SERVER-64577: Disallow wTags write concern in FCV less than 5.3

also fixes SERVER-63100

6 files changed, 163 insertions, 6 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index c3152e8c8bf..19b521180e7 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -452,15 +452,18 @@ env.Library(
 )
 
 env.Library(
-    target="write_concern_options",
+    target='write_concern_options',
     source=[
-        "write_concern_options.cpp",
+        'write_concern_options.cpp',
+        'write_concern_options.idl',
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/bson/util/bson_extract',
-        '$BUILD_DIR/mongo/idl/basic_types',
         'read_write_concern_provenance',
     ],
+    LIBDEPS_PRIVATE=[
+        '$BUILD_DIR/mongo/db/server_options_core', # For serverGlobalParams
+    ]
 )
 
 env.Library(
diff --git a/src/mongo/db/read_write_concern_provenance_base.idl b/src/mongo/db/read_write_concern_provenance_base.idl
index 4695d5f0a34..017b89a6984 100644
--- a/src/mongo/db/read_write_concern_provenance_base.idl
+++ b/src/mongo/db/read_write_concern_provenance_base.idl
@@ -32,6 +32,17 @@ global:
 imports:
     - "mongo/idl/basic_types.idl"
 
+enums:
+    ReadWriteConcernProvenanceSource:
+        description: "Provenance sources"
+        type: string
+        values:
+            clientSupplied: "clientSupplied"
+            implicitDefault: "implicitDefault"
+            customDefault: "customDefault"
+            getLastErrorDefaults: "getLastErrorDefaults"
+            internalWriteDefault: "internalWriteDefault"
+
 structs:
     ReadWriteConcernProvenanceBase:
         description: "Represents the 'provenance' (ie. original source) of a read or write concern."
diff --git a/src/mongo/db/write_concern_options.cpp b/src/mongo/db/write_concern_options.cpp
index 4f1822884fa..c87e21691fc 100644
--- a/src/mongo/db/write_concern_options.cpp
+++ b/src/mongo/db/write_concern_options.cpp
@@ -32,13 +32,13 @@
 #include <type_traits>
 
 #include "mongo/db/write_concern_options.h"
+#include "mongo/db/write_concern_options_gen.h"
 
 #include "mongo/base/status.h"
 #include "mongo/base/string_data.h"
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/field_parser.h"
 #include "mongo/db/repl/repl_set_config.h"
-#include "mongo/idl/basic_types_gen.h"
 #include "mongo/util/str.h"
 
 namespace mongo {
@@ -176,6 +176,70 @@ StatusWith<WriteConcernOptions> WriteConcernOptions::extractWCFromCommand(const
     return parse(writeConcernObj);
 }
 
+WriteConcernW deserializeWriteConcernW(BSONElement wEl) {
+    // Preserve pre-5.3 behavior to avoid issues with mixed-version clusters. This will eventually
+    // be removed when we release 7.0.
+    if (serverGlobalParams.featureCompatibility.isVersionInitialized() &&
+        serverGlobalParams.featureCompatibility.isLessThan(
+            multiversion::FeatureCompatibilityVersion::kVersion_5_3)) {
+        uassert(ErrorCodes::FailedToParse,
+                "w has to be a number or string; found: {}"_format(typeName(wEl.type())),
+                wEl.type() != BSONType::Object);
+    }
+
+    if (wEl.isNumber()) {
+        auto wNum = wEl.safeNumberLong();
+        if (wNum < 0 || wNum > static_cast<long long>(repl::ReplSetConfig::kMaxMembers)) {
+            uasserted(ErrorCodes::FailedToParse,
+                      "w has to be a non-negative number and not greater than {}; found: {}"_format(
+                          repl::ReplSetConfig::kMaxMembers, wNum));
+        }
+
+        return WriteConcernW{wNum};
+    } else if (wEl.type() == BSONType::String) {
+        return WriteConcernW{wEl.str()};
+    } else if (wEl.type() == BSONType::Object) {
+        auto wTags = wEl.Obj();
+        uassert(ErrorCodes::FailedToParse, "tagged write concern requires tags", !wTags.isEmpty());
+
+        WTags tags;
+        for (auto e : wTags) {
+            uassert(
+                ErrorCodes::FailedToParse,
+                "tags must be a single level document with only number values; found: {}"_format(
+                    e.toString()),
+                e.isNumber());
+
+            tags.try_emplace(e.fieldName(), e.safeNumberInt());
+        }
+
+        return WriteConcernW{std::move(tags)};
+    } else if (wEl.eoo() || wEl.type() == BSONType::jstNULL || wEl.type() == BSONType::Undefined) {
+        return WriteConcernW{};
+    }
+    uasserted(ErrorCodes::FailedToParse,
+              "w has to be a number, string, or object; found: {}"_format(typeName(wEl.type())));
+}
+
+void serializeWriteConcernW(const WriteConcernW& w, StringData fieldName, BSONObjBuilder* builder) {
+    stdx::visit(
+        visit_helper::Overloaded{[&](int64_t wNumNodes) {
+                                     builder->appendNumber(fieldName,
+                                                           static_cast<long long>(wNumNodes));
+                                 },
+                                 [&](std::string wMode) { builder->append(fieldName, wMode); },
+                                 [&](WTags wTags) { builder->append(fieldName, wTags); }},
+        w);
+}
+
+std::int64_t parseWTimeoutFromBSON(BSONElement element) {
+    constexpr std::array<mongo::BSONType, 4> validTypes{
+        NumberLong, NumberInt, NumberDecimal, NumberDouble};
+    bool isValidType = std::any_of(
+        validTypes.begin(), validTypes.end(), [&](auto type) { return element.type() == type; });
+    return isValidType ? element.safeNumberLong() : 0;
+}
+
 BSONObj WriteConcernOptions::toBSON() const {
     BSONObjBuilder builder;
     serializeWriteConcernW(w, "w", &builder);
diff --git a/src/mongo/db/write_concern_options.h b/src/mongo/db/write_concern_options.h
index 4478aa173fe..e1525ec29f3 100644
--- a/src/mongo/db/write_concern_options.h
+++ b/src/mongo/db/write_concern_options.h
@@ -33,12 +33,14 @@
 
