fix: security & privacy (rate limiter fix, csrf session cookie, logout on server, drafts stale token passw, login timing, password over 72b, JWT_SECRET complexity, SMTP TLS, CSV export neutralised, fonts bundled, upload metadata, hourly cleanup job, privacy.md report)

internal/infrastructure/imaging/webpMetadata.go

@@ -0,0 +1,88 @@
+package imaging
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+const (
+	riffHeaderSize      = 12
+	riffChunkHeaderSize = 8
+	webpVP8X            = "VP8X"
+	webpEXIF            = "EXIF"
+	webpXMP             = "XMP "
+	webpEXIFFlag        = 0x08
+	webpXMPFlag         = 0x04
+)
+
+func stripWebP(data []byte) ([]byte, error) {
+	if len(data) < riffHeaderSize || string(data[:4]) != "RIFF" || string(data[8:12]) != "WEBP" {
+		return nil, errMalformedContainer
+	}
+	declared := int(binary.LittleEndian.Uint32(data[4:])) + riffChunkHeaderSize
+	if declared > len(data) || declared < riffHeaderSize {
+		return nil, errMalformedContainer
+	}
+	data = data[:declared]
+
+	var chunks [][]byte
+	orientation := uint16(uprightOrientation)
+	for pos := riffHeaderSize; pos < len(data); {
+		available := len(data) - pos - riffChunkHeaderSize
+		if available < 0 {
+			return nil, errMalformedContainer
+		}
+		size := binary.LittleEndian.Uint32(data[pos+4:])
+		padded := uint64(size) + uint64(size%2)
+		if padded > uint64(available) {
+			return nil, errMalformedContainer
+		}
+		kind := string(data[pos : pos+4])
+		payload := data[pos+riffChunkHeaderSize : pos+riffChunkHeaderSize+int(size)]
+		end := pos + riffChunkHeaderSize + int(padded)
+		switch kind {
+		case webpEXIF:
+			if found, ok := exifOrientation(payload); ok {
+				orientation = found
+			}
+		case webpXMP:
+		default:
+			chunks = append(chunks, bytes.Clone(data[pos:end]))
+		}
+		pos = end
+	}
+
+	if len(chunks) == 0 {
+		return nil, errMalformedContainer
+	}
+	if string(chunks[0][:4]) == webpVP8X {
+		if len(chunks[0]) <= riffChunkHeaderSize {
+			return nil, errMalformedContainer
+		}
+		flags := &chunks[0][riffChunkHeaderSize]
+		*flags &^= webpEXIFFlag | webpXMPFlag
+		if needsOrientation(orientation) {
+			*flags |= webpEXIFFlag
+			chunks = append(chunks, riffChunk(webpEXIF, orientationOnlyTIFF(orientation)))
+		}
+	}
+	return riffContainer(chunks), nil
+}
+
+func riffChunk(kind string, payload []byte) []byte {
+	chunk := append([]byte(kind), binary.LittleEndian.AppendUint32(nil, uint32(len(payload)))...)
+	chunk = append(chunk, payload...)
+	if len(payload)%2 == 1 {
+		chunk = append(chunk, 0)
+	}
+	return chunk
+}
+
+func riffContainer(chunks [][]byte) []byte {
+	body := []byte("WEBP")
+	for _, chunk := range chunks {
+		body = append(body, chunk...)
+	}
+	out := append([]byte("RIFF"), binary.LittleEndian.AppendUint32(nil, uint32(len(body)))...)
+	return append(out, body...)
+}