Expose EVP_BytesToKey

This is based on work by pyrho.
Closes #88

4 files changed, 138 insertions, 23 deletions

diff --git a/openssl/src/crypto/mod.rs b/openssl/src/crypto/mod.rs
index e695de33..a33c5eb8 100644
--- a/openssl/src/crypto/mod.rs
+++ b/openssl/src/crypto/mod.rs
@@ -22,3 +22,5 @@ pub mod pkey;
 pub mod rand;
 pub mod symm;
 pub mod memcmp;
+
+mod symm_internal;
\ No newline at end of file
diff --git a/openssl/src/crypto/pkcs5.rs b/openssl/src/crypto/pkcs5.rs
index b101c3ed..b5f69732 100644
--- a/openssl/src/crypto/pkcs5.rs
+++ b/openssl/src/crypto/pkcs5.rs
@@ -1,6 +1,69 @@
 use libc::c_int;
+use std::ptr::null;
+
+use crypto::symm_internal::evpc;
+use crypto::hash;
+use crypto::symm;
 use ffi;
 
+#[derive(Clone, Eq, PartialEq, Hash, Debug)]
+pub struct KeyIvPair
+{
+    pub key: Vec<u8>,
+    pub iv: Vec<u8>
+}
+
+/// Derives a key and an IV from various parameters.
+///
+/// If specified `salt` must be 8 bytes in length.
+///
+/// If the total key and IV length is less than 16 bytes and MD5 is used then 
+/// the algorithm is compatible with the key derivation algorithm from PKCS#5 
+/// v1.5 or PBKDF1 from PKCS#5 v2.0.
+///
+/// New applications should not use this and instead use `pbkdf2_hmac_sha1` or 
+/// another more modern key derivation algorithm.
+pub fn evp_bytes_to_key_pbkdf1_compatible(typ: symm::Type, message_digest_type: hash::Type,
+                      data: &[u8], salt: Option<&[u8]>,
+                      count: u32) -> KeyIvPair {
+
+    unsafe {
+
+        let salt_ptr = match salt {
+            Some(salt) => {
+                assert_eq!(salt.len(), ffi::PKCS5_SALT_LEN as usize);
+                salt.as_ptr()
+            },
+            None => null()
+        };
+
+        ffi::init();
+
+        let (evp, keylen, _) = evpc(typ);
+
+        let message_digest = message_digest_type.evp_md();
+
+        let mut key = vec![0; keylen as usize];
+        let mut iv = vec![0; keylen as usize];
+
+
+        let ret: c_int = ffi::EVP_BytesToKey(evp,
+                                             message_digest,
+                                             salt_ptr,
+                                             data.as_ptr(),
+                                             data.len() as c_int,
+                                             count as c_int,
+                                             key.as_mut_ptr(),
+                                             iv.as_mut_ptr());
+        assert!(ret == keylen as c_int);
+        
+        KeyIvPair {
+            key: key,
+            iv: iv
+        }
+    }
+}
+
 /// Derives a key from a password and salt using the PBKDF2-HMAC-SHA1 algorithm.
 pub fn pbkdf2_hmac_sha1(pass: &str, salt: &[u8], iter: usize, keylen: usize) -> Vec<u8> {
     unsafe {
@@ -27,6 +90,9 @@ pub fn pbkdf2_hmac_sha1(pass: &str, salt: &[u8], iter: usize, keylen: usize) ->
 
 #[cfg(test)]
 mod tests {
+    use crypto::hash;
+    use crypto::symm;
+
     // Test vectors from
     // http://tools.ietf.org/html/draft-josefsson-pbkdf2-test-vectors-06
     #[test]
@@ -116,4 +182,47 @@ mod tests {
             )
         );
     }
+
+    #[test]
+    fn test_evp_bytes_to_key_pbkdf1_compatible() {
+        let salt = [
+            16_u8, 34_u8, 19_u8, 23_u8, 141_u8, 4_u8, 207_u8, 221_u8
+        ];
+
+        let data = [
+            143_u8, 210_u8, 75_u8, 63_u8, 214_u8, 179_u8, 155_u8,
+            241_u8, 242_u8, 31_u8, 154_u8, 56_u8, 198_u8, 145_u8, 192_u8, 64_u8,
+            2_u8, 245_u8, 167_u8, 220_u8, 55_u8, 119_u8, 233_u8, 136_u8, 139_u8,
+            27_u8, 71_u8, 242_u8, 119_u8, 175_u8, 65_u8, 207_u8
+        ];
+
+
+
+        let expected_key = vec![
+            249_u8, 115_u8, 114_u8, 97_u8, 32_u8, 213_u8, 165_u8, 146_u8, 58_u8,
+            87_u8, 234_u8, 3_u8, 43_u8, 250_u8, 97_u8, 114_u8, 26_u8, 98_u8,
+            245_u8, 246_u8, 238_u8, 177_u8, 229_u8, 161_u8, 183_u8, 224_u8,
+            174_u8, 3_u8, 6_u8, 244_u8, 236_u8, 255_u8
+        ];
+        let expected_iv = vec![
+            4_u8, 223_u8, 153_u8, 219_u8, 28_u8, 142_u8, 234_u8, 68_u8, 227_u8,
+            69_u8, 98_u8, 107_u8, 208_u8, 14_u8, 236_u8, 60_u8, 0_u8, 0_u8,
+            0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8, 0_u8,
+            0_u8, 0_u8, 0_u8
+        ];
+
+        assert_eq!(
+            super::evp_bytes_to_key_pbkdf1_compatible(
+                symm::Type::AES_256_CBC,
+                hash::Type::SHA1,
+                &data,
+                Some(&salt),
+                1
+            ),
+            super::KeyIvPair {
+                key: expected_key,
+                iv: expected_iv
+            }
+        );
+    }
 }
diff --git a/openssl/src/crypto/symm.rs b/openssl/src/crypto/symm.rs
index 79cffcc6..226b2cbf 100644
--- a/openssl/src/crypto/symm.rs
+++ b/openssl/src/crypto/symm.rs
@@ -2,6 +2,7 @@ use std::iter::repeat;
 use std::convert::AsRef;
 use libc::{c_int};
 
