Switch from report-only to actually using Sec-Fetch-Site for CSRF protection

As a fallback for Rails's token-based mechanism. To use Sec-Fetch-Site
exclusively, we'll wait until Rails offers that (when we upstream this).
This commit is contained in:
Rosa Gutierrez
2025-11-28 16:08:32 +01:00
committed by Rosa Gutierrez
parent 6941108cdb
commit f8a1e0500d
2 changed files with 51 additions and 112 deletions
@@ -4,8 +4,6 @@ class RequestForgeryProtectionTest < ActionDispatch::IntegrationTest
setup do
sign_in_as :kevin
# Forgery protection is disabled in test environment so we need to
# enable it here
@original_allow_forgery_protection = ActionController::Base.allow_forgery_protection
ActionController::Base.allow_forgery_protection = true
end
@@ -14,105 +12,90 @@ class RequestForgeryProtectionTest < ActionDispatch::IntegrationTest
ActionController::Base.allow_forgery_protection = @original_allow_forgery_protection
end
test "don't report when Sec-Fetch-Site is same-origin and CSRF token matches" do
assert_log(excludes: "CSRF protection check") do
test "succeeds when CSRF token is valid" do
assert_difference -> { Board.count }, +1 do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
headers: { "Sec-Fetch-Site" => "cross-site" }
end
assert_response :redirect
end
test "succeeds with same-origin Sec-Fetch-Site even without CSRF token" do
assert_difference -> { Board.count }, +1 do
post boards_path,
params: { board: { name: "Test Board" } },
headers: { "Sec-Fetch-Site" => "same-origin" }
end
assert_response :redirect
end
test "don't report when Sec-Fetch-Site is same-site and CSRF token matches" do
assert_log(excludes: "CSRF protection check") do
test "succeeds with same-site Sec-Fetch-Site even without CSRF token" do
assert_difference -> { Board.count }, +1 do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
params: { board: { name: "Test Board" } },
headers: { "Sec-Fetch-Site" => "same-site" }
end
assert_response :redirect
end
test "fail and report when token doesn't match, regardless of Sec-Fetch-Site" do
assert_report
assert_log(includes: [ "CSRF protection check", "sec_fetch_site pass (same-origin)", "token fail" ]) do
assert_no_difference -> { Board.count } do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: "invalid-token" },
headers: { "Sec-Fetch-Site" => "same-origin" }
end
test "fails with cross-site Sec-Fetch-Site and no CSRF token" do
assert_no_difference -> { Board.count } do
post boards_path,
params: { board: { name: "Test Board" } },
headers: { "Sec-Fetch-Site" => "cross-site" }
end
assert_response :unprocessable_entity
end
test "fail and report when Origin doesn't match, regardless of Sec-Fetch-Site" do
assert_report
assert_log(includes: [ "CSRF protection check", "sec_fetch_site pass (same-origin)",
"token pass", "origin fail (evil-site.com)" ]) do
assert_no_difference -> { Board.count } do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
headers: { "Sec-Fetch-Site" => "same-origin", Origin: "evil-site.com" }
end
test "fails with none Sec-Fetch-Site and no CSRF token" do
assert_no_difference -> { Board.count } do
post boards_path,
params: { board: { name: "Test Board" } },
headers: { "Sec-Fetch-Site" => "none" }
end
assert_response :unprocessable_entity
end
test "succeed and report when Sec-Fetch-Site is cross-site and CSRF token matches" do
assert_report
assert_log(includes: [ "CSRF protection check", "sec_fetch_site fail (cross-site)", "token pass" ]) do
assert_difference -> { Board.count }, +1 do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
headers: { "Sec-Fetch-Site" => "cross-site" }
end
test "fails when Sec-Fetch-Site header is missing and no CSRF token" do
assert_no_difference -> { Board.count } do
post boards_path, params: { board: { name: "Test Board" } }
end
assert_response :unprocessable_entity
end
test "succeed and report when Sec-Fetch-Site is none" do
assert_report
assert_log(includes: [ "CSRF protection check", "sec_fetch_site fail (none)", "token pass" ]) do
assert_difference -> { Board.count }, +1 do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
headers: { "Sec-Fetch-Site" => "none" }
end
test "fails with invalid CSRF token and cross-site Sec-Fetch-Site" do
assert_no_difference -> { Board.count } do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: "invalid-token" },
headers: { "Sec-Fetch-Site" => "cross-site" }
end
end
test "succeed and report when Sec-Fetch-Site is missing" do
assert_report
assert_log(includes: [ "CSRF protection check", "sec_fetch_site fail ()", "token pass" ]) do
assert_difference -> { Board.count }, +1 do
post boards_path, params: { board: { name: "Test Board" }, authenticity_token: csrf_token }
end
end
end
test "don't report and succeed for GET requests" do
assert_log(excludes: "CSRF protection check") do
get board_url(boards(:writebook)), headers: { "Sec-Fetch-Site" => "cross-site" }
assert_response :success
end
assert_response :unprocessable_entity
end
test "GET requests succeed regardless of Sec-Fetch-Site header" do
get board_url(boards(:writebook)), headers: { "Sec-Fetch-Site" => "cross-site" }
get board_path(boards(:writebook)), headers: { "Sec-Fetch-Site" => "cross-site" }
assert_response :success
end
test "appends Sec-Fetch-Site to existing Vary header" do
get board_url(boards(:writebook)), headers: { "Accept" => "text/html" }
test "appends Sec-Fetch-Site to Vary header on GET requests" do
get board_path(boards(:writebook))
assert_response :success
vary_values = response.headers["Vary"].split(",").map(&:strip)
assert_includes vary_values, "Sec-Fetch-Site"
assert_includes response.headers["Vary"], "Sec-Fetch-Site"
end
test "appends Sec-Fetch-Site to Vary header on POST requests" do
post boards_path,
params: { board: { name: "Test Board" }, authenticity_token: csrf_token },
params: { board: { name: "Test Board" } },
headers: { "Sec-Fetch-Site" => "same-origin" }
assert_response :redirect
@@ -120,30 +103,9 @@ class RequestForgeryProtectionTest < ActionDispatch::IntegrationTest
end
private
def assert_log(includes: [], excludes: [], &block)
original_logger = Rails.logger
log_output = StringIO.new
Rails.logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(log_output))
yield
Array(includes).each { assert_includes(log_output.string, it) }
Array(excludes).each { assert_not_includes(log_output.string, it) }
ensure
Rails.logger = original_logger
end
def assert_report
if Fizzy.saas?
Sentry.expects(:capture_message).with do |message, **kwargs|
message == "CSRF protection mismatch" && kwargs[:level] == :info
end
end
end
def csrf_token
@csrf_token ||= begin
get new_board_url
get new_board_path
response.body[/name="authenticity_token" value="([^"]+)"/, 1]
end
end