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Add a new `not_unsafe_ptr_arg_deref` lint

This commit is contained in:
mcarton 2016-06-07 16:55:55 +02:00 committed by Manish Goregaokar
parent d243d686fd
commit 7781f1d7c5
6 changed files with 174 additions and 17 deletions
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2
CHANGELOG.md
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@ -15,6 +15,7 @@ All notable changes to this project will be documented in this file.
## 0.0.76 — 2016-06-10
* Rustup to *rustc 1.11.0-nightly (7d2f75a95 2016-06-09)*
* `cargo clippy` now automatically defines the `clippy` feature
* New lint: [`not_unsafe_ptr_arg_deref`]
## 0.0.75 — 2016-06-08
* Rustup to *rustc 1.11.0-nightly (763f9234b 2016-06-06)*
@ -220,6 +221,7 @@ All notable changes to this project will be documented in this file.
[`non_ascii_literal`]: https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal
[`nonminimal_bool`]: https://github.com/Manishearth/rust-clippy/wiki#nonminimal_bool
[`nonsensical_open_options`]: https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options
[`not_unsafe_ptr_arg_deref`]: https://github.com/Manishearth/rust-clippy/wiki#not_unsafe_ptr_arg_deref
[`ok_expect`]: https://github.com/Manishearth/rust-clippy/wiki#ok_expect
[`option_map_unwrap_or`]: https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or
[`option_map_unwrap_or_else`]: https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or_else

1
README.md
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@ -115,6 +115,7 @@ name
[non_ascii_literal](https://github.com/Manishearth/rust-clippy/wiki#non_ascii_literal) | allow | using any literal non-ASCII chars in a string literal; suggests using the \\u escape instead
[nonminimal_bool](https://github.com/Manishearth/rust-clippy/wiki#nonminimal_bool) | allow | checks for boolean expressions that can be written more concisely
[nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options) | warn | nonsensical combination of options for opening a file
[not_unsafe_ptr_arg_deref](https://github.com/Manishearth/rust-clippy/wiki#not_unsafe_ptr_arg_deref) | warn | public functions dereferencing raw pointer arguments but not marked `unsafe`
[ok_expect](https://github.com/Manishearth/rust-clippy/wiki#ok_expect) | warn | using `ok().expect()`, which gives worse error messages than calling `expect` directly on the Result
[option_map_unwrap_or](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or) | warn | using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as `map_or(a, f)`
[option_map_unwrap_or_else](https://github.com/Manishearth/rust-clippy/wiki#option_map_unwrap_or_else) | warn | using `Option.map(f).unwrap_or_else(g)`, which is more succinctly expressed as `map_or_else(g, f)`

