Minor fixes

1. Fix unused symbols compilation warnings.
2. Add comments for the closing `endif`.

library/ecdh.c

@@ -76,7 +76,7 @@ int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp
 {
     return( ecdh_gen_public_restartable( grp, d, Q, f_rng, p_rng, NULL ) );
 }
-#endif /* MBEDTLS_ECDH_GEN_PUBLIC_ALT */
+#endif /* !MBEDTLS_ECDH_GEN_PUBLIC_ALT */
 
 #if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT)
 /*
@@ -122,7 +122,7 @@ int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
     return( ecdh_compute_shared_restartable( grp, z, Q, d,
                                              f_rng, p_rng, NULL ) );
 }
-#endif /* MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
+#endif /* !MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
 
 /*
  * Initialize context
@@ -191,7 +191,9 @@ int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
 {
     int ret;
     size_t grp_len, pt_len;
+#if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
     mbedtls_ecp_restart_ctx *rs_ctx = NULL;
+#endif
 
     if( ctx == NULL || ctx->grp.pbits == 0 )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
@@ -210,7 +212,7 @@ int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
     if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
                                              f_rng, p_rng, rs_ctx ) ) != 0 )
         return( ret );
-#endif
+#endif /* MBEDTLS_ECDH_GEN_PUBLIC_ALT */
 
     if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf, blen ) )
                 != 0 )
@@ -284,7 +286,9 @@ int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
                       void *p_rng )
 {
     int ret;
+#if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
     mbedtls_ecp_restart_ctx *rs_ctx = NULL;
+#endif
 
     if( ctx == NULL || ctx->grp.pbits == 0 )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
@@ -302,7 +306,7 @@ int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
     if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
                     f_rng, p_rng, rs_ctx ) ) != 0 )
         return( ret );
-#endif
+#endif /* MBEDTLS_ECDH_GEN_PUBLIC_ALT */
 
     return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
                                 olen, buf, blen );
@@ -338,7 +342,9 @@ int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
                       void *p_rng )
 {
     int ret;
+#if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT)
     mbedtls_ecp_restart_ctx *rs_ctx = NULL;
+#endif
 
     if( ctx == NULL || ctx->grp.pbits == 0 )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
@@ -360,7 +366,7 @@ int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
     {
         return( ret );
     }
-#endif
+#endif /* MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
 
     if( mbedtls_mpi_size( &ctx->z ) > blen )
         return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );

library/ecdsa.c

@@ -237,6 +237,7 @@ cleanup:
     return( ret );
 }
 
+#if !defined(MBEDTLS_ECDSA_SIGN_ALT)
 /*
  * Compute ECDSA signature of a hashed message (SEC1 4.1.3)
  * Obviously, compared to SEC1 4.1.3, we skip step 4 (hash message)
@@ -369,7 +370,6 @@ cleanup:
     return( ret );
 }
 
-#if !defined(MBEDTLS_ECDSA_SIGN_ALT)
 /*
  * Compute ECDSA signature of a hashed message
  */
@@ -380,7 +380,7 @@ int mbedtls_ecdsa_sign( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi *s,
     return( ecdsa_sign_restartable( grp, r, s, d, buf, blen,
                                     f_rng, p_rng, NULL ) );
 }
-#endif /* MBEDTLS_ECDSA_SIGN_ALT */
+#endif /* !MBEDTLS_ECDSA_SIGN_ALT */
 
 #if defined(MBEDTLS_ECDSA_DETERMINISTIC)
 /*
@@ -438,7 +438,7 @@ sign:
 #else
     ret = ecdsa_sign_restartable( grp, r, s, d, buf, blen,
                       mbedtls_hmac_drbg_random, p_rng, rs_ctx );
-#endif
+#endif /* MBEDTLS_ECDSA_SIGN_ALT */
 
 cleanup:
     mbedtls_hmac_drbg_free( &rng_ctx );
@@ -460,6 +460,7 @@ int mbedtls_ecdsa_sign_det( mbedtls_ecp_group *grp, mbedtls_mpi *r, mbedtls_mpi
 }
 #endif /* MBEDTLS_ECDSA_DETERMINISTIC */
 
+#if !defined(MBEDTLS_ECDSA_VERIFY_ALT)
 /*
  * Verify ECDSA signature of hashed message (SEC1 4.1.4)
  * Obviously, compared to SEC1 4.1.3, we skip step 2 (hash message)
@@ -569,7 +570,6 @@ cleanup:
     return( ret );
 }
 
-#if !defined(MBEDTLS_ECDSA_VERIFY_ALT)
 /*
  * Verify ECDSA signature of hashed message
  */
@@ -579,7 +579,7 @@ int mbedtls_ecdsa_verify( mbedtls_ecp_group *grp,
 {
     return( ecdsa_verify_restartable( grp, buf, blen, Q, r, s, NULL ) );
 }
-#endif /* MBEDTLS_ECDSA_VERIFY_ALT */
+#endif /* !MBEDTLS_ECDSA_VERIFY_ALT */
 
 /*
  * Convert a signature (given by context) to ASN.1
@@ -637,7 +637,7 @@ int mbedtls_ecdsa_write_signature_restartable( mbedtls_ecdsa_context *ctx,
 #else
     MBEDTLS_MPI_CHK( ecdsa_sign_restartable( &ctx->grp, &r, &s, &ctx->d,
                          hash, hlen, f_rng, p_rng, rs_ctx ) );
-#endif
+#endif /* MBEDTLS_ECDSA_SIGN_ALT */
 #endif
 
     MBEDTLS_MPI_CHK( ecdsa_signature_to_asn1( &r, &s, sig, slen ) );
@@ -730,7 +730,7 @@ int mbedtls_ecdsa_read_signature_restartable( mbedtls_ecdsa_context *ctx,
     if( ( ret = ecdsa_verify_restartable( &ctx->grp, hash, hlen,
                               &ctx->Q, &r, &s, rs_ctx ) ) != 0 )
         goto cleanup;
-#endif
+#endif /* MBEDTLS_ECDSA_VERIFY_ALT */
 
     /* At this point we know that the buffer starts with a valid signature.
      * Return 0 if the buffer just contains the signature, and a specific
@@ -755,7 +755,7 @@ int mbedtls_ecdsa_genkey( mbedtls_ecdsa_context *ctx, mbedtls_ecp_group_id gid,
     return( mbedtls_ecp_group_load( &ctx->grp, gid ) ||
             mbedtls_ecp_gen_keypair( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) );
 }
-#endif /* MBEDTLS_ECDSA_GENKEY_ALT */
+#endif /* !MBEDTLS_ECDSA_GENKEY_ALT */
 
 /*
  * Set context from an mbedtls_ecp_keypair