mirror of
https://github.com/M66B/FairEmail.git
synced 2026-04-04 16:16:33 +02:00
Show message signers
This commit is contained in:
M66B
@@ -1989,177 +1989,182 @@ public class MessageHelper {
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return true;
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}
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Boolean verifyDKIM(Context context) throws MessagingException, IOException {
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if (!(imessage instanceof IMAPMessage))
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return null;
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@NonNull
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List<String> verifyDKIM(Context context) {
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List<String> signers = new ArrayList<>();
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// Workaround reformatted headers
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Properties props = MessageHelper.getSessionProperties(true);
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Session isession = Session.getInstance(props, null);
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MimeMessage amessage = new MimeMessage(isession, ((IMAPMessage) imessage).getMimeStream());
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try {
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// Workaround reformatted headers
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Properties props = MessageHelper.getSessionProperties(true);
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Session isession = Session.getInstance(props, null);
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MimeMessage amessage = new MimeMessage(isession, ((IMAPMessage) imessage).getMimeStream());
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// https://datatracker.ietf.org/doc/html/rfc6376/
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String[] headers = amessage.getHeader("DKIM-Signature");
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if (headers == null || headers.length < 1)
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return null;
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// https://datatracker.ietf.org/doc/html/rfc6376/
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String[] headers = amessage.getHeader("DKIM-Signature");
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if (headers == null || headers.length < 1)
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return signers;
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boolean valid = false;
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for (String header : headers) {
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Map<String, String> kv = getKeyValues(MimeUtility.unfold(header));
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for (String header : headers) {
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Map<String, String> kv = getKeyValues(MimeUtility.unfold(header));
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String a = kv.get("a");
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String halgo;
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String salgo;
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if ("rsa-sha1".equals(a)) {
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halgo = "SHA-1";
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salgo = "SHA1withRSA";
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} else if ("rsa-sha256".equals(a)) {
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halgo = "SHA-256";
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salgo = "SHA256withRSA";
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} else {
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Log.i("DKIM a=" + a);
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return false;
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}
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try {
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String dns = kv.get("s") + "._domainkey." + kv.get("d");
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Log.i("DKIM lookup " + dns);
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DnsHelper.DnsRecord[] records = DnsHelper.lookup(context, dns, "txt");
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if (records.length > 0) {
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Log.i("DKIM got " + records[0].name);
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Map<String, String> dk = getKeyValues(records[0].name);
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Log.i("DKIM canonicalization=" + kv.get("c"));
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String[] c = kv.get("c").split("/");
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StringBuilder head = new StringBuilder();
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String hs = kv.get("h");
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Log.i("DKIM headers=" + hs);
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boolean from = false;
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List<String> _h = new ArrayList<>();
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for (String key : hs.split(":")) {
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_h.add(key.trim());
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from = (from || "from".equalsIgnoreCase(key.trim()));
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}
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if (!from)
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throw new IllegalArgumentException("from missing: " + hs);
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_h.add("DKIM-Signature");
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Map<String, Integer> index = new Hashtable<>();
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for (String n : _h) {
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// https://datatracker.ietf.org/doc/html/rfc6376/#section-5.4.2
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String _n = n.toLowerCase(Locale.ROOT);
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Integer idx = index.get(_n);
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idx = (idx == null ? 1 : idx + 1);
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index.put(_n, idx);
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String[] h = ("DKIM-Signature".equals(n) ? new String[]{header} : amessage.getHeader(n));
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if (h == null || idx > h.length) {
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// https://datatracker.ietf.org/doc/html/rfc6376/#section-5.4
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Log.i("DKIM missing header=" + n + "[" + idx + "/" + (h == null ? null : h.length) + "]");
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continue;
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}
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String v = h[h.length - idx];
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if ("DKIM-Signature".equals(n)) {
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int b = v.lastIndexOf("b=");
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int s = v.indexOf(";", b + 2);
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v = v.substring(0, b + 2) + (s < 0 ? "" : v.substring(s));
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} else
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Log.i("DKIM " + n + "=" + v.replaceAll("\\r?\\n", "|"));
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if ("simple".equals(c[0])) {
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if ("DKIM-Signature".equals(n))
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head.append(n).append(": ").append(v);
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else {
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// Find original header/name
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Enumeration<Header> oheaders = amessage.getAllHeaders();
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while (oheaders.hasMoreElements()) {
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Header oheader = oheaders.nextElement();
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if (n.equalsIgnoreCase(oheader.getName()))
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head.append(oheader.getName()).append(": ")
