ecp: introduce new ECP_LIGHT symbol

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>

include/mbedtls/build_info.h

@@ -105,6 +105,13 @@
 #define MBEDTLS_MD_LIGHT
 #endif
 
+/* MBEDTLS_ECP_C is now a subset of MBEDTLS_ECP_LIGHT which contains the
+ * arithmetic part. As a consequence if MBEDTLS_ECP_C is required for
+ * some reason, then MBEDTLS_ECP_LIGHT should be enabled as well. */
+#if defined(MBEDTLS_ECP_C)
+#define MBEDTLS_ECP_LIGHT
+#endif
+
 /* If MBEDTLS_PSA_CRYPTO_C is defined, make sure MBEDTLS_PSA_CRYPTO_CLIENT
  * is defined as well to include all PSA code.
  */

include/mbedtls/check_config.h

@@ -454,7 +454,7 @@
 #endif
 
 #if defined(MBEDTLS_PK_C) && \
-    !defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_ECP_C)
+    !defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_ECP_LIGHT)
 #error "MBEDTLS_PK_C defined, but not all prerequisites"
 #endif
 

include/mbedtls/ecp.h

@@ -312,7 +312,7 @@ mbedtls_ecp_group;
 /**
  * The maximum size of the groups, that is, of \c N and \c P.
  */
-#if !defined(MBEDTLS_ECP_C)
+#if !defined(MBEDTLS_ECP_LIGHT)
 /* Dummy definition to help code that has optional ECP support and
  * defines an MBEDTLS_ECP_MAX_BYTES-sized array unconditionally. */
 #define MBEDTLS_ECP_MAX_BITS 1
@@ -343,9 +343,9 @@ mbedtls_ecp_group;
 #define MBEDTLS_ECP_MAX_BITS 192
 #elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
 #define MBEDTLS_ECP_MAX_BITS 192
-#else
+#else /* !MBEDTLS_ECP_LIGHT */
 #error "Missing definition of MBEDTLS_ECP_MAX_BITS"
-#endif
+#endif /* !MBEDTLS_ECP_LIGHT */
 
 #define MBEDTLS_ECP_MAX_BYTES    ((MBEDTLS_ECP_MAX_BITS + 7) / 8)
 #define MBEDTLS_ECP_MAX_PT_LEN   (2 * MBEDTLS_ECP_MAX_BYTES + 1)

library/ecp.c

@@ -70,7 +70,7 @@
 #if defined(MBEDTLS_ECP_INTERNAL_ALT)
 #endif
 
-#if defined(MBEDTLS_ECP_C)
+#if defined(MBEDTLS_ECP_LIGHT)
 
 #include "mbedtls/ecp.h"
 #include "mbedtls/threading.h"
@@ -93,7 +93,10 @@
  * Counts of point addition and doubling, and field multiplications.
  * Used to test resistance of point multiplication to simple timing attacks.
  */
-static unsigned long add_count, dbl_count, mul_count;
+#if defined(MBEDTLS_ECP_C)
+static unsigned long add_count, dbl_count;
+#endif /* MBEDTLS_ECP_C */
+static unsigned long mul_count;
 #endif
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)
@@ -320,6 +323,7 @@ int mbedtls_ecp_check_budget(const mbedtls_ecp_group *grp,
 
 #endif /* MBEDTLS_ECP_RESTARTABLE */
 
+#if defined(MBEDTLS_ECP_C)
 static void mpi_init_many(mbedtls_mpi *arr, size_t size)
 {
     while (size--) {
@@ -333,6 +337,7 @@ static void mpi_free_many(mbedtls_mpi *arr, size_t size)
         mbedtls_mpi_free(arr++);
     }
 }
+#endif /* MBEDTLS_ECP_C */
 
 /*
  * List of supported curves:
@@ -1306,7 +1311,10 @@ cleanup:
     mbedtls_mpi_free(&exp);
     return ret;
 }
+#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */
 
+#if defined(MBEDTLS_ECP_C)
+#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED)
 /*
  * For curves in short Weierstrass form, we do all the internal operations in
  * Jacobian coordinates.
@@ -2723,6 +2731,7 @@ int mbedtls_ecp_mul(mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
 {
     return mbedtls_ecp_mul_restartable(grp, R, m, P, f_rng, p_rng, NULL);
 }
+#endif /* MBEDTLS_ECP_C */
 
 #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED)
 /*
@@ -2763,6 +2772,7 @@ cleanup:
 }
 #endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */
 
+#if defined(MBEDTLS_ECP_C)
 #if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED)
 /*
  * R = m * P with shortcuts for m == 0, m == 1 and m == -1
@@ -2914,6 +2924,7 @@ int mbedtls_ecp_muladd(mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
     return mbedtls_ecp_muladd_restartable(grp, R, m, P, n, Q, NULL);
 }
 #endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */
+#endif /* MBEDTLS_ECP_C */
 
 #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED)
 #if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
@@ -3159,6 +3170,7 @@ int mbedtls_ecp_gen_privkey(const mbedtls_ecp_group *grp,
     return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
 }
 
+#if defined(MBEDTLS_ECP_C)
 /*
  * Generate a keypair with configurable base point
  */
@@ -3200,6 +3212,7 @@ int mbedtls_ecp_gen_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
 
     return mbedtls_ecp_gen_keypair(&key->grp, &key->d, &key->Q, f_rng, p_rng);
 }
+#endif /* MBEDTLS_ECP_C */
 
 #define ECP_CURVE25519_KEY_SIZE 32
 #define ECP_CURVE448_KEY_SIZE   56
@@ -3316,7 +3329,7 @@ cleanup:
     return ret;
 }
 
-
+#if defined(MBEDTLS_ECP_C)
 /*
  * Check a public-private key pair
  */
@@ -3357,6 +3370,7 @@ cleanup:
 
     return ret;
 }
+#endif /* MBEDTLS_ECP_C */
 
 /*
  * Export generic key-pair parameters.
@@ -3383,6 +3397,7 @@ int mbedtls_ecp_export(const mbedtls_ecp_keypair *key, mbedtls_ecp_group *grp,
 
 #if defined(MBEDTLS_SELF_TEST)
 
+#if defined(MBEDTLS_ECP_C)
 /*
  * PRNG for test - !!!INSECURE NEVER USE IN PRODUCTION!!!
  *
@@ -3490,12 +3505,14 @@ cleanup:
     }
     return ret;
 }
+#endif /* MBEDTLS_ECP_C */
 
 /*
  * Checkup routine
  */
 int mbedtls_ecp_self_test(int verbose)
 {
+#if defined(MBEDTLS_ECP_C)
     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     mbedtls_ecp_group grp;
     mbedtls_ecp_point R, P;
@@ -3609,10 +3626,14 @@ cleanup:
     }
 
     return ret;
+#else /* MBEDTLS_ECP_C */
+    (void) verbose;
+    return 0;
+#endif /* MBEDTLS_ECP_C */
 }
 
 #endif /* MBEDTLS_SELF_TEST */
 
 #endif /* !MBEDTLS_ECP_ALT */
 
-#endif /* MBEDTLS_ECP_C */
+#endif /* MBEDTLS_ECP_LIGHT */