fix(api): apply baggage size and entry caps on extract

api/lib/opentelemetry/baggage/propagation/text_map_propagator.rb

@@ -54,18 +54,12 @@ def inject(carrier, context: Context.current, setter: Context::Propagation.text_
         def extract(carrier, context: Context.current, getter: Context::Propagation.text_map_getter)
           header = getter.get(carrier, BAGGAGE_KEY)
           return context if header.nil? || header.empty?
+          return context if header.bytesize > MAX_TOTAL_LENGTH
 
           entries = header.gsub(/\s/, '').split(',')
 
           OpenTelemetry::Baggage.build(context: context) do |builder|
-            entries.each do |entry|
-              # Note metadata is currently unused in OpenTelemetry, but is part
-              # the W3C spec where it's referred to as properties. We preserve
-              # the properties (as-is) so that they can be propagated elsewhere.
-              kv, meta = entry.split(';', 2)
-              k, v = kv.split('=').map!(&URI.method(:decode_uri_component))
-              builder.set_value(k, v, metadata: meta)
-            end
+            decode_entries(entries, builder)
           end
         rescue StandardError => e
           OpenTelemetry.logger.debug "Error extracting W3C baggage: #{e.message}"
@@ -82,6 +76,22 @@ def fields
 
         private
 
+        def decode_entries(entries, builder)
+          decoded_count = 0
+          entries.each do |entry|
+            break if decoded_count >= MAX_ENTRIES
+            next if entry.bytesize > MAX_ENTRY_LENGTH
+
+            # Note metadata is currently unused in OpenTelemetry, but is part
+            # the W3C spec where it's referred to as properties. We preserve
+            # the properties (as-is) so that they can be propagated elsewhere.
+            kv, meta = entry.split(';', 2)
+            k, v = kv.split('=').map!(&URI.method(:decode_uri_component))
+            builder.set_value(k, v, metadata: meta)
+            decoded_count += 1
+          end
+        end
+
         def encode(baggage)
           result = +''
           encoded_count = 0

api/test/opentelemetry/baggage/propagation/text_map_propagator_test.rb

@@ -70,6 +70,41 @@
         _(context.object_id).wont_equal(empty_context.object_id)
       end
     end
+
+    describe 'limits mirroring #inject' do
+      it 'returns the same context object when the header exceeds the total length of 8192 bytes' do
+        header = (['k=' + ('v' * 96)] * 100).join(',')
+        _(header.bytesize).must_be :>, 8192
+        carrier = { header_key => header }
+        empty_context = Context.empty
+        context = propagator.extract(carrier, context: empty_context)
+        _(context.object_id).must_equal(empty_context.object_id)
+      end
+
+      it 'enforces max of 180 entries on extract' do
+        header = (0..199).map { |i| "k#{i}=v#{i}" }.join(',')
+        carrier = { header_key => header }
+        context = propagator.extract(carrier, context: Context.empty)
+        entries = OpenTelemetry::Baggage.raw_entries(context: context)
+        _(entries.size).must_equal(180)
+        _(entries['k0']).wont_be_nil
+        _(entries['k179']).wont_be_nil
+        _(entries['k180']).must_be_nil
+        _(entries['k199']).must_be_nil
+      end
+
+      it 'skips entries whose size exceeds the max entry length of 4096 bytes' do
+        oversize_value = 'v' * 4096
+        header = "big=#{oversize_value},key2=val2"
+        _(header.bytesize).must_be :<=, 8192
+        carrier = { header_key => header }
+        context = propagator.extract(carrier, context: Context.empty)
+        entries = OpenTelemetry::Baggage.raw_entries(context: context)
+        _(entries['big']).must_be_nil
+        _(entries['key2']).wont_be_nil
+        _(entries['key2'].value).must_equal('val2')
+      end
+    end
   end
 
   describe '#inject' do