Handle unreachable code in different ways

The idea is to remove unreachable code where possible. To change it to
asserts where it makes sense. To mark it with explicit assert(false)
where unreachable code can't be removed.

There are cases where unreachable code needs to exist to silence
compiler warnings. Eg. default cases for switch. Mark them with
assert(false) so it's immediately visible that the flow should never
reach them (e.g. because the check has been performed earlier and it's
internal function).

Change-Id: I7d53c9772fe54b5c4dfd0f7205eec633fe4b9c20

diff --git a/src/crypto.c b/src/crypto.c
index a22d9c5..7123ea8 100644 (file)
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -62,8 +62,7 @@ static int getrandom_wrapper(unsigned char *buf, int num)
        size_t remaining = num;
 
 #ifndef SYS_getrandom
-       if (urandom_fd == -2)
-               return 0;
+       assert(urandom_fd != -2);
 #endif /* SYS_getrandom */
 
        while (remaining > 0) {

diff --git a/src/digest.c b/src/digest.c
index 1d7cbad..9812d6d 100644 (file)
--- a/src/digest.c
+++ b/src/digest.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *  Copyright (c) 2016-2020 Samsung Electronics Co., Ltd All Rights Reserved
  *
  *  Contact: Krzysztof Jackiewicz <k.jackiewicz@samsung.com>
  *
@@ -86,8 +86,10 @@ static int get_digest_output_length(const yaca_context_h ctx,
        assert(output_len != NULL);
 
        struct yaca_digest_context_s *c = get_digest_context(ctx);
+       assert(c != NULL);
+       assert(c->md_ctx != NULL);
 
-       if (c == NULL || input_len != 0)
+       if (input_len != 0)
                return YACA_ERROR_INVALID_PARAMETER;
 
        int md_size = EVP_MD_CTX_size(c->md_ctx);
@@ -102,9 +104,7 @@ static int get_digest_output_length(const yaca_context_h ctx,
 static void destroy_digest_context(yaca_context_h ctx)
 {
        struct yaca_digest_context_s *c = get_digest_context(ctx);
-
-       if (c == NULL)
-               return;
+       assert(c != NULL);
 
        EVP_MD_CTX_destroy(c->md_ctx);
        c->md_ctx = NULL;

diff --git a/src/encrypt.c b/src/encrypt.c
index e3b6fe4..dfc2fcb 100644 (file)
--- a/src/encrypt.c
+++ b/src/encrypt.c
@@ -260,6 +260,7 @@ static bool is_valid_tag_len(int mode, size_t tag_len)
                }
                return false;
        default:
+               assert(false);
                return false;
        }
 }
@@ -280,9 +281,7 @@ static struct yaca_encrypt_context_s *get_encrypt_context(const yaca_context_h c
 static void destroy_encrypt_context(const yaca_context_h ctx)
 {
        struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
-
-       if (c == NULL)
-               return;
+       assert(c != NULL);
 
        if (c->backup_ctx != NULL) {
                yaca_key_destroy(c->backup_ctx->iv);
@@ -299,11 +298,9 @@ static int get_encrypt_output_length(const yaca_context_h ctx, size_t input_len,
 {
        assert(output_len != NULL);
 
-       struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
        int block_size;
-
-       if (c == NULL)
-               return YACA_ERROR_INVALID_PARAMETER;
+       struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
+       assert(c != NULL);
        assert(c->cipher_ctx != NULL);
 
        block_size = EVP_CIPHER_CTX_block_size(c->cipher_ctx);
@@ -320,8 +317,7 @@ static int get_encrypt_output_length(const yaca_context_h ctx, size_t input_len,
        } else {
                *output_len = block_size;
        }
-       if (*output_len == 0)
-               return YACA_ERROR_INTERNAL;
+       assert(*output_len != 0);
 
        return YACA_ERROR_NONE;
 }
@@ -331,8 +327,7 @@ static int get_wrap_output_length(const yaca_context_h ctx, size_t input_len, si
        assert(output_len != NULL);
 
        struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
-       if (c == NULL)
-               return YACA_ERROR_INVALID_PARAMETER;
+       assert(c != NULL);
        assert(c->cipher_ctx != NULL);
 
        bool encryption = is_encryption_op(c->op_type);
@@ -509,13 +504,11 @@ static int encrypt_ctx_setup(struct yaca_encrypt_context_s *c,
        assert(key != YACA_KEY_NULL);
 
        const EVP_CIPHER *cipher = EVP_CIPHER_CTX_cipher(c->cipher_ctx);
-
        if (cipher == NULL)
                return YACA_ERROR_INTERNAL;
 
        lkey = key_get_simple(key);
-       if (lkey == NULL)
-               return YACA_ERROR_INVALID_PARAMETER;
+       assert(lkey != NULL);
 
        liv = key_get_simple(iv);
 
