Merge branch 'master' into ft-ks_flash

13 files changed, 232 insertions, 139 deletions

diff --git a/.gitignore b/.gitignore
index 7131463..1625b1a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,14 +11,15 @@ tests/test-bus
 tests/test-ecdsa
 tests/test-ecdsa-*.der
 tests/test-hash
+tests/test-mkmif
 tests/test-pbkdf2
+tests/test-rpc_get_random
+tests/test-rpc_get_version
 tests/test-rpc_hash
 tests/test-rpc_pkey
 tests/test-rpc_server
 tests/test-rsa
 tests/test-rsa-*.der
 tests/test-trng
-tests/test-rpc_get_version
-tests/test-rpc_get_random
 utils/cores
 utils/eim_peek_poke
diff --git a/GNUmakefile b/GNUmakefile
index 0b3647b..14e94c6 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -37,29 +37,61 @@ STATIC_PKEY_STATE_BLOCKS = 6
 INC		= hal.h hal_internal.h
 LIB		= libhal.a
 
-USAGE = "usage: make [IO_BUS=eim|i2c|fmc] [RPC_CLIENT=local|remote|mixed] [RPC_SERVER=yes] [KS=mmap|volatile|flash]"
+# Error checking on known control options, some of which allow the user entirely too much rope.
+
+USAGE := "usage: ${MAKE} [IO_BUS=eim|i2c|fmc] [RPC_MODE=none|server|client-simple|client-mixed] [KS=volatile|mmap|flash] [RPC_TRANSPORT=none|loopback|serial|daemon] [MODEXP_CORE=no|yes]"
+
+IO_BUS		?= eim
+KS		?= volatile
+RPC_MODE	?= none
+RPC_TRANSPORT	?= daemon
+MODEXP_CORE	?= no
+
+ifeq (,$(and \
+	$(filter	none eim i2c fmc			,${IO_BUS}),\
+	$(filter	none server client-simple client-mixed	,${RPC_MODE}),\
+	$(filter	volatile mmap flash			,${KS}),\
+	$(filter	none loopback serial daemon		,${RPC_TRANSPORT}),\
+	$(filter	no yes					,${MODEXP_CORE})))
+  $(error ${USAGE})
+endif
+
+$(info Building libhal with configuration IO_BUS=${IO_BUS} RPC_MODE=${RPC_MODE} KS=${KS} RPC_TRANSPORT=${RPC_TRANSPORT} MODEXP_CORE=${MODEXP_CORE})
+
+# Whether the RSA code should use the ModExp | ModExpS6 | ModExpA7 core.
+
+ifeq "${MODEXP_CORE}" "yes"
+  RSA_USE_MODEXP_CORE := 1
+else
+  RSA_USE_MODEXP_CORE := 0
+endif
+
+# Object files to build, initialized with ones we always want.
+# There's a balance here between skipping files we don't strictly
+# need and reducing the number of unnecessary conditionals in this
+# makefile, so the working definition of "always want" is sometimes
+# just "building this is harmless even if we don't use it."
+
+OBJ = errorstrings.o hash.o asn1.o ecdsa.o rsa.o ${KS_OBJ}
 
-OBJ = errorstrings.o
-CORE_OBJ = core.o ${HASH_OBJ} ${MISC_OBJ} ${PKEY_OBJ} ${PKEY2_OBJ} ${KS_OBJ} ${IO_OBJ} ${MKMIF_OBJ}
-HASH_OBJ = hash.o
-MISC_OBJ = csprng.o pbkdf2.o
-PKEY_OBJ = asn1.o ecdsa.o rsa.o
-PKEY2_OBJ = aes_keywrap.o modexp.o
-MKMIF_OBJ = mkmif.o
+# Object files to build when we're on a platform with direct access
+# to our hardware (Verilog) cores.
+
+CORE_OBJ = core.o csprng.o pbkdf2.o aes_keywrap.o modexp.o mkmif.o ${IO_OBJ}
 
 # I/O bus to the FPGA
 #
-# IO_BUS = eim | i2c | fmc
-#   eim: EIM bus from Novena
-#   i2c: older I2C bus from Novena
-#   fmc: FMC bus from dev-bridge and alpha boards
+# IO_BUS = none | eim | i2c | fmc
+#  none:	No FPGA I/O bus
+#   eim:	EIM bus from Novena
+#   i2c:	Older I2C bus from Novena
+#   fmc:	FMC bus from dev-bridge and alpha boards
 
