commit cefbcbcb15556af524e146a9dfca410f5541f153
author Branden Archer <brarcher@google.com> Fri Dec 28 12:24:53 2018 -0800
committer Branden Archer <brarcher@google.com> Thu Jan 10 09:03:17 2019 -0800
tree d0be0f5e192d9ff0e9570bd1c3a53d831622f8d4
parent 44d1afa2c02e782ba3023770063c057faf4687f3

Use SHA256 for 32 byte keys

For NIAP certification keys need to be generated using SHA256 or
higher. Presently SHA1 is used. To satisfy this requirement,
SHA256 will be used for new keys. As the master key has recently
increased in size, the key size is used to determine if SHA1 is used
(for older keys) or SHA256.

Bug: 121272336
Test: Ran Keystore CTS tests against Walleye

Change-Id: I6099156173e04b22c6edafd9fb0e072f7201c5ee

keystore/user_state.cpp

diff --git a/keystore/user_state.cpp b/keystore/user_state.cpp
index 9fe1347..7c3ca16 100644
--- a/keystore/user_state.cpp
+++ b/keystore/user_state.cpp
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <sys/stat.h>
 
+#include <openssl/digest.h>
 #include <openssl/evp.h>
 #include <openssl/rand.h>
 
@@ -247,8 +248,15 @@
         saltSize = sizeof("keystore");
     }
 
-    PKCS5_PBKDF2_HMAC_SHA1(reinterpret_cast<const char*>(pw.string()), pw.length(), salt, saltSize,
-                           8192, keySize, key);
+    const EVP_MD* digest = EVP_sha256();
+
+    // SHA1 was used prior to increasing the key size
+    if (keySize == SHA1_DIGEST_SIZE_BYTES) {
+        digest = EVP_sha1();
+    }
+
+    PKCS5_PBKDF2_HMAC(reinterpret_cast<const char*>(pw.string()), pw.length(), salt, saltSize, 8192,
+                      digest, keySize, key);
 }
 
 bool UserState::generateSalt() {

keystore/user_state.h

diff --git a/keystore/user_state.h b/keystore/user_state.h
index 6cac02a..a1dc6a2 100644
--- a/keystore/user_state.h
+++ b/keystore/user_state.h
@@ -74,7 +74,10 @@
     bool operator<(uid_t userId) const;
 
   private:
-    static const int MASTER_KEY_SIZE_BYTES = 16;
+    static const int SHA1_DIGEST_SIZE_BYTES = 16;
+    static const int SHA256_DIGEST_SIZE_BYTES = 32;
+
+    static const int MASTER_KEY_SIZE_BYTES = SHA1_DIGEST_SIZE_BYTES;
     static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
 
     static const int MAX_RETRY = 4;