SERVER-119317 Improve object lifecycle of MD5 hash state (#47995)

GitOrigin-RevId: 5d25c835745d06f712320b6cdae9d50b7b43663e

etc/backports_required_for_multiversion_tests.yml

@@ -21,6 +21,8 @@
 #
 last-continuous:
   all:
+    - test_file: jstests/core/administrative/filemd5.js
+      ticket: SERVER-119317
     - test_file: jstests/core/index/elemmatch_index.js
       ticket: SERVER-108945
     - test_file: jstests/replsets/malformed_heartbeat_request.js
@@ -525,6 +527,8 @@ last-continuous:
   suites: null
 last-lts:
   all:
+    - test_file: jstests/core/administrative/filemd5.js
+      ticket: SERVER-119317
     - test_file: jstests/core/index/elemmatch_index.js
       ticket: SERVER-108945
     - test_file: jstests/replsets/malformed_heartbeat_request.js

jstests/core/administrative/filemd5.js

@@ -20,4 +20,25 @@ assert.commandFailedWithCode(db.runCommand({filemd5: 1, root: "fs", partialOk: 1
 assert.commandWorked(db.fs.chunks.insert({files_id: 2, n: 0}));
 assert.commandFailedWithCode(db.runCommand({filemd5: 2, root: "fs"}), 50848);
 assert.commandWorked(db.fs.chunks.update({files_id: 2, n: 0}, {$set: {data: 5}}));
-assert.commandFailedWithCode(db.runCommand({filemd5: 2, root: "fs"}), 50849);
+assert.commandFailedWithCode(db.runCommand({filemd5: 2, root: "fs"}), 50849);
+
+{
+    const result = assert.commandWorked(
+        db.runCommand({
+            filemd5: ObjectId("000000000000000000000000"),
+            root: "fs",
+            partialOk: true,
+        }),
+    );
+
+    assert(result.md5state !== undefined,
+           "Expected md5state in filemd5 response with partialOk: true");
+    const hex = result.md5state.hex();
+    const totalBytes = hex.length / 2;
+    assert.gt(totalBytes, 100, "md5state expected to be larger than 100 bytes");
+
+    const checkFromByte = 100;
+    const paddingHex = hex.substring(checkFromByte * 2);
+    const allZeros = "0".repeat(paddingHex.length);
+    assert.eq(paddingHex, allZeros, "md5state expected to be zero padded");
+}

src/mongo/util/md5.cpp

@@ -35,6 +35,7 @@
 namespace mongo {
 
 void md5_init_state(md5_state_t* pms) {
+    memset(pms, 0, sizeof(md5_state_t));
     md5_init(pms);
 }