Commit 83481414 authored by Sean McGivern's avatar Sean McGivern Committed by James Edwards-Jones
Browse files

Merge branch 'fix-re2-infinite-loop-nick' into 'security-9-3'

Fix an infinite loop in Gitlab:UntrustedRegexp

See merge request !2146
parent 365a8acb0a2e
---
title: Fix an infinite loop when handling user-supplied regular expressions
merge_request:
author:
......@@ -22,13 +22,28 @@ def replace_all(text, rewrite)
end
def scan(text)
scan_regexp.scan(text).map do |match|
if regexp.number_of_capturing_groups == 0
match.first
else
match
end
text = text.dup # modified in-place
results = []
loop do
match = scan_regexp.match(text)
break unless match
# Ruby scan returns empty strings, not nil
groups = match.to_a.map(&:to_s)
results <<
if regexp.number_of_capturing_groups.zero?
groups[0]
else
groups[1..-1]
end
text.slice!(0, match.end(0) || 1)
break unless text.present?
end
results
end
def replace(text, rewrite)
......@@ -43,7 +58,7 @@ def replace(text, rewrite)
# groups, so work around it
def scan_regexp
@scan_regexp ||=
if regexp.number_of_capturing_groups == 0
if regexp.number_of_capturing_groups.zero?
RE2::Regexp.new('(' + regexp.source + ')')
else
regexp
......
......@@ -46,10 +46,28 @@
context 'malicious regexp' do
let(:text) { malicious_text }
let(:regexp) { malicious_regexp }
include_examples 'malicious regexp'
end
context 'empty regexp' do
let(:regexp) { '' }
let(:text) { 'foo' }
it 'returns an array of empty matches' do
is_expected.to eq(['', '', ''])
end
end
context 'empty capture group regexp' do
let(:regexp) { '()' }
let(:text) { 'foo' }
it 'returns arrays of empty matches in an array' do
is_expected.to eq([[''], [''], ['']])
end
end
context 'no capture group' do
let(:regexp) { '.+' }
let(:text) { 'foo' }
......
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