Lazy values not set (#265)

* The imports of messages from scout-audit-internal were removed. Now, the detector information is exposed in the library by exporting the 'lint_info' function defined by the macros of 'scout-audit-dylint-linting'.

* removed cli app (now on https://github.com/CoinFabrik/scout-audit) added ci scripts

* remove branch from ci

* first version of lazy-values-not-set detector

* Documentation added, code improved to allow the use of attributes to change lint level

* fix

* Folder structure fixed

* run cargo clippy

* remove readme.md

* fix on another test case for ci pass

* changed detector number

* fix

.github/workflows/test-detectors.yml

@@ -119,9 +119,9 @@ jobs:
         with:
           path: ~/.cargo
           key: ${{ runner.os }}-tests-${{ hashFiles('**/Cargo.lock') }}.
-# This is broken until ink! solves stdsimd problem.
-#      - name: Run unit and integration tests
-#        run: python scripts/run-tests.py --detector=${{ matrix.detector }}
+  # This is broken until ink! solves stdsimd problem.
+  #      - name: Run unit and integration tests
+  #        run: python scripts/run-tests.py --detector=${{ matrix.detector }}
 
   comment-on-pr:
     name: Comment on PR

detectors/Cargo.toml

@@ -7,6 +7,6 @@ dylint_testing = "3.0.0"
 if_chain = "1.0.2"
 
 scout-audit-clippy-utils = { version = "=0.2.3" }
-
-itertools = { version = "0.12" }
+scout-audit-internal = { version = "=0.2.3", features = ["detector", "lint_helper"] }
 dylint_linting = { package = "scout-audit-dylint-linting", version = "3.0.1" }
+itertools = { version = "0.12" }

detectors/lazy-values-not-set/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "lazy-values-not-set"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+scout-audit-clippy-utils = { workspace = true }
+dylint_linting = { workspace = true }
+if_chain = { workspace = true }
+
+
+[dev-dependencies]
+dylint_testing = { workspace = true }
+
+[package.metadata.rust-analyzer]
+rustc_private = true

