sqlite: re-validate database state after reading options

prepare(), function(), aggregate(), deserialize(), applyChangeset() and
backup() validated the connection, then read their options bag with
Object::Get(). A property getter runs arbitrary JavaScript at that
point, so a getter calling close() invalidates what was just checked.
Five of the six then passed a null sqlite3* to SQLite and crashed;
prepare() reported a spurious "out of memory".

Re-check IsOpen() after option parsing, immediately before the SQLite
call, keeping the early check so invalid calls still fail before any
user code runs. IsOpen() is the only condition a getter can change:
authorizer and callback depths are RAII-managed. createSession()
already parsed options first, so it only gains the early check.

deserialize() also latched the buffer length before reading
options.dbName. A getter that shrank the backing store left the length
too large; CopyContents() then handed the uninitialized remainder to
SQLite, from where serialize() returned it to JavaScript. Check the
CopyContents() result instead of discarding it.

function() and aggregate() cast the callback's length property with
As<Int32>() and no IsInt32() guard. length is configurable, so any type
reached the cast and produced a silently wrong arity.

Fixes: #65586
Signed-off-by: Trevor Burnham <trevorburnham@gmail.com>

Author: TrevorBurnham

doc/api/sqlite.md

@@ -243,7 +243,8 @@ Registers a new aggregate function with the SQLite database. This method is a wr
     JavaScript numbers. **Default:** `false`.
   * `varargs` {boolean} If `true`, `options.step` and `options.inverse` may be invoked with any number of
     arguments (between zero and [`SQLITE_MAX_FUNCTION_ARG`][]). If `false`,
-    `inverse` and `step` must be invoked with exactly `length` arguments.
+    `inverse` and `step` must be invoked with exactly `length` arguments, and
+    their `length` properties must be integers.
     **Default:** `false`.
   * `start` {number | string | null | Array | Object | Function} The identity
     value for the aggregation function. This value is used when the aggregation
@@ -430,7 +431,8 @@ added:
     JavaScript numbers. **Default:** `false`.
   * `varargs` {boolean} If `true`, `function` may be invoked with any number of
     arguments (between zero and [`SQLITE_MAX_FUNCTION_ARG`][]). If `false`,
-    `function` must be invoked with exactly `function.length` arguments.
+    `function` must be invoked with exactly `function.length` arguments, which
+    must be an integer.
     **Default:** `false`.
 * `fn` {Function} The JavaScript function to call when the SQLite function is
   invoked. The return value of this function should be a valid SQLite data type:

src/node_sqlite.cc

@@ -1718,6 +1718,10 @@ void DatabaseSync::Prepare(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
+  // Reading the options bag above can run user JavaScript through a property
+  // getter, which may have closed the database since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   Utf8Value sql(env->isolate(), args[0].As<String>());
   sqlite3_stmt* s = nullptr;
 
@@ -1905,9 +1909,22 @@ void DatabaseSync::CustomFunction(const FunctionCallbackInfo<Value>& args) {
     if (!fn->Get(env->context(), env->length_string()).ToLocal(&js_len)) {
       return;
     }
+
+    if (!js_len->IsInt32()) {
+      THROW_ERR_INVALID_ARG_TYPE(
+          env->isolate(),
+          "The \"function.length\" property must be an integer.");
+      return;
+    }
+
     argc = js_len.As<Int32>()->Value();
   }
 
+  // Reading the options bag and "function.length" above can run user
+  // JavaScript through a property getter, which may have closed the database
+  // since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   UserDefinedFunction* user_data = new UserDefinedFunction(
       env, fn, BaseObjectWeakPtr<DatabaseSync>(db), use_bigint_args);
   int text_rep = SQLITE_UTF8;
@@ -2070,6 +2087,10 @@ void DatabaseSync::Deserialize(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
+  // Reading the options bag above can run user JavaScript through a property
+  // getter, which may have closed the database since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   // sqlite3_malloc64 is required because SQLITE_DESERIALIZE_FREEONCLOSE
   // transfers ownership to SQLite, which calls sqlite3_free() on close.
   // See: https://www.sqlite.org/c3ref/deserialize.html
@@ -2080,7 +2101,16 @@ void DatabaseSync::Deserialize(const FunctionCallbackInfo<Value>& args) {
     return;
   }
 
