Merge pull request #141 from gkoz/borrow_mut

Improve Hasher and HMAC APIs

openssl-sys/src/lib.rs

@@ -370,6 +370,7 @@ extern "C" {
     pub fn EVP_DigestFinal_ex(ctx: *mut EVP_MD_CTX, res: *mut u8, n: *mut u32) -> c_int;
 
     pub fn EVP_MD_CTX_create() -> *mut EVP_MD_CTX;
+    pub fn EVP_MD_CTX_copy_ex(dst: *mut EVP_MD_CTX, src: *const EVP_MD_CTX) -> c_int;
     pub fn EVP_MD_CTX_destroy(ctx: *mut EVP_MD_CTX);
 
     pub fn EVP_PKEY_new() -> *mut EVP_PKEY;
@@ -383,6 +384,7 @@ extern "C" {
     pub fn HMAC_Final(ctx: *mut HMAC_CTX, output: *mut u8, len: *mut c_uint) -> c_int;
     pub fn HMAC_Update(ctx: *mut HMAC_CTX, input: *const u8, len: c_uint) -> c_int;
     pub fn HMAC_CTX_cleanup(ctx: *mut HMAC_CTX);
+    pub fn HMAC_CTX_copy(dst: *mut HMAC_CTX, src: *const HMAC_CTX) -> c_int;
 
 
     pub fn PEM_read_bio_X509(bio: *mut BIO, out: *mut *mut X509, callback: Option<PasswordCallback>,

src/crypto/hash.rs

@@ -1,12 +1,12 @@
 use libc::c_uint;
-use std::ptr;
-use std::old_io;
 use std::iter::repeat;
+use std::old_io::{IoError, Writer};
 
 use ffi;
 
+/// Message digest (hash) type.
 #[derive(Copy)]
-pub enum HashType {
+pub enum Type {
     MD5,
     SHA1,
     SHA224,
@@ -16,219 +16,318 @@ pub enum HashType {
     RIPEMD160
 }
 
-pub fn evpmd(t: HashType) -> (*const ffi::EVP_MD, u32) {
+impl Type {
-    unsafe {
+    /// Returns the length of the message digest.
-        match t {
+    #[inline]
-            HashType::MD5 => (ffi::EVP_md5(), 16),
+    pub fn md_len(&self) -> usize {
-            HashType::SHA1 => (ffi::EVP_sha1(), 20),
+        use self::Type::*;
-            HashType::SHA224 => (ffi::EVP_sha224(), 28),
+        match *self {
-            HashType::SHA256 => (ffi::EVP_sha256(), 32),
+            MD5 => 16,
-            HashType::SHA384 => (ffi::EVP_sha384(), 48),
+            SHA1 => 20,
-            HashType::SHA512 => (ffi::EVP_sha512(), 64),
+            SHA224 => 28,
-            HashType::RIPEMD160 => (ffi::EVP_ripemd160(), 20),
+            SHA256 => 32,
+            SHA384 => 48,
+            SHA512 => 64,
+            RIPEMD160 => 20,
+        }
+    }
+
+    /// Internal interface subject to removal.
+    #[inline]
+    pub fn evp_md(&self) -> *const ffi::EVP_MD {
+        unsafe {
+            use self::Type::*;
+            match *self {
+                MD5 => ffi::EVP_md5(),
+                SHA1 => ffi::EVP_sha1(),
+                SHA224 => ffi::EVP_sha224(),
+                SHA256 => ffi::EVP_sha256(),
+                SHA384 => ffi::EVP_sha384(),
+                SHA512 => ffi::EVP_sha512(),
+                RIPEMD160 => ffi::EVP_ripemd160(),
+            }
         }
     }
 }
 
-pub struct HasherContext {
+#[derive(PartialEq, Copy)]
-    ptr: *mut ffi::EVP_MD_CTX
+enum State {
+    Reset,
+    Updated,
+    Finalized,
 }
 
-impl HasherContext {
+use self::State::*;
-    pub fn new() -> HasherContext {
+
+/// Provides message digest (hash) computation.
+///
+/// # Examples
+///
+/// Calculate a hash in one go.
+///
+/// ```
+/// use openssl::crypto::hash::{hash, Type};
+/// let data = b"\x42\xF4\x97\xE0";
+/// let spec = b"\x7c\x43\x0f\x17\x8a\xef\xdf\x14\x87\xfe\xe7\x14\x4e\x96\x41\xe2";
+/// let res = hash(Type::MD5, data);
+/// assert_eq!(res, spec);
+/// ```
+///
+/// Use the `Writer` trait to supply the input in chunks.
+///
+/// ```
+/// use std::old_io::Writer;
+/// use openssl::crypto::hash::{Hasher, Type};
+/// let data = [b"\x42\xF4", b"\x97\xE0"];
+/// let spec = b"\x7c\x43\x0f\x17\x8a\xef\xdf\x14\x87\xfe\xe7\x14\x4e\x96\x41\xe2";
+/// let mut h = Hasher::new(Type::MD5);
+/// h.write_all(data[0]);
+/// h.write_all(data[1]);
+/// let res = h.finish();
+/// assert_eq!(res, spec);
+/// ```
+///
+/// # Warning
+///
+/// Don't actually use MD5 and SHA-1 hashes, they're not secure anymore.
+///
+/// Don't ever hash passwords, use `crypto::pkcs5` or bcrypt/scrypt instead.
+pub struct Hasher {
+    ctx: *mut ffi::EVP_MD_CTX,
+    md: *const ffi::EVP_MD,
+    type_: Type,
+    state: State,
+}
+
+impl Hasher {
+    /// Creates a new `Hasher` with the specified hash type.
+    pub fn new(ty: Type) -> Hasher {
         ffi::init();
 