detectors/lazy-values-not-set/src/lib.rs

@@ -0,0 +1,330 @@
+#![feature(rustc_private)]
+#![recursion_limit = "256"]
+
+extern crate rustc_ast;
+extern crate rustc_hir;
+extern crate rustc_middle;
+extern crate rustc_span;
+
+use std::collections::HashMap;
+
+use rustc_hir::def_id::DefId;
+use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
+use rustc_hir::{Body, FnDecl};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::mir::traversal::preorder;
+use rustc_middle::mir::{Local, Operand, Rvalue, TerminatorKind};
+use rustc_middle::ty::TyKind;
+use rustc_span::def_id::LocalDefId;
+use rustc_span::Span;
+use scout_audit_clippy_utils::match_def_path;
+
+const LINT_MESSAGE: &str = "Lazy value was gotten here but never set afterwards";
+
+dylint_linting::impl_late_lint! {
+    pub LAZY_VALUES_NOT_SET,
+    Warn,
+    LINT_MESSAGE,
+    LazyValuesNotSet::default(),
+    {
+        name: "Lazy values get and not set",
+        long_message: "When a get is performed, a copy of the value is received; if that copy is modified, the new value must be set afterwards.",
+        severity: "Critical",
+        help: "https://coinfabrik.github.io/scout/docs/vulnerabilities/lazy-values-not-set",
+        vulnerability_class: "Best practices",
+    }
+}
+
+#[derive(Default)]
+pub struct LazyValuesNotSet {
+    lazy_set_defid: Option<DefId>,
+    lazy_get_defid: Option<DefId>,
+    mapping_insert_defid: Option<DefId>,
+    mapping_get_defid: Option<DefId>,
+}
+
+struct FunFinderVisitor<'a, 'tcx: 'a> {
+    cx: &'a LateContext<'tcx>,
+    lazy_set_defid: Option<DefId>,
+    lazy_get_defid: Option<DefId>,
+    mapping_insert_defid: Option<DefId>,
+    mapping_get_defid: Option<DefId>,
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for FunFinderVisitor<'a, 'tcx> {
+    fn visit_expr(&mut self, expr: &'tcx rustc_hir::Expr<'tcx>) {
+        if let rustc_hir::ExprKind::MethodCall(path, receiver, _, _) = expr.kind {
+            if path.ident.to_string().contains("get")
+                || path.ident.to_string().contains("set")
+                || path.ident.to_string().contains("insert")
+            {
+                let defid = self.cx.typeck_results().type_dependent_def_id(expr.hir_id);
+
+                let receiver_type = self.cx.typeck_results().expr_ty(receiver);
+                if let TyKind::Adt(def, _) = receiver_type.kind() {
+                    if match_def_path(self.cx, def.did(), &["ink_storage", "lazy", "Lazy"]) {
+                        if path.ident.to_string().contains("get") {
+                            self.lazy_get_defid = defid;
+                        } else {
+                            self.lazy_set_defid = defid;
+                        }
+                    } else if match_def_path(
+                        self.cx,
+                        def.did(),
+                        &["ink_storage", "lazy", "mapping", "Mapping"],
+                    ) {
+                        if path.ident.to_string().contains("get") {
+                            self.mapping_get_defid = defid;
+                        } else {
+                            self.mapping_insert_defid = defid;
+                        }
+                    }
+                }
+            }
+        }
+        walk_expr(self, expr);
+    }
+}
+
+impl<'tcx> LateLintPass<'tcx> for LazyValuesNotSet {
+    fn check_fn(
+        &mut self,
+        cx: &LateContext<'tcx>,
+        _: FnKind<'tcx>,
+        _: &'tcx FnDecl<'_>,
+        body: &'tcx Body<'_>,
+        _: Span,
+        id: LocalDefId,
+    ) {
+        //search for the defids of the different functions
+        let mut visitor = FunFinderVisitor {
+            cx,
+            lazy_set_defid: None,
+            lazy_get_defid: None,
+            mapping_insert_defid: None,
+            mapping_get_defid: None,
+        };
+        visitor.visit_expr(body.value);
+        if visitor.lazy_set_defid.is_some() {
+            self.lazy_set_defid = visitor.lazy_set_defid;
+        }
+        if visitor.lazy_get_defid.is_some() {
+            self.lazy_get_defid = visitor.lazy_get_defid;
+        }
+        if visitor.mapping_insert_defid.is_some() {
+            self.mapping_insert_defid = visitor.mapping_insert_defid;
+        }
+        if visitor.mapping_get_defid.is_some() {
+            self.mapping_get_defid = visitor.mapping_get_defid;
+        }
+
+        let (_, hm) = self.get_func_info(cx, id.to_def_id(), &[], &[], &mut vec![]);
+        for val in hm.values() {
+            scout_audit_clippy_utils::diagnostics::span_lint(
+                cx,
+                LAZY_VALUES_NOT_SET,
+                *val,
+                LINT_MESSAGE,
+            );
+        }
+    }
+}
+
+fn clean_local_upwards(local: Local, hm: &HashMap<Local, Vec<Local>>) -> Vec<Local> {
+    let val = hm.get(&local);
+    let mut ret_vec: Vec<Local> = vec![];
+    if let Some(locals_vec) = val {
+        ret_vec.extend(locals_vec);
+        for local in locals_vec {
+            ret_vec.extend(clean_local_upwards(*local, hm))
+        }
+    }
+    ret_vec.dedup();
+    ret_vec
+}
+
+impl LazyValuesNotSet {
+    fn get_func_info(
+        &mut self,
+        cx: &LateContext,
+        func_defid: DefId,
+        tainted_get_map: &[Local],
+        tainted_get_lazy: &[Local],
+        visited_funs: &mut Vec<DefId>,
+    ) -> (Vec<Local>, HashMap<Local, Span>) {
+        if visited_funs.contains(&func_defid) {
+            return (vec![], HashMap::new());
+        }
+        visited_funs.push(func_defid);
+        let mir = cx.tcx.optimized_mir(func_defid);
+        let mir_preorder = preorder(mir);
+        let mut mapping_get_tainted_args: Vec<Local> = tainted_get_map.to_owned();
+        let mut lazy_get_tainted_args: Vec<Local> = tainted_get_lazy.to_owned();
+        let mut span_local: HashMap<Local, Span> = HashMap::new();
+        let mut locals_dependencies: HashMap<Local, Vec<Local>> = HashMap::new();
+        let mut locals_to_clean: Vec<Local> = vec![];
+        for basicblock in mir_preorder {
+            for stmt in basicblock.1.statements.iter().rev() {
+                if let rustc_middle::mir::StatementKind::Assign(box_) = &stmt.kind {
+                    let locals = get_locals_in_rvalue(&box_.1);
+                    locals_dependencies.insert(box_.0.local, locals.clone());
+                    for local in locals {
+                        if mapping_get_tainted_args.contains(&local) {
+                            mapping_get_tainted_args.push(box_.0.local);
+                        }
+                        if lazy_get_tainted_args.contains(&local) {
+                            lazy_get_tainted_args.push(box_.0.local);
+                        }
+                    }
+                }
+            }
+            if let Some(terminator) = &basicblock.1.terminator {
+                if let TerminatorKind::Call {
+                    func,
+                    args,
+                    destination,
+                    fn_span,
+                    ..
+                } = &terminator.kind
+                {
+                    match func {
+                        rustc_middle::mir::Operand::Copy(_)
+                        | rustc_middle::mir::Operand::Move(_) => {}
+                        rustc_middle::mir::Operand::Constant(b) => {
