SERVER-35804 Disallow dropping config and admin from mongos

7 files changed, 27 insertions, 174 deletions

diff --git a/jstests/sharding/basic_drop_coll.js b/jstests/sharding/basic_drop_coll.js
index e457dc5c9fd..dd868506a24 100644
--- a/jstests/sharding/basic_drop_coll.js
+++ b/jstests/sharding/basic_drop_coll.js
@@ -17,6 +17,11 @@ assert.neq(null, testDB.bar.findOne({x: 1}));
 assert.commandWorked(testDB.runCommand({drop: 'bar'}));
 assert.eq(null, testDB.bar.findOne({x: 1}));
 
+assert.commandFailedWithCode(st.s.getDB('admin').runCommand({drop: 'secrets'}),
+                             ErrorCodes.IllegalOperation);
+assert.commandFailedWithCode(st.s.getDB('config').runCommand({drop: 'settings'}),
+                             ErrorCodes.IllegalOperation);
+
 // Test dropping a sharded collection.
 
 assert.commandWorked(st.s.adminCommand({enableSharding: 'test'}));
diff --git a/jstests/sharding/configsvr_metadata_commands_require_majority_write_concern.js b/jstests/sharding/configsvr_metadata_commands_require_majority_write_concern.js
index 8edcab6b8e8..14a866ab7d7 100644
--- a/jstests/sharding/configsvr_metadata_commands_require_majority_write_concern.js
+++ b/jstests/sharding/configsvr_metadata_commands_require_majority_write_concern.js
@@ -169,7 +169,15 @@ checkCommandConfigSvr(
     {_configsvrRemoveShard: newShardName}, setupFuncs.addShard, cleanupFuncs.noop);
 
 // dropCollection
-checkCommandMongos({drop: ns}, setupFuncs.createDatabase, cleanupFuncs.dropDatabase);
+// We can't use the checkCommandMongos wrapper because it calls adminCommand and dropping admin
+// collections are not allowed in mongos.
+checkCommand(st.s.getDB(dbName),
+             {drop: collName},
+             unacceptableWCsForMongos,
+             acceptableWCsForMongos,
+             false,
+             setupFuncs.createDatabase,
+             cleanupFuncs.dropDatabase);
 checkCommandConfigSvr(
     {_configsvrDropCollection: ns}, setupFuncs.createDatabase, cleanupFuncs.dropDatabase);
 
