Merge commit from fork

httplib.h

@@ -6950,7 +6950,8 @@ inline bool is_chunked_transfer_encoding(const Headers &headers) {
 template <typename T, typename U>
 bool prepare_content_receiver(T &x, int &status,
                               ContentReceiverWithProgress receiver,
-                              bool decompress, U callback) {
+                              bool decompress, size_t payload_max_length,
+                              bool &exceed_payload_max_length, U callback) {
   if (decompress) {
     std::string encoding = x.get_header_value("Content-Encoding");
     std::unique_ptr<decompressor> decompressor;
@@ -6966,12 +6967,22 @@ bool prepare_content_receiver(T &x, int &status,
 
     if (decompressor) {
       if (decompressor->is_valid()) {
+        size_t decompressed_size = 0;
         ContentReceiverWithProgress out = [&](const char *buf, size_t n,
                                               size_t off, size_t len) {
-          return decompressor->decompress(buf, n,
-                                          [&](const char *buf2, size_t n2) {
-                                            return receiver(buf2, n2, off, len);
-                                          });
+          return decompressor->decompress(
+              buf, n, [&](const char *buf2, size_t n2) {
+                // Guard against zip-bomb: check
+                // decompressed size against limit.
+                if (payload_max_length > 0 &&
+                    (decompressed_size >= payload_max_length ||
+                     n2 > payload_max_length - decompressed_size)) {
+                  exceed_payload_max_length = true;
+                  return false;
+                }
+                decompressed_size += n2;
+                return receiver(buf2, n2, off, len);
+              });
         };
         return callback(std::move(out));
       } else {
@@ -6992,11 +7003,14 @@ template <typename T>
 bool read_content(Stream &strm, T &x, size_t payload_max_length, int &status,
                   DownloadProgress progress,
                   ContentReceiverWithProgress receiver, bool decompress) {
+  bool exceed_payload_max_length = false;
   return prepare_content_receiver(
-      x, status, std::move(receiver), decompress,
-      [&](const ContentReceiverWithProgress &out) {
+      x, status, std::move(receiver), decompress, payload_max_length,
+      exceed_payload_max_length, [&](const ContentReceiverWithProgress &out) {
         auto ret = true;
-        auto exceed_payload_max_length = false;
+        // Note: exceed_payload_max_length may also be set by the decompressor
+        // wrapper in prepare_content_receiver when the decompressed payload
+        // size exceeds the limit.
 
         if (is_chunked_transfer_encoding(x.headers)) {
           auto result = read_content_chunked(strm, x, payload_max_length, out);
@@ -11288,45 +11302,63 @@ inline bool Server::routing(Request &req, Response &res, Stream &strm) {
   if (detail::expect_content(req)) {
     // Content reader handler
     {
+      // Track whether the ContentReader was aborted due to the decompressed
+      // payload exceeding `payload_max_length_`.
+      // The user handler runs after the lambda returns, so we must restore the
+      // 413 status if the handler overwrites it.
+      bool content_reader_payload_too_large = false;
+
       ContentReader reader(
           [&](ContentReceiver receiver) {
             auto result = read_content_with_content_receiver(
                 strm, req, res, std::move(receiver), nullptr, nullptr);
-            if (!result) { output_error_log(Error::Read, &req); }
+            if (!result) {
+              output_error_log(Error::Read, &req);
+              if (res.status == StatusCode::PayloadTooLarge_413) {
+                content_reader_payload_too_large = true;
+              }
+            }
             return result;
           },
           [&](FormDataHeader header, ContentReceiver receiver) {
             auto result = read_content_with_content_receiver(
                 strm, req, res, nullptr, std::move(header),
                 std::move(receiver));
-            if (!result) { output_error_log(Error::Read, &req); }
+            if (!result) {
+              output_error_log(Error::Read, &req);
+              if (res.status == StatusCode::PayloadTooLarge_413) {
+                content_reader_payload_too_large = true;
+              }
+            }
             return result;
           });
 
+      bool dispatched = false;
       if (req.method == "POST") {
-        if (dispatch_request_for_content_reader(
-                req, res, std::move(reader),
-                post_handlers_for_content_reader_)) {
-          return true;
-        }
+        dispatched = dispatch_request_for_content_reader(
+            req, res, std::move(reader), post_handlers_for_content_reader_);
       } else if (req.method == "PUT") {
-        if (dispatch_request_for_content_reader(
-                req, res, std::move(reader),
-                put_handlers_for_content_reader_)) {
-          return true;
-        }
+        dispatched = dispatch_request_for_content_reader(
+            req, res, std::move(reader), put_handlers_for_content_reader_);
       } else if (req.method == "PATCH") {
-        if (dispatch_request_for_content_reader(
-                req, res, std::move(reader),
-                patch_handlers_for_content_reader_)) {
-          return true;
-        }
+        dispatched = dispatch_request_for_content_reader(
+            req, res, std::move(reader), patch_handlers_for_content_reader_);
       } else if (req.method == "DELETE") {
-        if (dispatch_request_for_content_reader(
-                req, res, std::move(reader),
-                delete_handlers_for_content_reader_)) {
-          return true;
+        dispatched = dispatch_request_for_content_reader(
+            req, res, std::move(reader), delete_handlers_for_content_reader_);
+      }
+
+      if (dispatched) {
+        if (content_reader_payload_too_large) {
+          // Enforce the limit: override any status the handler may have set
+          // and return false so the error path sends a plain 413 response.
+          res.status = StatusCode::PayloadTooLarge_413;
+          res.body.clear();
+          res.content_length_ = 0;
+          res.content_provider_ = nullptr;
+          return false;
         }
+        return true;
       }
     }