+                            if let TyKind::FnDef(defid, _args) = b.ty().kind() {
+                                //if the function is set or insert taint destinations local
+                                if self.lazy_get_defid.is_some_and(|did| did == *defid) {
+                                    lazy_get_tainted_args.push(destination.local);
+                                    span_local.insert(destination.local, *fn_span);
+                                } else if self.mapping_get_defid.is_some_and(|did| did == *defid) {
+                                    mapping_get_tainted_args.push(destination.local);
+                                    span_local.insert(destination.local, *fn_span);
+                                }
+                                //if the function is defined in the local crate call get_func_info recursively
+                                else if defid.is_local() {
+                                    //translate from my locals to the locals into the call
+                                    let mut mapping_args: Vec<Local> = vec![];
+                                    let mut lazy_args: Vec<Local> = vec![];
+                                    for arg in args.iter().enumerate() {
+                                        match arg.1 {
+                                            Operand::Copy(a) | Operand::Move(a) => {
+                                                if mapping_get_tainted_args.contains(&a.local) {
+                                                    mapping_args.push(Local::from_usize(arg.0 + 1));
+                                                }
+                                                if lazy_get_tainted_args.contains(&a.local) {
+                                                    lazy_args.push(Local::from_usize(arg.0 + 1));
+                                                }
+                                            }
+                                            Operand::Constant(_) => {}
+                                        }
+                                    }
+                                    let cleaned_taints = self.get_func_info(
+                                        cx,
+                                        *defid,
+                                        &mapping_args,
+                                        &lazy_args,
+                                        visited_funs,
+                                    );
+                                    //get the locals translated from call locals
+                                    for local in cleaned_taints.0 {
+                                        let op_arg = args.get(local.as_usize() - 1);
+                                        if let Some(arg) = op_arg {
+                                            match arg {
+                                                Operand::Copy(a) | Operand::Move(a) => {
+                                                    //clean the taints
+                                                    mapping_get_tainted_args
+                                                        .retain(|i| a.local != *i);
+                                                    lazy_get_tainted_args.retain(|i| a.local != *i);
+                                                    //push locals to be cleaned before
+                                                    locals_to_clean.push(a.local)
+                                                }
+                                                Operand::Constant(_) => {}
+                                            }
+                                        }
+                                    }
+                                }
+                                //if is an insert call clean the taints upwards
+                                else if self.lazy_set_defid.is_some_and(|did| did == *defid) {
+                                    for arg in args {
+                                        match arg {
+                                            Operand::Copy(a) | Operand::Move(a) => {
+                                                locals_to_clean.push(a.local);
+                                            }
+                                            Operand::Constant(_) => {}
+                                        }
+                                    }
+                                } else if self.mapping_insert_defid.is_some_and(|did| did == *defid)
+                                {
+                                    for arg in args {
+                                        match arg {
+                                            Operand::Copy(a) | Operand::Move(a) => {
+                                                locals_to_clean.push(a.local);
+                                            }
+                                            Operand::Constant(_) => {}
+                                        }
+                                    }
+                                } else {
+                                    let mut args_locals = vec![];
+                                    for arg in args {
+                                        match arg {
+                                            Operand::Copy(a) | Operand::Move(a) => {
+                                                args_locals.push(a.local);
+                                            }
+                                            Operand::Constant(_) => {}
+                                        }
+                                    }
+                                    locals_dependencies.insert(destination.local, args_locals);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        for local in locals_to_clean.clone() {
+            locals_to_clean.extend(clean_local_upwards(local, &locals_dependencies));
+        }
+        locals_to_clean.dedup();
+        for local in &locals_to_clean {
+            span_local.remove(local);
+        }
+        (
+            locals_to_clean
+                .clone()
+                .into_iter()
+                .filter(|l| l.as_usize() <= mir.arg_count)
+                .collect::<Vec<Local>>(),
+            span_local,
+        )
+    }
+}
+
+fn get_locals_in_rvalue(rvalue: &Rvalue) -> Vec<Local> {
+    fn op_local(op: &Operand) -> Vec<Local> {
+        match op {
+            rustc_middle::mir::Operand::Copy(p) | rustc_middle::mir::Operand::Move(p) => {
+                vec![p.local]
+            }
+            rustc_middle::mir::Operand::Constant(_) => vec![],
+        }
+    }
+    match rvalue {
+        rustc_middle::mir::Rvalue::Use(op)
+        | rustc_middle::mir::Rvalue::Repeat(op, _)
+        | rustc_middle::mir::Rvalue::Cast(_, op, _)
+        | rustc_middle::mir::Rvalue::UnaryOp(_, op) => op_local(op),
+        rustc_middle::mir::Rvalue::Ref(_, _, p)
+        | rustc_middle::mir::Rvalue::AddressOf(_, p)
+        | rustc_middle::mir::Rvalue::Len(p)
+        | rustc_middle::mir::Rvalue::CopyForDeref(p) => {
+            vec![p.local]
+        }
+        rustc_middle::mir::Rvalue::BinaryOp(_, ops)
+        | rustc_middle::mir::Rvalue::CheckedBinaryOp(_, ops) => {
+            let mut v = op_local(&ops.0);
+            v.extend(op_local(&ops.1));
+            v
+        }
+        _ => vec![],
+    }
+}