128
clippy_lints/src/functions.rs
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@ -1,9 +1,11 @@
use rustc::lint::*;
use rustc::hir;
use rustc::hir::intravisit;
use rustc::hir;
use rustc::ty;
use rustc::lint::*;
use std::collections::HashSet;
use syntax::ast;
use syntax::codemap::Span;
use utils::span_lint;
use utils::{span_lint, type_is_unsafe_function};
/// **What it does:** Check for functions with too many parameters.
///
@ -15,7 +17,7 @@ use utils::span_lint;
///
/// **Example:**
///
/// ```
/// ```rust
/// fn foo(x: u32, y: u32, name: &str, c: Color, w: f32, h: f32, a: f32, b: f32) { .. }
/// ```
declare_lint! {
@ -24,6 +26,30 @@ declare_lint! {
"functions with too many arguments"
}
/// **What it does:** Check for public functions that dereferences raw pointer arguments but are
/// not marked unsafe.
///
/// **Why is this bad?** The function should probably be marked `unsafe`, since for an arbitrary
/// raw pointer, there is no way of telling for sure if it is valid.
///
/// **Known problems:**
///
/// * It does not check functions recursively so if the pointer is passed to a private non-
/// `unsafe` function which does the dereferencing, the lint won't trigger.
/// * It only checks for arguments whose type are raw pointers, not raw pointers got from an
/// argument in some other way (`fn foo(bar: &[*const u8])` or `some_argument.get_raw_ptr()`).
///
/// **Example:**
///
/// ```rust
/// pub fn foo(x: *const u8) { println!("{}", unsafe { *x }); }
/// ```
declare_lint! {
pub NOT_UNSAFE_PTR_ARG_DEREF,
Warn,
"public functions dereferencing raw pointer arguments but not marked `unsafe`"
}
#[derive(Copy,Clone)]
pub struct Functions {
threshold: u64,
@ -37,29 +63,41 @@ impl Functions {
impl LintPass for Functions {
fn get_lints(&self) -> LintArray {
lint_array!(TOO_MANY_ARGUMENTS)
lint_array!(TOO_MANY_ARGUMENTS, NOT_UNSAFE_PTR_ARG_DEREF)
}
}
impl LateLintPass for Functions {
fn check_fn(&mut self, cx: &LateContext, _: intravisit::FnKind, decl: &hir::FnDecl, _: &hir::Block, span: Span,
nodeid: ast::NodeId) {
fn check_fn(&mut self, cx: &LateContext, kind: intravisit::FnKind, decl: &hir::FnDecl, block: &hir::Block, span: Span, nodeid: ast::NodeId) {
use rustc::hir::map::Node::*;
if let Some(NodeItem(ref item)) = cx.tcx.map.find(cx.tcx.map.get_parent_node(nodeid)) {
match item.node {
hir::ItemImpl(_, _, _, Some(_), _, _) |
hir::ItemDefaultImpl(..) => return,
_ => (),
}
let is_impl = if let Some(NodeItem(ref item)) = cx.tcx.map.find(cx.tcx.map.get_parent_node(nodeid)) {
matches!(item.node, hir::ItemImpl(_, _, _, Some(_), _, _) | hir::ItemDefaultImpl(..))
} else {
false
};
let unsafety = match kind {
hir::intravisit::FnKind::ItemFn(_, _, unsafety, _, _, _, _) => unsafety,
hir::intravisit::FnKind::Method(_, sig, _, _) => sig.unsafety,
hir::intravisit::FnKind::Closure(_) => return,
};
// don't warn for implementations, it's not their fault
if !is_impl {
self.check_arg_number(cx, decl, span);
}
self.check_arg_number(cx, decl, span);
self.check_raw_ptr(cx, unsafety, decl, block, span, nodeid);
}
fn check_trait_item(&mut self, cx: &LateContext, item: &hir::TraitItem) {
if let hir::MethodTraitItem(ref sig, _) = item.node {
if let hir::MethodTraitItem(ref sig, ref block) = item.node {
self.check_arg_number(cx, &sig.decl, item.span);
if let Some(ref block) = *block {
self.check_raw_ptr(cx, sig.unsafety, &sig.decl, block, item.span, item.id);
}
}
}
}
@ -74,4 +112,64 @@ impl Functions {
&format!("this function has too many arguments ({}/{})", args, self.threshold));
}
}
fn check_raw_ptr(&self, cx: &LateContext, unsafety: hir::Unsafety, decl: &hir::FnDecl, block: &hir::Block, span: Span, nodeid: ast::NodeId) {
if unsafety == hir::Unsafety::Normal && cx.access_levels.is_exported(nodeid) {
let raw_ptrs = decl.inputs.iter().filter_map(|arg| raw_ptr_arg(cx, arg)).collect::<HashSet<_>>();
if !raw_ptrs.is_empty() {
let mut v = DerefVisitor {
cx: cx,
ptrs: raw_ptrs,
};
hir::intravisit::walk_block(&mut v, block);
}
}
}
}
fn raw_ptr_arg(cx: &LateContext, arg: &hir::Arg) -> Option<hir::def_id::DefId> {
if let (&hir::PatKind::Binding(_, _, _), &hir::TyPtr(_)) = (&arg.pat.node, &arg.ty.node) {
cx.tcx.def_map.borrow().get(&arg.pat.id).map(hir::def::PathResolution::def_id)
} else {
None
}
}
struct DerefVisitor<'a, 'tcx: 'a> {
cx: &'a LateContext<'a, 'tcx>,
ptrs: HashSet<hir::def_id::DefId>,
}
impl<'a, 'tcx, 'v> hir::intravisit::Visitor<'v> for DerefVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'v hir::Expr) {
let ptr = match expr.node {
hir::ExprUnary(hir::UnDeref, ref ptr) => Some(ptr),
hir::ExprMethodCall(_, _, ref args) => {
let method_call = ty::MethodCall::expr(expr.id);
let base_type = self.cx.tcx.tables.borrow().method_map[&method_call].ty;
if type_is_unsafe_function(base_type) {
Some(&args[0])
} else {
None
}
}
_ => None,
};
if let Some(ptr) = ptr {
if let Some(def) = self.cx.tcx.def_map.borrow().get(&ptr.id) {
if self.ptrs.contains(&def.def_id()) {
span_lint(self.cx,
NOT_UNSAFE_PTR_ARG_DEREF,
ptr.span,
"this public function dereferences a raw pointer but is not marked `unsafe`");
}
}
}
hir::intravisit::walk_expr(self, expr);
}
}

