CBMC: Prove mlkem_shake256_prf and mlkem_shake256_rkprf

cbmc/proofs/mlkem_shake256_prf/Makefile

@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: Apache-2.0
+
+include ../Makefile_params.common
+
+HARNESS_ENTRY = harness
+HARNESS_FILE = mlkem_shake256_prf_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 = mlkem_shake256_prf
+
+DEFINES +=
+INCLUDES +=
+
+REMOVE_FUNCTION_BODY +=
+UNWINDSET +=
+
+PROOF_SOURCES += $(PROOFDIR)/$(HARNESS_FILE).c
+PROJECT_SOURCES += $(SRCDIR)/mlkem/symmetric-shake.c
+
+CHECK_FUNCTION_CONTRACTS=$(MLKEM_NAMESPACE)mlkem_shake256_prf
+USE_FUNCTION_CONTRACTS=$(FIPS202_NAMESPACE)shake256
+APPLY_LOOP_CONTRACTS=on
+USE_DYNAMIC_FRAMES=1
+
+# Disable any setting of EXTERNAL_SAT_SOLVER, and choose SMT backend instead
+EXTERNAL_SAT_SOLVER=
+CBMCFLAGS=--bitwuzla
+
+FUNCTION_NAME = $(MLKEM_NAMESPACE)mlkem_shake256_prf
+
+# 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

cbmc/proofs/mlkem_shake256_prf/cbmc-proof.txt

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# This file marks this directory as containing a CBMC proof.

cbmc/proofs/mlkem_shake256_prf/mlkem_shake256_prf_harness.c

@@ -0,0 +1,29 @@
+// Copyright (c) 2024 The mlkem-native project authors
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: MIT-0
+
+/*
+ * Insert copyright notice
+ */
+
+
+/*
+ * Insert project header files that
+ *   - include the declaration of the function
+ *   - include the types needed to declare function arguments
+ */
+#include <stdint.h>
+#include "symmetric.h"
+
+/**
+ * @brief Starting point for formal analysis
+ *
+ */
+void harness(void)
+{
+  uint8_t *out;
+  size_t outlen;
+  uint8_t *key;
+  uint8_t nonce;
+  mlkem_shake256_prf(out, outlen, key, nonce);
+}

cbmc/proofs/mlkem_shake256_rkprf/Makefile

@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: Apache-2.0
+
+include ../Makefile_params.common
+
+HARNESS_ENTRY = harness
+HARNESS_FILE = mlkem_shake256_rkprf_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 = mlkem_shake256_rkprf
+
+DEFINES +=
+INCLUDES +=
+
+REMOVE_FUNCTION_BODY +=
+UNWINDSET +=
+
+PROOF_SOURCES += $(PROOFDIR)/$(HARNESS_FILE).c
+PROJECT_SOURCES += $(SRCDIR)/mlkem/symmetric-shake.c $(SRCDIR)/fips202/fips202.c
+
+CHECK_FUNCTION_CONTRACTS=$(MLKEM_NAMESPACE)mlkem_shake256_rkprf
+USE_FUNCTION_CONTRACTS=$(FIPS202_NAMESPACE)shake256_inc_absorb $(FIPS202_NAMESPACE)shake256_inc_finalize $(FIPS202_NAMESPACE)shake256_inc_squeeze $(FIPS202_NAMESPACE)shake256_inc_init
+APPLY_LOOP_CONTRACTS=on
+USE_DYNAMIC_FRAMES=1
+
+# Disable any setting of EXTERNAL_SAT_SOLVER, and choose SMT backend instead
+EXTERNAL_SAT_SOLVER=
+CBMCFLAGS=--bitwuzla
+
+FUNCTION_NAME = $(MLKEM_NAMESPACE)mlkem_shake256_rkprf
+
+# 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

cbmc/proofs/mlkem_shake256_rkprf/cbmc-proof.txt

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# This file marks this directory as containing a CBMC proof.

