emile: do not rely on the struct size

Summary:
in newer versions of openssl, most of the public structures are made
opaque. So we should use the openssl api to allocate this structure.

Since ctx is now a pointer we dont need opened anymore, so those vars
are replaced with ctx checks. ctx is always NULL'ed after a free

fix T4923

Reviewers: cedric, jpeg, stefan_schmidt

Reviewed By: jpeg, stefan_schmidt

Subscribers: stefan_schmidt, ManMower, jpeg

Maniphest Tasks: T4923

Differential Revision: https://phab.enlightenment.org/D4456

src/lib/emile/emile_cipher_openssl.c

@@ -102,9 +102,8 @@ emile_binbuf_cipher(Emile_Cipher_Algorithm algo,
    unsigned int salt;
    unsigned int tmp = 0;
    unsigned int crypted_length;
-   int opened = 0;
    /* Openssl declarations*/
-   EVP_CIPHER_CTX ctx;
+   EVP_CIPHER_CTX *ctx = NULL;
    unsigned int *buffer = NULL;
    int tmp_len;
 
@@ -151,29 +150,28 @@ emile_binbuf_cipher(Emile_Cipher_Algorithm algo,
 
    /* Openssl create the corresponding cipher
       AES with a 256 bit key, Cipher Block Chaining mode */
-   EVP_CIPHER_CTX_init(&ctx);
-   if (!EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, ik, iv))
+   ctx = EVP_CIPHER_CTX_new();
+   if (!EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, ik, iv))
      goto on_error;
 
-   opened = 1;
-
    memset(iv, 0, sizeof (iv));
    memset(ik, 0, sizeof (ik));
 
    pointer = (unsigned char*) eina_binbuf_string_get(result);
 
    /* Openssl encrypt */
-   if (!EVP_EncryptUpdate(&ctx, pointer + sizeof (int), &tmp_len,
+   if (!EVP_EncryptUpdate(ctx, pointer + sizeof (int), &tmp_len,
                           (unsigned char *)buffer,
                           eina_binbuf_length_get(data) + sizeof(unsigned int)))
      goto on_error;
 
    /* Openssl close the cipher */
-   if (!EVP_EncryptFinal_ex(&ctx, pointer + sizeof (int) + tmp_len,
+   if (!EVP_EncryptFinal_ex(ctx, pointer + sizeof (int) + tmp_len,
                             &tmp_len))
      goto on_error;
 
-   EVP_CIPHER_CTX_cleanup(&ctx);
+   EVP_CIPHER_CTX_free(ctx);
+   ctx = NULL;
    free(buffer);
 
    return result;
@@ -183,8 +181,8 @@ on_error:
    memset(ik, 0, sizeof (ik));
 
    /* Openssl error */
-   if (opened)
-     EVP_CIPHER_CTX_cleanup(&ctx);
+   if (ctx)
+     EVP_CIPHER_CTX_cleanup(ctx);
 
    free(buffer);
 
@@ -203,7 +201,7 @@ emile_binbuf_decipher(Emile_Cipher_Algorithm algo,
 {
    Eina_Binbuf *result = NULL;
    unsigned int *over;
-   EVP_CIPHER_CTX ctx;
+   EVP_CIPHER_CTX *ctx = NULL;
    unsigned char ik[MAX_KEY_LEN];
    unsigned char iv[MAX_IV_LEN];
    unsigned char key_material[MAX_KEY_LEN + MAX_IV_LEN];
@@ -211,7 +209,6 @@ emile_binbuf_decipher(Emile_Cipher_Algorithm algo,
    unsigned int size;
    int tmp_len;
    int tmp = 0;
-   int opened = 0;
 
    if (algo != EMILE_AES256_CBC) return NULL;
    if (!emile_cipher_init()) return NULL;
@@ -247,23 +244,23 @@ emile_binbuf_decipher(Emile_Cipher_Algorithm algo,
    eina_binbuf_append_length(result, (unsigned char*) (over + 1), tmp_len);
 
    /* Openssl create the corresponding cipher */
-   EVP_CIPHER_CTX_init(&ctx);
-   opened = 1;
+   ctx = EVP_CIPHER_CTX_new();
 
-   if (!EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, ik, iv))
+   if (!EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, ik, iv))
      goto on_error;
 
    memset(iv, 0, sizeof (iv));
    memset(ik, 0, sizeof (ik));
 
    /* Openssl decrypt */
-   if (!EVP_DecryptUpdate(&ctx,
+   if (!EVP_DecryptUpdate(ctx,
                           (void*) eina_binbuf_string_get(result), &tmp,
                           (void*) (over + 1), tmp_len))
      goto on_error;
 
    /* Openssl close the cipher*/
-   EVP_CIPHER_CTX_cleanup(&ctx);
+   EVP_CIPHER_CTX_free(ctx);
+   ctx = NULL;
 
    /* Get the decrypted data size */
    tmp = *(unsigned int*)(eina_binbuf_string_get(result));
@@ -281,8 +278,8 @@ on_error:
    memset(iv, 0, sizeof (iv));
    memset(ik, 0, sizeof (ik));
 
-   if (opened)
-     EVP_CIPHER_CTX_cleanup(&ctx);
+   if (ctx)
+     EVP_CIPHER_CTX_free(ctx);
 
    eina_binbuf_free(result);