SERVER-21388 validate captrunc argument

2 files changed, 12 insertions, 0 deletions

diff --git a/jstests/noPassthroughWithMongod/capped_truncate.js b/jstests/noPassthroughWithMongod/capped_truncate.js
index 1c7771ce0bd..8408ea7294b 100644
--- a/jstests/noPassthroughWithMongod/capped_truncate.js
+++ b/jstests/noPassthroughWithMongod/capped_truncate.js
@@ -17,6 +17,13 @@
                                          autoIndexId: true }));
     var t = db.capped_truncate;
 
+    // It is an error to remove a non-positive number of documents.
+    assert.commandFailed(db.runCommand({ captrunc: "capped_truncate", n: -1 }),
+                         "captrunc didn't return an error when attempting to remove a negative " +
+                         "number of documents");
+    assert.commandFailed(db.runCommand({ captrunc: "capped_truncate", n: 0 }),
+                         "captrunc didn't return an error when attempting to remove 0 documents");
+
     for (var j = 1; j <= 10; j++) {
         assert.writeOK(t.insert({x:j}));
     }
diff --git a/src/mongo/db/commands/test_commands.cpp b/src/mongo/db/commands/test_commands.cpp
index fcfafbf5607..485998c4e3a 100644
--- a/src/mongo/db/commands/test_commands.cpp
+++ b/src/mongo/db/commands/test_commands.cpp
@@ -228,6 +228,11 @@ public:
         int n = cmdObj.getIntField("n");
         bool inc = cmdObj.getBoolField("inc");  // inclusive range?
 
+        if (n <= 0) {
+            return appendCommandStatus(result,
+                                       {ErrorCodes::BadValue, "n must be a positive integer"});
+        }
+
         OldClientWriteContext ctx(txn, fullNs);
         Collection* collection = ctx.getCollection();