work in progress on the new & improved atrust handler

2 files changed, 436 insertions, 0 deletions

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java
new file mode 100644
index 00000000..6f6e5301
--- /dev/null
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java
@@ -0,0 +1,208 @@
+package at.asit.pdfover.gui.bku;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import javax.annotation.Nonnull;
+
+import org.apache.hc.client5.http.classic.methods.HttpGet;
+import org.apache.hc.client5.http.classic.methods.HttpPost;
+import org.apache.hc.client5.http.entity.UrlEncodedFormEntity;
+import org.apache.hc.client5.http.entity.mime.MultipartEntityBuilder;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
+import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
+import org.apache.hc.client5.http.impl.classic.HttpClients;
+import org.apache.hc.core5.http.ClassicHttpRequest;
+import org.apache.hc.core5.http.ContentType;
+import org.apache.hc.core5.http.Header;
+import org.apache.hc.core5.http.HttpEntity;
+import org.apache.hc.core5.http.HttpStatus;
+import org.apache.hc.core5.http.NameValuePair;
+import org.apache.hc.core5.http.ProtocolException;
+import org.apache.hc.core5.http.io.entity.EntityUtils;
+import org.apache.hc.core5.http.message.BasicNameValuePair;
+import org.jsoup.Jsoup;
+import org.jsoup.nodes.Document;
+import org.jsoup.nodes.Element;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import at.asit.pdfover.commons.Constants;
+import at.asit.pdfover.gui.bku.mobile.ATrustParser;
+import at.asit.pdfover.gui.workflow.states.MobileBKUState;
+import at.asit.pdfover.gui.workflow.states.MobileBKUState.UsernameAndPassword;
+import at.asit.pdfover.signer.BkuSlConnector;
+import at.asit.pdfover.signer.SignatureException;
+import at.asit.pdfover.signer.UserCancelledException;
+import at.asit.pdfover.signer.pdfas.PdfAs4SLRequest;
+
+import static at.asit.pdfover.commons.Constants.ISNOTNULL;
+
+public class MobileBKUConnector implements BkuSlConnector {
+    private static final Logger log = LoggerFactory.getLogger(MobileBKUConnector.class);
+    
+    private final @Nonnull MobileBKUState state;
+    public MobileBKUConnector(@Nonnull MobileBKUState state) {
+        this.state = state;
+        state.storeRememberedCredentialsTo(this.credentials);
+    }
+
+    public @Nonnull UsernameAndPassword credentials = new UsernameAndPassword();
+
+    /**
+     * This method takes the SLRequest from PDF-AS, and blocks until it has obtained a response
+     */
+    @Override
+	public String handleSLRequest(PdfAs4SLRequest slRequest) throws SignatureException, UserCancelledException {
+        log.debug("Got security layer request: (has file part: {})\n{}", (slRequest.signatureData != null), slRequest.xmlRequest);
+        try (final CloseableHttpClient httpClient = HttpClients.custom().disableRedirectHandling().build()) {
+            ClassicHttpRequest currentRequest = buildInitialRequest(slRequest);
+            ATrustParser.Result response;
+            while ((response = sendHTTPRequest(httpClient, currentRequest)).slResponse == null)
+                currentRequest = presentResponseToUserAndReturnNextRequest(ISNOTNULL(response.html));
+            log.debug("Returning security layer response:\n{}", response.slResponse);
+            return response.slResponse;
+        } catch (UserCancelledException e) {
+            throw e;
+        } catch (Exception e) {
+            throw new SignatureException(e);
+        }
+    }
+
+    /**
+     * Sends the specified request, following redirects (including meta-tag redirects) recursively
+     * @return The JSOUP document retrieved
+     * @throws IOException on HTTP error codes
+     * @throws ProtocolException
+     * @throws URISyntaxException
+     * @throws InterruptedException
+     */
+    private @Nonnull ATrustParser.Result sendHTTPRequest(CloseableHttpClient httpClient, ClassicHttpRequest request) throws IOException, ProtocolException, URISyntaxException {
+        log.debug("Sending request to '{}'...", request.getUri().toString());
+        try (final CloseableHttpResponse response = httpClient.execute(request)) {