+use crypto::symm_internal::evpc;
 use ffi;
 
 #[derive(Copy, Clone)]
@@ -34,29 +35,6 @@ pub enum Type {
     RC4_128,
 }
 
-fn evpc(t: Type) -> (*const ffi::EVP_CIPHER, u32, u32) {
-    unsafe {
-        match t {
-            Type::AES_128_ECB => (ffi::EVP_aes_128_ecb(), 16, 16),
-            Type::AES_128_CBC => (ffi::EVP_aes_128_cbc(), 16, 16),
-            #[cfg(feature = "aes_xts")]
-            Type::AES_128_XTS => (ffi::EVP_aes_128_xts(), 32, 16),
-            #[cfg(feature = "aes_ctr")]
-            Type::AES_128_CTR => (ffi::EVP_aes_128_ctr(), 16, 0),
-            //AES_128_GCM => (EVP_aes_128_gcm(), 16, 16),
-
-            Type::AES_256_ECB => (ffi::EVP_aes_256_ecb(), 32, 16),
-            Type::AES_256_CBC => (ffi::EVP_aes_256_cbc(), 32, 16),
-            #[cfg(feature = "aes_xts")]
-            Type::AES_256_XTS => (ffi::EVP_aes_256_xts(), 64, 16),
-            #[cfg(feature = "aes_ctr")]
-            Type::AES_256_CTR => (ffi::EVP_aes_256_ctr(), 32, 0),
-            //AES_256_GCM => (EVP_aes_256_gcm(), 32, 16),
-
-            Type::RC4_128 => (ffi::EVP_rc4(), 16, 0),
-        }
-    }
-}
 
 /// Represents a symmetric cipher context.
 pub struct Crypter {
diff --git a/openssl/src/crypto/symm_internal.rs b/openssl/src/crypto/symm_internal.rs
new file mode 100644
index 00000000..c42efb79
--- /dev/null
+++ b/openssl/src/crypto/symm_internal.rs
@@ -0,0 +1,26 @@
+use crypto::symm;
+use ffi;
+
+pub fn evpc(t: symm::Type) -> (*const ffi::EVP_CIPHER, u32, u32) {
+    unsafe {
+        match t {
+            symm::Type::AES_128_ECB => (ffi::EVP_aes_128_ecb(), 16, 16),
+            symm::Type::AES_128_CBC => (ffi::EVP_aes_128_cbc(), 16, 16),
+            #[cfg(feature = "aes_xts")]
+            symm::Type::AES_128_XTS => (ffi::EVP_aes_128_xts(), 32, 16),
+            #[cfg(feature = "aes_ctr")]
+            symm::Type::AES_128_CTR => (ffi::EVP_aes_128_ctr(), 16, 0),
+            //AES_128_GCM => (EVP_aes_128_gcm(), 16, 16),
+
+            symm::Type::AES_256_ECB => (ffi::EVP_aes_256_ecb(), 32, 16),
+            symm::Type::AES_256_CBC => (ffi::EVP_aes_256_cbc(), 32, 16),
+            #[cfg(feature = "aes_xts")]
+            symm::Type::AES_256_XTS => (ffi::EVP_aes_256_xts(), 64, 16),
+            #[cfg(feature = "aes_ctr")]
+            symm::Type::AES_256_CTR => (ffi::EVP_aes_256_ctr(), 32, 0),
+            //AES_256_GCM => (EVP_aes_256_gcm(), 32, 16),
+
+            symm::Type::RC4_128 => (ffi::EVP_rc4(), 16, 0),
+        }
+    }
+}
\ No newline at end of file