SERVER-60817 Check write concern string for validity

15 files changed, 74 insertions, 4 deletions

diff --git a/src/mongo/db/commands/rwc_defaults_commands.cpp b/src/mongo/db/commands/rwc_defaults_commands.cpp
index bb8266929bc..f02cd506186 100644
--- a/src/mongo/db/commands/rwc_defaults_commands.cpp
+++ b/src/mongo/db/commands/rwc_defaults_commands.cpp
@@ -116,6 +116,14 @@ public:
             auto& rwcDefaults = ReadWriteConcernDefaults::get(opCtx->getServiceContext());
             auto newDefaults = rwcDefaults.generateNewCWRWCToBeSavedOnDisk(
                 opCtx, request().getDefaultReadConcern(), request().getDefaultWriteConcern());
+            // We don't want to check if the custom write concern exists on the config servers
+            // because it only has to exist on the actual shards in order to be valid.
+            if (serverGlobalParams.clusterRole != ClusterRole::ConfigServer) {
+                if (auto optWC = newDefaults.getDefaultWriteConcern()) {
+                    uassertStatusOK(
+                        repl::ReplicationCoordinator::get(opCtx)->validateWriteConcern(*optWC));
+                }
+            }
 
             updatePersistedDefaultRWConcernDocument(opCtx, newDefaults);
             LOGV2(20498,
diff --git a/src/mongo/db/repl/repl_set_config.cpp b/src/mongo/db/repl/repl_set_config.cpp
index a626634af15..ecae0048ee3 100644
--- a/src/mongo/db/repl/repl_set_config.cpp
+++ b/src/mongo/db/repl/repl_set_config.cpp
@@ -427,7 +427,7 @@ Status ReplSetConfig::_validate(bool allowSplitHorizonIP) const {
 
 Status ReplSetConfig::checkIfWriteConcernCanBeSatisfied(
     const WriteConcernOptions& writeConcern) const {
-    if (!writeConcern.wMode.empty() && writeConcern.wMode != WriteConcernOptions::kMajority) {
+    if (writeConcern.writeModeIsCustom()) {
         StatusWith<ReplSetTagPattern> tagPatternStatus = findCustomWriteMode(writeConcern.wMode);
         if (!tagPatternStatus.isOK()) {
             return tagPatternStatus.getStatus();
@@ -738,6 +738,13 @@ bool ReplSetConfig::containsCustomizedGetLastErrorDefaults() const {
              getLastErrorDefaults.syncMode == WriteConcernOptions::SyncMode::UNSET);
 }
 
+Status ReplSetConfig::validateWriteConcern(const WriteConcernOptions& writeConcern) const {
+    if (writeConcern.writeModeIsCustom()) {
+        return findCustomWriteMode(writeConcern.wMode).getStatus();
+    }
+    return Status::OK();
+}
+
 bool ReplSetConfig::isSplitConfig() const {
     return !!_recipientConfig;
 }
diff --git a/src/mongo/db/repl/repl_set_config.h b/src/mongo/db/repl/repl_set_config.h
index 0de35a94b9c..0ff4711f14d 100644
--- a/src/mongo/db/repl/repl_set_config.h
+++ b/src/mongo/db/repl/repl_set_config.h
@@ -536,6 +536,12 @@ public:
     bool containsCustomizedGetLastErrorDefaults() const;
 
     /**
+     * Returns Status::OK if write concern is valid for this config, or appropriate status
+     * otherwise.
+     */
+    Status validateWriteConcern(const WriteConcernOptions& writeConcern) const;
+
+    /**
      * Returns true if this config is a split config, which is determined by checking if it contains
      * a recipient config for a shard split operation.
      */
diff --git a/src/mongo/db/repl/replication_coordinator.h b/src/mongo/db/repl/replication_coordinator.h
index db983ff46ce..12dd736fdd0 100644
--- a/src/mongo/db/repl/replication_coordinator.h
+++ b/src/mongo/db/repl/replication_coordinator.h
@@ -673,6 +673,11 @@ public:
     virtual BSONObj getConfigBSON() const = 0;
 
     /**
+     * Validates the given WriteConcernOptions on the current ReplSetConfig.
+     */
+    virtual Status validateWriteConcern(const WriteConcernOptions& writeConcern) const = 0;
+
+    /**
      * Returns a pointer to the MemberConfig corresponding to the member with the given
      * HostAndPort in the current ReplSetConfig, or NULL if there is no member with that address.
      */
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index cb64681b369..55b52fcf4c0 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -3223,6 +3223,12 @@ Milliseconds ReplicationCoordinatorImpl::getConfigHeartbeatInterval() const {
     return _rsConfig.getHeartbeatInterval();
 }
 