@@ -687,13 +680,14 @@ static int set_encrypt_property(yaca_context_h ctx,
                                                                const void *value,
                                                                size_t value_len)
 {
-       struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
        int len;
        int ret = YACA_ERROR_NONE;
+       struct yaca_encrypt_context_s *c = get_encrypt_context(ctx);
+       assert(c != NULL);
+       assert(c->cipher_ctx != NULL);
 
-       if (c == NULL || value == NULL || value_len == 0)
+       if (value == NULL || value_len == 0)
                return YACA_ERROR_INVALID_PARAMETER;
-       assert(c->cipher_ctx != NULL);
 
        int mode = EVP_CIPHER_CTX_mode(c->cipher_ctx);
        int nid = EVP_CIPHER_CTX_nid(c->cipher_ctx);
@@ -963,8 +957,7 @@ int encrypt_initialize(yaca_context_h *ctx,
                return YACA_ERROR_INVALID_PARAMETER;
 
        lsym_key = key_get_simple(sym_key);
-       if (lsym_key == NULL)
-               return YACA_ERROR_INVALID_PARAMETER;
+       assert(lsym_key != NULL);
 
        if (lsym_key->key.type != YACA_KEY_TYPE_DES &&
                lsym_key->key.type != YACA_KEY_TYPE_SYMMETRIC)

diff --git a/src/key.c b/src/key.c
index af701e4..15bc937 100644 (file)
--- a/src/key.c
+++ b/src/key.c
@@ -429,13 +429,10 @@ static int import_evp(yaca_key_h *key,
 
        /* Neither PEM nor DER will ever be shorter then 4 bytes (12 seems
         * to be minimum for DER, much more for PEM). This is just to make
-        * sure we have at least 4 bytes for strncmp() below.
-        */
-       if (data_len < 4)
-               return YACA_ERROR_INVALID_PARAMETER;
-
-       /* This is because of BIO_new_mem_buf() having its length param typed int */
-       if (data_len > INT_MAX)
+        * sure we have at least 4 bytes for strncmp() below. INT_MAX is
+        * because of BIO_new_mem_buf() having its length param typed
+        * int */
+       if (data_len < 4 || data_len > INT_MAX)
                return YACA_ERROR_INVALID_PARAMETER;
 
        src = BIO_new_mem_buf(data, data_len);
@@ -750,7 +747,8 @@ static int export_evp_default_bio(struct yaca_key_evp_s *evp_key,
                        break;
 
                default:
-                       return YACA_ERROR_INVALID_PARAMETER;
+                       assert(false);
+                       return YACA_ERROR_INTERNAL;
                }
 
                break;
@@ -790,7 +788,8 @@ static int export_evp_default_bio(struct yaca_key_evp_s *evp_key,
                }
 
                default:
-                       return YACA_ERROR_INVALID_PARAMETER;
+                       assert(false);
+                       return YACA_ERROR_INTERNAL;
                }
 
                break;
@@ -1083,7 +1082,6 @@ static int generate_evp_pkey_params(int evp_id, size_t key_bit_len, EVP_PKEY **p
 
                break;
        default:
-               /* We shouldn't be here */
                assert(false);
                return YACA_ERROR_INTERNAL;
        }
@@ -1225,7 +1223,7 @@ static int generate_evp(yaca_key_type_e out_type, size_t key_bit_len,
        assert(key_bit_len > 0 || params != NULL);
 
        int ret;
-       int evp_id;
+       int evp_id = -1;
        EVP_PKEY *pkey_out = NULL;
        EVP_PKEY *pkey_params = NULL;
 
