Add "symmetric signature" (really HMAC) support

3 files changed, 291 insertions, 1 deletions

diff --git a/Makefile.am b/Makefile.am
index 26a8d16..92bdeef 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -35,7 +35,7 @@ AM_CPPFLAGS = -I $(top_srcdir)/include $(GLIB_CFLAGS) $(NSS_CFLAGS) \
 ## Targets
 lib_LTLIBRARIES = lib/libncrypto.la
 pkginclude_HEADERS = include/ncrypto/ncrypto.h
-TESTS = tests/digests tests/rsa tests/symm_ciphers
+TESTS = tests/digests tests/rsa tests/symm_ciphers tests/symm_signatures
 
 ## Rules
 noinst_PROGRAMS = $(TESTS)
@@ -51,3 +51,6 @@ tests_rsa_LDFLAGS = -no-install
 
 tests_symm_ciphers_LDADD = lib/libncrypto.la $(GLIB_LIBS)
 tests_symm_ciphers_LDFLAGS = -no-install
+
+tests_symm_signatures_LDADD = lib/libncrypto.la $(GLIB_LIBS)
+tests_symm_signatures_LDFLAGS = -no-install
diff --git a/include/ncrypto/ncrypto.h b/include/ncrypto/ncrypto.h
index aef6bb4..24d8e8e 100644
--- a/include/ncrypto/ncrypto.h
+++ b/include/ncrypto/ncrypto.h
@@ -183,4 +183,38 @@ CK_RV ncr_symm_cipher_decrypt (struct ncr_symm_cipher_session *sess, void *dest,
 			       size_t *dest_size_ptr, const void *src,
 			       size_t src_size);
 
+ /* Symmetric signatures */
+
+struct ncr_symm_signature_session;
+
+/* Session lifetime management. */
+CK_RV ncr_symm_signature_alloc (struct ncr_symm_signature_session **sess,
+				CK_MECHANISM_TYPE mech);
+CK_RV ncr_symm_signature_free (struct ncr_symm_signature_session *sess);
+/* Use either ncr_symm_signature_sign_{init,update,final} (), or
+   ncr_symm_signature_{sign_init,sign} ().  After finishing such a call
+   sequence, a new sequence can be started within the same session.  Same for
+   verification sequences.
+
+   Symmetric signature mechanisms  tend to use keys of type
+   CKK_GENERIC_SECRET. */
+CK_RV ncr_symm_signature_sign_init (struct ncr_symm_signature_session *sess,
+				    struct ncr_symm_key *key);
+CK_RV ncr_symm_signature_sign_update (struct ncr_symm_signature_session *sess,
+				      const void *data, size_t size);
+CK_RV ncr_symm_signature_sign_final (struct ncr_symm_signature_session *sess,
+				     void *dest, size_t *size_ptr);
+CK_RV ncr_symm_signature_sign (struct ncr_symm_signature_session *sess,
+			       void *dest, size_t *dest_size_ptr,
+			       const void *data, size_t data_size);
+CK_RV ncr_symm_signature_verify_init (struct ncr_symm_signature_session *sess,
+				      struct ncr_symm_key *key);
+CK_RV ncr_symm_signature_verify_update (struct ncr_symm_signature_session *sess,
+					const void *data, size_t size);
+CK_RV ncr_symm_signature_verify_final (struct ncr_symm_signature_session *sess,
+				       const void *signature, size_t size);
+CK_RV ncr_symm_signature_verify (struct ncr_symm_signature_session *sess,
+				 const void *signature, size_t signature_size,
+				 const void *data, size_t data_size);
+
 #endif
diff --git a/lib/ncrypto_local.c b/lib/ncrypto_local.c
index 8f6473c..8cf4667 100644
--- a/lib/ncrypto_local.c
+++ b/lib/ncrypto_local.c
@@ -32,6 +32,7 @@ Red Hat author: Miloslav Trmač <mitr@redhat.com> */
 
 #include <glib.h>
 #include <openssl/evp.h>
+#include <openssl/hmac.h>
 #include <openssl/rand.h>
 