-        unsafe {
+        let ctx = unsafe {
-            HasherContext { ptr: ffi::EVP_MD_CTX_create() }
+            let r = ffi::EVP_MD_CTX_create();
+            assert!(!r.is_null());
+            r
+        };
+        let md = ty.evp_md();
+
+        let mut h = Hasher { ctx: ctx, md: md, type_: ty, state: Finalized };
+        h.init();
+        h
+    }
+
+    #[inline]
+    fn init(&mut self) {
+        match self.state {
+            Reset => return,
+            Updated => { self.finalize(); },
+            Finalized => (),
         }
+        unsafe {
+            let r = ffi::EVP_DigestInit_ex(self.ctx, self.md, 0 as *const _);
+            assert_eq!(r, 1);
+        }
+        self.state = Reset;
+    }
+
+    #[inline]
+    fn update(&mut self, data: &[u8]) {
+        if self.state == Finalized {
+            self.init();
+        }
+        unsafe {
+            let r = ffi::EVP_DigestUpdate(self.ctx, data.as_ptr(),
+                                          data.len() as c_uint);
+            assert_eq!(r, 1);
+        }
+        self.state = Updated;
+    }
+
+    #[inline]
+    fn finalize(&mut self) -> Vec<u8> {
+        if self.state == Finalized {
+            self.init();
+        }
+        let md_len = self.type_.md_len();
+        let mut res: Vec<u8> = repeat(0).take(md_len).collect();
+        unsafe {
+            let mut len = 0;
+            let r = ffi::EVP_DigestFinal_ex(self.ctx, res.as_mut_ptr(), &mut len);
+            assert_eq!(len as usize, md_len);
+            assert_eq!(r, 1);
+        }
+        self.state = Finalized;
+        res
+    }
+
+    /// Returns the hash of the data written since creation or
+    /// the last `finish` and resets the hasher.
+    #[inline]
+    pub fn finish(&mut self) -> Vec<u8> {
+        self.finalize()
     }
 }
 
-impl Drop for HasherContext {
+impl Writer for Hasher {
-    fn drop(&mut self) {
+    #[inline]
-        unsafe {
+    fn write_all(&mut self, buf: &[u8]) -> Result<(), IoError> {
-            ffi::EVP_MD_CTX_destroy(self.ptr);
-        }
-    }
-}
-
-#[allow(dead_code)]
-pub struct Hasher {
-    evp: *const ffi::EVP_MD,
-    ctx: HasherContext,
-    len: u32,
-}
-
-impl old_io::Writer for Hasher {
-    fn write_all(&mut self, buf: &[u8]) -> old_io::IoResult<()> {
         self.update(buf);
         Ok(())
     }
 }
 
-impl Hasher {
+impl Clone for Hasher {
-    pub fn new(ht: HashType) -> Hasher {
+    fn clone(&self) -> Hasher {
-        let ctx = HasherContext::new();
+        let ctx = unsafe {
-        Hasher::with_context(ctx, ht)
+            let ctx = ffi::EVP_MD_CTX_create();
-    }
+            assert!(!ctx.is_null());
-
+            let r = ffi::EVP_MD_CTX_copy_ex(ctx, self.ctx);
-    pub fn with_context(ctx: HasherContext, ht: HashType) -> Hasher {
+            assert_eq!(r, 1);
-        let (evp, mdlen) = evpmd(ht);
+            ctx
-        unsafe {
-            ffi::EVP_DigestInit_ex(ctx.ptr, evp, 0 as *const _);
-        }
-
-        Hasher { evp: evp, ctx: ctx, len: mdlen }
-    }
-
-    /// Update this hasher with more input bytes
-    pub fn update(&mut self, data: &[u8]) {
-        unsafe {
-            ffi::EVP_DigestUpdate(self.ctx.ptr, data.as_ptr(), data.len() as c_uint);
-        }
-    }
-
-    /**
-     * Return the digest of all bytes added to this hasher since its last
-     * initialization
-     */
-    pub fn finalize(self) -> Vec<u8> {
-        let (res, _) = self.finalize_reuse();
-        res
-    }
-
-    /**
-     * Return the digest of all bytes added to this hasher since its last
-     * initialization and its context for reuse
-     */
-    pub fn finalize_reuse(self) -> (Vec<u8>, HasherContext) {
-        let mut res = repeat(0u8).take(self.len as usize).collect::<Vec<_>>();
-        unsafe {
-            ffi::EVP_DigestFinal_ex(self.ctx.ptr, res.as_mut_ptr(), ptr::null_mut())
         };
-        (res, self.ctx)
+        Hasher { ctx: ctx, md: self.md, type_: self.type_, state: self.state }
     }
 }
 