cbmc/proofs/mlkem_shake256_rkprf/mlkem_shake256_rkprf_harness.c

@@ -0,0 +1,28 @@
+// Copyright (c) 2024 The mlkem-native project authors
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: MIT-0
+
+/*
+ * Insert copyright notice
+ */
+
+
+/*
+ * Insert project header files that
+ *   - include the declaration of the function
+ *   - include the types needed to declare function arguments
+ */
+#include <stdint.h>
+#include "symmetric.h"
+
+/**
+ * @brief Starting point for formal analysis
+ *
+ */
+void harness(void)
+{
+  uint8_t *out;
+  uint8_t *key;
+  uint8_t *input;
+  mlkem_shake256_rkprf(out, key, input);
+}

fips202/fips202.h

@@ -61,21 +61,43 @@ void shake128_ctx_release(shake128ctx *state);
 
 /* Initialize incremental hashing API */
 #define shake256_inc_init FIPS202_NAMESPACE(shake256_inc_init)
-void shake256_inc_init(shake256incctx *state);
+void shake256_inc_init(shake256incctx *state)
+__contract__(
+  requires(memory_no_alias(state, sizeof(shake256incctx)))
+  assigns(memory_slice(state, sizeof(shake256incctx)))
+);
+
+
 #define shake256_inc_absorb FIPS202_NAMESPACE(shake256_inc_absorb)
 void shake256_inc_absorb(shake256incctx *state, const uint8_t *input,
-                         size_t inlen);
+                         size_t inlen)
+__contract__(
+  requires(memory_no_alias(state, sizeof(shake256incctx)))
+  requires(memory_no_alias(input, inlen))
+  assigns(memory_slice(state, sizeof(shake256incctx)))
+);
+
+
 /* Prepares for squeeze phase */
 #define shake256_inc_finalize FIPS202_NAMESPACE(shake256_inc_finalize)
-void shake256_inc_finalize(shake256incctx *state);
+void shake256_inc_finalize(shake256incctx *state)
+__contract__(
+  requires(memory_no_alias(state, sizeof(shake256incctx)))
+  assigns(memory_slice(state, sizeof(shake256incctx)))
+);
 
 /* Squeeze output out of the sponge.
  *
  * Supports being called multiple times
  */
 #define shake256_inc_squeeze FIPS202_NAMESPACE(shake256_inc_squeeze)
-void shake256_inc_squeeze(uint8_t *output, size_t outlen,
-                          shake256incctx *state);
+void shake256_inc_squeeze(uint8_t *output, size_t outlen, shake256incctx *state)
+__contract__(
+  requires(memory_no_alias(state, sizeof(shake256incctx)))
+  requires(memory_no_alias(output, outlen))
+  assigns(memory_slice(output, outlen))
+  assigns(memory_slice(state, sizeof(shake256incctx)))
+);
 
 /* Free the state */
 #define shake256_inc_ctx_release FIPS202_NAMESPACE(shake256_inc_ctx_release)

fips202/fips202x4.h

@@ -16,8 +16,15 @@
 #define shake128x4_absorb FIPS202_NAMESPACE(shake128x4_absorb)
 void shake128x4_absorb(keccakx4_state *state, const uint8_t *in0,
                        const uint8_t *in1, const uint8_t *in2,
-                       const uint8_t *in3, size_t inlen);
-
+                       const uint8_t *in3, size_t inlen)
+__contract__(
+  requires(memory_no_alias(state, sizeof(keccakx4_state)))
+  requires(memory_no_alias(in0, inlen))
+  requires(memory_no_alias(in1, inlen))
+  requires(memory_no_alias(in2, inlen))
+  requires(memory_no_alias(in3, inlen))
+  assigns(object_whole(state))
+);
 
 #define shake256x4_absorb FIPS202_NAMESPACE(shake256x4_absorb)
 void shake256x4_absorb(keccakx4_state *state, const uint8_t *in0,