From 2f73d3148a85397c6022c27471d5f8a148a0c603 Mon Sep 17 00:00:00 2001
From: sabjank <sabjan.krisztian@gmail.com>
Date: Fri, 17 Feb 2023 18:04:30 +0100
Subject: [PATCH] Expose SHA512-256

---
 boring/src/hash.rs |  4 +++
 boring/src/nid.rs  |  1 +
 boring/src/sha.rs  | 74 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+)

diff --git a/boring/src/hash.rs b/boring/src/hash.rs
index 011fa54b..8565e82b 100644
--- a/boring/src/hash.rs
+++ b/boring/src/hash.rs
@@ -64,6 +64,10 @@ impl MessageDigest {
         unsafe { MessageDigest(ffi::EVP_sha512()) }
     }
 
+    pub fn sha512_256() -> MessageDigest {
+        unsafe { MessageDigest(ffi::EVP_sha512_256()) }
+    }
+
     #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn as_ptr(&self) -> *const ffi::EVP_MD {
         self.0
diff --git a/boring/src/nid.rs b/boring/src/nid.rs
index 52b0c2d6..8f9b400a 100644
--- a/boring/src/nid.rs
+++ b/boring/src/nid.rs
@@ -728,6 +728,7 @@ impl Nid {
     pub const SHA256: Nid = Nid(ffi::NID_sha256);
     pub const SHA384: Nid = Nid(ffi::NID_sha384);
     pub const SHA512: Nid = Nid(ffi::NID_sha512);
+    pub const SHA512_256: Nid = Nid(ffi::NID_sha512_256);
     pub const SHA224: Nid = Nid(ffi::NID_sha224);
     pub const DSA_WITH_SHA224: Nid = Nid(ffi::NID_dsa_with_SHA224);
     pub const DSA_WITH_SHA256: Nid = Nid(ffi::NID_dsa_with_SHA256);
diff --git a/boring/src/sha.rs b/boring/src/sha.rs
index 66fd8ad2..98aa26ba 100644
--- a/boring/src/sha.rs
+++ b/boring/src/sha.rs
@@ -107,6 +107,17 @@ pub fn sha512(data: &[u8]) -> [u8; 64] {
     }
 }
 
+/// Computes the SHA512-256 hash of some data.
+#[inline]
+#[allow(deprecated)] // https://github.com/rust-lang/rust/issues/63566
+pub fn sha512_256(data: &[u8]) -> [u8; 32] {
+    unsafe {
+        let mut hash: MaybeUninit<[u8; 32]> = MaybeUninit::uninit();
+        ffi::SHA512_256(data.as_ptr(), data.len(), hash.as_mut_ptr().cast());
+        hash.assume_init()
+    }
+}
+
 /// An object which calculates a SHA1 hash of some data.
 ///
 /// # Warning
@@ -337,6 +348,51 @@ impl Sha512 {
     }
 }
 
+/// An object which calculates a SHA512-256 hash of some data.
+#[derive(Clone)]
+pub struct Sha512_256(ffi::SHA512_CTX);
+
+impl Default for Sha512_256 {
+    #[inline]
+    fn default() -> Sha512_256 {
+        Sha512_256::new()
+    }
+}
+
+impl Sha512_256 {
+    /// Creates a new hasher.
+    #[inline]
+    #[allow(deprecated)] // https://github.com/rust-lang/rust/issues/63566
+    pub fn new() -> Sha512_256 {
+        unsafe {
+            let mut ctx = MaybeUninit::uninit();
+            ffi::SHA512_256_Init(ctx.as_mut_ptr());
+            Sha512_256(ctx.assume_init())
+        }
+    }
+
+    /// Feeds some data into the hasher.
+    ///
+    /// This can be called multiple times.
+    #[inline]
+    pub fn update(&mut self, buf: &[u8]) {
+        unsafe {
+            ffi::SHA512_256_Update(&mut self.0, buf.as_ptr() as *const c_void, buf.len());
+        }
+    }
+
+    /// Returns the hash of the data.
+    #[inline]
+    #[allow(deprecated)] // https://github.com/rust-lang/rust/issues/63566
+    pub fn finish(mut self) -> [u8; 32] {
+        unsafe {
+            let mut hash: MaybeUninit<[u8; 32]> = MaybeUninit::uninit();
+            ffi::SHA512_256_Final(hash.as_mut_ptr().cast(), &mut self.0);
+            hash.assume_init()
+        }
+    }
+}
+
 #[cfg(test)]
 mod test {
     use hex;
@@ -454,4 +510,22 @@ mod test {
         hasher.update(b"bc");
         assert_eq!(hex::encode(&hasher.finish()[..]), expected);
     }
+
+    #[test]
+    fn standalone_512_256() {
+        let data = b"abc";
+        let expected = "53048e2681941ef99b2e29b76b4c7dabe4c2d0c634fc6d46e0e2f13107e7af23";
+
+        assert_eq!(hex::encode(&sha512_256(data)[..]), expected);
+    }
+
+    #[test]
+    fn struct_512_256() {
+        let expected = "53048e2681941ef99b2e29b76b4c7dabe4c2d0c634fc6d46e0e2f13107e7af23";
+
+        let mut hasher = Sha512_256::new();
+        hasher.update(b"a");
+        hasher.update(b"bc");
+        assert_eq!(hex::encode(&hasher.finish()[..]), expected);
+    }
 }