-/**
+impl Drop for Hasher {
- * Hashes the supplied input data using hash t, returning the resulting hash
+    fn drop(&mut self) {
- * value
+        unsafe {
- */
+            if self.state != Finalized {
-pub fn hash(t: HashType, data: &[u8]) -> Vec<u8> {
+                let mut buf: Vec<u8> = repeat(0).take(self.type_.md_len()).collect();
+                let mut len = 0;
+                ffi::EVP_DigestFinal_ex(self.ctx, buf.as_mut_ptr(), &mut len);
+            }
+            ffi::EVP_MD_CTX_destroy(self.ctx);
+        }
+    }
+}
+
+/// Computes the hash of the `data` with the hash `t`.
+pub fn hash(t: Type, data: &[u8]) -> Vec<u8> {
     let mut h = Hasher::new(t);
-    h.update(data);
+    let _ = h.write_all(data);
-    h.finalize()
+    h.finish()
 }
 
 #[cfg(test)]
 mod tests {
     use serialize::hex::{FromHex, ToHex};
+    use super::{hash, Hasher, Type};
+    use std::old_io::Writer;
 
-    struct HashTest {
+    fn hash_test(hashtype: Type, hashtest: &(&str, &str)) {
-        input: Vec<u8>,
+        let res = hash(hashtype, &*hashtest.0.from_hex().unwrap());
-        expected_output: String
+        assert_eq!(res.to_hex(), hashtest.1);
     }
 
-    #[allow(non_snake_case)]
+    fn hash_recycle_test(h: &mut Hasher, hashtest: &(&str, &str)) {
-    fn HashTest(input: &str, output: &str) -> HashTest {
+        let _ = h.write_all(&*hashtest.0.from_hex().unwrap());
-        HashTest { input: input.from_hex().unwrap(),
+        let res = h.finish();
-                   expected_output: output.to_string() }
+        assert_eq!(res.to_hex(), hashtest.1);
-    }
-
-    fn compare(calced_raw: Vec<u8>, hashtest: &HashTest) {
-        let calced = calced_raw.as_slice().to_hex().to_string();
-
-        if calced != hashtest.expected_output {
-            println!("Test failed - {} != {}", calced, hashtest.expected_output);
-        }
-
-        assert!(calced == hashtest.expected_output);
-    }
-
-    fn hash_test(hashtype: super::HashType, hashtest: &HashTest) {
-        let calced_raw = super::hash(hashtype, hashtest.input.as_slice());
-        compare(calced_raw, hashtest);
-    }
-
-    fn hash_reuse_test(ctx: super::HasherContext, hashtype: super::HashType,
-                       hashtest: &HashTest) -> super::HasherContext {
-        let mut h = super::Hasher::with_context(ctx, hashtype);
-        h.update(hashtest.input.as_slice());
-        let (calced_raw, ctx) = h.finalize_reuse();
-
-        compare(calced_raw, hashtest);
-
-        ctx
-    }
-
-    pub fn hash_writer(t: super::HashType, data: &[u8]) -> Vec<u8> {
-        let mut h = super::Hasher::new(t);
-        h.write_all(data).unwrap();
-        h.finalize()
     }
 