+            int httpStatus = response.getCode();
+            if ((httpStatus == HttpStatus.SC_MOVED_PERMANENTLY) || (httpStatus == HttpStatus.SC_MOVED_TEMPORARILY)) {
+                Header redirectPath = response.getHeader("location");
+                if (redirectPath == null)
+                    throw new IOException("Received HTTP redirect, but no Location header.");
+                return sendHTTPRequest(httpClient, buildRedirectedRequest(request.getUri(), redirectPath.getValue()));
+            }
+
+            if (httpStatus != HttpStatus.SC_OK) {
+                throw new IOException("Got HTTP status " + httpStatus + " " + Optional.ofNullable(response.getReasonPhrase()).orElse("(null)"));
+            }
+                        
+            Header refreshHeader = response.getHeader("refresh");
+            if (refreshHeader != null)
+                return sendHTTPRequest(httpClient, buildRefreshHeaderRequest(request.getUri(), refreshHeader.getValue()));
+
+            HttpEntity responseEntity = response.getEntity();
+            if (responseEntity == null)
+                throw new IOException("Did not get a HTTP body (entity == null)");
+            
+            ContentType contentType = ContentType.parse(responseEntity.getContentType());
+            String entityBody = EntityUtils.toString(response.getEntity(),contentType.getCharset());
+            if (entityBody == null)
+                throw new IOException("Did not get a HTTP body (entity content == null)");
+
+            if ("text/html".equals(contentType.getMimeType())) {
+                Document resultDocument = Jsoup.parse(entityBody, request.getUri().toASCIIString());
+                if (resultDocument == null)
+                {
+                    log.error("Failed to parse A-Trust server response as HTML:\n{}", entityBody);
+                    throw new IOException("Failed to parse HTML");
+                }
+
+                Element metaRefresh = resultDocument.selectFirst("meta[http-equiv=\"refresh\"i]");
+                if (metaRefresh != null) {
+                    String refreshContent = metaRefresh.attr("content");
+                    if (!refreshContent.isEmpty())
+                        return sendHTTPRequest(httpClient, buildRefreshHeaderRequest(request.getUri(), refreshContent));
+                }
+                return ATrustParser.Parse(resultDocument);
+            } else {
+                return ATrustParser.Parse(request.getUri(), contentType.getMimeType(), entityBody);
+            }
+        }
+    }
+
+    /**
+     * Builds a HttpRequest for the given base URI and (potentially relative) redirect path
+     */
+    private static @Nonnull ClassicHttpRequest buildRedirectedRequest(URI baseURI, String redirectLocation) {
+        log.debug("following redirect: {}", redirectLocation);
+        return new HttpGet(baseURI.resolve(redirectLocation));
+    }
+
+    /**
+     * Builds a HttpRequest for redirection to a given Refresh header value
+     */
+    private static @Nonnull ClassicHttpRequest buildRefreshHeaderRequest(URI baseURI, String refreshHeader) throws IOException {
+        // refresh value is delay in seconds, semicolon, URL=, url
+        Pattern pattern = Pattern.compile("^\\s*[0-9\\.]+\\s*;\\s*(?:[uU][rR][lL]\s*=\s*)(.+)$");
+        Matcher matcher = pattern.matcher(refreshHeader);
+        if (!matcher.matches())
+            throw new IOException("Got invalid Refresh header with value \"" + refreshHeader + "\".");
+        String redirectURL = matcher.group(1);
+        return buildRedirectedRequest(baseURI, redirectURL);
+    }
+
+    /**
+     * Builds the initial request to A-Trust based on the specified SL request
+     */
+    private static @Nonnull ClassicHttpRequest buildInitialRequest(PdfAs4SLRequest slRequest) {
+        HttpPost post = new HttpPost(Constants.MOBILE_BKU_URL);
+        if (slRequest.signatureData != null) {
+            post.setEntity(MultipartEntityBuilder.create()
+                .addBinaryBody("fileupload", slRequest.signatureData.getByteArray(), ContentType.APPLICATION_PDF, "sign.pdf")
+                .addTextBody("XMLRequest", slRequest.xmlRequest)