 #include <ncrypto/ncrypto.h>
@@ -695,3 +696,255 @@ ncr_symm_cipher_decrypt (struct ncr_symm_cipher_session *sess, void *dest,
 {
   return symm_cipher (sess, false, dest, dest_size_ptr, src, src_size);
 }
+
+ /* Symmetric signature handling */
+
+static const EVP_MD *
+symm_signature_evp_from_hmac_mech (CK_MECHANISM_TYPE mech)
+{
+  switch (mech)
+    {
+#define E(M, E)					\
+    case CKM_##M##_HMAC:			\
+      return EVP_##E ();
+      E (MD5, md5);
+      E (SHA_1, sha1);
+      E (SHA224, sha224);
+      E (SHA256, sha256);
+      E (SHA384, sha384);
+      E (SHA512, sha512);
+#undef E
+    default:
+      g_return_val_if_reached (NULL);
+    }
+}
+
+struct ncr_symm_signature_session
+{
+  HMAC_CTX ctx;
+  const EVP_MD *md;
+  size_t md_size;
+  bool signing;
+  /* Debugging only */
+  enum { NSSS_NEW, NSSS_INITIALIZED, NSSS_UPDATED, NSSS_FINISHED } state;
+};
+
+CK_RV
+ncr_symm_signature_alloc (struct ncr_symm_signature_session **sess,
+			  CK_MECHANISM_TYPE mech)
+{
+  struct ncr_symm_signature_session *s;
+  const EVP_MD *md;
+
+  g_return_val_if_fail (sess != NULL, CKR_ARGUMENTS_BAD);
+
+  md = symm_signature_evp_from_hmac_mech (mech);
+  if (md == NULL)
+    return CKR_MECHANISM_INVALID;
+
+  s = malloc (sizeof (*s));
+  if (s == NULL)
+    return CKR_HOST_MEMORY;
+
+  HMAC_CTX_init (&s->ctx);
+  s->state = NSSS_NEW;
+  s->md = md;
+  s->md_size = EVP_MD_size (md);
+  g_assert (s->md_size <= EVP_MAX_MD_SIZE);
+  *sess = s;
+  return CKR_OK;
+}
+
+CK_RV
+ncr_symm_signature_free (struct ncr_symm_signature_session *sess)
+{
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+
+  HMAC_CTX_cleanup (&sess->ctx);
+  free (sess);
+  return CKR_OK;
+}
+
+static CK_RV
+symm_signature_init (struct ncr_symm_signature_session *sess, bool sign,
+		     struct ncr_symm_key *key)
+{
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (sess->state == NSSS_NEW || sess->state == NSSS_FINISHED,
+			CKR_OPERATION_ACTIVE);
+  g_return_val_if_fail (key != NULL, CKR_KEY_HANDLE_INVALID);
+
+  /* This is not assured, but holds for supported mechanisms. */
+  g_return_val_if_fail (key->type == CKK_GENERIC_SECRET,
+			CKR_KEY_TYPE_INCONSISTENT);
+
+  if (HMAC_Init_ex (&sess->ctx, key->value, key->size, sess->md, NULL) == 0)
+    return ckr_openssl ();
+
+  sess->signing = sign;
+  sess->state = NSSS_INITIALIZED;
+  return CKR_OK;
+}
+
+static CK_RV
+symm_signature_update (struct ncr_symm_signature_session *sess, bool sign,
+		       const void *data, size_t size)
+{
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (data != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (sess->state == NSSS_INITIALIZED
+			|| sess->state == NSSS_UPDATED,
+			CKR_OPERATION_NOT_INITIALIZED);
+  g_return_val_if_fail (sess->signing == sign, CKR_OPERATION_NOT_INITIALIZED);
+
+  if (HMAC_Update (&sess->ctx, data, size) == 0)
+    return ckr_openssl ();
+
+  sess->state = NSSS_UPDATED;
+  return CKR_OK;
+}
+
+CK_RV
+ncr_symm_signature_sign_init (struct ncr_symm_signature_session *sess,
+			      struct ncr_symm_key *key)
+{
+  return symm_signature_init (sess, true, key);
+}
+
+CK_RV
+ncr_symm_signature_sign_update (struct ncr_symm_signature_session *sess,
+				const void *data, size_t size)
+{
+  return symm_signature_update (sess, true, data, size);
+}
+
+CK_RV
+ncr_symm_signature_sign_final (struct ncr_symm_signature_session *sess,
+			       void *dest, size_t *size_ptr)
+{
+  int res;
+
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (sess->state == NSSS_INITIALIZED
+			|| sess->state == NSSS_UPDATED,
+			CKR_OPERATION_NOT_INITIALIZED);