     // Test vectors from http://www.nsrl.nist.gov/testdata/
+    #[allow(non_upper_case_globals)]
+    const md5_tests: [(&'static str, &'static str); 13] = [
+        ("", "d41d8cd98f00b204e9800998ecf8427e"),
+        ("7F", "83acb6e67e50e31db6ed341dd2de1595"),
+        ("EC9C", "0b07f0d4ca797d8ac58874f887cb0b68"),
+        ("FEE57A", "e0d583171eb06d56198fc0ef22173907"),
+        ("42F497E0", "7c430f178aefdf1487fee7144e9641e2"),
+        ("C53B777F1C", "75ef141d64cb37ec423da2d9d440c925"),
+        ("89D5B576327B", "ebbaf15eb0ed784c6faa9dc32831bf33"),
+        ("5D4CCE781EB190", "ce175c4b08172019f05e6b5279889f2c"),
+        ("81901FE94932D7B9", "cd4d2f62b8cdb3a0cf968a735a239281"),
+        ("C9FFDEE7788EFB4EC9", "e0841a231ab698db30c6c0f3f246c014"),
+        ("66AC4B7EBA95E53DC10B", "a3b3cea71910d9af56742aa0bb2fe329"),
+        ("A510CD18F7A56852EB0319", "577e216843dd11573574d3fb209b97d8"),
+        ("AAED18DBE8938C19ED734A8D", "6f80fb775f27e0a4ce5c2f42fc72c5f1")
+    ];
+
     #[test]
     fn test_md5() {
-        let tests = [
+        for test in md5_tests.iter() {
-            HashTest("", "d41d8cd98f00b204e9800998ecf8427e"),
+            hash_test(Type::MD5, test);
-            HashTest("7F", "83acb6e67e50e31db6ed341dd2de1595"),
-            HashTest("EC9C", "0b07f0d4ca797d8ac58874f887cb0b68"),
-            HashTest("FEE57A", "e0d583171eb06d56198fc0ef22173907"),
-            HashTest("42F497E0", "7c430f178aefdf1487fee7144e9641e2"),
-            HashTest("C53B777F1C", "75ef141d64cb37ec423da2d9d440c925"),
-            HashTest("89D5B576327B", "ebbaf15eb0ed784c6faa9dc32831bf33"),
-            HashTest("5D4CCE781EB190", "ce175c4b08172019f05e6b5279889f2c"),
-            HashTest("81901FE94932D7B9", "cd4d2f62b8cdb3a0cf968a735a239281"),
-            HashTest("C9FFDEE7788EFB4EC9", "e0841a231ab698db30c6c0f3f246c014"),
-            HashTest("66AC4B7EBA95E53DC10B", "a3b3cea71910d9af56742aa0bb2fe329"),
-            HashTest("A510CD18F7A56852EB0319", "577e216843dd11573574d3fb209b97d8"),
-            HashTest("AAED18DBE8938C19ED734A8D", "6f80fb775f27e0a4ce5c2f42fc72c5f1")];
-
-        let mut ctx = super::HasherContext::new();
-
-        for test in tests.iter() {
-            ctx = hash_reuse_test(ctx, super::HashType::MD5, test);
         }
     }
 
+    #[test]
+    fn test_md5_recycle() {
+        let mut h = Hasher::new(Type::MD5);
+        for test in md5_tests.iter() {
+            hash_recycle_test(&mut h, test);
+        }
+    }
+
+    #[test]
+    fn test_finish_twice() {
+        let mut h = Hasher::new(Type::MD5);
+        let _ = h.write_all(&*md5_tests[6].0.from_hex().unwrap());
+        let _ = h.finish();
+        let res = h.finish();
+        let null = hash(Type::MD5, &[]);
+        assert_eq!(res, null);
+    }
+
+    #[test]
+    fn test_clone() {
+        let i = 7;
+        let inp = md5_tests[i].0.from_hex().unwrap();
+        assert!(inp.len() > 2);
+        let p = inp.len() / 2;
+        let h0 = Hasher::new(Type::MD5);
+
+        println!("Clone a new hasher");
+        let mut h1 = h0.clone();
+        let _ = h1.write_all(&inp[..p]);
+        {
+            println!("Clone an updated hasher");
+            let mut h2 = h1.clone();
+            let _ = h2.write_all(&inp[p..]);
+            let res = h2.finish();
+            assert_eq!(res.to_hex(), md5_tests[i].1);
+        }
+        let _ = h1.write_all(&inp[p..]);
+        let res = h1.finish();
+        assert_eq!(res.to_hex(), md5_tests[i].1);
+
+        println!("Clone a finished hasher");
+        let mut h3 = h1.clone();
+        let _ = h3.write_all(&*md5_tests[i + 1].0.from_hex().unwrap());
+        let res = h3.finish();
+        assert_eq!(res.to_hex(), md5_tests[i + 1].1);
+    }
+
     #[test]
     fn test_sha1() {
         let tests = [
-            HashTest("616263", "a9993e364706816aba3e25717850c26c9cd0d89d"),
+            ("616263", "a9993e364706816aba3e25717850c26c9cd0d89d"),
             ];
 
         for test in tests.iter() {
-            hash_test(super::HashType::SHA1, test);
+            hash_test(Type::SHA1, test);
         }
     }
 
     #[test]
     fn test_sha256() {
         let tests = [
-            HashTest("616263", "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad")
+            ("616263", "ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad")
             ];
 
         for test in tests.iter() {
-            hash_test(super::HashType::SHA256, test);
+            hash_test(Type::SHA256, test);
         }
     }
 
