SERVER-45920 Validate writeConcern.w

6 files changed, 27 insertions, 6 deletions

diff --git a/jstests/replsets/drop_db.js b/jstests/replsets/drop_db.js
index 49ee3e04406..bebc101a7f9 100644
--- a/jstests/replsets/drop_db.js
+++ b/jstests/replsets/drop_db.js
@@ -49,10 +49,10 @@ checkWriteConcern(() => assert.commandWorked(primaryDB.dropDatabase({w: 1})), (c
 });
 
 primaryDB.createCollection(collName);
-checkWriteConcern(() => assert.commandFailedWithCode(primaryDB.dropDatabase({w: 100000}),
+checkWriteConcern(() => assert.commandFailedWithCode(primaryDB.dropDatabase({w: 45}),
                                                      ErrorCodes.UnsatisfiableWriteConcern),
                   (cmdObj) => {
-                      assert.eq(cmdObj.writeConcern, {w: 100000});
+                      assert.eq(cmdObj.writeConcern, {w: 45});
                   });
 
 rst.stopSet();
diff --git a/jstests/replsets/server_status_metrics.js b/jstests/replsets/server_status_metrics.js
index f3579a44a2d..28178a4711e 100644
--- a/jstests/replsets/server_status_metrics.js
+++ b/jstests/replsets/server_status_metrics.js
@@ -175,7 +175,8 @@ assert.commandWorked(testDB.a.insert({x: 1}, {writeConcern: {w: 1, wtimeout: 500
 assert.eq(testDB.serverStatus().metrics.getLastError.wtime.totalMillis, startMillis);
 assert.eq(testDB.serverStatus().metrics.getLastError.wtime.num, startNum);
 
-assert.commandWorked(testDB.a.insert({x: 1}, {writeConcern: {w: -11, wtimeout: 5000}}));
+assert.commandFailedWithCode(testDB.a.insert({x: 1}, {writeConcern: {w: -11, wtimeout: 5000}}),
+                             ErrorCodes.FailedToParse);
 assert.eq(testDB.serverStatus().metrics.getLastError.wtime.totalMillis, startMillis);
 assert.eq(testDB.serverStatus().metrics.getLastError.wtime.num, startNum);
 
diff --git a/src/mongo/db/repl/repl_set_config.cpp b/src/mongo/db/repl/repl_set_config.cpp
index c19addc5cda..375e2a73d61 100644
--- a/src/mongo/db/repl/repl_set_config.cpp
+++ b/src/mongo/db/repl/repl_set_config.cpp
@@ -47,7 +47,6 @@ namespace repl {
 // Allow the heartbeat interval to be forcibly overridden on this node.
 MONGO_FAIL_POINT_DEFINE(forceHeartbeatIntervalMS);
 
-const size_t ReplSetConfig::kMaxMembers;
 const size_t ReplSetConfig::kMaxVotingMembers;
 const Milliseconds ReplSetConfig::kInfiniteCatchUpTimeout(-1);
 const Milliseconds ReplSetConfig::kCatchUpDisabled(0);
diff --git a/src/mongo/db/repl/repl_set_config.h b/src/mongo/db/repl/repl_set_config.h
index 66075c5c105..d5f065d5f7b 100644
--- a/src/mongo/db/repl/repl_set_config.h
+++ b/src/mongo/db/repl/repl_set_config.h
@@ -63,7 +63,11 @@ public:
     // should never be included in a valid configuration document.
     static const std::string kRepairedFieldName;
 
-    static const size_t kMaxMembers = 50;
+    /**
+     * Inline `kMaxMembers` to allow others (e.g, `WriteConcernOptions`) use
+     * the constant without linking to `repl_set_config.cpp`.
+     */
+    inline static const size_t kMaxMembers = 50;
     static const size_t kMaxVotingMembers = 7;
     static const Milliseconds kInfiniteCatchUpTimeout;
     static const Milliseconds kCatchUpDisabled;
diff --git a/src/mongo/db/write_concern_options.cpp b/src/mongo/db/write_concern_options.cpp
index 80e1c8bd0e4..f24ec703469 100644
--- a/src/mongo/db/write_concern_options.cpp
+++ b/src/mongo/db/write_concern_options.cpp
@@ -35,6 +35,7 @@
 #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/util/str.h"
 
 namespace mongo {
@@ -151,7 +152,14 @@ StatusWith<WriteConcernOptions> WriteConcernOptions::parse(const BSONObj& obj) {
     }
 
     if (wEl.isNumber()) {
-        writeConcern.wNumNodes = wEl.numberInt();
+        auto wNumNodes = wEl.safeNumberLong();
+        if (wNumNodes < 0 ||
+            wNumNodes > static_cast<decltype(wNumNodes)>(repl::ReplSetConfig::kMaxMembers)) {
+            return Status(ErrorCodes::FailedToParse,
+                          str::stream() << "w has to be a non-negative number and not greater than "
+                                        << repl::ReplSetConfig::kMaxMembers);
+        }
+        writeConcern.wNumNodes = static_cast<decltype(writeConcern.wNumNodes)>(wNumNodes);
         writeConcern.usedDefaultW = false;
     } else if (wEl.type() == String) {
         writeConcern.wNumNodes = 0;
diff --git a/src/mongo/db/write_concern_options_test.cpp b/src/mongo/db/write_concern_options_test.cpp
index d99eaab2204..70df61cb16a 100644
--- a/src/mongo/db/write_concern_options_test.cpp
+++ b/src/mongo/db/write_concern_options_test.cpp
@@ -110,6 +110,15 @@ TEST(WriteConcernOptionsTest, ParseReturnsFailedToParseIfWIsNotNumberOrString) {
     ASSERT_EQUALS("w has to be a number or a string", status.reason());
 }
 
+TEST(WriteConcernOptionsTest, ParseReturnsFailedToParseIfWIsNegativeOrExceedsMaxMembers) {
+    auto st1 = WriteConcernOptions::parse(BSON("w" << 123)).getStatus();
+    ASSERT_EQUALS(ErrorCodes::FailedToParse, st1);
+
+    auto st2 = WriteConcernOptions::parse(BSON("w" << -1)).getStatus();
+    ASSERT_EQUALS(ErrorCodes::FailedToParse, st2);
+    ASSERT_EQUALS(st1.reason(), st2.reason());
+}
+
 TEST(WriteConcernOptionsTest, ParseSetsWNumNodesIfWIsANumber) {
     auto sw = WriteConcernOptions::parse(BSON("w" << 3));
     ASSERT_OK(sw.getStatus());