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[cleanup] vulnerabilities.py #92

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Merged
merged 1 commit into from
Mar 9, 2018
Merged

[cleanup] vulnerabilities.py #92

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40 changes: 16 additions & 24 deletions pyt/vulnerabilities.py
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@


class TriggerNode():
def __init__(self, trigger_word, sanitisers, cfg_node, secondary_nodes=None):
def __init__(self, trigger_word, sanitisers, cfg_node, secondary_nodes=[]):
self.trigger_word = trigger_word
self.sanitisers = sanitisers
self.cfg_node = cfg_node
Expand Down Expand Up @@ -280,6 +280,10 @@ def get_vulnerability(source,

Uses triggers to find sanitisers.

Note: When a secondary node is in_constraint with the sink
but not the source, the secondary is a save_N_LHS
node made in process_function in interprocedural_cfg.

Args:
source(TriggerNode): TriggerNode of the source.
sink(TriggerNode): TriggerNode of the sink.
Expand All @@ -291,41 +295,29 @@ def get_vulnerability(source,
Returns:
A Vulnerability if it exists, else None
"""
source_in_sink = lattice.in_constraint(source.cfg_node, sink.cfg_node)

secondary_nodes_in_sink = list()
if source.secondary_nodes:
secondary_nodes_in_sink = [secondary for secondary in source.secondary_nodes
if lattice.in_constraint(secondary,
sink.cfg_node)]

trigger_node_in_sink = source_in_sink or secondary_nodes_in_sink

secondary_nodes_in_sink = [secondary for secondary in source.secondary_nodes
if lattice.in_constraint(secondary,
sink.cfg_node)]
sink_args = get_sink_args(sink.cfg_node)

secondary_node_in_sink_args = None
tainted_node_in_sink_arg = None
if sink_args:
if source.cfg_node.left_hand_side in sink_args:
tainted_node_in_sink_arg = source.cfg_node
for node in secondary_nodes_in_sink:
if node.left_hand_side in sink_args:
secondary_node_in_sink_args = node
tainted_node_in_sink_arg = node

trimmed_reassignment_nodes = list()
if secondary_node_in_sink_args:
trimmed_reassignment_nodes.append(secondary_node_in_sink_args)
node_in_the_vulnerability_chain = secondary_node_in_sink_args
if tainted_node_in_sink_arg:
trimmed_reassignment_nodes = list()
trimmed_reassignment_nodes.append(tainted_node_in_sink_arg)
node_in_the_vulnerability_chain = tainted_node_in_sink_arg
# Here is where we do backwards slicing to traceback which nodes led to the vulnerability
for secondary in reversed(source.secondary_nodes):
if lattice.in_constraint(secondary, sink.cfg_node):
if secondary.left_hand_side in node_in_the_vulnerability_chain.right_hand_side_variables:
node_in_the_vulnerability_chain = secondary
trimmed_reassignment_nodes.insert(0, node_in_the_vulnerability_chain)

source_lhs_in_sink_args = source.cfg_node.left_hand_side in sink_args\
if sink_args else None

lhs_in_sink_args = source_lhs_in_sink_args or secondary_node_in_sink_args

if trigger_node_in_sink and lhs_in_sink_args:
source_trigger_word = source.trigger_word
sink_trigger_word = sink.trigger_word
sink_is_sanitised = is_sanitised(
Expand Down