diff --git a/jstests/sharding/drop_collection_in_admin_and_config_dbs.js b/jstests/sharding/drop_collection_in_admin_and_config_dbs.js
deleted file mode 100644
index 0015204b0c9..00000000000
--- a/jstests/sharding/drop_collection_in_admin_and_config_dbs.js
+++ /dev/null
@@ -1,137 +0,0 @@
-/**
- * The admin and config databases are special in that their primary shard is always the config
- * shard. This test verifies that dropping unsharded collections in the admin or config database
- * applies the drop on (only) the config shard.
- */
-
-(function() {
-"use strict";
-
-load("jstests/sharding/libs/track_unsharded_collections_helpers.js");
-
-// Disable the logical session cache refresh on config servers because it auto-recreates the
-// config.system.sessions collection if config.system.sessions is dropped, and this test manually
-// controls config.system.sessions.
-const st = new ShardingTest({
-    shards: 1,
-    other: {configOptions: {setParameter: {"disableLogicalSessionCacheRefresh": true}}}
-});
-
-(() => {
-    jsTest.log(
-        "Dropping a user collection in the admin database only executes on the config shard");
-
-    const [collName, ns] = getNewNs("admin");
-
-    // Insert a document through mongos; it should be inserted on the config shard.
-    assert.commandWorked(st.s.getDB("admin").getCollection(collName).insert(
-        {_id: 1}, {writeConcern: {w: "majority"}}));
-    assert.eq({_id: 1}, st.configRS.getPrimary().getDB("admin").getCollection(collName).findOne());
-    assert.eq(null, st.rs0.getPrimary().getDB("admin").getCollection(collName).findOne());
-
-    // Insert a document directly on the shard.
-    assert.commandWorked(st.shard0.getDB("admin").getCollection(collName).insert(
-        {_id: 2}, {writeConcern: {w: "majority"}}));
-    assert.eq({_id: 2}, st.rs0.getPrimary().getDB("admin").getCollection(collName).findOne());
-
-    // Drop the collection through mongos; it should be executed only on the config shard.
-    st.s.getDB("admin").getCollection(collName).drop();
-    assert.eq(null, st.configRS.getPrimary().getDB("admin").getCollection(collName).findOne());
-    assert.eq({_id: 2}, st.rs0.getPrimary().getDB("admin").getCollection(collName).findOne());
-})();
-
-(() => {
-    jsTest.log(
-        "Dropping a user collection in the config database only executes on the config shard");
-
-    const [collName, ns] = getNewNs("config");
-
-    // Insert a document through mongos; it should be inserted on the config shard.
-    assert.commandWorked(st.s.getDB("config").getCollection(collName).insert(
-        {_id: 1}, {writeConcern: {w: "majority"}}));
-    assert.eq({_id: 1}, st.configRS.getPrimary().getDB("config").getCollection(collName).findOne());
-    assert.eq(null, st.rs0.getPrimary().getDB("config").getCollection(collName).findOne());
-
-    // Insert a document directly on the shard.
-    assert.commandWorked(st.shard0.getDB("config").getCollection(collName).insert(
-        {_id: 2}, {writeConcern: {w: "majority"}}));
-    assert.eq({_id: 2}, st.rs0.getPrimary().getDB("config").getCollection(collName).findOne());
-
-    // Drop the collection through mongos; it should be executed only on the config shard.
-    st.s.getDB("config").getCollection(collName).drop();
-    assert.eq(null, st.configRS.getPrimary().getDB("config").getCollection(collName).findOne());
-    assert.eq({_id: 2}, st.rs0.getPrimary().getDB("config").getCollection(collName).findOne());
-})();
-
-(() => {
-    jsTest.log("Dropping config.system.sessions always only executes on non-config shards");
-
-    // Wait for the config.system.sessions collection to be created and sharded.
-    assert.soon(function() {
-        return st.s.getDB("config").collections.findOne({_id: "config.system.sessions"}) != null;
-    });
-    assert.eq(0,
-              st.configRS.getPrimary()
-                  .getDB("config")
-                  .getCollectionInfos({name: "system.sessions"})
-                  .length);
-    assert.eq(1, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-
-    // Create a separate config.system.sessions directly on the config shard.
-    assert.commandWorked(st.configRS.getPrimary().getDB("config").system.sessions.insert(
-        {_id: 1}, {writeConcern: {w: "majority"}}));
-    assert.eq(1,
-              st.configRS.getPrimary()
-                  .getDB("config")
-                  .getCollectionInfos({name: "system.sessions"})
-                  .length);
-
-    // Drop the config.system.sessions collection through mongos; the drop should be executed only
-    // on the regular shard.
-    st.s.getDB("config").system.sessions.drop();
-    assert.eq(0, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-    assert.eq(1,
-              st.configRS.getPrimary()
-                  .getDB("config")
-                  .getCollectionInfos({name: "system.sessions"})
-                  .length);
-
-    // Re-create a config.system.sessions collection directly on the regular shard.
-    assert.commandWorked(st.shard0.getDB("config").system.sessions.insert(
-        {_id: 2}, {writeConcern: {w: "majority"}}));
-    assert.eq(1, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-
-    // Drop the config.system.sessions collection through mongos; the drop should be executed only
-    // on the regular shard even though config.system.sessions is marked as dropped: true.
-    assert.eq(true,
-              st.s.getDB("config").collections.findOne({_id: "config.system.sessions"}).dropped);
-    st.s.getDB("config").system.sessions.drop();
-    assert.eq(0, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-    assert.eq(1,
-              st.configRS.getPrimary()
-                  .getDB("config")
-                  .getCollectionInfos({name: "system.sessions"})
-                  .length);
-
-    // Re-create a config.system.sessions collection directly on the regular shard.
-    assert.commandWorked(st.shard0.getDB("config").system.sessions.insert(
-        {_id: 2}, {writeConcern: {w: "majority"}}));
-    assert.eq(1, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-
-    // Remove the entry for config.system.sessions from config.collections.
-    assert.commandWorked(st.s.getDB("config").collections.remove({_id: "config.system.sessions"},
-                                                                 {writeConcern: {w: "majority"}}));
-
-    // Drop the config.system.sessions collection through mongos; the drop should be executed only
-    // on the regular shard even though config.system.sessions is not in config.collections.
-    st.s.getDB("config").system.sessions.drop();
-    assert.eq(0, st.shard0.getDB("config").getCollectionInfos({name: "system.sessions"}).length);
-    assert.eq(1,
-              st.configRS.getPrimary()
-                  .getDB("config")
-                  .getCollectionInfos({name: "system.sessions"})
-                  .length);
-})();
-
-st.stop();
-})();
diff --git a/jstests/sharding/drop_configdb.js b/jstests/sharding/drop_configdb.js
index 180741530b9..5e2b704cf6d 100644
--- a/jstests/sharding/drop_configdb.js
+++ b/jstests/sharding/drop_configdb.js
@@ -3,17 +3,9 @@
 (function() {
 "use strict";
 
-var getConfigsvrToWriteTo = function(st) {
-    if (st.configRS) {
-        return st.configRS.getPrimary();
-    } else {
-        return st._configServers[0];
-    }
-};
-
 var st = new ShardingTest({shards: 2});
 var mongos = st.s;
-var config = getConfigsvrToWriteTo(st).getDB('config');
+var config = st.configRS.getPrimary().getDB('config');
 