-IO_BUS ?= eim
-ifeq (${IO_BUS},eim)
+ifeq "${IO_BUS}" "eim"
   IO_OBJ = hal_io_eim.o novena-eim.o
-else ifeq (${IO_BUS},i2c)
+else ifeq "${IO_BUS}" "i2c"
   IO_OBJ = hal_io_i2c.o
-else ifeq (${IO_BUS},fmc)
+else ifeq "${IO_BUS}" "fmc"
   IO_OBJ = hal_io_fmc.o
 endif
 
@@ -67,7 +99,7 @@ endif
 # hard-to-debug function pointer errors. OTOH, if we're building for Linux
 # (even on the Novena), we want to make it possible to build a shared library.
 
-ifneq (${IO_BUS},fmc)
+ifneq "${IO_BUS}" "fmc"
   CFLAGS += -fPIC
 endif
 
@@ -80,91 +112,75 @@ endif
 # and we haven't yet written the flash code for the bridge board.
 
 KS_OBJ = ks.o
-KS ?= mmap
-ifeq (${KS},mmap)
+
+ifeq "${KS}" "mmap"
   KS_OBJ += ks_mmap.o
-else ifeq (${KS},volatile)
+else ifeq "${KS}" "volatile"
   KS_OBJ += ks_volatile.o
-else ifeq (${KS},flash)
+else ifeq "${KS}" "flash"
   KS_OBJ += ks_flash.o
 endif
 
-# RPC_CLIENT = local | remote | mixed
-#   local: Build for Novena or dev-bridge, access FPGA cores directly.
-#   remote: Build for other host, communicate with RPC server.
-#   mixed: Do hashing locally in software, other functions remotely.
-#
-# RPC_SERVER = yes
+# RPC_MODE = none | server | client-simple | client-mixed
+#   none:		Build without RPC client, use cores directly.
+#   server:		Build for server side of RPC (HSM), use cores directly.
+#   client-simple:	Build for other host, communicate with cores via RPC server.
+#   client-mixed:	Like client-simple but do hashing locally in software and
+#			support a local keystore (for PKCS #11 public keys, etc)
 #
 # RPC_TRANSPORT = loopback | serial | daemon
-#   loopback: communicate over loopback socket on Novena
-#   serial: communicate over USB in serial pass-through mode
-#   daemon: communicate over USB via a daemon, to arbitrate multiple clients
+#   loopback:		Communicate over loopback socket on Novena
+#   serial:		Communicate over USB in serial pass-through mode
+#   daemon:		Communicate over USB via a daemon, to arbitrate multiple clients
+#
+# Note that RPC_MODE setting also controls the RPC_CLIENT setting passed to the C
+# preprocessor via CFLAGS.  Whatever we pass here must evaluate to an integer in
+# the C preprocessor: we can use symbolic names so long as they're defined as macros
+# in the C code, but we can't use things like C enum symbols.
 
-RPC_TRANSPORT ?= daemon
+ifneq "${RPC_MODE}" "none"
+  OBJ += rpc_api.o xdr.o
+endif
 
-RPC_CLIENT_OBJ = rpc_api.o rpc_client.o xdr.o
-ifeq (${RPC_TRANSPORT},loopback)
+ifeq "${RPC_TRANSPORT}" "serial"
+  OBJ += slip.o
+endif
+
+RPC_CLIENT_OBJ = rpc_client.o
+ifeq "${RPC_TRANSPORT}" "loopback"
   RPC_CLIENT_OBJ += rpc_client_loopback.o
-else ifeq (${RPC_TRANSPORT},serial)
-  RPC_CLIENT_OBJ += rpc_client_serial.o slip.o
-else ifeq (${RPC_TRANSPORT},daemon)
+else ifeq "${RPC_TRANSPORT}" "serial"
+  RPC_CLIENT_OBJ += rpc_client_serial.o
+else ifeq "${RPC_TRANSPORT}" "daemon"
   RPC_CLIENT_OBJ += rpc_client_daemon.o
 endif
 
