Add overflow checking for str::get with inclusive ranges

Fixes #42401

diff --git a/src/libcollections/tests/lib.rs b/src/libcollections/tests/lib.rs
index 8af8786994e407ba321a207805b7182d5debaddf..f64a549a05d4d72048e82df9bd35bfcd5631647a 100644 (file)
--- a/src/libcollections/tests/lib.rs
+++ b/src/libcollections/tests/lib.rs
@@ -22,6 +22,7 @@
 #![feature(rand)]
 #![feature(slice_rotate)]
 #![feature(splice)]
+#![feature(str_checked_slicing)]
 #![feature(str_escape)]
 #![feature(test)]
 #![feature(unboxed_closures)]

diff --git a/src/libcollections/tests/str.rs b/src/libcollections/tests/str.rs
index c9b7104fec4f0072d2256f2b0de70153fd4648a9..9d8ca38b20e48c822af8beb5f756c25c88ad5d7e 100644 (file)
--- a/src/libcollections/tests/str.rs
+++ b/src/libcollections/tests/str.rs
@@ -358,6 +358,48 @@ fn test_slice_fail() {
     &"中华Việt Nam"[0..2];
 }
 
+#[test]
+#[should_panic]
+fn test_str_slice_rangetoinclusive_max_panics() {
+    &"hello"[...usize::max_value()];
+}
+
+#[test]
+#[should_panic]
+fn test_str_slice_rangeinclusive_max_panics() {
+    &"hello"[1...usize::max_value()];
+}
+
+#[test]
+#[should_panic]
+fn test_str_slicemut_rangetoinclusive_max_panics() {
+    let mut s = "hello".to_owned();
+    let s: &mut str = &mut s;
+    &mut s[...usize::max_value()];
+}
+
+#[test]
+#[should_panic]
+fn test_str_slicemut_rangeinclusive_max_panics() {
+    let mut s = "hello".to_owned();
+    let s: &mut str = &mut s;
+    &mut s[1...usize::max_value()];
+}
+
+#[test]
+fn test_str_get_maxinclusive() {
+    let mut s = "hello".to_owned();
+    {
+        let s: &str = &s;
+        assert_eq!(s.get(...usize::max_value()), None);
+        assert_eq!(s.get(1...usize::max_value()), None);
+    }
+    {
+        let s: &mut str = &mut s;
+        assert_eq!(s.get(...usize::max_value()), None);
+        assert_eq!(s.get(1...usize::max_value()), None);
+    }
+}
 
 #[test]
 fn test_is_char_boundary() {

diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 76a5d0c0b50b158668427e20f64aa0277f0c30ac..34aca592b1e95434d598a990930dcad2d004cd1f 100644 (file)
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1918,11 +1918,19 @@ impl SliceIndex<str> for ops::RangeInclusive<usize> {
         type Output = str;
         #[inline]
         fn get(self, slice: &str) -> Option<&Self::Output> {
-            (self.start..self.end+1).get(slice)
+            if let Some(end) = self.end.checked_add(1) {
+                (self.start..end).get(slice)
+            } else {
+                None
+            }
         }
         #[inline]
         fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
-            (self.start..self.end+1).get_mut(slice)
+            if let Some(end) = self.end.checked_add(1) {
+                (self.start..end).get_mut(slice)
+            } else {
+                None
+            }
         }
         #[inline]
         unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
@@ -1953,7 +1961,7 @@ impl SliceIndex<str> for ops::RangeToInclusive<usize> {
         type Output = str;
         #[inline]
         fn get(self, slice: &str) -> Option<&Self::Output> {
-            if slice.is_char_boundary(self.end + 1) {
+            if self.end < usize::max_value() && slice.is_char_boundary(self.end + 1) {
                 Some(unsafe { self.get_unchecked(slice) })
             } else {
                 None
@@ -1961,7 +1969,7 @@ fn get(self, slice: &str) -> Option<&Self::Output> {
         }
         #[inline]
         fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
-            if slice.is_char_boundary(self.end + 1) {
+            if self.end < usize::max_value() && slice.is_char_boundary(self.end + 1) {
                 Some(unsafe { self.get_unchecked_mut(slice) })
             } else {
                 None