+Status ReplicationCoordinatorImpl::validateWriteConcern(
+    const WriteConcernOptions& writeConcern) const {
+    stdx::lock_guard<Latch> lock(_mutex);
+    return _rsConfig.validateWriteConcern(writeConcern);
+}
+
 WriteConcernOptions ReplicationCoordinatorImpl::_getOplogCommitmentWriteConcern(WithLock lk) {
     auto syncMode = getWriteConcernMajorityShouldJournal_inlock()
         ? WriteConcernOptions::SyncMode::JOURNAL
diff --git a/src/mongo/db/repl/replication_coordinator_impl.h b/src/mongo/db/repl/replication_coordinator_impl.h
index 73af8253f16..e2403064ea3 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_impl.h
@@ -257,6 +257,8 @@ public:
 
     virtual Milliseconds getConfigHeartbeatInterval() const override;
 
+    virtual Status validateWriteConcern(const WriteConcernOptions& writeConcern) const override;
+
     virtual void processReplSetGetConfig(BSONObjBuilder* result,
                                          bool commitmentStatus = false,
                                          bool includeNewlyAdded = false) override;
diff --git a/src/mongo/db/repl/replication_coordinator_mock.cpp b/src/mongo/db/repl/replication_coordinator_mock.cpp
index 9a01fdf5c88..f88130cf440 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_mock.cpp
@@ -418,6 +418,12 @@ BSONObj ReplicationCoordinatorMock::getConfigBSON() const {
     return _getConfigReturnValue.toBSON();
 }
 
+Status ReplicationCoordinatorMock::validateWriteConcern(
+    const WriteConcernOptions& writeConcern) const {
+    stdx::lock_guard<Latch> lock(_mutex);
+    return _getConfigReturnValue.validateWriteConcern(writeConcern);
+}
+
 const MemberConfig* ReplicationCoordinatorMock::findConfigMemberByHostAndPort(
     const HostAndPort& hap) const {
     stdx::lock_guard<Mutex> lock(_mutex);
diff --git a/src/mongo/db/repl/replication_coordinator_mock.h b/src/mongo/db/repl/replication_coordinator_mock.h
index cb17793befe..d927664194a 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_mock.h
@@ -220,6 +220,8 @@ public:
     virtual const MemberConfig* findConfigMemberByHostAndPort(
         const HostAndPort& hap) const override;
 
+    virtual Status validateWriteConcern(const WriteConcernOptions& writeConcern) const override;
+
     virtual bool isConfigLocalHostAllowed() const override;
 
     virtual Milliseconds getConfigHeartbeatInterval() const override;
diff --git a/src/mongo/db/repl/replication_coordinator_noop.cpp b/src/mongo/db/repl/replication_coordinator_noop.cpp
index 38639d12dab..e2d0994e89d 100644
--- a/src/mongo/db/repl/replication_coordinator_noop.cpp
+++ b/src/mongo/db/repl/replication_coordinator_noop.cpp
@@ -346,6 +346,11 @@ Milliseconds ReplicationCoordinatorNoOp::getConfigHeartbeatInterval() const {
     MONGO_UNREACHABLE;
 }
 
+Status ReplicationCoordinatorNoOp::validateWriteConcern(
+    const WriteConcernOptions& writeConcern) const {
+    MONGO_UNREACHABLE;
+}
+
 void ReplicationCoordinatorNoOp::processReplSetGetConfig(BSONObjBuilder* result,
                                                          bool commitmentStatus,
                                                          bool includeNewlyAdded) {
diff --git a/src/mongo/db/repl/replication_coordinator_noop.h b/src/mongo/db/repl/replication_coordinator_noop.h
index 6764deafacd..c355ce73e37 100644
--- a/src/mongo/db/repl/replication_coordinator_noop.h
+++ b/src/mongo/db/repl/replication_coordinator_noop.h
@@ -197,6 +197,8 @@ public:
 
     Milliseconds getConfigHeartbeatInterval() const final;
 
+    Status validateWriteConcern(const WriteConcernOptions& writeConcern) const final;
+
     void processReplSetGetConfig(BSONObjBuilder*,
                                  bool commitmentStatus = false,
                                  bool includeNewlyAdded = false) final;
diff --git a/src/mongo/db/write_concern.cpp b/src/mongo/db/write_concern.cpp
index 2cdd02e6913..f574d63ef72 100644
--- a/src/mongo/db/write_concern.cpp
+++ b/src/mongo/db/write_concern.cpp
@@ -189,10 +189,9 @@ Status validateWriteConcern(OperationContext* opCtx, const WriteConcernOptions&
         return Status(ErrorCodes::BadValue, "cannot use 'w' > 1 when a host is not replicated");
     }
 