@@ -1234,11 +1232,8 @@ static int generate_evp(yaca_key_type_e out_type, size_t key_bit_len,
                yaca_key_type_e params_type = params->key.type;
 
                ret = convert_params_to_priv(params_type, &key_type);
-               if (ret != YACA_ERROR_NONE)
-                       return ret;
-
-               if (out_type != key_type)
-                       return YACA_ERROR_INVALID_PARAMETER;
+               assert(ret == YACA_ERROR_NONE);
+               assert(out_type == key_type);
 
                pkey_params = params->evp;
        }
@@ -1249,8 +1244,7 @@ static int generate_evp(yaca_key_type_e out_type, size_t key_bit_len,
        case YACA_KEY_TYPE_EC_PARAMS:
                assert(params == NULL);
                ret = convert_params_to_evp_id(out_type, &evp_id);
-               if (ret != YACA_ERROR_NONE)
-                       return ret;
+               assert(ret == YACA_ERROR_NONE);
 
                ret = generate_evp_pkey_params(evp_id, key_bit_len, &pkey_out);
                break;
@@ -1259,13 +1253,13 @@ static int generate_evp(yaca_key_type_e out_type, size_t key_bit_len,
        case YACA_KEY_TYPE_DH_PRIV:
        case YACA_KEY_TYPE_EC_PRIV:
                ret = convert_priv_to_evp_id(out_type, &evp_id);
-               if (ret != YACA_ERROR_NONE)
-                       return ret;
+               assert(ret == YACA_ERROR_NONE);
 
                ret = generate_evp_pkey_key(evp_id, key_bit_len, pkey_params, &pkey_out);
                break;
        default:
-               return YACA_ERROR_INVALID_PARAMETER;
+               assert(false);
+               return YACA_ERROR_INTERNAL;
        }
        if (ret != YACA_ERROR_NONE)
                return ret;
@@ -1449,7 +1443,6 @@ API int yaca_key_get_bit_length(const yaca_key_h key, size_t *key_bit_len)
                        return convert_nid_to_ec(nid, key_bit_len);
                }
                default:
-                       /* We shouldn't be here */
                        assert(false);
                        return YACA_ERROR_INTERNAL;
                }
@@ -1575,6 +1568,7 @@ API int yaca_key_generate(yaca_key_type_e key_type,
                *key = (yaca_key_h)nk_evp;
        } else {
                assert(false);
+               return YACA_ERROR_INTERNAL;
        }
 
        return YACA_ERROR_NONE;
@@ -1591,9 +1585,7 @@ API int yaca_key_generate_from_parameters(const yaca_key_h params, yaca_key_h *p
        if (evp_params == NULL || prv_key == NULL)
                return YACA_ERROR_INVALID_PARAMETER;
 
-       ret = yaca_key_get_type(params, &params_type);
-       if (ret != YACA_ERROR_NONE)
-               return ret;
+       params_type = evp_params->key.type;
 
        ret = convert_params_to_priv(params_type, &key_type);
        if (ret != YACA_ERROR_NONE)
@@ -1624,9 +1616,7 @@ API int yaca_key_extract_public(const yaca_key_h prv_key, yaca_key_h *pub_key)
        if (evp_key == NULL || pub_key == NULL)
                return YACA_ERROR_INVALID_PARAMETER;
 
-       ret = yaca_key_get_type(prv_key, &prv_type);
-       if (ret != YACA_ERROR_NONE)
-               return ret;
+       prv_type = evp_key->key.type;
 
        ret = convert_priv_to_pub(prv_type, &pub_type);
        if (ret != YACA_ERROR_NONE)
@@ -1688,9 +1678,7 @@ API int yaca_key_extract_parameters(const yaca_key_h key, yaca_key_h *params)
        if (evp_key == NULL || params == NULL)
                return YACA_ERROR_INVALID_PARAMETER;
 
-       ret = yaca_key_get_type(key, &key_type);
-       if (ret != YACA_ERROR_NONE)
-               return ret;
+       key_type = evp_key->key.type;
 
        ret = convert_priv_to_params(key_type, &params_type);
        if (ret != YACA_ERROR_NONE)

diff --git a/src/rsa.c b/src/rsa.c
index 7fbb6e4..21077b9 100644 (file)
--- a/src/rsa.c
+++ b/src/rsa.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *  Copyright (c) 2016-2020 Samsung Electronics Co., Ltd All Rights Reserved
  *
  *  Contact: Krzysztof Jackiewicz <k.jackiewicz@samsung.com>
  *
@@ -50,6 +50,7 @@ int rsa_padding2openssl(yaca_padding_e padding)
        case YACA_PADDING_PKCS1_SSLV23:
                return RSA_SSLV23_PADDING;
        default:
+               assert(false);
                return -1;
        }
 }
@@ -75,7 +76,6 @@ static int encrypt_decrypt(yaca_padding_e padding,
                return YACA_ERROR_INVALID_PARAMETER;
 
        lpadding = rsa_padding2openssl(padding);
-       assert(lpadding != -1);
 
        lasym_key = key_get_evp(key);
        assert(lasym_key != NULL);

diff --git a/src/sign.c b/src/sign.c
index 03f1cb0..66fd5b2 100644 (file)
--- a/src/sign.c
+++ b/src/sign.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *  Copyright (c) 2016-2020 Samsung Electronics Co., Ltd All Rights Reserved
  *
  *  Contact: Krzysztof Jackiewicz <k.jackiewicz@samsung.com>
  *
@@ -84,14 +84,14 @@ static int get_sign_output_length(const yaca_context_h ctx,
 {
        assert(output_len != NULL);
 
