more fuzzing, recursion, prevent including block devices, utf8 fix

src/parser.rs

@@ -1,7 +1,7 @@
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 use crate::tokenizer::{
-    Token,
+    Loc, Token,
     TokenType::{self, Identifier},
     ZernError, error,
 };
@@ -79,6 +79,40 @@ pub enum Stmt {
     },
 }
 
+// https://stackoverflow.com/a/29963675
+pub struct ScopeCall<F: FnMut()> {
+    pub c: F,
+}
+
+impl<F: FnMut()> Drop for ScopeCall<F> {
+    fn drop(&mut self) {
+        (self.c)();
+    }
+}
+
+macro_rules! recursion_guard {
+    ($self:ident) => {
+        $self.depth += 1;
+        if $self.depth > 200 {
+            return error!(
+                Loc {
+                    filename: "<unknown>".into(),
+                    line: 0,
+                    column: 0,
+                },
+                "maximum expression depth reached"
+            );
+        }
+        let self_ptr = $self as *mut Self;
+        let _scope_call = ScopeCall {
+            c: || unsafe {
+                (*self_ptr).depth -= 1;
+            },
+        };
+    };
+}
+pub(crate) use recursion_guard;
+
 pub static NEXT_EXPR_ID: AtomicUsize = AtomicUsize::new(0);
 
 #[derive(Debug, Clone)]
@@ -479,17 +513,12 @@ impl Parser {
     }
 
     fn expression(&mut self) -> Result<Expr, ZernError> {
-        self.depth += 1;
-        if self.depth > 200 {
-            return error!(self.previous().loc, "maximum expression depth reached");
-        }
-
-        let out = self.or_and();
-        self.depth -= 1;
-        out
+        recursion_guard!(self);
+        self.or_and()
     }
 
     fn or_and(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.equality()?;
 
         while self.match_token(&[TokenType::LogicalOr, TokenType::LogicalAnd]) {
@@ -506,6 +535,7 @@ impl Parser {
     }
 
     fn equality(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.comparison()?;
 
         while self.match_token(&[TokenType::DoubleEqual, TokenType::NotEqual]) {
@@ -522,6 +552,7 @@ impl Parser {
     }
 
     fn comparison(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.term()?;
 
         while self.match_token(&[
@@ -543,6 +574,7 @@ impl Parser {
     }
 
     fn term(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.factor()?;
 
         while self.match_token(&[
@@ -565,6 +597,7 @@ impl Parser {
     }
 
     fn factor(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.cast()?;
 
         while self.match_token(&[
@@ -587,6 +620,7 @@ impl Parser {
     }
 
     fn cast(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.unary()?;
 
         while self.match_token(&[TokenType::KeywordAs]) {
@@ -601,6 +635,8 @@ impl Parser {
     }
 
     fn unary(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
+
         if self.match_token(&[TokenType::Xor]) {
             let op = self.previous().clone();
             let right = self.unary()?;
@@ -622,6 +658,7 @@ impl Parser {
     }
 
     fn call(&mut self) -> Result<Expr, ZernError> {
+        recursion_guard!(self);
         let mut expr = self.primary()?;
 
         loop {

src/tokenizer.rs

@@ -2,6 +2,7 @@ use std::{
     cmp::Ordering,
     collections::HashSet,
     fmt, fs,
+    os::unix::fs::FileTypeExt,
     path::{Path, PathBuf},
 };
 
@@ -473,6 +474,19 @@ impl<'a> Tokenizer<'a> {
             return Ok(());
         }
 
+        let meta = match std::fs::metadata(&canonical) {
+            Ok(x) => x,
+            Err(_) => {
+                return error!(self.loc, format!("failed to access {}", path));
+            }
+        };
+        if !meta.file_type().is_file() {
+            return error!(
+                self.loc,
+                format!("refusing to read {} because it is not a regular file", path)
+            );
+        }
+
         let source = match fs::read_to_string(&canonical) {
             Ok(x) => x,
             Err(_) => {

src/typechecker.rs

@@ -1,9 +1,9 @@
 use std::collections::HashMap;
 
 use crate::{
-    parser::{Expr, ExprKind, Params, Stmt},
+    parser::{Expr, ExprKind, Params, ScopeCall, Stmt, recursion_guard},
     symbol_table::{FnParams, SymbolTable},
-    tokenizer::{TokenType, ZernError, error},
+    tokenizer::{Loc, TokenType, ZernError, error},
 };
 
 macro_rules! expect_type {
@@ -73,6 +73,7 @@ pub struct TypeChecker<'a> {
     symbol_table: &'a SymbolTable,
     pub expr_types: HashMap<usize, String>,
     current_function_return_type: String,
+    depth: usize,
 }
 
 impl<'a> TypeChecker<'a> {
@@ -81,6 +82,7 @@ impl<'a> TypeChecker<'a> {
             symbol_table,
             expr_types: HashMap::new(),
             current_function_return_type: String::new(),
+            depth: 0,
         }
     }
 
@@ -373,6 +375,8 @@ impl<'a> TypeChecker<'a> {
     }
 
     pub fn typecheck_expr(&mut self, env: &mut Env, expr: &Expr) -> Result<String, ZernError> {
+        recursion_guard!(self);
+
         let expr_type = match &expr.kind {
             ExprKind::Binary { left, op, right } => {
                 let left_type = self.typecheck_expr(env, left)?;
@@ -685,7 +689,7 @@ impl<'a> TypeChecker<'a> {
             if let Some(args) = inner {
                 return args.iter().all(|arg| self.is_valid_type_name(arg));
             }
-            return false;
+            unreachable!();
         }
         if BUILTIN_TYPES.contains(&name) {
             return true;
@@ -700,7 +704,8 @@ impl<'a> TypeChecker<'a> {
 fn parse_generic_type(s: &str) -> (&str, Option<Vec<&str>>) {
     if let Some(lt_pos) = s.find('<') {
         let base = &s[..lt_pos];
-        let inner = &s[lt_pos + 1..s.len() - 1];
+        let close_pos = s.rfind('>').unwrap_or(s.len());
+        let inner = &s[lt_pos + 1..close_pos];
         let mut args = Vec::new();
         let mut depth = 0;
         let mut start = 0;