 RPC_DISPATCH_OBJ = rpc_hash.o rpc_misc.o rpc_pkey.o
 
-RPC_SERVER_OBJ = rpc_api.o rpc_server.o xdr.o ${RPC_DISPATCH_OBJ}
-ifeq (${RPC_TRANSPORT},loopback)
+RPC_SERVER_OBJ = rpc_server.o
+ifeq "${RPC_TRANSPORT}" "loopback"
   RPC_SERVER_OBJ += rpc_server_loopback.o
-else ifeq (${RPC_TRANSPORT},serial)
-  RPC_SERVER_OBJ += rpc_server_serial.o slip.o
-endif
-
-# Not building any of the RPC stuff, access FPGA cores directly.
-ifndef RPC_CLIENT
-  ifndef RPC_SERVER
-    OBJ += ${CORE_OBJ}
-  endif
+else ifeq "${RPC_TRANSPORT}" "serial"
+  RPC_SERVER_OBJ += rpc_server_serial.o
 endif
 
-# Building the RPC server.
-ifdef RPC_SERVER
-  OBJ += ${CORE_OBJ} ${RPC_SERVER_OBJ}
-endif
-
-# Building the RPC client, in all its variations.
-ifdef RPC_CLIENT
+ifeq "${RPC_MODE}" "none"
+  OBJ += ${CORE_OBJ}
+  CFLAGS += -DHAL_RSA_USE_MODEXP=${RSA_USE_MODEXP_CORE}
+else ifeq "${RPC_MODE}" "server"
+  OBJ += ${CORE_OBJ} ${RPC_SERVER_OBJ} ${RPC_DISPATCH_OBJ}
+  CFLAGS += -DRPC_CLIENT=RPC_CLIENT_LOCAL -DHAL_RSA_USE_MODEXP=${RSA_USE_MODEXP_CORE}
+else ifeq "${RPC_MODE}" "client-simple"
   OBJ += ${RPC_CLIENT_OBJ}
-  ifeq (${RPC_CLIENT},local)
-    OBJ += ${CORE_OBJ} ${RPC_DISPATCH_OBJ}
-  else
-    CFLAGS += -DHAL_RSA_USE_MODEXP=0
-    OBJ +=  ${PKEY_OBJ}
-    ifeq (${RPC_CLIENT},mixed)
-      KS = volatile
-      OBJ += ${HASH_OBJ} ${PKEY2_OBJ} ${RPC_DISPATCH_OBJ} ${KS_OBJ}
-    endif
-  endif
-endif
-
-# RPC client locality, for rpc_client.c. This has to be kept in sync with
-# hal_internal.h. Yeah, it's ugly, but the C preprocessor can only
-# compare integers, not strings.
-
-ifeq (${RPC_CLIENT},local)
-  RPC_CLIENT_FLAG = 0
-else ifeq (${RPC_CLIENT},remote)
-  RPC_CLIENT_FLAG = 1
-else ifeq (${RPC_CLIENT},mixed)
-  RPC_CLIENT_FLAG = 2
-endif
-ifdef RPC_CLIENT_FLAG
-CFLAGS		+= -DRPC_CLIENT=${RPC_CLIENT_FLAG}
+  CFLAGS += -DRPC_CLIENT=RPC_CLIENT_REMOTE -DHAL_RSA_USE_MODEXP=0
+else ifeq "${RPC_MODE}" "client-mixed"
+  OBJ += ${RPC_CLIENT_OBJ} ${RPC_DISPATCH_OBJ}
+  CFLAGS += -DRPC_CLIENT=RPC_CLIENT_MIXED -DHAL_RSA_USE_MODEXP=0
+  KS = volatile
 endif
 
 TFMDIR		:= $(abspath ../thirdparty/libtfm)
-CFLAGS		+= -g3 -Wall -std=c99 -I${TFMDIR}
+CFLAGS		+= -g3 -Wall -std=c99 -Wno-strict-aliasing -I${TFMDIR}
 LDFLAGS		:= -g3 -L${TFMDIR} -ltfm
 