+                .build());
+        } else {
+            post.setEntity(UrlEncodedFormEntityBuilder.create()
+                .add("XMLRequest", slRequest.xmlRequest)
+                .build());
+        }
+        return post;
+    }
+
+    private static @Nonnull ClassicHttpRequest buildFormSubmit(@Nonnull ATrustParser.HTMLResult html) {
+        HttpPost post = new HttpPost(html.formTarget);
+        
+        var builder = MultipartEntityBuilder.create();
+        for (var pair : html.iterateFormOptions())
+            builder.addTextBody(pair.getKey(), pair.getValue());
+        
+        post.setEntity(builder.build());
+        return post;
+    }
+
+    /**
+     * Main lifting function for MobileBKU UX
+     * @return the next request to make, or null if the current response should be returned
+     */
+    private @Nonnull ClassicHttpRequest presentResponseToUserAndReturnNextRequest(@Nonnull ATrustParser.HTMLResult html) throws UserCancelledException {
+        if (html.usernamePasswordBlock != null) {
+            while ((this.credentials.username == null) || (this.credentials.password == null)) {
+                this.state.getCredentialsFromUserTo(this.credentials, null);
+            }
+            html.usernamePasswordBlock.setUsernamePassword(this.credentials.username, this.credentials.password);
+            return buildFormSubmit(html);
+        }
+        throw new IllegalStateException("No top-level block is set? Something has gone terribly wrong.");
+    }
+
+    private static class UrlEncodedFormEntityBuilder {
+        private UrlEncodedFormEntityBuilder() {}
+        private List<NameValuePair> values = new ArrayList<>();
+        public static @Nonnull UrlEncodedFormEntityBuilder create() { return new UrlEncodedFormEntityBuilder(); }
+        public @Nonnull UrlEncodedFormEntityBuilder add(String key, String value) { values.add(new BasicNameValuePair(key, value)); return this; }
+        public @Nonnull UrlEncodedFormEntity build() { return new UrlEncodedFormEntity(values, Charset.forName("utf-8")); }
+    }
+}
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
new file mode 100644
index 00000000..f452202d
--- /dev/null
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
@@ -0,0 +1,228 @@
+package at.asit.pdfover.gui.bku.mobile;
+
+import java.lang.reflect.InvocationTargetException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import org.jsoup.Jsoup;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static at.asit.pdfover.commons.Constants.ISNOTNULL;
+
+public class ATrustParser {
+    private static final Logger log = LoggerFactory.getLogger(ATrustParser.class);
+
+    private static class ComponentParseFailed extends Exception {}
+
+    private static class TopLevelFormBlock {
+        protected @Nonnull org.jsoup.nodes.Document htmlDocument;
+        protected @Nonnull Map<String, String> formOptions;
+        protected TopLevelFormBlock(@Nonnull org.jsoup.nodes.Document d, @Nonnull Map<String,String> fO) { this.htmlDocument = d; this.formOptions = fO; }
+
+        protected void abortIfElementMissing(@Nonnull String selector) throws ComponentParseFailed {
+            if (this.htmlDocument.selectFirst(selector) != null) return;
+            log.debug("Tested for element {} -- not found.", selector);
+            throw new ComponentParseFailed();
+        }
+        protected @Nonnull String getAttributeEnsureNotNull(@Nonnull String selector, @Nonnull String attribute) throws ComponentParseFailed {
+            var elm = this.htmlDocument.selectFirst(selector);
+            if (elm == null) { log.warn("Expected element not found in response: {}", selector); throw new ComponentParseFailed(); }
+            if (!elm.hasAttr(attribute)) { log.warn("Element {} is missing expected attribute '{}'.", selector, attribute); throw new ComponentParseFailed(); }
+            return ISNOTNULL(elm.attr(attribute));
+        }
+        protected @Nonnull URI getURIAttributeEnsureNotNull(@Nonnull String selector, @Nonnull String attribute) throws ComponentParseFailed {
+            String value = getAttributeEnsureNotNull(selector, attribute);
+            try {
+                return new URI(value);