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.append(oheader.getValue());
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}
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}
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} else if ("relaxed".equals(c[0])) {
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v = MimeUtility.unfold(v);
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head.append(_n).append(':')
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.append(v.replaceAll("\\s+", " ").trim());
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} else
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throw new IllegalArgumentException(c[0]);
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if (!"DKIM-Signature".equals(n))
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head.append("\r\n");
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}
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Log.i("DKIM head=" + head.toString().replace("\r\n", "|"));
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ByteArrayOutputStream bos = new ByteArrayOutputStream();
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Helper.copy(amessage.getRawInputStream(), bos);
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String body = bos.toString(); // TODO: charset
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if ("simple".equals(c[c.length > 1 ? 1 : 0])) {
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if (TextUtils.isEmpty(body))
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body = "\r\n";
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else if (!body.endsWith("\r\n"))
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body += "\r\n";
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else {
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while (body.endsWith("\r\n\r\n"))
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body = body.substring(0, body.length() - 2);
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}
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} else if ("relaxed".equals(c[c.length > 1 ? 1 : 0])) {
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if (TextUtils.isEmpty(body))
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body = "";
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else {
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body = body.replaceAll("[ \\t]+\r\n", "\r\n");
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body = body.replaceAll("[ \\t]+", " ");
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while (body.endsWith("\r\n\r\n"))
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body = body.substring(0, body.length() - 2);
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if ("\r\n".equals(body))
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body = "";
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}
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} else
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throw new IllegalArgumentException(c[1]);
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Log.i("DKIM body=" + body.replace("\r\n", "|"));
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byte[] bh = MessageDigest.getInstance(halgo).digest(body.getBytes()); // TODO: charset
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Log.i("DKIM bh=" + Base64.encodeToString(bh, Base64.NO_WRAP) + "/" + kv.get("bh"));
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String p = dk.get("p").replaceAll("\\s+", "");
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Log.i("DKIM pubkey=" + p);
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X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(Base64.decode(p, Base64.DEFAULT));
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KeyFactory keyFactory = KeyFactory.getInstance("RSA");
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PublicKey pubKey = keyFactory.generatePublic(pubKeySpec);
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Signature sig = Signature.getInstance(salgo); // a=
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String s = kv.get("b").replaceAll("\\s+", "");
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Log.i("DKIM signature=" + s);
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byte[] signature = Base64.decode(s, Base64.DEFAULT);
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// TODO: check signature length
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sig.initVerify(pubKey);
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sig.update(head.toString().getBytes());
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boolean verified = sig.verify(signature);
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Log.i("DKIM valid=" + verified +
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" dns=" + dns +
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" from=" + formatAddresses(getFrom()));
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if (verified)
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valid = true;
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String a = kv.get("a");
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String halgo;
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String salgo;
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if ("rsa-sha1".equals(a)) {
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halgo = "SHA-1";
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salgo = "SHA1withRSA";
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} else if ("rsa-sha256".equals(a)) {
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halgo = "SHA-256";
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salgo = "SHA256withRSA";
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} else {
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Log.i("DKIM a=" + a);
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continue;
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}
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try {
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String signer = kv.get("d");
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String dns = kv.get("s") + "._domainkey." + signer;
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Log.i("DKIM lookup " + dns);
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DnsHelper.DnsRecord[] records = DnsHelper.lookup(context, dns, "txt");
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if (records.length > 0) {
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Log.i("DKIM got " + records[0].name);
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Map<String, String> dk = getKeyValues(records[0].name);
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Log.i("DKIM canonicalization=" + kv.get("c"));
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String[] c = kv.get("c").split("/");
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StringBuilder head = new StringBuilder();
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String hs = kv.get("h");
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Log.i("DKIM headers=" + hs);
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boolean from = false;
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List<String> _h = new ArrayList<>();
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for (String key : hs.split(":")) {
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_h.add(key.trim());
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from = (from || "from".equalsIgnoreCase(key.trim()));
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}
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if (!from)
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throw new IllegalArgumentException("from missing: " + hs);
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_h.add("DKIM-Signature");
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Map<String, Integer> index = new Hashtable<>();
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for (String n : _h) {
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// https://datatracker.ietf.org/doc/html/rfc6376/#section-5.4.2
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String _n = n.toLowerCase(Locale.ROOT);
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Integer idx = index.get(_n);
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idx = (idx == null ? 1 : idx + 1);
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index.put(_n, idx);
