handler/stop: add no js solution option

html/index.html

@@ -154,6 +154,19 @@
             transition: ease-in-out 0.1s;
         }
 
+        .link,
+        .link:visited,
+        .link:link,
+        .link:focus,
+        .link:active {
+            color: #c03940;
+            text-decoration: none;
+        }
+
+        .link:hover {
+            text-decoration: underline;
+        }
+
         @media (pointer:none),
         (pointer:coarse) {
             .big-icon {
@@ -198,10 +211,76 @@
 
         <noscript>
             <p class="text-description">
-                This website uses <a href="https://github.com/vaxerski/checkpoint">checkpoint</a> and requires javascript. Please enable javascript to complete the Proof of Work challenge.
+                This website uses <a class="link" href="https://github.com/vaxerski/checkpoint">checkpoint</a> and
+                requires
+                javascript to
+                automatically verify you are not a bot.<br /><br />
+                You seem to be running without Javascript enabled, and thus will have to do this manually.<br /><br />
+                Paste this command into your Linux terminal and provide the output below:
             </p>
 
+            <p class="code-block">
+                perl -MDigest::SHA=sha256_hex -e '$nonce="{{ tl:text challengeNonce }}"; $d={{ tl:text
+                challengeDifficulty
+                }}; for($i=0;; $i++){ $h=sha256_hex($nonce.$i); if(substr($h,0,$d) eq "0"x$d){ print "$i\n"; last }}'
+            </p>
+
+            <form action="/checkpoint/challengeNoJs" method="get">
+                <div>
+                    <label class="form-label" for="name">Enter the output: </label>
+                    <input class="form-input" type="text" name="solution" id="solution" required />
+                </div>
+                <input class="input-hidden" type="text" name="fingerprint" id="fingerprint"
+                    value="{{ tl:text challengeFingerprint }}" />
+                <input class="input-hidden" type="text" name="challenge" id="challenge"
+                    value="{{ tl:text challengeNonce }}" />
+                <input class="input-hidden" type="text" name="sig" id="sig" value="{{ tl:text challengeSignature }}" />
+                <input class="input-hidden" type="text" name="timestamp" id="timestamp"
+                    value="{{ tl:text challengeTimestamp }}" />
+                <input class="input-hidden" type="text" name="difficulty" id="difficulty"
+                    value="{{ tl:text challengeDifficulty }}" />
+                <input class="form-button" type="submit" value="Send" />
+            </form>
+
             <style>
+                .form-label {
+                    color: #fff;
+                    display: block;
+                    text-align: center;
+                }
+
+                .form-button {
+                    margin-left: 9.5rem;
+                    width: calc(100%-19rem);
+                    display: block;
+                    position: relative;
+                }
+
+                .form-input {
+                    margin-left: 9.5rem;
+                    width: calc(100%-19rem);
+                }
+
+                .code-block {
+                    background-color: #161616;
+                    color: #d9d9d9;
+                    border-radius: 1rem;
+                    font: "Monospace";
+                    margin: 1rem;
+                    width: calc(100% - 3rem);
+                    max-width: 100%;
+                    text-wrap: break-word;
+                    overflow-wrap: break-word;
+                    padding: 0.5rem;
+                    text-align: left;
+                    border: 1px solid #280d0e;
+                }
+
+                .input-hidden {
+                    visibility: hidden;
+                    position: absolute;
+                }
+
                 .require-js {
                     display: none;
                 }

src/core/Challenge.cpp

@@ -46,6 +46,38 @@ CChallenge::CChallenge(const std::string& jsonResponse) {
     m_valid = true;
 }
 
+CChallenge::CChallenge(const Pistache::Http::Request& reqResponse) {
+    auto& q = reqResponse.query();
+
+    if (!q.has("solution")
+        || !q.has("fingerprint")
+        || !q.has("challenge")
+        || !q.has("timestamp")
+        || !q.has("sig")
+        || !q.has("difficulty"))
+        return;
+
+    m_challenge = q.get("challenge").value();
+    m_fingerprint = q.get("fingerprint").value();
+    m_sig = q.get("sig").value();
+
+    try {
+        m_issued = std::chrono::system_clock::time_point(std::chrono::seconds(std::stoull(q.get("timestamp").value())));
+    } catch (std::exception& e) { return; }
+
+    if (!g_pCrypto->verifySignature(getSigString(), m_sig))
+        return;
+
+    const auto SHA = g_pCrypto->sha256(m_challenge + q.get("solution").value());
+
+    for (size_t i = 0; i < m_difficulty; ++i) {
+        if (SHA.at(i) != '0')
+            return;
+    }
+
+    m_valid = true;
+}
+
 std::string CChallenge::fingerprint() const {
     return m_fingerprint;
 }