+            } catch (URISyntaxException e) {
+                if (attribute.startsWith("abs:"))
+                    attribute = ISNOTNULL(attribute.substring(4));
+                log.warn("Element {} attribute {} is '{}', could not be parsed as URI", selector, attribute, getAttributeEnsureNotNull(selector, attribute));
+                throw new ComponentParseFailed();
+            }
+        }
+    }
+
+    public static class UsernamePasswordBlock extends TopLevelFormBlock {
+        private @Nonnull String usernameKey;
+        private @Nonnull String passwordKey;
+
+        public void setUsernamePassword(String username, String password) {
+            formOptions.put(usernameKey, username); formOptions.put(passwordKey, password);
+        }
+
+        private UsernamePasswordBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#handynummer");
+            this.usernameKey = getAttributeEnsureNotNull("#handynummer", "name");
+            this.passwordKey = getAttributeEnsureNotNull("#signaturpasswort", "name");
+            
+            /* remove unused submit buttons */
+            // TODO: we should generalize this somehow for input type="submit"
+            // TODO: do we maybe want to use the actual cancel button?
+            formOptions.remove(getAttributeEnsureNotNull("#Button_Cancel", "name"));
+            formOptions.remove(getAttributeEnsureNotNull("#Button_localBku", "name"));
+        }
+    }
+
+    public static class QRCodeBlock extends TopLevelFormBlock {
+        public @Nonnull URI qrCodeURI;
+
+        private QRCodeBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#qrimage");
+            this.qrCodeURI = getURIAttributeEnsureNotNull("#qrimage", "abs:src");
+        }
+    }
+
+    public static class Fido2Block extends TopLevelFormBlock {
+        private @Nonnull String fidoOptions;
+        private @Nonnull String credentialResultKey;
+
+        public @Nonnull String getFIDOOptions() { return fidoOptions; }
+        public void setFIDOResult(String result) { formOptions.put(credentialResultKey, result); }
+
+        private Fido2Block(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            abortIfElementMissing("#fidoBlock");
+            this.fidoOptions = getAttributeEnsureNotNull("#credentialOptions", "value");
+            this.credentialResultKey = getAttributeEnsureNotNull("#credentialResult", "name");
+        }
+    }
+
+    public static class HTMLResult {
+        public final @Nonnull org.jsoup.nodes.Document htmlDocument;
+        public final @Nonnull URI formTarget;
+        public final @Nonnull Map<String, String> formOptions = new HashMap<>();
+
+        public @Nonnull Iterable<Map.Entry<String, String>> iterateFormOptions() { return ISNOTNULL(formOptions.entrySet()); }
+
+        /* optional mode switch links (any number may or may not be null) */
+        public final @CheckForNull URI fido2Link;
+
+        /* top-level blocks (exactly one is not null) */
+        public final @CheckForNull UsernamePasswordBlock usernamePasswordBlock;
+        public final @CheckForNull QRCodeBlock qrCodeBlock;
+        public final @CheckForNull Fido2Block fido2Block;
+
+        private void validate() {
+            Set<String> populated = new HashSet<>();
+
+            if (usernamePasswordBlock != null) populated.add("usernamePasswordBlock");
+            if (qrCodeBlock != null) populated.add("qrCodeBlock");
+            if (fido2Block != null) populated.add("fido2Block");
+
+            switch (populated.size()) {
+                case 0: log.error("Did not find any top-level blocks.\n{}", this.htmlDocument.toString()); break;
+                case 1: /* passed */ return;
+                default: log.error("Found too many top-level blocks: {}\n", String.join(", ", populated), this.htmlDocument.toString()); break;
+            }
+            throw new IllegalArgumentException("Unknown A-Trust page reached?");
+        }
+
+        private @Nullable URI getHrefIfExists(String selector) {
+            var elm = htmlDocument.selectFirst(selector);
+            if (elm == null) return null;
+
+            String url = elm.absUrl("href");
