CBMC: Prove AArch64 mlk_poly_mulcache_compute_native based on HOL-Light spec

Signed-off-by: Matthias J. Kannwischer <matthias@kannwischer.eu>

Author: mkannwischer

dev/aarch64_clean/src/arith_native_aarch64.h

@@ -82,8 +82,19 @@ __contract__(
 );
 
 #define mlk_poly_mulcache_compute_asm MLK_NAMESPACE(poly_mulcache_compute_asm)
-void mlk_poly_mulcache_compute_asm(int16_t *, const int16_t *, const int16_t *,
-                                   const int16_t *);
+void mlk_poly_mulcache_compute_asm(int16_t *cache, const int16_t *mlk_poly,
+                                   const int16_t *zetas,
+                                   const int16_t *zetas_twisted)
+/* This must be kept in sync with the HOL-Light specification
+ * in proofs/hol_light/arm/proofs/mlkem_poly_mulcache_compute.ml */
+__contract__(
+  requires(memory_no_alias(cache, sizeof(int16_t) * (MLKEM_N / 2)))
+  requires(memory_no_alias(mlk_poly, sizeof(int16_t) * MLKEM_N))
+  requires(zetas == mlk_aarch64_zetas_mulcache_native)
+  requires(zetas_twisted == mlk_aarch64_zetas_mulcache_twisted_native)
+  assigns(object_whole(cache))
+  ensures(array_abs_bound(cache, 0, MLKEM_N / 2, MLKEM_Q))
+);
 
 #define mlk_poly_tobytes_asm MLK_NAMESPACE(poly_tobytes_asm)
 void mlk_poly_tobytes_asm(uint8_t *r, const int16_t *a)

dev/aarch64_opt/src/arith_native_aarch64.h

@@ -82,8 +82,19 @@ __contract__(
 );
 
 #define mlk_poly_mulcache_compute_asm MLK_NAMESPACE(poly_mulcache_compute_asm)
-void mlk_poly_mulcache_compute_asm(int16_t *, const int16_t *, const int16_t *,
-                                   const int16_t *);
+void mlk_poly_mulcache_compute_asm(int16_t *cache, const int16_t *mlk_poly,
+                                   const int16_t *zetas,
+                                   const int16_t *zetas_twisted)
+/* This must be kept in sync with the HOL-Light specification
+ * in proofs/hol_light/arm/proofs/mlkem_poly_mulcache_compute.ml */
+__contract__(
+  requires(memory_no_alias(cache, sizeof(int16_t) * (MLKEM_N / 2)))
+  requires(memory_no_alias(mlk_poly, sizeof(int16_t) * MLKEM_N))
+  requires(zetas == mlk_aarch64_zetas_mulcache_native)
+  requires(zetas_twisted == mlk_aarch64_zetas_mulcache_twisted_native)
+  assigns(object_whole(cache))
+  ensures(array_abs_bound(cache, 0, MLKEM_N / 2, MLKEM_Q))
+);
 
 #define mlk_poly_tobytes_asm MLK_NAMESPACE(poly_tobytes_asm)
 void mlk_poly_tobytes_asm(uint8_t *r, const int16_t *a)

mlkem/native/aarch64/src/arith_native_aarch64.h

@@ -82,8 +82,19 @@ __contract__(
 );
 
 #define mlk_poly_mulcache_compute_asm MLK_NAMESPACE(poly_mulcache_compute_asm)
-void mlk_poly_mulcache_compute_asm(int16_t *, const int16_t *, const int16_t *,
-                                   const int16_t *);
+void mlk_poly_mulcache_compute_asm(int16_t *cache, const int16_t *mlk_poly,
+                                   const int16_t *zetas,
+                                   const int16_t *zetas_twisted)
+/* This must be kept in sync with the HOL-Light specification
+ * in proofs/hol_light/arm/proofs/mlkem_poly_mulcache_compute.ml */
+__contract__(
+  requires(memory_no_alias(cache, sizeof(int16_t) * (MLKEM_N / 2)))
+  requires(memory_no_alias(mlk_poly, sizeof(int16_t) * MLKEM_N))
+  requires(zetas == mlk_aarch64_zetas_mulcache_native)
+  requires(zetas_twisted == mlk_aarch64_zetas_mulcache_twisted_native)
+  assigns(object_whole(cache))
+  ensures(array_abs_bound(cache, 0, MLKEM_N / 2, MLKEM_Q))
+);
 