     #[test]
     fn test_ripemd160() {
         let tests = [
-            HashTest("616263", "8eb208f7e05d987a9b044a8e98c6b087f15a0bfc")
+            ("616263", "8eb208f7e05d987a9b044a8e98c6b087f15a0bfc")
             ];
 
         for test in tests.iter() {
-            hash_test(super::HashType::RIPEMD160, test);
+            hash_test(Type::RIPEMD160, test);
         }
     }
-
-    #[test]
-    fn test_writer() {
-        let tv = "rust-openssl".as_bytes();
-        let ht = super::HashType::RIPEMD160;
-        assert!(hash_writer(ht, tv) == super::hash(ht, tv));
-    }
 }

src/crypto/hmac.rs

@@ -16,66 +16,201 @@
 
 use libc::{c_int, c_uint};
 use std::iter::repeat;
+use std::old_io::{IoError, Writer};
 
-use crypto::hash;
+use crypto::hash::Type;
 use ffi;
 
-pub struct HMAC {
+#[derive(PartialEq, Copy)]
-    ctx: ffi::HMAC_CTX,
+enum State {
-    len: u32,
+    Reset,
+    Updated,
+    Finalized,
 }
 
-#[allow(non_snake_case)]
+use self::State::*;
-pub fn HMAC(ht: hash::HashType, key: &[u8]) -> HMAC {
-    unsafe {
-        ffi::init();
 
-        let (evp, mdlen) = hash::evpmd(ht);
+/// Provides HMAC computation.
-
+///
-        let mut ctx : ffi::HMAC_CTX = ::std::mem::uninitialized();
+/// # Examples
-
+///
-        ffi::HMAC_CTX_init(&mut ctx);
+/// Calculate a HMAC in one go.
-        ffi::HMAC_Init_ex(&mut ctx,
+///
-                          key.as_ptr(),
+/// ```
-                          key.len() as c_int,
+/// use openssl::crypto::hash::Type;
-                          evp, 0 as *const _);
+/// use openssl::crypto::hmac::hmac;
-
+/// let key = b"Jefe";
-        HMAC { ctx: ctx, len: mdlen }
+/// let data = b"what do ya want for nothing?";
-    }
+/// let spec = b"\x75\x0c\x78\x3e\x6a\xb0\xb5\x03\xea\xa8\x6e\x31\x0a\x5d\xb7\x38";
+/// let res = hmac(Type::MD5, key, data);
+/// assert_eq!(spec, res);
+/// ```
+///
+/// Use the `Writer` trait to supply the input in chunks.
+///
+/// ```
+/// use std::old_io::Writer;
+/// use openssl::crypto::hash::Type;
+/// use openssl::crypto::hmac::HMAC;
+/// let key = b"Jefe";
+/// let data = [b"what do ya ", b"want for nothing?"];
+/// let spec = b"\x75\x0c\x78\x3e\x6a\xb0\xb5\x03\xea\xa8\x6e\x31\x0a\x5d\xb7\x38";
+/// let mut h = HMAC::new(Type::MD5, &*key);
+/// h.write_all(data[0]);
+/// h.write_all(data[1]);
+/// let res = h.finish();
+/// assert_eq!(spec, res);
+/// ```
+pub struct HMAC {
+    ctx: ffi::HMAC_CTX,
+    type_: Type,
+    state: State,
 }
 
 impl HMAC {
-    pub fn update(&mut self, data: &[u8]) {
+    /// Creates a new `HMAC` with the specified hash type using the `key`.
-        unsafe {
+    pub fn new(ty: Type, key: &[u8]) -> HMAC {
-            ffi::HMAC_Update(&mut self.ctx, data.as_ptr(), data.len() as c_uint);
+        ffi::init();
-        }
+
+        let ctx = unsafe {
+            let mut ctx = ::std::mem::uninitialized();
+            ffi::HMAC_CTX_init(&mut ctx);
+            ctx
+        };
+        let md = ty.evp_md();
+
+        let mut h = HMAC { ctx: ctx, type_: ty, state: Finalized };
+        h.init_once(md, key);
+        h
     }
 
