From bb9279e2a639bed51a64802e73ed1030241bb803 Mon Sep 17 00:00:00 2001
From: Elichai Turkel <elichai.turkel@gmail.com>
Date: Mon, 12 Jun 2023 22:28:14 +0300
Subject: [PATCH 1/2] Optionally implement Zeroize on ArrayVec/ArrayString

---
 Cargo.toml          |  5 +++++
 src/array_string.rs | 24 ++++++++++++++++++++++++
 src/arrayvec.rs     | 26 ++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/Cargo.toml b/Cargo.toml
index ea041136..a0a44cd1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,6 +19,11 @@ version = "1.0"
 optional = true
 default-features = false
 
+[dependencies.zeroize]
+version = "1.4"
+optional = true
+default-features = false
+
 [dev-dependencies.serde_test]
 version = "1.0"
 
diff --git a/src/array_string.rs b/src/array_string.rs
index 864daeae..90cfc090 100644
--- a/src/array_string.rs
+++ b/src/array_string.rs
@@ -647,3 +647,27 @@ impl<'a, const CAP: usize> TryFrom<fmt::Arguments<'a>> for ArrayString<CAP>
         Ok(v)
     }
 }
+
+#[cfg(feature = "zeroize")]
+/// "Best efforts" zeroing of the `ArrayString`'s buffer when the `zeroize` feature is enabled.
+///
+/// The length is set to 0, and the buffer is dropped and zeroized.
+/// Cannot ensure that previous moves of the `ArrayString` did not leave values on the stack.
+///
+/// ```
+/// use arrayvec::ArrayString;
+/// use zeroize::Zeroize;
+/// let mut string = ArrayString::<6>::from("foobar").unwrap();
+/// string.zeroize();
+/// assert_eq!(string.len(), 0);
+/// unsafe { string.set_len(string.capacity()) };
+/// assert_eq!(&*string, "\0\0\0\0\0\0");
+/// ```
+impl<const CAP: usize> zeroize::Zeroize for ArrayString<CAP> {
+    fn zeroize(&mut self) {
+        // There are no elements to drop
+        self.clear();
+        // Zeroize the backing array.
+        self.xs.zeroize();
+    }
+}
diff --git a/src/arrayvec.rs b/src/arrayvec.rs
index f5b89e8d..37e151a6 100644
--- a/src/arrayvec.rs
+++ b/src/arrayvec.rs
@@ -848,6 +848,32 @@ impl<T, const CAP: usize> IntoIterator for ArrayVec<T, CAP> {
 }
 
 
+#[cfg(feature = "zeroize")]
+/// "Best efforts" zeroing of the `ArrayVec`'s buffer when the `zeroize` feature is enabled.
+///
+/// The length is set to 0, and the buffer is dropped and zeroized.
+/// Cannot ensure that previous moves of the `ArrayVec` did not leave values on the stack.
+///
+/// ```
+/// use arrayvec::ArrayVec;
+/// use zeroize::Zeroize;
+/// let mut array = ArrayVec::from([1, 2, 3]);
+/// array.zeroize();
+/// assert_eq!(array.len(), 0);
+/// let data = unsafe { core::slice::from_raw_parts(array.as_ptr(), array.capacity()) };
+/// assert_eq!(data, [0, 0, 0]);
+/// ```
+impl<Z: zeroize::Zeroize, const CAP: usize> zeroize::Zeroize for ArrayVec<Z, CAP> {
+    fn zeroize(&mut self) {
+        // Zeroize all the contained elements.
+        self.iter_mut().zeroize();
+        // Drop all the elements and set the length to 0.
+        self.clear();
+        // Zeroize the backing array.
+        self.xs.zeroize();
+    }
+}
+
 /// By-value iterator for `ArrayVec`.
 pub struct IntoIter<T, const CAP: usize> {
     index: usize,

From 71200c01b96b01e6a3d5f634a411b3a433def98a Mon Sep 17 00:00:00 2001
From: Elichai Turkel <elichai.turkel@gmail.com>
Date: Tue, 13 Jun 2023 22:02:06 +0300
Subject: [PATCH 2/2] Add Zeroize and benches to the CI matrix

---
 .github/workflows/ci.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ccbf4234..56fdb0f2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,12 +22,13 @@ jobs:
             experimental: false
           - rust: stable
             features:
+            bench: true
             experimental: false
           - rust: beta
             features: serde
             experimental: false
           - rust: nightly
-            features: serde
+            features: serde, zeroize
             experimental: false
 
     steps:
@@ -57,4 +58,4 @@ jobs:
           rustup override set nightly
           cargo miri setup
       - name: Test with Miri
-        run: cargo miri test
+        run: cargo miri test --all-features