Adding a model implementation for ODBC.

(cherry picked from commit 04147f8)

Author: bdrodes

cpp/ql/lib/semmle/code/cpp/models/Models.qll

@@ -9,6 +9,7 @@ private import implementations.Iterator
 private import implementations.MemberFunction
 private import implementations.Memcpy
 private import implementations.Memset
+private import implementations.ODBC
 private import implementations.Printf
 private import implementations.Pure
 private import implementations.Strcat

cpp/ql/lib/semmle/code/cpp/models/implementations/ODBC.qll

@@ -0,0 +1,30 @@
+/**
+ * Provides implementation classes modeling the ODBC C/C++ API.
+ * See `semmle.code.cpp.models.Models` for usage information.
+ */
+
+private import semmle.code.cpp.models.interfaces.Sql
+private import semmle.code.cpp.models.interfaces.FunctionInputsAndOutputs
+
+/**
+ * The `SQLExecDirect`, and `SQLPrepare` from the ODBC C/C++ API:
+ * https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlexecdirect-function?view=sql-server-ver16
+ * https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlprepare-function?view=sql-server-ver16
+ *
+ * Note, `SQLExecute` is not included because it operates on a SQLHSTMT type, not a string.
+ * The SQLHSTMT parameter for `SQLExecute` is set through a `SQLPrepare`, which is modeled.
+ * The other source of input to a `SQLExecute` is via a `SQLBindParameter`, which sanitizes user input,
+ * and would be considered a barrier to SQL injection.
+ */
+private class ODBCExecutionFunction extends SqlExecutionFunction {
+  ODBCExecutionFunction() {
+    exists(string s | s in ["SQLExecDirect", "SQLPrepare"] and this.hasName(s))
+  }
+
+  override predicate hasSqlArgument(FunctionInput input) { input.isParameterDeref(1) }
+}
+// NOTE: no need to define a barrier explicitly.
+// `SQLBindParameter` is the typical means for sanitizing user input.
+//       https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlbindparameter-function?view=sql-server-ver16
+// First a query is establisehed via `SQLPrepare`, then parameters are bound via `SQLBindParameter`, before
+// the query is executed via `SQLExecute`. We are not modeling SQLExecute, so we do not need to model SQLBindParameter.