-  input->CopyContents(buf, byte_length);
+  // The same user JavaScript may also have shrunk or detached the backing
+  // store, in which case byte_length is stale and CopyContents() leaves the
+  // remainder of buf uninitialized. Handing that to SQLite would disclose it
+  // through serialize().
+  if (input->CopyContents(buf, byte_length) != byte_length) {
+    sqlite3_free(buf);
+    THROW_ERR_INVALID_STATE(
+        env, "The \"buffer\" argument was resized while reading \"options\"");
+    return;
+  }
 
   db->FinalizeStatements();
 
@@ -2218,17 +2248,37 @@ void DatabaseSync::AggregateFunction(const FunctionCallbackInfo<Value>& args) {
       return;
     }
 
+    if (!js_len->IsInt32()) {
+      THROW_ERR_INVALID_ARG_TYPE(
+          env->isolate(),
+          "The \"options.step.length\" property must be an integer.");
+      return;
+    }
+
     // Subtract 1 because the first argument is the aggregate value.
     argc = js_len.As<Int32>()->Value() - 1;
-    if (!inverseFunc.IsEmpty() &&
-        !inverseFunc->Get(env->context(), env->length_string())
-             .ToLocal(&js_len)) {
-      return;
+    if (!inverseFunc.IsEmpty()) {
+      if (!inverseFunc->Get(env->context(), env->length_string())
+               .ToLocal(&js_len)) {
+        return;
+      }
+
+      if (!js_len->IsInt32()) {
+        THROW_ERR_INVALID_ARG_TYPE(
+            env->isolate(),
+            "The \"options.inverse.length\" property must be an integer.");
+        return;
+      }
     }
 
     argc = std::max({argc, js_len.As<Int32>()->Value() - 1, 0});
   }
 
+  // Reading the options bag and the step/inverse "length" properties above can
+  // run user JavaScript through a property getter, which may have closed the
+  // database since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   int text_rep = SQLITE_UTF8;
   if (direct_only) {
     text_rep |= SQLITE_DIRECTONLY;
@@ -2257,10 +2307,15 @@ void DatabaseSync::AggregateFunction(const FunctionCallbackInfo<Value>& args) {
 }
 
 void DatabaseSync::CreateSession(const FunctionCallbackInfo<Value>& args) {
+  DatabaseSync* db;
+  ASSIGN_OR_RETURN_UNWRAP(&db, args.This());
+  Environment* env = Environment::GetCurrent(args);
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+  THROW_AND_RETURN_IF_IN_AUTHORIZER(env, db);
+
   std::string table;
   std::string db_name = "main";
 
-  Environment* env = Environment::GetCurrent(args);
   if (args.Length() > 0) {
     if (!args[0]->IsObject()) {
       THROW_ERR_INVALID_ARG_TYPE(env->isolate(),
@@ -2311,10 +2366,9 @@ void DatabaseSync::CreateSession(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
-  DatabaseSync* db;
-  ASSIGN_OR_RETURN_UNWRAP(&db, args.This());
+  // Reading the options bag above can run user JavaScript through a property
+  // getter, which may have closed the database since it was checked.
   THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
-  THROW_AND_RETURN_IF_IN_AUTHORIZER(env, db);
 
   sqlite3_session* pSession;
   int r =
@@ -2441,6 +2495,11 @@ void Backup(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
+  // Reading the destination path and the options bag above can run user
+  // JavaScript through a property getter, which may have closed the database
+  // since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   Local<Promise::Resolver> resolver;
   if (!Promise::Resolver::New(env->context()).ToLocal(&resolver)) {
     return;
@@ -2584,6 +2643,10 @@ void DatabaseSync::ApplyChangeset(const FunctionCallbackInfo<Value>& args) {
     }
   }
 
+  // Reading the options bag above can run user JavaScript through a property
+  // getter, which may have closed the database since it was checked.
+  THROW_AND_RETURN_ON_BAD_STATE(env, !db->IsOpen(), "database is not open");
+
   // Keep the database alive during sqlite3changeset_apply(), which may
   // call conflict or filter callbacks that trigger JavaScript execution.
   // If the JavaScript callback drops all references to the database,