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String[] h = ("DKIM-Signature".equals(n) ? new String[]{header} : amessage.getHeader(n));
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if (h == null || idx > h.length) {
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// https://datatracker.ietf.org/doc/html/rfc6376/#section-5.4
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Log.i("DKIM missing header=" + n + "[" + idx + "/" + (h == null ? null : h.length) + "]");
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continue;
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}
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String v = h[h.length - idx];
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if ("DKIM-Signature".equals(n)) {
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int b = v.lastIndexOf("b=");
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int s = v.indexOf(";", b + 2);
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v = v.substring(0, b + 2) + (s < 0 ? "" : v.substring(s));
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} else
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Log.i("DKIM " + n + "=" + v.replaceAll("\\r?\\n", "|"));
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if ("simple".equals(c[0])) {
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if ("DKIM-Signature".equals(n))
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head.append(n).append(": ").append(v);
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else {
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// Find original header/name
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Enumeration<Header> oheaders = amessage.getAllHeaders();
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while (oheaders.hasMoreElements()) {
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Header oheader = oheaders.nextElement();
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if (n.equalsIgnoreCase(oheader.getName()))
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head.append(oheader.getName()).append(": ")
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.append(oheader.getValue());
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}
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}
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} else if ("relaxed".equals(c[0])) {
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v = MimeUtility.unfold(v);
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head.append(_n).append(':')
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.append(v.replaceAll("\\s+", " ").trim());
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} else
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throw new IllegalArgumentException(c[0]);
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if (!"DKIM-Signature".equals(n))
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head.append("\r\n");
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}
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Log.i("DKIM head=" + head.toString().replace("\r\n", "|"));
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ByteArrayOutputStream bos = new ByteArrayOutputStream();
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Helper.copy(amessage.getRawInputStream(), bos);
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String body = bos.toString(); // TODO: charset
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if ("simple".equals(c[c.length > 1 ? 1 : 0])) {
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if (TextUtils.isEmpty(body))
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body = "\r\n";
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else if (!body.endsWith("\r\n"))
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body += "\r\n";
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else {
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while (body.endsWith("\r\n\r\n"))
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body = body.substring(0, body.length() - 2);
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}
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} else if ("relaxed".equals(c[c.length > 1 ? 1 : 0])) {
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if (TextUtils.isEmpty(body))
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body = "";
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else {
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body = body.replaceAll("[ \\t]+\r\n", "\r\n");
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body = body.replaceAll("[ \\t]+", " ");
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while (body.endsWith("\r\n\r\n"))
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body = body.substring(0, body.length() - 2);
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if ("\r\n".equals(body))
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body = "";
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}
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} else
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throw new IllegalArgumentException(c[1]);
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Log.i("DKIM body=" + body.replace("\r\n", "|"));
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byte[] bh = MessageDigest.getInstance(halgo).digest(body.getBytes()); // TODO: charset
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Log.i("DKIM bh=" + Base64.encodeToString(bh, Base64.NO_WRAP) + "/" + kv.get("bh"));
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String p = dk.get("p").replaceAll("\\s+", "");
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Log.i("DKIM pubkey=" + p);
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X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(Base64.decode(p, Base64.DEFAULT));
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KeyFactory keyFactory = KeyFactory.getInstance("RSA");
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PublicKey pubKey = keyFactory.generatePublic(pubKeySpec);
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Signature sig = Signature.getInstance(salgo); // a=
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String s = kv.get("b").replaceAll("\\s+", "");
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Log.i("DKIM signature=" + s);
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byte[] signature = Base64.decode(s, Base64.DEFAULT);
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// TODO: check signature length
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sig.initVerify(pubKey);
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sig.update(head.toString().getBytes());
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boolean verified = sig.verify(signature);
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Log.i("DKIM valid=" + verified +
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" dns=" + dns +
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" from=" + formatAddresses(getFrom()));
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if (verified &&
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!signers.contains(signer))
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signers.add(signer);
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}
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} catch (Throwable ex) {
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Log.e("DKIM", ex);
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}
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} catch (Throwable ex) {
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Log.i("DKIM error=" + ex);
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Log.e(ex);
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}
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Log.i("DKIM signers=" + TextUtils.join(",", signers));
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} catch (Throwable ex) {
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Log.e("DKIM", ex);
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}
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Log.i("DKIM passed=" + valid);
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return valid;
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return signers;
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}
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Address[] getMailFrom(String[] headers) {
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