 CFLAGS		+= -DHAL_STATIC_HASH_STATE_BLOCKS=${STATIC_HASH_STATE_BLOCKS}
@@ -175,24 +191,17 @@ all: ${LIB}
 	cd tests; ${MAKE} CFLAGS='${CFLAGS} -I..' LDFLAGS='${LDFLAGS}' $@
 	cd utils; ${MAKE} CFLAGS='${CFLAGS} -I..' LDFLAGS='${LDFLAGS}' $@
 
-local:
-	${MAKE} RPC_CLIENT=local RPC_TRANSPORT=none
-
 client:
-	${MAKE} RPC_CLIENT=remote
+	${MAKE} RPC_MODE=client-simple
 
 mixed:
-	${MAKE} RPC_CLIENT=mixed KS=volatile
+	${MAKE} RPC_MODE=client-mixed
 
 server:
-	${MAKE} RPC_SERVER=yes
-
-loopback:
-	${MAKE} RPC_CLIENT=remote RPC_SERVER=yes RPC_TRANSPORT=loopback
+	${MAKE} RPC_MODE=server
 
 daemon: cryptech_rpcd
-#	${MAKE} RPC_CLIENT=mixed RPC_TRANSPORT=daemon
-	${MAKE} RPC_CLIENT=remote RPC_TRANSPORT=daemon
+	${MAKE} RPC_MODE=client-mixed RPC_TRANSPORT=daemon
 
 cryptech_rpcd: daemon.o slip.o rpc_serial.o xdr.o
 	${CC} ${CFLAGS} -o $@ $^ ${LDFLAGS}
@@ -212,7 +221,7 @@ last_gasp_pin_internal.h:
 	./utils/last_gasp_default_pin >$@
 
 test: all
-	export RPC_CLIENT RPC_SERVER
+	export RPC_MODE
 	cd tests; ${MAKE} -k $@
 
 clean:
@@ -227,3 +236,6 @@ tags: TAGS
 
 TAGS: *.[ch] tests/*.[ch] utils/*.[ch]
 	etags $^
+
+help usage:
+	@echo ${USAGE}
diff --git a/core.c b/core.c
index b7bf3b0..ffe61e6 100644
--- a/core.c
+++ b/core.c
@@ -108,6 +108,7 @@ static int name_matches(const hal_core_t *const core, const char * const name)
 static const struct { const char *name; hal_addr_t extra; } gaps[] = {
   { "csprng",  11 * CORE_SIZE }, /* empty slots after csprng */
   { "modexps6", 3 * CORE_SIZE }, /* ModexpS6 uses four slots */
+  { "modexpa7", 3 * CORE_SIZE }, /* ModexpA7 uses four slots */
 };
 
 static hal_core_t *probe_cores(void)
diff --git a/hal.h b/hal.h
index 12ed579..776acac 100644
--- a/hal.h
+++ b/hal.h
@@ -90,8 +90,14 @@
 #define CHACHA_NAME             "chacha  "
 #define CHACHA_VERSION          "0.80"
 
-#define MODEXPS6_NAME		"modexps6"
-#define MODEXPS6_VERSION	"0.10"
+#define MODEXP_NAME             "modexp"
+#define MODEXP_VERSION          "0.10"
+
+#define MODEXPS6_NAME           "modexps6"
+#define MODEXPS6_VERSION        "0.10"
+
+#define MODEXPA7_NAME           "modexpa7"
+#define MODEXPA7_VERSION        "0.10"
 
 #define MKMIF_NAME              "mkmif   "
 #define MKMIF_VERSION           "0.10"
diff --git a/hal_internal.h b/hal_internal.h
index 0934718..0c38c00 100644
--- a/hal_internal.h
+++ b/hal_internal.h
@@ -241,7 +241,7 @@ extern const hal_rpc_pkey_dispatch_t hal_rpc_local_pkey_dispatch, hal_rpc_remote
  * See code in rpc_pkey.c for how this flag fits into the pkey handle.
  */
 
-#define	HAL_PKEY_HANDLE_PROXIMATE_FLAG	(1 << 31)
+#define HAL_PKEY_HANDLE_PROXIMATE_FLAG  (1 << 31)
 
