Remove dead callbacks in OMEMO plugin

The callbacks aren't used by libomemo-c. The callbacks passed appear to
be buggy because the return value of `gcry_md_read` is passed to `free`,
but it is supposed to be automatically freed on `gcry_md_reset`.
Additionally, `gcry_md_reset` is called before the return value of
`gcry_md_read` is used, which is also against the documentation:

https://www.gnupg.org/documentation/manuals/gcrypt-devel/Working-with-hash-algorithms.html

> `gcry_md_read` returns the message digest after finalizing the
> calculation. […] The returned message digest is allocated within the
> message context and therefore valid until the handle is released or
> reseted (using `gcry_md_close` or `gcry_md_reset`. […]

2 files changed, 4 insertions, 56 deletions

diff --git a/plugins/omemo/src/native/helper.c b/plugins/omemo/src/native/helper.c
index c6af15e3..2d808cde 100644
--- a/plugins/omemo/src/native/helper.c
+++ b/plugins/omemo/src/native/helper.c
@@ -124,54 +124,6 @@ void signal_vala_hmac_sha256_cleanup(void *hmac_context, void *user_data) {
     }
 }
 
-int signal_vala_sha512_digest_init(void **digest_context, void *user_data) {
-    gcry_md_hd_t* ctx = malloc(sizeof(gcry_mac_hd_t));
-    if (!ctx) return SG_ERR_NOMEM;
-
-    if (gcry_md_open(ctx, GCRY_MD_SHA512, 0)) {
-        free(ctx);
-        return SG_ERR_UNKNOWN;
-    }
-
-    *digest_context = ctx;
-
-    return SG_SUCCESS;
-}
-
-int signal_vala_sha512_digest_update(void *digest_context, const uint8_t *data, size_t data_len, void *user_data) {
-    gcry_md_hd_t* ctx = digest_context;
-
-    gcry_md_write(*ctx, data, data_len);
-
-    return SG_SUCCESS;
-}
-
-int signal_vala_sha512_digest_final(void *digest_context, signal_buffer **output, void *user_data) {
-    size_t len = gcry_md_get_algo_dlen(GCRY_MD_SHA512);
-    gcry_md_hd_t* ctx = digest_context;
-
-    uint8_t* md = gcry_md_read(*ctx, GCRY_MD_SHA512);
-    if (!md) return SG_ERR_UNKNOWN;
-
-    gcry_md_reset(*ctx);
-
-    signal_buffer *output_buffer = signal_buffer_create(md, len);
-    free(md);
-    if (!output_buffer) return SG_ERR_NOMEM;
-
-    *output = output_buffer;
-
-    return SG_SUCCESS;
-}
-
-void signal_vala_sha512_digest_cleanup(void *digest_context, void *user_data) {
-    gcry_md_hd_t* ctx = digest_context;
-    if (ctx) {
-        gcry_md_close(*ctx);
-        free(ctx);
-    }
-}
-
 const int aes_cipher(int cipher, size_t key_len, int* algo, int* mode) {
     switch (key_len) {
         case 16:
@@ -364,10 +316,10 @@ void setup_signal_vala_crypto_provider(signal_context *context)
             .hmac_sha256_update_func = signal_vala_hmac_sha256_update,
             .hmac_sha256_final_func = signal_vala_hmac_sha256_final,
             .hmac_sha256_cleanup_func = signal_vala_hmac_sha256_cleanup,
-            .sha512_digest_init_func = signal_vala_sha512_digest_init,
-            .sha512_digest_update_func = signal_vala_sha512_digest_update,
-            .sha512_digest_final_func = signal_vala_sha512_digest_final,
-            .sha512_digest_cleanup_func = signal_vala_sha512_digest_cleanup,
+            .sha512_digest_init_func = NULL,
+            .sha512_digest_update_func = NULL,
+            .sha512_digest_final_func = NULL,
+            .sha512_digest_cleanup_func = NULL,
             .encrypt_func = signal_vala_encrypt,
             .decrypt_func = signal_vala_decrypt,
             .user_data = 0
diff --git a/plugins/omemo/src/native/helper.h b/plugins/omemo/src/native/helper.h
index 98c96dfb..3cc21d8a 100644
--- a/plugins/omemo/src/native/helper.h
+++ b/plugins/omemo/src/native/helper.h
@@ -23,10 +23,6 @@ int signal_vala_hmac_sha256_init(void **hmac_context, const uint8_t *key, size_t
 int signal_vala_hmac_sha256_update(void *hmac_context, const uint8_t *data, size_t data_len, void *user_data);
 int signal_vala_hmac_sha256_final(void *hmac_context, signal_buffer **output, void *user_data);
 void signal_vala_hmac_sha256_cleanup(void *hmac_context, void *user_data);
-int signal_vala_sha512_digest_init(void **digest_context, void *user_data);
-int signal_vala_sha512_digest_update(void *digest_context, const uint8_t *data, size_t data_len, void *user_data);
-int signal_vala_sha512_digest_final(void *digest_context, signal_buffer **output, void *user_data);
-void signal_vala_sha512_digest_cleanup(void *digest_context, void *user_data);
 
 int signal_vala_encrypt(signal_buffer **output,
         int cipher,