1 use std::str::Utf8Error; 2 3 use rustc_ast::{BorrowKind, LitKind}; 4 use rustc_hir::{Expr, ExprKind}; 5 use rustc_span::source_map::Spanned; 6 use rustc_span::sym; 7 8 use crate::lints::InvalidFromUtf8Diag; 9 use crate::{LateContext, LateLintPass, LintContext}; 10 11 declare_lint! { 12 /// The `invalid_from_utf8_unchecked` lint checks for calls to 13 /// `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut` 14 /// with an invalid UTF-8 literal. 15 /// 16 /// ### Example 17 /// 18 /// ```rust,compile_fail 19 /// # #[allow(unused)] 20 /// unsafe { 21 /// std::str::from_utf8_unchecked(b"Ru\x82st"); 22 /// } 23 /// ``` 24 /// 25 /// {{produces}} 26 /// 27 /// ### Explanation 28 /// 29 /// Creating such a `str` would result in undefined behavior as per documentation 30 /// for `std::str::from_utf8_unchecked` and `std::str::from_utf8_unchecked_mut`. 31 pub INVALID_FROM_UTF8_UNCHECKED, 32 Deny, 33 "using a non UTF-8 literal in `std::str::from_utf8_unchecked`" 34 } 35 36 declare_lint! { 37 /// The `invalid_from_utf8` lint checks for calls to 38 /// `std::str::from_utf8` and `std::str::from_utf8_mut` 39 /// with an invalid UTF-8 literal. 40 /// 41 /// ### Example 42 /// 43 /// ```rust 44 /// # #[allow(unused)] 45 /// std::str::from_utf8(b"Ru\x82st"); 46 /// ``` 47 /// 48 /// {{produces}} 49 /// 50 /// ### Explanation 51 /// 52 /// Trying to create such a `str` would always return an error as per documentation 53 /// for `std::str::from_utf8` and `std::str::from_utf8_mut`. 54 pub INVALID_FROM_UTF8, 55 Warn, 56 "using a non UTF-8 literal in `std::str::from_utf8`" 57 } 58 59 declare_lint_pass!(InvalidFromUtf8 => [INVALID_FROM_UTF8_UNCHECKED, INVALID_FROM_UTF8]); 60 61 impl<'tcx> LateLintPass<'tcx> for InvalidFromUtf8 { check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>)62 fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) { 63 if let ExprKind::Call(path, [arg]) = expr.kind 64 && let ExprKind::Path(ref qpath) = path.kind 65 && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() 66 && let Some(diag_item) = cx.tcx.get_diagnostic_name(def_id) 67 && [sym::str_from_utf8, sym::str_from_utf8_mut, 68 sym::str_from_utf8_unchecked, sym::str_from_utf8_unchecked_mut].contains(&diag_item) 69 { 70 let lint = |utf8_error: Utf8Error| { 71 let label = arg.span; 72 let method = diag_item.as_str().strip_prefix("str_").unwrap(); 73 let method = format!("std::str::{method}"); 74 let valid_up_to = utf8_error.valid_up_to(); 75 let is_unchecked_variant = diag_item.as_str().contains("unchecked"); 76 77 cx.emit_spanned_lint( 78 if is_unchecked_variant { INVALID_FROM_UTF8_UNCHECKED } else { INVALID_FROM_UTF8 }, 79 expr.span, 80 if is_unchecked_variant { 81 InvalidFromUtf8Diag::Unchecked { method, valid_up_to, label } 82 } else { 83 InvalidFromUtf8Diag::Checked { method, valid_up_to, label } 84 } 85 ) 86 }; 87 88 match &arg.kind { 89 ExprKind::Lit(Spanned { node: lit, .. }) => { 90 if let LitKind::ByteStr(bytes, _) = &lit 91 && let Err(utf8_error) = std::str::from_utf8(bytes) 92 { 93 lint(utf8_error); 94 } 95 }, 96 ExprKind::AddrOf(BorrowKind::Ref, _, Expr { kind: ExprKind::Array(args), .. }) => { 97 let elements = args.iter().map(|e|{ 98 match &e.kind { 99 ExprKind::Lit(Spanned { node: lit, .. }) => match lit { 100 LitKind::Byte(b) => Some(*b), 101 LitKind::Int(b, _) => Some(*b as u8), 102 _ => None 103 } 104 _ => None 105 } 106 }).collect::<Option<Vec<_>>>(); 107 108 if let Some(elements) = elements 109 && let Err(utf8_error) = std::str::from_utf8(&elements) 110 { 111 lint(utf8_error); 112 } 113 } 114 _ => {} 115 } 116 } 117 } 118 } 119