 /*
  * Keystore API.
@@ -257,9 +257,9 @@ extern const hal_rpc_pkey_dispatch_t hal_rpc_local_pkey_dispatch, hal_rpc_remote
  *
  * 2048-bit RSA:        1194 bytes
  * 4096-bit RSA:        2351 bytes
- * 8192-bit RSA:	4655 bytes
- * EC P-256:		 121 bytes
- * EC P-384:		 167 bytes
+ * 8192-bit RSA:        4655 bytes
+ * EC P-256:             121 bytes
+ * EC P-384:             167 bytes
  * EC P-521:             223 bytes
  *
  * Plus we need a bit of AES-keywrap overhead, since we're storing the
@@ -271,7 +271,7 @@ extern const hal_rpc_pkey_dispatch_t hal_rpc_local_pkey_dispatch, hal_rpc_remote
  * to keep them private, they don't require tamper-protected RAM.
  */
 
-#define	HAL_KS_WRAPPED_KEYSIZE  ((4655 + 15) & ~7)
+#define HAL_KS_WRAPPED_KEYSIZE  ((4655 + 15) & ~7)
 
 #ifndef HAL_STATIC_PKEY_STATE_BLOCKS
 #define HAL_STATIC_PKEY_STATE_BLOCKS 0
@@ -435,14 +435,17 @@ typedef enum {
     RPC_FUNC_PKEY_RENAME,
 } rpc_func_num_t;
 
-#define RPC_VERSION 0x00010000		/* 0.1.0.0 */
+#define RPC_VERSION 0x00010000          /* 0.1.0.0 */
 
-/* RPC client locality. These have to be defines rather than an enum,
+/*
+ * RPC client locality. These have to be defines rather than an enum,
  * because they're handled by the preprocessor.
  */
-#define RPC_CLIENT_LOCAL	0
-#define RPC_CLIENT_REMOTE	1
-#define RPC_CLIENT_MIXED	2
+
+#define RPC_CLIENT_LOCAL        0
+#define RPC_CLIENT_REMOTE       1
+#define RPC_CLIENT_MIXED        2
+#define RPC_CLIENT_NONE         3
 
 #endif /* _HAL_INTERNAL_H_ */
 
diff --git a/hash.c b/hash.c
index 225a99d..5fface0 100644
--- a/hash.c
+++ b/hash.c
@@ -1031,7 +1031,7 @@ static hal_error_t sw_hash_core_sha256(hal_hash_state_t *state)
   uint32_t *H = (uint32_t *) state->core_state, S[8], W[64];
 
   if (state->block_count == 0) {
-    switch (state->driver_ctrl_mode & SHA256_MODE_MASK) {
+    switch (state->driver->ctrl_mode & SHA256_MODE_MASK) {
     case SHA256_MODE_SHA_224:   memcpy(H, sha224_iv, sizeof(sha224_iv)); break;
     case SHA256_MODE_SHA_256:   memcpy(H, sha256_iv, sizeof(sha256_iv)); break;
     default:                    return HAL_ERROR_IMPOSSIBLE;
diff --git a/ks.c b/ks.c
index b6cb32f..d252620 100644
--- a/ks.c
+++ b/ks.c
@@ -42,12 +42,28 @@
 
 #define KEK_LENGTH (bitsToBytes(256))
 
+/*
+ * In "remote" and "mixed" RPC modes we're a software only RPC client
+ * without (direct) access to secure hardware, thus there is no real
+ * point in encrypting keys.  As precautions, we (a) warn about this
+ * when configured in one of these modes, and (b) refuse to store any
+ * sort of private keys.
+ */
+
+#define USE_KEK (RPC_CLIENT != RPC_CLIENT_REMOTE && RPC_CLIENT != RPC_CLIENT_MIXED)
+
+#if !USE_KEK
+#warning ks.c compiled without KEK support and will only accept public keys -- this is normal for the host-side build of libhsm
+#endif
+
 static inline int acceptable_key_type(const hal_key_type_t type)
 {
   switch (type) {
+#if USE_KEK
   case HAL_KEY_TYPE_RSA_PRIVATE:
-  case HAL_KEY_TYPE_RSA_PUBLIC:
   case HAL_KEY_TYPE_EC_PRIVATE:
+#endif
+  case HAL_KEY_TYPE_RSA_PUBLIC:
   case HAL_KEY_TYPE_EC_PUBLIC:
     return 1;
   default:
@@ -96,6 +112,8 @@ hal_error_t hal_ks_store(const hal_key_type_t type,
   memset(&k, 0, sizeof(k));
   k.der_len = sizeof(k.der);
 