-    pub fn finalize(&mut self) -> Vec<u8> {
+    #[inline]
+    fn init_once(&mut self, md: *const ffi::EVP_MD, key: &[u8]) {
         unsafe {
-            let mut res: Vec<u8> = repeat(0).take(self.len as usize).collect();
+            let r = ffi::HMAC_Init_ex(&mut self.ctx,
-            let mut outlen = 0;
+                                      key.as_ptr(), key.len() as c_int,
-            ffi::HMAC_Final(&mut self.ctx, res.as_mut_ptr(), &mut outlen);
+                                      md, 0 as *const _);
-            assert!(self.len == outlen as u32);
+            assert_eq!(r, 1);
-            res
         }
+        self.state = Reset;
+    }
+
+    #[inline]
+    fn init(&mut self) {
+        match self.state {
+            Reset => return,
+            Updated => { self.finalize(); },
+            Finalized => (),
+        }
+        // If the key and/or md is not supplied it's reused from the last time
+        // avoiding redundant initializations
+        unsafe {
+            let r = ffi::HMAC_Init_ex(&mut self.ctx,
+                                      0 as *const _, 0,
+                                      0 as *const _, 0 as *const _);
+            assert_eq!(r, 1);
+        }
+        self.state = Reset;
+    }
+
+    #[inline]
+    fn update(&mut self, data: &[u8]) {
+        if self.state == Finalized {
+            self.init();
+        }
+        unsafe {
+            let r = ffi::HMAC_Update(&mut self.ctx, data.as_ptr(),
+                                     data.len() as c_uint);
+            assert_eq!(r, 1);
+        }
+        self.state = Updated;
+    }
+
+    #[inline]
+    fn finalize(&mut self) -> Vec<u8> {
+        if self.state == Finalized {
+            self.init();
+        }
+        let md_len = self.type_.md_len();
+        let mut res: Vec<u8> = repeat(0).take(md_len).collect();
+        unsafe {
+            let mut len = 0;
+            let r = ffi::HMAC_Final(&mut self.ctx, res.as_mut_ptr(), &mut len);
+            assert_eq!(len as usize, md_len);
+            assert_eq!(r, 1);
+        }
+        self.state = Finalized;
+        res
+    }
+
+    /// Returns the hash of the data written since creation or
+    /// the last `finish` and resets the hasher.
+    #[inline]
+    pub fn finish(&mut self) -> Vec<u8> {
+        self.finalize()
+    }
+}
+
+impl Writer for HMAC {
+    #[inline]
+    fn write_all(&mut self, buf: &[u8]) -> Result<(), IoError> {
+        self.update(buf);
+        Ok(())
+    }
+}
+
+impl Clone for HMAC {
+    fn clone(&self) -> HMAC {
+        let mut ctx: ffi::HMAC_CTX;
+        unsafe {
+            ctx = ::std::mem::uninitialized();
+            let r = ffi::HMAC_CTX_copy(&mut ctx, &self.ctx);
+            assert_eq!(r, 1);
+        }
+        HMAC { ctx: ctx, type_: self.type_, state: self.state }
     }
 }
 
 impl Drop for HMAC {
     fn drop(&mut self) {
         unsafe {
+            if self.state != Finalized {
+                let mut buf: Vec<u8> = repeat(0).take(self.type_.md_len()).collect();
+                let mut len = 0;
+                ffi::HMAC_Final(&mut self.ctx, buf.as_mut_ptr(), &mut len);
+            }
             ffi::HMAC_CTX_cleanup(&mut self.ctx);
         }
     }
 }
 
+/// Computes the HMAC of the `data` with the hash `t` and `key`.
+pub fn hmac(t: Type, key: &[u8], data: &[u8]) -> Vec<u8> {
+    let mut h = HMAC::new(t, key);
+    let _ = h.write_all(data);
+    h.finish()
+}
+
 #[cfg(test)]
 mod tests {
     use std::iter::repeat;
     use serialize::hex::FromHex;
-    use crypto::hash::HashType::{self, MD5, SHA1, SHA224, SHA256, SHA384, SHA512};
+    use crypto::hash::Type;
-    use super::HMAC;
+    use crypto::hash::Type::*;
+    use super::{hmac, HMAC};
+    use std::old_io::Writer;
+
+    fn test_hmac(ty: Type, tests: &[(Vec<u8>, Vec<u8>, Vec<u8>)]) {
+        for &(ref key, ref data, ref res) in tests.iter() {
+            assert_eq!(hmac(ty, &**key, &**data), *res);
+        }
+    }
+
+    fn test_hmac_recycle(h: &mut HMAC, test: &(Vec<u8>, Vec<u8>, Vec<u8>)) {
+        let &(_, ref data, ref res) = test;
+        let _ = h.write_all(&**data);
+        assert_eq!(h.finish(), *res);
+    }
 
     #[test]
     fn test_hmac_md5() {
@@ -103,13 +238,78 @@ mod tests {
              "6f630fad67cda0ee1fb1f562db3aa53e".from_hex().unwrap())
         ];
 
-        for &(ref key, ref data, ref res) in tests.iter() {
+        test_hmac(MD5, &tests);
-            let mut hmac = HMAC(MD5, key.as_slice());
+    }
-            hmac.update(data.as_slice());
+
-            assert_eq!(hmac.finalize(), *res);
+    #[test]
+    fn test_hmac_md5_recycle() {
+        let tests: [(Vec<u8>, Vec<u8>, Vec<u8>); 2] = [
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key - Hash Key First".to_vec(),
+             "6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd".from_hex().unwrap()),
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key \
+               and Larger Than One Block-Size Data".to_vec(),
+             "6f630fad67cda0ee1fb1f562db3aa53e".from_hex().unwrap())
+        ];
+
+        let mut h = HMAC::new(MD5, &*tests[0].0);
+        for i in 0..100us {
+            let test = &tests[i % 2];
+            test_hmac_recycle(&mut h, test);
         }
     }
 
