastref; # Restore the last simple rule
} else {
if ( $firstrule ->{simple} ) {
#
#empty builtin chain -- change it's policy
# Easy case -- the rule is a simple jump
#
$chainref->{policy} = $target;
trace( $chainref, 'P', undef, 'ACCEPT' ) if $debug;
$count++;
if ( $chainref->{builtin} ) {
#
# A built-in chain. If the target is a user chain without 'dont_move',
# we can copy its rules to the built-in
#
if ( conditionally_copy_rules $chainref, $firstrule->{target} ) {
#
# Target was a user chain -- rules moved
#
$progress = 1;
} else {
#
# Target was a built-in. Ignore this chain in follow-on passes
#
$chainref->{optflags} |= DONT_OPTIMIZE;
}
} elsif ( ( $firstrule->{target} || '' ) eq 'RETURN' ) {
#
# A chain with a single 'RETURN' rule -- get rid of it
#
delete_chain_and_references( $chainref );
} else {
#
# Replace all references to this chain with references to the target
#
replace_references $chainref, $firstrule->{target}, $firstrule->{targetopts};
$progress = 1;
}
} elsif ( $firstrule->{target} ) {
#
# Not so easy -- the rule contains matches
#
if ( $chainref->{builtin} || ! $globals{KLUDGEFREE} || $firstrule->{policy} ) {
#
# This case requires a new rule merging algorithm. Ignore this chain for
# now on.
#
$chainref->{optflags} |= DONT_OPTIMIZE;
} else {
#
# Replace references to this chain with the target and add the matches
#
$progress = 1 if replace_references1 $chainref, $firstrule;
}
}
} else {
#
# Chain has more than one rule. If the last rule is a simple jump, then delete
# all immediately preceding rules that have the same target
#
my $rulesref = $chainref->{rules};
progress_message " $count $target rules deleted from chain $chainref->{name}" if $count;
if ( $lastref->{simple} && $lastref->{target} && ! $lastref->{targetopts} ) {
my $target = $lastref->{target};
my $count = 0;
my $rule = @$rulesref - 1;
pop @$rulesref; #Pop the last simple rule
while ( @$rulesref ) {
my $rule1ref = $rulesref->[-1];
last unless ( $rule1ref->{target} || '' ) eq $target && ! $rule1ref->{targetopts};
trace ( $chainref, 'D', $rule, $rule1ref ) if $debug;
pop @$rulesref;
$progress = 1;
$count++;
$rule--;
}
if ( @$rulesref || ! $chainref->{builtin} || $target !~ /^(?:ACCEPT|DROP|REJECT)$/ ) {
push @$rulesref, $lastref; # Restore the last simple rule
} else {
#
#empty builtin chain -- change it's policy
#
$chainref->{policy} = $target;
trace( $chainref, 'P', undef, 'ACCEPT' ) if $debug;
$count++;
}
progress_message " $count $target rules deleted from chain $name" if $count;
}
}
}
}