src/core/Challenge.hpp

@@ -3,10 +3,14 @@
 #include <string>
 #include <chrono>
 
+#include <pistache/http.h>
+
 class CChallenge {
   public:
+    CChallenge() = default;
     CChallenge(const std::string& fingerprint, const std::string& challenge, int difficulty);
     CChallenge(const std::string& jsonResponse);
+    CChallenge(const Pistache::Http::Request& reqResponse);
 
     std::string fingerprint() const;
     std::string challenge() const;

src/core/Handler.cpp

@@ -195,7 +195,15 @@ void CServerHandler::onRequest(const Pistache::Http::Request& req, Pistache::Htt
 
     if (req.resource() == "/checkpoint/challenge") {
         if (req.method() == Pistache::Http::Method::Post)
-            challengeSubmitted(req, response);
+            challengeSubmitted(req, response, true);
+        else
+            response.send(Pistache::Http::Code::Bad_Request, "Bad Request");
+        return;
+    }
+
+    if (req.resource() == "/checkpoint/challengeNoJs") {
+        if (req.method() == Pistache::Http::Method::Get)
+            challengeSubmitted(req, response, false);
         else
             response.send(Pistache::Http::Code::Bad_Request, "Bad Request");
         return;
@@ -323,11 +331,15 @@ void CServerHandler::onTimeout(const Pistache::Http::Request& request, Pistache:
     response.send(Pistache::Http::Code::Request_Timeout, "Timeout").then([=](ssize_t) {}, PrintException());
 }
 
-void CServerHandler::challengeSubmitted(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response) {
+void CServerHandler::challengeSubmitted(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response, bool js) {
     const auto JSON        = req.body();
     const auto FINGERPRINT = fingerprintForRequest(req);
 
-    const auto CHALLENGE = CChallenge(req.body());
+    CChallenge CHALLENGE;
+    if (!js)
+        CHALLENGE = CChallenge(req);
+    else
+        CHALLENGE = CChallenge(req.body());
 
     if (!CHALLENGE.valid()) {
         response.send(Pistache::Http::Code::Bad_Request, "Bad request");
@@ -353,7 +365,12 @@ void CServerHandler::challengeSubmitted(const Pistache::Http::Request& req, Pist
     response.headers().add(
         std::make_shared<SetCookieHeader>(std::string{TOKEN_COOKIE_NAME} + "=" + TOKEN.tokenCookie() + "; Domain=" + hostDomain + "; HttpOnly; Path=/; Secure; SameSite=Lax"));
 
-    response.send(Pistache::Http::Code::Ok, "Ok");
+    if (js)
+        response.send(Pistache::Http::Code::Ok, "Ok");
+    else {
+        response.headers().add<Pistache::Http::Header::Location>("/");
+        response.send(Pistache::Http::Code::Moved_Permanently, "");
+    }
 }
 
 void CServerHandler::serveStop(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response, int difficulty) {
@@ -376,6 +393,8 @@ void CServerHandler::serveStop(const Pistache::Http::Request& req, Pistache::Htt
     page.add("challengeTimestamp", CTinylatesProp(CHALLENGE.timestampAsString()));
     page.add("hostDomain", CTinylatesProp(hostDomain));
     page.add("checkpointVersion", CTinylatesProp(CHECKPOINT_VERSION));
+
+    response.setMime(Pistache::Http::Mime::MediaType("text/html"));
     response.send(Pistache::Http::Code::Ok, page.render().value_or("error"));
 }
 

src/core/Handler.hpp

@@ -21,7 +21,7 @@ class CServerHandler : public Pistache::Http::Handler {
     void        proxyPass(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response);
     void        proxyPassInternal(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response, bool async = false);
     void        proxyPassAsync(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response);
-    void        challengeSubmitted(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response);
+    void        challengeSubmitted(const Pistache::Http::Request& req, Pistache::Http::ResponseWriter& response, bool js);
     std::string fingerprintForRequest(const Pistache::Http::Request& req);
     std::string ipForRequest(const Pistache::Http::Request& req);