1
clippy_lints/src/lib.rs
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@ -322,6 +322,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
format::USELESS_FORMAT,
formatting::SUSPICIOUS_ASSIGNMENT_FORMATTING,
formatting::SUSPICIOUS_ELSE_FORMATTING,
functions::NOT_UNSAFE_PTR_ARG_DEREF,
functions::TOO_MANY_ARGUMENTS,
identity_op::IDENTITY_OP,
len_zero::LEN_WITHOUT_IS_EMPTY,

9
clippy_lints/src/utils/mod.rs
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@ -813,3 +813,12 @@ pub fn recover_for_loop(expr: &Expr) -> Option<(&Pat, &Expr, &Expr)> {
}}
None
}
/// Return whether the given type is an `unsafe` function.
pub fn type_is_unsafe_function(ty: ty::Ty) -> bool {
match ty.sty {
ty::TyFnDef(_, _, ref f) |
ty::TyFnPtr(ref f) => f.unsafety == Unsafety::Unsafe,
_ => false,
}
}

50
tests/compile-fail/functions.rs
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@ -3,20 +3,24 @@
#![deny(clippy)]
#![allow(dead_code)]
#![allow(unused_unsafe)]
// TOO_MANY_ARGUMENTS
fn good(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool) {}
fn bad(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool, _eight: ()) {
//~^ ERROR: this function has too many arguments (8/7)
}
trait Foo {
pub trait Foo {
fn good(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool);
fn bad(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool, _eight: ());
//~^ ERROR: this function has too many arguments (8/7)
fn ptr(p: *const u8);
}
struct Bar;
pub struct Bar;
impl Bar {
fn good_method(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool) {}
@ -28,6 +32,48 @@ impl Bar {
impl Foo for Bar {
fn good(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool) {}
fn bad(_one: u32, _two: u32, _three: &str, _four: bool, _five: f32, _six: f32, _seven: bool, _eight: ()) {}
fn ptr(p: *const u8) {
println!("{}", unsafe { *p });
//~^ ERROR: this public function dereferences a raw pointer but is not marked `unsafe`
}
}
// NOT_UNSAFE_PTR_ARG_DEREF
fn private(p: *const u8) {
println!("{}", unsafe { *p });
}
pub fn public(p: *const u8) {
println!("{}", unsafe { *p });
//~^ ERROR: this public function dereferences a raw pointer but is not marked `unsafe`
println!("{:?}", unsafe { p.as_ref() });
//~^ ERROR: this public function dereferences a raw pointer but is not marked `unsafe`
}
impl Bar {
fn private(self, p: *const u8) {
println!("{}", unsafe { *p });
}
pub fn public(self, p: *const u8) {
println!("{}", unsafe { *p });
//~^ ERROR: this public function dereferences a raw pointer but is not marked `unsafe`
println!("{:?}", unsafe { p.as_ref() });
//~^ ERROR: this public function dereferences a raw pointer but is not marked `unsafe`
}
pub fn public_ok(self, p: *const u8) {
if !p.is_null() {
println!("{:p}", p);
}
}
pub unsafe fn public_unsafe(self, p: *const u8) {
println!("{}", unsafe { *p });
println!("{:?}", unsafe { p.as_ref() });
}
}
fn main() {}