 #define mlk_poly_tobytes_asm MLK_NAMESPACE(poly_tobytes_asm)
 void mlk_poly_tobytes_asm(uint8_t *r, const int16_t *a)

proofs/cbmc/poly_mulcache_compute_native_aarch64/Makefile

@@ -0,0 +1,57 @@
+# Copyright (c) The mlkem-native project authors
+# SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT
+
+include ../Makefile_params.common
+
+HARNESS_ENTRY = harness
+HARNESS_FILE = poly_mulcache_compute_native_aarch64_harness
+
+# This should be a unique identifier for this proof, and will appear on the
+# Litani dashboard. It can be human-readable and contain spaces if you wish.
+PROOF_UID = poly_mulcache_compute_native_aarch64
+
+# We need to set MLK_CHECK_APIS as otherwise mlkem/native/api.h won't be
+# included, which contains the CBMC specifications.
+DEFINES += -DMLK_CONFIG_USE_NATIVE_BACKEND_ARITH -DMLK_CONFIG_ARITH_BACKEND_FILE="\"$(SRCDIR)/mlkem/native/aarch64/meta.h\"" -DMLK_CHECK_APIS
+INCLUDES +=
+
+REMOVE_FUNCTION_BODY +=
+UNWINDSET +=
+
+PROOF_SOURCES += $(PROOFDIR)/$(HARNESS_FILE).c
+PROJECT_SOURCES += $(SRCDIR)/mlkem/poly.c  $(SRCDIR)/mlkem/native/aarch64/src/aarch64_zetas.c
+
+CHECK_FUNCTION_CONTRACTS=mlk_poly_mulcache_compute_native
+USE_FUNCTION_CONTRACTS=mlk_poly_mulcache_compute_asm
+APPLY_LOOP_CONTRACTS=on
+USE_DYNAMIC_FRAMES=1
+
+# Disable any setting of EXTERNAL_SAT_SOLVER, and choose SMT backend instead
+EXTERNAL_SAT_SOLVER=
+CBMCFLAGS=--smt2
+
+FUNCTION_NAME = poly_mulcache_compute_native_aarch64
+
+# If this proof is found to consume huge amounts of RAM, you can set the
+# EXPENSIVE variable. With new enough versions of the proof tools, this will
+# restrict the number of EXPENSIVE CBMC jobs running at once. See the
+# documentation in Makefile.common under the "Job Pools" heading for details.
+# EXPENSIVE = true
+
+# This function is large enough to need...
+CBMC_OBJECT_BITS = 8
+
+# If you require access to a file-local ("static") function or object to conduct
+# your proof, set the following (and do not include the original source file
+# ("mlkem/poly.c") in PROJECT_SOURCES).
+# REWRITTEN_SOURCES = $(PROOFDIR)/<__SOURCE_FILE_BASENAME__>.i
+# include ../Makefile.common
+# $(PROOFDIR)/<__SOURCE_FILE_BASENAME__>.i_SOURCE = $(SRCDIR)/mlkem/poly.c
+# $(PROOFDIR)/<__SOURCE_FILE_BASENAME__>.i_FUNCTIONS = foo bar
+# $(PROOFDIR)/<__SOURCE_FILE_BASENAME__>.i_OBJECTS = baz
+# Care is required with variables on the left-hand side: REWRITTEN_SOURCES must
+# be set before including Makefile.common, but any use of variables on the
+# left-hand side requires those variables to be defined. Hence, _SOURCE,
+# _FUNCTIONS, _OBJECTS is set after including Makefile.common.
+
+include ../Makefile.common

proofs/cbmc/poly_mulcache_compute_native_aarch64/poly_mulcache_compute_native_aarch64_harness.c

@@ -0,0 +1,16 @@
+// Copyright (c) The mlkem-native project authors
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: MIT-0
+
+#include <stdint.h>
+#include "cbmc.h"
+#include "params.h"
+
+void mlk_poly_mulcache_compute_native(int16_t cache[MLKEM_N / 2],
+                                      const int16_t mlk_poly[MLKEM_N]);
+
+void harness(void)
+{
+  int16_t *r, *c;
+  mlk_poly_mulcache_compute_native(c, r);
+}

proofs/hol_light/arm/proofs/mlkem_poly_mulcache_compute.ml

@@ -95,6 +95,9 @@ let have_mulcache_zetas = define
                          iword (EL i mulcache_zetas_twisted))
  `;;
 
+(* NOTE: This must be kept in sync with the CBMC specification
+ * in mlkem/native/aarch64/src/arith_native_aarch64.h *)
+
 let poly_mulcache_compute_GOAL = `forall pc src dst zetas zetas_twisted x y returnaddress.
     ALL (nonoverlapping (dst, 256))
         [(word pc, LENGTH poly_mulcache_compute_mc); (src, 512); (zetas, 256); (zetas_twisted, 256)]