+    #[test]
+    fn test_finish_twice() {
+        let test: (Vec<u8>, Vec<u8>, Vec<u8>) =
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key - Hash Key First".to_vec(),
+             "6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd".from_hex().unwrap());
+
+        let mut h = HMAC::new(Type::MD5, &*test.0);
+        let _ = h.write_all(&*test.1);
+        let _ = h.finish();
+        let res = h.finish();
+        let null = hmac(Type::MD5, &*test.0, &[]);
+        assert_eq!(res, null);
+    }
+
+    #[test]
+    fn test_clone() {
+        let tests: [(Vec<u8>, Vec<u8>, Vec<u8>); 2] = [
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key - Hash Key First".to_vec(),
+             "6b1ab7fe4bd7bf8f0b62e6ce61b9d0cd".from_hex().unwrap()),
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key \
+               and Larger Than One Block-Size Data".to_vec(),
+             "6f630fad67cda0ee1fb1f562db3aa53e".from_hex().unwrap()),
+        ];
+        let p = tests[0].0.len() / 2;
+        let h0 = HMAC::new(Type::MD5, &*tests[0].0);
+
+        println!("Clone a new hmac");
+        let mut h1 = h0.clone();
+        let _ = h1.write_all(&tests[0].1[..p]);
+        {
+            println!("Clone an updated hmac");
+            let mut h2 = h1.clone();
+            let _ = h2.write_all(&tests[0].1[p..]);
+            let res = h2.finish();
+            assert_eq!(res, tests[0].2);
+        }
+        let _ = h1.write_all(&tests[0].1[p..]);
+        let res = h1.finish();
+        assert_eq!(res, tests[0].2);
+
+        println!("Clone a finished hmac");
+        let mut h3 = h1.clone();
+        let _ = h3.write_all(&*tests[1].1);
+        let res = h3.finish();
+        assert_eq!(res, tests[1].2);
+    }
+
     #[test]
     fn test_hmac_sha1() {
         // test vectors from RFC 2202
@@ -136,14 +336,31 @@ mod tests {
              "e8e99d0f45237d786d6bbaa7965c7808bbff1a91".from_hex().unwrap())
         ];
 
-        for &(ref key, ref data, ref res) in tests.iter() {
+        test_hmac(SHA1, &tests);
-            let mut hmac = HMAC(SHA1, key.as_slice());
+    }
-            hmac.update(data.as_slice());
+
-            assert_eq!(hmac.finalize(), *res);
+    #[test]
+    fn test_hmac_sha1_recycle() {
+        let tests: [(Vec<u8>, Vec<u8>, Vec<u8>); 2] = [
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key - Hash Key First".to_vec(),
+             "aa4ae5e15272d00e95705637ce8a3b55ed402112".from_hex().unwrap()),
+            (repeat(0xaa_u8).take(80).collect(),
+             b"Test Using Larger Than Block-Size Key \
+               and Larger Than One Block-Size Data".to_vec(),
+             "e8e99d0f45237d786d6bbaa7965c7808bbff1a91".from_hex().unwrap())
+        ];
+
+        let mut h = HMAC::new(SHA1, &*tests[0].0);
+        for i in 0..100us {
+            let test = &tests[i % 2];
+            test_hmac_recycle(&mut h, test);
         }
     }
 
-    fn test_sha2(ty: HashType, results: &[Vec<u8>]) {
+
+
+    fn test_sha2(ty: Type, results: &[Vec<u8>]) {
         // test vectors from RFC 4231
         let tests: [(Vec<u8>, Vec<u8>); 6] = [
             (repeat(0xb_u8).take(20).collect(), b"Hi There".to_vec()),
@@ -161,9 +378,15 @@ mod tests {
         ];
 
         for (&(ref key, ref data), res) in tests.iter().zip(results.iter()) {
-            let mut hmac = HMAC(ty, key.as_slice());
+            assert_eq!(hmac(ty, &**key, &**data), *res);
-            hmac.update(data.as_slice());
+        }
-            assert_eq!(hmac.finalize(), *res);
+
+        // recycle test
+        let mut h = HMAC::new(ty, &*tests[5].0);
+        for i in 0..100us {
+            let test = &tests[4 + i % 2];
+            let tup = (test.0.clone(), test.1.clone(), results[4 + i % 2].clone());
+            test_hmac_recycle(&mut h, &tup);
         }
     }
 

src/crypto/pkey.rs

@@ -3,7 +3,8 @@ use std::iter::repeat;
 use std::mem;
 use std::ptr;
 use bio::{MemBio};
-use crypto::hash::HashType;
+use crypto::hash;
+use crypto::hash::Type as HashType;
 use ffi;
 use ssl::error::{SslError, StreamError};
 
@@ -276,7 +277,7 @@ impl PKey {
      */
     pub fn verify(&self, m: &[u8], s: &[u8]) -> bool { self.verify_with_hash(m, s, HashType::SHA256) }
 
