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Fix soundness issue for replace_range and range

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This commit is contained in:
dylni 2021-01-18 22:14:38 -05:00
parent d98d2f57d9
commit b96063cf47
3 changed files with 70 additions and 6 deletions
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13
library/alloc/src/collections/btree/navigate.rs
View file

@ -25,7 +25,12 @@ where
K: Borrow<Q>,
R: RangeBounds<Q>,
{
match (range.start_bound(), range.end_bound()) {
// WARNING: Inlining these variables would be unsound (#81138)
// We assume the bounds reported by `range` remain the same, but
// an adversarial implementation could change between calls
let start = range.start_bound();
let end = range.end_bound();
match (start, end) {
(Excluded(s), Excluded(e)) if s == e => {
panic!("range start and end are equal and excluded in BTreeMap")
}
@ -41,7 +46,8 @@ where
let mut max_found = false;
loop {
let front = match (min_found, range.start_bound()) {
// Using `range` again would be unsound (#81138)
let front = match (min_found, start) {
(false, Included(key)) => match min_node.search_node(key) {
SearchResult::Found(kv) => {
min_found = true;
@ -61,7 +67,8 @@ where
(_, Unbounded) => min_node.first_edge(),
};
let back = match (max_found, range.end_bound()) {
// Using `range` again would be unsound (#81138)
let back = match (max_found, end) {
(false, Included(key)) => match max_node.search_node(key) {
SearchResult::Found(kv) => {
max_found = true;

13
library/alloc/src/string.rs
View file

@ -1553,18 +1553,25 @@ impl String {
// Replace_range does not have the memory safety issues of a vector Splice.
// of the vector version. The data is just plain bytes.
match range.start_bound() {
// WARNING: Inlining this variable would be unsound (#81138)
let start = range.start_bound();
match start {
Included(&n) => assert!(self.is_char_boundary(n)),
Excluded(&n) => assert!(self.is_char_boundary(n + 1)),
Unbounded => {}
};
match range.end_bound() {
// WARNING: Inlining this variable would be unsound (#81138)
let end = range.end_bound();
match end {
Included(&n) => assert!(self.is_char_boundary(n + 1)),
Excluded(&n) => assert!(self.is_char_boundary(n)),
Unbounded => {}
};
unsafe { self.as_mut_vec() }.splice(range, replace_with.bytes());
// Using `range` again would be unsound (#81138)
// We assume the bounds reported by `range` remain the same, but
// an adversarial implementation could change between calls
unsafe { self.as_mut_vec() }.splice((start, end), replace_with.bytes());
}
/// Converts this `String` into a [`Box`]`<`[`str`]`>`.