+  g_return_val_if_fail (size_ptr != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (sess->signing == true, CKR_OPERATION_NOT_INITIALIZED);
+
+  if (dest == NULL)
+    {
+      *size_ptr = sess->md_size;
+      return CKR_OK;
+    }
+  if (*size_ptr < sess->md_size)
+    {
+      *size_ptr = sess->md_size;
+      return CKR_BUFFER_TOO_SMALL;
+    }
+  *size_ptr = sess->md_size;
+
+  g_return_val_if_fail (dest != NULL, CKR_ARGUMENTS_BAD);
+
+  res = HMAC_Final (&sess->ctx, dest, NULL);
+  sess->state = NSSS_FINISHED;
+  return res ? CKR_OK : ckr_openssl ();
+}
+
+CK_RV
+ncr_symm_signature_sign (struct ncr_symm_signature_session *sess, void *dest,
+			 size_t *dest_size_ptr, const void *data,
+			 size_t data_size)
+{
+  int res;
+
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (sess->state == NSSS_INITIALIZED,
+			CKR_OPERATION_NOT_INITIALIZED);
+  g_return_val_if_fail (dest_size_ptr != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (sess->signing == true, CKR_OPERATION_NOT_INITIALIZED);
+
+  if (dest == NULL)
+    {
+      *dest_size_ptr = sess->md_size;
+      return CKR_OK;
+    }
+  if (*dest_size_ptr < sess->md_size)
+    {
+      *dest_size_ptr = sess->md_size;
+      return CKR_BUFFER_TOO_SMALL;
+    }
+  *dest_size_ptr = sess->md_size;
+
+  g_return_val_if_fail (data != NULL, CKR_ARGUMENTS_BAD);
+
+  res = (HMAC_Update (&sess->ctx, data, data_size) != 0
+	 && HMAC_Final (&sess->ctx, dest, NULL) != 0);
+  sess->state = NSSS_FINISHED;
+  return res ? CKR_OK : ckr_openssl ();
+}
+
+CK_RV
+ncr_symm_signature_verify_init (struct ncr_symm_signature_session *sess,
+				struct ncr_symm_key *key)
+{
+  return symm_signature_init (sess, false, key);
+}
+
+CK_RV
+ncr_symm_signature_verify_update (struct ncr_symm_signature_session *sess,
+				  const void *data, size_t size)
+{
+  return symm_signature_update (sess, false, data, size);
+}
+
+CK_RV
+ncr_symm_signature_verify_final (struct ncr_symm_signature_session *sess,
+				 const void *signature, size_t size)
+{
+  uint8_t buf[EVP_MAX_MD_SIZE];
+  int res;
+
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (sess->state == NSSS_INITIALIZED
+			|| sess->state == NSSS_UPDATED,
+			CKR_OPERATION_NOT_INITIALIZED);
+  g_return_val_if_fail (signature != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (sess->signing == false, CKR_OPERATION_NOT_INITIALIZED);
+
+  res = HMAC_Final (&sess->ctx, buf, NULL);
+  sess->state = NSSS_FINISHED;
+  if (res == 0)
+    return ckr_openssl ();
+  if (size != sess->md_size)
+    return CKR_SIGNATURE_LEN_RANGE;
+  if (memcmp (signature, buf, size) != 0)
+    return CKR_SIGNATURE_INVALID;
+  return CKR_OK;
+}
+
+CK_RV
+ncr_symm_signature_verify (struct ncr_symm_signature_session *sess,
+			   const void *signature, size_t signature_size,
+			   const void *data, size_t data_size)
+{
+  uint8_t buf[EVP_MAX_MD_SIZE];
+  int res;
+
+  g_return_val_if_fail (sess != NULL, CKR_SESSION_HANDLE_INVALID);
+  g_return_val_if_fail (sess->state == NSSS_INITIALIZED,
+			CKR_OPERATION_NOT_INITIALIZED);
+  g_return_val_if_fail (data != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (signature != NULL, CKR_ARGUMENTS_BAD);
+  g_return_val_if_fail (sess->signing == false, CKR_OPERATION_NOT_INITIALIZED);
+
+  res = (HMAC_Update (&sess->ctx, data, data_size) != 0
+	 && HMAC_Final (&sess->ctx, buf, NULL) != 0);
+  sess->state = NSSS_FINISHED;
+  if (res == 0)
+    return ckr_openssl ();
+  if (signature_size != sess->md_size)
+    return CKR_SIGNATURE_LEN_RANGE;
+  if (memcmp (signature, buf, signature_size) != 0)
+    return CKR_SIGNATURE_INVALID;
+  return CKR_OK;
+}