-       struct yaca_sign_context_s *c = get_sign_context(ctx);
        EVP_PKEY_CTX *pctx;
+       struct yaca_sign_context_s *c = get_sign_context(ctx);
+       assert(c != NULL);
+       assert(c->md_ctx != NULL);
 
-       if (c == NULL || input_len != 0)
+       if (input_len != 0)
                return YACA_ERROR_INVALID_PARAMETER;
 
-       assert(c->md_ctx != NULL);
-
        pctx = EVP_MD_CTX_pkey_ctx(c->md_ctx);
        if (pctx == NULL)
                return YACA_ERROR_INTERNAL;
@@ -115,9 +115,7 @@ static int get_sign_output_length(const yaca_context_h ctx,
 static void destroy_sign_context(yaca_context_h ctx)
 {
        struct yaca_sign_context_s *c = get_sign_context(ctx);
-
-       if (c == NULL)
-               return;
+       assert(c != NULL);
 
        EVP_MD_CTX_destroy(c->md_ctx);
        c->md_ctx = NULL;
@@ -129,17 +127,17 @@ int set_sign_property(yaca_context_h ctx,
                                          size_t value_len)
 {
        int ret;
-       struct yaca_sign_context_s *c = get_sign_context(ctx);
        yaca_padding_e padding;
        int pad;
        EVP_PKEY *pkey;
        EVP_PKEY_CTX *pctx;
+       struct yaca_sign_context_s *c = get_sign_context(ctx);
+       assert(c != NULL);
+       assert(c->md_ctx != NULL);
 
-       if (c == NULL || value == NULL || c->state == CTX_FINALIZED)
+       if (value == NULL || c->state == CTX_FINALIZED)
                return YACA_ERROR_INVALID_PARAMETER;
 
-       assert(c->md_ctx != NULL);
-
        pctx = EVP_MD_CTX_pkey_ctx(c->md_ctx);
        if (pctx == NULL)
                return YACA_ERROR_INTERNAL;
@@ -160,7 +158,6 @@ int set_sign_property(yaca_context_h ctx,
        }
 
        pad = rsa_padding2openssl(padding);
-       assert(pad != -1);
 
        pkey = EVP_PKEY_CTX_get0_pkey(pctx);
        if (pkey == NULL) {

diff --git a/src/simple.c b/src/simple.c
index e4c7a38..e1ec24b 100644 (file)
--- a/src/simple.c
+++ b/src/simple.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *  Copyright (c) 2016-2020 Samsung Electronics Co., Ltd All Rights Reserved
  *
  *  Contact: Krzysztof Jackiewicz <k.jackiewicz@samsung.com>
  *
@@ -147,12 +147,6 @@ API int yaca_simple_encrypt(yaca_encrypt_algorithm_e algo,
        written += out_len;
        assert(written <= lciphertext_len);
 
-       if (((bcm == YACA_BCM_CBC || bcm == YACA_BCM_ECB) && written == 0) ||
-               (bcm != YACA_BCM_CBC && bcm != YACA_BCM_ECB && plaintext_len == 0 && written > 0)) {
-               ret = YACA_ERROR_INTERNAL;
-               goto exit;
-       }
-
        if (written > 0) {
                ret = yaca_realloc(written, (void**)&lciphertext);
                if (ret != YACA_ERROR_NONE)
@@ -239,11 +233,6 @@ API int yaca_simple_decrypt(yaca_encrypt_algorithm_e algo,
        written += out_len;
        assert(written <= lplaintext_len);
 
-       if (bcm != YACA_BCM_CBC && bcm != YACA_BCM_ECB && ciphertext_len == 0 && written > 0) {
-               ret = YACA_ERROR_INTERNAL;
-               goto exit;
-       }
-
        if (written > 0) {
                ret = yaca_realloc(written, (void**)&lplaintext);
                if (ret != YACA_ERROR_NONE)