+#if USE_KEK
+
   uint8_t kek[KEK_LENGTH];
   size_t kek_len;
 
@@ -107,6 +125,16 @@ hal_error_t hal_ks_store(const hal_key_type_t type,
   if (err != HAL_OK)
     return err;
 
+#else /* USE_KEK */
+
+  if (der_len > k.der_len)
+    return HAL_ERROR_RESULT_TOO_LONG;
+
+  k.der_len = der_len;
+  memcpy(k.der, der, der_len);
+
+#endif /* USE_KEK */
+
   assert(name_len <= sizeof(k.name));
   memcpy(k.name, name, name_len);
   k.name_len = name_len;
@@ -199,6 +227,9 @@ hal_error_t hal_ks_fetch(const hal_key_type_t type,
     *der_len = k->der_len;
 
   if (der != NULL) {
+
+#if USE_KEK
+
     uint8_t kek[KEK_LENGTH];
     size_t kek_len, der_len_;
     hal_error_t err;
@@ -215,6 +246,18 @@ hal_error_t hal_ks_fetch(const hal_key_type_t type,
 
     if (err != HAL_OK)
       return err;
+
+#else /* USE_KEK */
+
+    if (k->der_len > der_max)
+      return HAL_ERROR_RESULT_TOO_LONG;
+
+    if (der_len != NULL)
+      *der_len = k->der_len;
+
+    memcpy(der, k->der, k->der_len);
+
+#endif /* USE_KEK */
   }
 
   return HAL_OK;
diff --git a/rpc_client.c b/rpc_client.c
index 3ac6d6e..c92571b 100644
--- a/rpc_client.c
+++ b/rpc_client.c
@@ -971,15 +971,14 @@ const hal_rpc_pkey_dispatch_t hal_rpc_mixed_pkey_dispatch = {
 
 #endif /* RPC_CLIENT != RPC_CLIENT_LOCAL */
 
-#if RPC_CLIENT == RPC_CLIENT_LOCAL
-const hal_rpc_misc_dispatch_t * hal_rpc_misc_dispatch = &hal_rpc_local_misc_dispatch;
-const hal_rpc_hash_dispatch_t * hal_rpc_hash_dispatch = &hal_rpc_local_hash_dispatch;
-const hal_rpc_pkey_dispatch_t * hal_rpc_pkey_dispatch = &hal_rpc_local_pkey_dispatch;
-#elif RPC_CLIENT == RPC_CLIENT_REMOTE
+
+#if RPC_CLIENT == RPC_CLIENT_REMOTE
 const hal_rpc_misc_dispatch_t * hal_rpc_misc_dispatch = &hal_rpc_remote_misc_dispatch;
 const hal_rpc_hash_dispatch_t * hal_rpc_hash_dispatch = &hal_rpc_remote_hash_dispatch;
 const hal_rpc_pkey_dispatch_t * hal_rpc_pkey_dispatch = &hal_rpc_remote_pkey_dispatch;
-#elif RPC_CLIENT == RPC_CLIENT_MIXED
+#endif
+
+#if RPC_CLIENT == RPC_CLIENT_MIXED
 const hal_rpc_misc_dispatch_t * hal_rpc_misc_dispatch = &hal_rpc_remote_misc_dispatch;
 const hal_rpc_hash_dispatch_t * hal_rpc_hash_dispatch = &hal_rpc_local_hash_dispatch;
 const hal_rpc_pkey_dispatch_t * hal_rpc_pkey_dispatch = &hal_rpc_mixed_pkey_dispatch;
diff --git a/rpc_server.c b/rpc_server.c
index a1bca26..65ba6bb 100644
--- a/rpc_server.c
+++ b/rpc_server.c
@@ -738,9 +738,11 @@ void hal_rpc_server_main(void)
  * Dispatch vectors.
  */
 