 // Try to drop config db via configsvr
 
@@ -26,10 +18,8 @@ assert.eq("Cannot drop 'config' database if mongod started with --configsvr",
 var config = mongos.getDB("config");
 
 print("1: Try to drop config database via mongos");
-assert.eq(0, config.dropDatabase().ok);
-
-// 20 = ErrorCodes::IllegalOperation
-assert.eq(20, config.dropDatabase().code);
+assert.commandFailedWithCode(config.dropDatabase(), ErrorCodes.IllegalOperation);
+assert.commandFailedWithCode(mongos.getDB("admin").dropDatabase(), ErrorCodes.IllegalOperation);
 
 st.stop();
-}());
\ No newline at end of file
+}());
diff --git a/jstests/sharding/query_config.js b/jstests/sharding/query_config.js
index 889999b6173..582d9899940 100644
--- a/jstests/sharding/query_config.js
+++ b/jstests/sharding/query_config.js
@@ -84,7 +84,9 @@ var testListConfigCollections = function(st) {
     var cursor;
     var cursorArray;
 
-    dropCollectionIfExists(userAddedColl);
+    // Dropping collections under config is not allowed via mongos.
+    let configPrimary = st.configRS.getPrimary();
+    dropCollectionIfExists(configPrimary.getDB("config").userAddedColl);
     configDB.createCollection(userAddedColl.getName());
     configCollList.push(userAddedColl.getName());
 
@@ -103,8 +105,6 @@ var testListConfigCollections = function(st) {
     assert(cursor.hasNext());
     assert.eq(cursor.objsLeftInBatch(), 1);
     assert(cursorArray.indexOf(cursor.next().name) > -1);
-
-    assert(userAddedColl.drop());
 };
 
 /**
@@ -256,8 +256,9 @@ var queryUserCreated = function(database) {
     var cursorArray;
     var result;
 
-    // Setup.
-    dropCollectionIfExists(userColl);
+    // Dropping collections under config is not allowed via mongos.
+    let configPrimary = st.configRS.getPrimary();
+    dropCollectionIfExists(configPrimary.getDB(database.getName()).userColl);
     for (var i = 0; i < userCollData.length; i++) {
         assert.commandWorked(userColl.insert(userCollData[i]));
     }
@@ -328,8 +329,6 @@ var queryUserCreated = function(database) {
     assert.eq(
         sortArrayById(result.results),
         [{_id: 1, value: {count: 2}}, {_id: 2, value: {count: 3}}, {_id: 3, value: {count: 2}}]);
-
-    assert(userColl.drop());
 };
 
 var st = new ShardingTest({shards: 2, mongos: 1});
diff --git a/jstests/sharding/range_deleter_interacts_correctly_with_refine_shard_key.js b/jstests/sharding/range_deleter_interacts_correctly_with_refine_shard_key.js
index 74241d79631..bba1f712d2f 100644
--- a/jstests/sharding/range_deleter_interacts_correctly_with_refine_shard_key.js
+++ b/jstests/sharding/range_deleter_interacts_correctly_with_refine_shard_key.js
@@ -355,10 +355,10 @@ function test(st, description, testBody) {
              hangDonorAtEndOfMigration.off();
 
              // TODO (SERVER-47003): There will be a left-over entry in config.migrations after the
-             // previous moveChunk fails with MaxTimeMSExpired, so we drop the collection. Otherwise
-             // future migrations would receive a DuplicateKeyError when trying to update
+             // previous moveChunk fails with MaxTimeMSExpired, so we clear the collection.
+             // Otherwise future migrations would receive a DuplicateKeyError when trying to update
              // config.migrations.
-             st.config.getSiblingDB('config').migrations.drop();
+             st.config.getSiblingDB('config').migrations.remove({}, false /* justOne */);
          });
 
     test(st,
diff --git a/jstests/sharding/sessions_collection_auto_healing.js b/jstests/sharding/sessions_collection_auto_healing.js
index 6efb9cf2274..6e80c992776 100644
--- a/jstests/sharding/sessions_collection_auto_healing.js
+++ b/jstests/sharding/sessions_collection_auto_healing.js
@@ -146,18 +146,6 @@ var shardConfig = shard.getDB("config");
     validateSessionsCollection(shard, true, false);
 }
 
-// Test that if we drop the collection, it will be recreated only by the config server.
-{
-    assertDropCollection(mongosConfig, "system.sessions");
-    validateSessionsCollection(shard, false, false);
-
-    assert.commandWorked(shardAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
-    validateSessionsCollection(shard, false, false);
-
-    assert.commandWorked(configAdmin.runCommand({refreshLogicalSessionCacheNow: 1}));
-    validateSessionsCollection(shard, true, true);
-}
-
 st.stop();
 rs.stopSet();
 })();