-    pub fn sign_with_hash(&self, s: &[u8], hash: HashType) -> Vec<u8> {
+    pub fn sign_with_hash(&self, s: &[u8], hash: hash::Type) -> Vec<u8> {
         unsafe {
             let rsa = ffi::EVP_PKEY_get1_RSA(self.evp);
             let len = ffi::RSA_size(rsa);
@@ -300,7 +301,7 @@ impl PKey {
         }
     }
 
-    pub fn verify_with_hash(&self, m: &[u8], s: &[u8], hash: HashType) -> bool {
+    pub fn verify_with_hash(&self, m: &[u8], s: &[u8], hash: hash::Type) -> bool {
         unsafe {
             let rsa = ffi::EVP_PKEY_get1_RSA(self.evp);
 
@@ -332,7 +333,7 @@ impl Drop for PKey {
 
 #[cfg(test)]
 mod tests {
-    use crypto::hash::HashType::{MD5, SHA1};
+    use crypto::hash::Type::{MD5, SHA1};
 
     #[test]
     fn test_gen_pub() {

src/ssl/tests.rs

@@ -3,7 +3,7 @@ use std::old_io::net::tcp::TcpStream;
 use std::old_io::{Writer};
 use std::thread::Thread;
 
-use crypto::hash::HashType::{SHA256};
+use crypto::hash::Type::{SHA256};
 use ssl::SslMethod::Sslv23;
 use ssl::{SslContext, SslStream, VerifyCallback};
 use ssl::SslVerifyMode::SslVerifyPeer;

src/x509/mod.rs

@@ -8,7 +8,8 @@ use std::ptr;
 
 use asn1::{Asn1Time};
 use bio::{MemBio};
-use crypto::hash::{HashType, evpmd};
+use crypto::hash;
+use crypto::hash::Type as HashType;
 use crypto::pkey::{PKey};
 use crypto::rand::rand_bytes;
 use ffi;
@@ -152,14 +153,14 @@ impl<'a, T: AsStr<'a>> ToStr for Vec<T> {
 /// use std::old_io::{File, Open, Write};
 /// # use std::old_io::fs;
 ///
-/// use openssl::crypto::hash::HashType;
+/// use openssl::crypto::hash::Type;
 /// use openssl::x509::{KeyUsage, X509Generator};
 ///
 /// let gen = X509Generator::new()
 ///        .set_bitlength(2048)
 ///        .set_valid_period(365*2)
 ///        .set_CN("SuperMegaCorp Inc.")
-///        .set_sign_hash(HashType::SHA256)
+///        .set_sign_hash(Type::SHA256)
 ///        .set_usage(&[KeyUsage::DigitalSignature]);
 ///
 /// let (cert, pkey) = gen.generate().unwrap();
@@ -236,7 +237,7 @@ impl X509Generator {
         self
     }
 
-    pub fn set_sign_hash(mut self, hash_type: HashType) -> X509Generator {
+    pub fn set_sign_hash(mut self, hash_type: hash::Type) -> X509Generator {
         self.hash_type = hash_type;
         self
     }
@@ -331,7 +332,7 @@ impl X509Generator {
                                                   self.ext_key_usage.to_str().as_slice()));
             }
 
-            let (hash_fn, _) = evpmd(self.hash_type);
+            let hash_fn = self.hash_type.evp_md();
             try_ssl!(ffi::X509_sign(x509.handle, p_key.get_handle(), hash_fn));
             Ok((x509, p_key))
         }
@@ -387,8 +388,9 @@ impl<'ctx> X509<'ctx> {
     }
 
     /// Returns certificate fingerprint calculated using provided hash
-    pub fn fingerprint(&self, hash_type: HashType) -> Option<Vec<u8>> {
+    pub fn fingerprint(&self, hash_type: hash::Type) -> Option<Vec<u8>> {
-        let (evp, len) = evpmd(hash_type);
+        let evp = hash_type.evp_md();
+        let len = hash_type.md_len();
         let v: Vec<u8> = repeat(0).take(len as usize).collect();
         let act_len: c_uint = 0;
         let res = unsafe {
@@ -399,7 +401,7 @@ impl<'ctx> X509<'ctx> {
         match res {
             0 => None,
             _ => {
-                let act_len = act_len as u32;
+                let act_len = act_len as usize;
                 match len.cmp(&act_len) {
                     Ordering::Greater => None,
                     Ordering::Equal => Some(v),

src/x509/tests.rs

@@ -2,7 +2,7 @@ use serialize::hex::FromHex;
 use std::old_io::{File, Open, Read};
 use std::old_io::util::NullWriter;
 
-use crypto::hash::HashType::{SHA256};
+use crypto::hash::Type::{SHA256};
 use x509::{X509, X509Generator};
 use x509::KeyUsage::{DigitalSignature, KeyEncipherment};
 use x509::ExtKeyUsage::{ClientAuth, ServerAuth};