+#if RPC_CLIENT == RPC_CLIENT_LOCAL
 const hal_rpc_misc_dispatch_t *hal_rpc_misc_dispatch = &hal_rpc_local_misc_dispatch;
 const hal_rpc_hash_dispatch_t *hal_rpc_hash_dispatch = &hal_rpc_local_hash_dispatch;
 const hal_rpc_pkey_dispatch_t *hal_rpc_pkey_dispatch = &hal_rpc_local_pkey_dispatch;
+#endif
 
 hal_error_t hal_rpc_server_init(void)
 {
diff --git a/rsa.c b/rsa.c
index 7269aa9..c8a1479 100644
--- a/rsa.c
+++ b/rsa.c
@@ -197,7 +197,8 @@ static hal_error_t modexp(const hal_core_t *core,
 {
   hal_error_t err = HAL_OK;
 
-  if ((err = hal_core_check_name(&core, MODEXPS6_NAME)) != HAL_OK)
+  if (((err = hal_core_check_name(&core, MODEXPS6_NAME)) != HAL_OK) &&
+      ((err = hal_core_check_name(&core, MODEXPA7_NAME)) != HAL_OK))
     return err;
 
   assert(msg != NULL && exp != NULL && mod != NULL && res != NULL);
@@ -697,7 +698,7 @@ hal_error_t hal_rsa_private_key_to_der(const hal_rsa_key_t * const key,
 {
   hal_error_t err = HAL_OK;
 
-  if (key == NULL || der_len == NULL || key->type != HAL_KEY_TYPE_RSA_PRIVATE)
+  if (key == NULL || key->type != HAL_KEY_TYPE_RSA_PRIVATE)
     return HAL_ERROR_BAD_ARGUMENTS;
 
   fp_int version[1] = INIT_FP_INT;
@@ -706,9 +707,9 @@ hal_error_t hal_rsa_private_key_to_der(const hal_rsa_key_t * const key,
    * Calculate data length.
    */
 
-  size_t vlen = 0;
+  size_t hlen = 0, vlen = 0;
 
-#define _(x) { size_t i; if ((err = hal_asn1_encode_integer(x, NULL, &i, der_max - vlen)) != HAL_OK) return err; vlen += i; }
+#define _(x) { size_t n; if ((err = hal_asn1_encode_integer(x, NULL, &n, der_max - vlen)) != HAL_OK) return err; vlen += n; }
   RSAPrivateKey_fields;
 #undef _
 
@@ -716,11 +717,11 @@ hal_error_t hal_rsa_private_key_to_der(const hal_rsa_key_t * const key,
    * Encode header.
    */
 
-  if ((err = hal_asn1_encode_header(ASN1_SEQUENCE, vlen, der, der_len, der_max))  != HAL_OK)
+  if ((err = hal_asn1_encode_header(ASN1_SEQUENCE, vlen, der, &hlen, der_max))  != HAL_OK)
     return err;
 
-  const size_t hlen = *der_len;
-  *der_len += vlen;
+  if (der_len != NULL)
+    *der_len = hlen + vlen;
 
   if (der == NULL)
     return HAL_OK;
@@ -731,7 +732,7 @@ hal_error_t hal_rsa_private_key_to_der(const hal_rsa_key_t * const key,
 
   der += hlen;
 
-#define _(x) { size_t i; if ((err = hal_asn1_encode_integer(x, der, &i, vlen)) != HAL_OK) return err; der += i; vlen -= i; }
+#define _(x) { size_t n; if ((err = hal_asn1_encode_integer(x, der, &n, vlen)) != HAL_OK) return err; der += n; vlen -= n; }
   RSAPrivateKey_fields;
 #undef _
 
diff --git a/tests/GNUmakefile b/tests/GNUmakefile
index 65c7a25..f4299a0 100644
--- a/tests/GNUmakefile
+++ b/tests/GNUmakefile
@@ -29,21 +29,27 @@
 