+            try {
+                return new URI(url);
+            } catch (Exception e) {
+                log.warn("Invalid {} href attribute: {} ({})", selector, elm.attr("href"), url);
+                return null;
+            }
+        }
+
+        /**
+         * tries to parse T using its constructor; if ComponentParseFailed is thrown, swallows it
+         */
+        private <T extends TopLevelFormBlock> @Nullable T TryParseMainBlock(Class<T> clazz) {
+            try {
+                return clazz.getDeclaredConstructor(org.jsoup.nodes.Document.class, Map.class).newInstance(this.htmlDocument, this.formOptions);
+            } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | IllegalArgumentException | SecurityException e) {
+                log.error("Internal parser error; check your method signatures?", e);
+                return null;
+            } catch (InvocationTargetException wrappedE) {
+                Throwable e = wrappedE.getCause();
+                if (!(e instanceof ComponentParseFailed)) {
+                    if (e instanceof RuntimeException)
+                        throw (RuntimeException)e;
+                    log.warn("Unexpected parser failure.", e);
+                }
+                return null;
+            }
+        }
+
+        private HTMLResult(@Nonnull org.jsoup.nodes.Document htmlDocument) {
+            this.htmlDocument = htmlDocument;
+
+            var forms = htmlDocument.getElementsByTag("form");
+            if (forms.size() != 1) {
+                log.error("Found {} forms in A-Trust response document, expected 1. Document:\n{}", forms.size(), htmlDocument.toString());
+                throw new IllegalArgumentException("Failed to parse A-Trust response page");
+            }
+
+            var mainForm = ISNOTNULL(forms.first()); /* size check above */
+            String formAction = mainForm.absUrl("action");
+            try {
+                this.formTarget = new URI(formAction);
+            } catch (URISyntaxException e) {
+                log.error("Invalid form target in page: {} ({})", mainForm.attr("action"), formAction, e);
+                throw new IllegalArgumentException("Failed to parse A-Trust response page");
+            }
+
+            for (var input : mainForm.select("input")) {
+                String name = input.attr("name");
+                if (name.isEmpty())
+                    continue;
+                this.formOptions.put(name, input.attr("value"));
+            }
+
+            this.fido2Link = getHrefIfExists("#FidoButton");
+
+            this.usernamePasswordBlock = TryParseMainBlock(UsernamePasswordBlock.class);
+            this.qrCodeBlock = TryParseMainBlock(QRCodeBlock.class);
+            this.fido2Block = TryParseMainBlock(Fido2Block.class);
+            
+            validate();
+        }
+    }
+
+    public static class Result {
+        public final @CheckForNull String slResponse;
+        public final @CheckForNull HTMLResult html;
+
+        private Result(@Nonnull String slResponse) { this.slResponse = slResponse; this.html = null; }
+        private Result(@Nonnull org.jsoup.nodes.Document htmlDocument) { this.slResponse = null; this.html = new HTMLResult(htmlDocument); }
+    }
+
+    public static @Nonnull Result Parse(@Nonnull org.jsoup.nodes.Document htmlDocument) { return new Result(htmlDocument); }
+
+    public static @Nonnull Result Parse(URI baseURI, String contentType, @Nonnull String content) {
+        if (contentType.equals("text/html"))
+        {
+            var document = Jsoup.parse(content, baseURI.toASCIIString());
+            if (document == null)
+            {
+                log.error("Failed to parse HTML (document == null):\n{}", content);
+                throw new IllegalArgumentException("A-Trust parsing failed");
+            }
+            return Parse(document);
+        }
+
+        if (contentType.endsWith("/xml"))
+            return new Result(content);
+        
+        log.error("Unknown content-type \"{}\" from URI {}", contentType, baseURI.toString());
+        throw new IllegalArgumentException("Unknown A-Trust page reached?");
+    }
+}