-    if (replMode != repl::ReplicationCoordinator::modeReplSet && !writeConcern.wMode.empty() &&
-        writeConcern.wMode != WriteConcernOptions::kMajority) {
+    if (replMode != repl::ReplicationCoordinator::modeReplSet && writeConcern.writeModeIsCustom()) {
         return Status(ErrorCodes::BadValue,
-                      string("cannot use non-majority 'w' mode ") + writeConcern.wMode +
+                      string("cannot use custom 'w' mode ") + writeConcern.wMode +
                           " when a host is not a member of a replica set");
     }
 
diff --git a/src/mongo/db/write_concern_options.h b/src/mongo/db/write_concern_options.h
index 2eb0468b804..039a2c3a4a2 100644
--- a/src/mongo/db/write_concern_options.h
+++ b/src/mongo/db/write_concern_options.h
@@ -130,6 +130,10 @@ public:
         return usedDefaultConstructedWC || _provenance.isImplicitDefault();
     }
 
+    bool writeModeIsCustom() const {
+        return !wMode.empty() && wMode != WriteConcernOptions::kMajority;
+    }
+
     SyncMode syncMode;
 
     // The w parameter for this write concern. The wMode represents the string format and
diff --git a/src/mongo/embedded/replication_coordinator_embedded.cpp b/src/mongo/embedded/replication_coordinator_embedded.cpp
index 784de9edccf..b178e9d1972 100644
--- a/src/mongo/embedded/replication_coordinator_embedded.cpp
+++ b/src/mongo/embedded/replication_coordinator_embedded.cpp
@@ -372,6 +372,11 @@ Milliseconds ReplicationCoordinatorEmbedded::getConfigHeartbeatInterval() const
     UASSERT_NOT_IMPLEMENTED;
 }
 
+Status ReplicationCoordinatorEmbedded::validateWriteConcern(
+    const WriteConcernOptions& writeConcern) const {
+    UASSERT_NOT_IMPLEMENTED;
+}
+
 void ReplicationCoordinatorEmbedded::processReplSetGetConfig(BSONObjBuilder*,
                                                              bool commitmentStatus,
                                                              bool includeNewlyAdded) {
diff --git a/src/mongo/embedded/replication_coordinator_embedded.h b/src/mongo/embedded/replication_coordinator_embedded.h
index b41f8430096..9a6bad99f28 100644
--- a/src/mongo/embedded/replication_coordinator_embedded.h
+++ b/src/mongo/embedded/replication_coordinator_embedded.h
@@ -206,6 +206,8 @@ public:
 
     Milliseconds getConfigHeartbeatInterval() const override;
 
+    Status validateWriteConcern(const WriteConcernOptions& writeConcern) const override;
+
     void processReplSetGetConfig(BSONObjBuilder*,
                                  bool commitmentStatus = false,
                                  bool includeNewlyAdded = false) override;
diff --git a/src/mongo/s/commands/cluster_rwc_defaults_commands.cpp b/src/mongo/s/commands/cluster_rwc_defaults_commands.cpp
index abb36e4ab89..6bf1755941d 100644
--- a/src/mongo/s/commands/cluster_rwc_defaults_commands.cpp
+++ b/src/mongo/s/commands/cluster_rwc_defaults_commands.cpp
@@ -36,6 +36,7 @@
 #include "mongo/db/commands/rwc_defaults_commands_gen.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/read_write_concern_defaults.h"
+#include "mongo/logv2/log.h"
 #include "mongo/s/cluster_commands_helpers.h"
 #include "mongo/s/grid.h"
 
@@ -70,6 +71,16 @@ public:
         // Quickly pick up the new defaults by setting them in the cache.
         auto newDefaults = RWConcernDefault::parse(
             IDLParserErrorContext("ClusterSetDefaultRWConcern"), cmdResponse.response);
+        if (auto optWC = newDefaults.getDefaultWriteConcern()) {
+            if (optWC->writeModeIsCustom()) {
+                LOGV2_WARNING(
+                    6081700,
+                    "A custom write concern is being set as the default write concern in a sharded "
+                    "cluster. This set is unchecked, but if the custom write concern does not "
+                    "exist on all shards in the cluster, errors will occur upon writes",
+                    "customWriteConcern"_attr = optWC->wMode);
+            }
+        }
         ReadWriteConcernDefaults::get(opCtx).setDefault(opCtx, std::move(newDefaults));
 
         CommandHelpers::filterCommandReplyForPassthrough(cmdResponse.response, &result);