 INC	= ../hal.h
 LIB	= ../libhal.a
-BIN	:= test-aes-key-wrap test-hash test-pbkdf2 test-ecdsa test-bus test-trng test-rsa
-ifndef RPC_SERVER
-  ifdef RPC_CLIENT
-    ifneq (${RPC_CLIENT},local)
-      # If we're only building a remote RPC client lib, don't include
-      # tests that access the FPGA cores.
-      BIN :=
-    endif
-  endif
-endif
-ifdef RPC_CLIENT
-  BIN	+= test-rpc_hash test-rpc_pkey test-rpc_get_version test-rpc_get_random
-endif
-ifdef RPC_SERVER
-  BIN	+= test-rpc_server
+
+# Which tests to build depends on how the library was compiled.
+
+CORE_TESTS	= test-aes-key-wrap test-hash test-pbkdf2 test-ecdsa test-bus test-trng test-rsa test-mkmif
+SERVER_TESTS	= test-rpc_server
+CLIENT_TESTS	= test-rpc_hash test-rpc_pkey test-rpc_get_version test-rpc_get_random
+
+ALL_TESTS	= ${CORE_TESTS} ${SERVER_TESTS} ${CLIENT_TESTS}
+
+ifeq "${RPC_MODE}" "none"
+
+  BIN += ${CORE_TESTS}
+
+else ifeq "${RPC_MODE}" "server"
+
+  BIN += ${CORE_TESTS} ${SERVER_TESTS}
+
+else
+
+  BIN += ${CLIENT_TESTS}
+
 endif
 
 CFLAGS	= -g3 -Wall -fPIC -std=c99 -I..
@@ -53,8 +59,8 @@ all: ${BIN}
 test: all
 	for i in ${BIN}; do (set -x; ./$$i); done
 
-clean:
-	rm -f *.o ${BIN}
+clean distclean:
+	rm -f *.o ${ALL_TESTS}
 
 ${BIN}: %: %.o ${LIB}
 	${CC} ${CFLAGS} -o $@ $^ ${LDFLAGS}
diff --git a/tests/test-rsa.c b/tests/test-rsa.c
index 1fc516b..60fe2a5 100644
--- a/tests/test-rsa.c
+++ b/tests/test-rsa.c
@@ -299,6 +299,8 @@ static int test_rsa(const hal_core_t *core, const rsa_tc_t * const tc)
 int main(int argc, char *argv[])
 {
   const hal_core_t *core = hal_core_find(MODEXPS6_NAME, NULL);
+  if (core == NULL)
+      core = hal_core_find(MODEXPA7_NAME, NULL);
   const hal_core_info_t *core_info = hal_core_info(core);
 
   if (core_info != NULL)
diff --git a/verilog_constants.h b/verilog_constants.h
index 085b973..f0ae070 100644
--- a/verilog_constants.h
+++ b/verilog_constants.h
@@ -224,6 +224,23 @@
 #define MODEXPS6_ADDR_RESULT            (MODEXPS6_ADDR_OPERANDS + 3 * MODEXPS6_OPERAND_WORDS)
 
 /*
+ * ModExpA7 core.  MODEXPA7_OPERAND_BITS is size in bits of largest
+ * supported modulus.
+ */
+
+#define MODEXPA7_OPERAND_BITS           (4096)
+#define MODEXPA7_OPERAND_WORDS          (MODEXPA7_OPERAND_BITS / 32)
+#define MODEXPA7_ADDR_REGISTERS         (0 * MODEXPA7_OPERAND_WORDS)
+#define MODEXPA7_ADDR_OPERANDS          (4 * MODEXPA7_OPERAND_WORDS)
+#define MODEXPA7_ADDR_MODE              (MODEXPA7_ADDR_REGISTERS + 0x10)
+#define MODEXPA7_ADDR_MODULUS_WIDTH     (MODEXPA7_ADDR_REGISTERS + 0x11)
+#define MODEXPA7_ADDR_EXPONENT_WIDTH    (MODEXPA7_ADDR_REGISTERS + 0x12)
+#define MODEXPA7_ADDR_MODULUS           (MODEXPA7_ADDR_OPERANDS + 0 * MODEXPA7_OPERAND_WORDS)
+#define MODEXPA7_ADDR_MESSAGE           (MODEXPA7_ADDR_OPERANDS + 1 * MODEXPA7_OPERAND_WORDS)
+#define MODEXPA7_ADDR_EXPONENT          (MODEXPA7_ADDR_OPERANDS + 2 * MODEXPA7_OPERAND_WORDS)
+#define MODEXPA7_ADDR_RESULT            (MODEXPA7_ADDR_OPERANDS + 3 * MODEXPA7_OPERAND_WORDS)
+
+/*
  * Utility cores.
  */