 #include "mongo/db/jsobj.h"
 #include "mongo/db/read_write_concern_provenance.h"
-#include "mongo/idl/basic_types_gen.h"
 
 namespace mongo {
 
 class Status;
 
+using WTags = StringMap<int64_t>;
+using WriteConcernW = stdx::variant<std::string, std::int64_t, WTags>;
+
 struct WriteConcernOptions {
 public:
     enum class SyncMode { UNSET, NONE, FSYNC, JOURNAL };
@@ -175,4 +177,9 @@ private:
     ReadWriteConcernProvenance _provenance;
 };
 
+// Helpers for IDL parsing
+WriteConcernW deserializeWriteConcernW(BSONElement wEl);
+void serializeWriteConcernW(const WriteConcernW& w, StringData fieldName, BSONObjBuilder* builder);
+std::int64_t parseWTimeoutFromBSON(BSONElement element);
+
 }  // namespace mongo
diff --git a/src/mongo/db/write_concern_options.idl b/src/mongo/db/write_concern_options.idl
index 07c3cdbffc4..8f9c595f24e 100644
--- a/src/mongo/db/write_concern_options.idl
+++ b/src/mongo/db/write_concern_options.idl
@@ -33,7 +33,7 @@ global:
 
 imports:
     - "mongo/idl/basic_types.idl"
-
+    - "mongo/db/read_write_concern_provenance_base.idl"
 
 types:
     WriteConcern:
@@ -42,3 +42,63 @@ types:
         cpp_type: "mongo::WriteConcernOptions"
         serializer: "mongo::WriteConcernOptions::toBSON"
         deserializer: "mongo::WriteConcernOptions::deserializerForIDL"
+
+    writeConcernW:
+        bson_serialization_type: any
+        description: >-
+            A string or integer representing the 'w' option in a document specifying write concern.
+            See https://docs.mongodb.com/manual/reference/write-concern/"
+        cpp_type: "mongo::WriteConcernW"
+        serializer: "::mongo::serializeWriteConcernW"
+        deserializer: "::mongo::deserializeWriteConcernW"
+
+    writeConcernWTimeout:
+        bson_serialization_type: any
+        description: >-
+            An integer representing the 'wtimeout' option in a document specifying write concern.
+            See https://docs.mongodb.com/manual/reference/write-concern/"
+        cpp_type: std::int64_t
+        deserializer: "::mongo::parseWTimeoutFromBSON"
+
+structs:
+    WriteConcernIdl:
+        description: "WriteConcern object parser"
+        strict: true
+        fields:
+            w:
+                type: writeConcernW
+                cpp_name: writeConcernW
+                optional: true
+                unstable: false
+            j:
+                type: safeBool
+                optional: true
+                unstable: false
+            wtimeout:
+                type: writeConcernWTimeout
+                default: 0
+                unstable: false
+            fsync:
+                type: safeBool
+                optional: true
+                unstable: false
+            # Fields with names wElectionId, wOpTime, and getLastError are accepted in the WriteConcern document for
+            # backwards-compatibility reasons, but their values are entirely ignored.
+            wElectionId:
+                type: any
+                ignore: true
+                unstable: false
+            wOpTime:
+                type: any
+                ignore: true
+                unstable: false
+            getLastError:
+                type: any
+                ignore: true
+                unstable: false
+            provenance:
+                description: "The source for this provenance"
+                cpp_name: source
+                type: ReadWriteConcernProvenanceSource
+                optional: true
+                unstable: false
diff --git a/src/mongo/db/write_concern_options_test.cpp b/src/mongo/db/write_concern_options_test.cpp
index e9a3d111a08..abce6fa331e 100644
--- a/src/mongo/db/write_concern_options_test.cpp
+++ b/src/mongo/db/write_concern_options_test.cpp
@@ -187,6 +187,10 @@ TEST(WriteConcernOptionsTest, ParseWithTags) {
     ASSERT_STRING_CONTAINS(status.reason(),
                            "tags must be a single level document with only number values");
 
+    status = WriteConcernOptions::parse(BSON("w" << BSONObj())).getStatus();
+    ASSERT_EQUALS(ErrorCodes::FailedToParse, status);
+    ASSERT_STRING_CONTAINS(status.reason(), "tagged write concern requires tags");
+
     auto sw = WriteConcernOptions::parse(BSON("w" << BSON("abc" << 1)));
     ASSERT_OK(sw.getStatus());
 
@@ -209,5 +213,13 @@ TEST(WriteConcernOptionsTest, ParseWithTags) {
     ASSERT(wc != wc5);
 }
 
+TEST(WriteConcernOptionsTest, WTagsNotPermittedFCVLessThan53) {
+    serverGlobalParams.mutableFeatureCompatibility.setVersion(
+        multiversion::FeatureCompatibilityVersion::kVersion_5_2);
+    auto status = WriteConcernOptions::parse(BSON("w" << BSON("abc" << 1))).getStatus();
+    ASSERT_EQUALS(ErrorCodes::FailedToParse, status);
+    ASSERT_STRING_CONTAINS(status.reason(), "w has to be a number or string");
+}
+
 }  // namespace
 }  // namespace mongo