From 2893b979bdb5ff1d902dc78c478162854eeb4a4b Mon Sep 17 00:00:00 2001
From: Vitaly Chikunov <vt@altlinux.org>
Date: Wed, 13 May 2020 00:25:35 +0300
Subject: [PATCH] gost_md: Rework digest registration, add GostR3411_94_digest

Introduce `GOST_digest' to hold digest registration data, and
`GOST_init_digest'/`GOST_deinit_digest` helpers to handle it.

It's single-level templatized.
---
 gost_lcl.h | 22 ++++++++++++++++
 gost_md.c  | 77 ++++++++++++++++++++++++++++++++++++++----------------
 2 files changed, 77 insertions(+), 22 deletions(-)

diff --git a/gost_lcl.h b/gost_lcl.h
index 5e21e85..d2d2e79 100644
--- a/gost_lcl.h
+++ b/gost_lcl.h
@@ -360,5 +360,27 @@ extern GOST_cipher grasshopper_ctr_acpkm_omac_cipher;
 extern GOST_cipher magma_kexp15_cipher;
 extern GOST_cipher kuznyechik_kexp15_cipher;
 
+struct gost_digest_st {
+    struct gost_digest_st *template;
+    int nid;
+    EVP_MD *digest;
+    int result_size;
+    int input_blocksize;
+    int app_datasize;
+    int flags;
+    int (*init)(EVP_MD_CTX *ctx);
+    int (*update)(EVP_MD_CTX *ctx, const void *data, size_t count);
+    int (*final)(EVP_MD_CTX *ctx, unsigned char *md);
+    int (*copy)(EVP_MD_CTX *to, const EVP_MD_CTX *from);
+    int (*cleanup)(EVP_MD_CTX *ctx);
+    int (*ctrl)(EVP_MD_CTX *ctx, int cmd, int p1, void *p2);
+};
+typedef struct gost_digest_st GOST_digest;
+
+EVP_MD *GOST_init_digest(GOST_digest *d);
+void GOST_deinit_digest(GOST_digest *d);
+
+extern GOST_digest GostR3411_94_digest;
+
 #endif
 /* vim: set expandtab cinoptions=\:0,l1,t0,g0,(0 sw=4 : */
diff --git a/gost_md.c b/gost_md.c
index 5d2c537..1de9ffd 100644
--- a/gost_md.c
+++ b/gost_md.c
@@ -19,36 +19,68 @@ static int gost_digest_final(EVP_MD_CTX *ctx, unsigned char *md);
 static int gost_digest_copy(EVP_MD_CTX *to, const EVP_MD_CTX *from);
 static int gost_digest_cleanup(EVP_MD_CTX *ctx);
 
-static EVP_MD *_hidden_GostR3411_94_md = NULL;
+GOST_digest GostR3411_94_digest = {
+    .nid = NID_id_GostR3411_94,
+    .result_size = 32,
+    .input_blocksize = 32,
+    .app_datasize = sizeof(struct ossl_gost_digest_ctx),
+    .init = gost_digest_init,
+    .update = gost_digest_update,
+    .final = gost_digest_final,
+    .copy = gost_digest_copy,
+    .cleanup = gost_digest_cleanup,
+};
 
-EVP_MD *digest_gost(void)
+/*
+ * Single level template accessor.
+ * Note: that you cannot template 0 value.
+ */
+#define TPL(st,field) ( \
+    ((st)->field) ?: TPL_VAL(st,field) \
+)
+
+#define TPL_VAL(st,field) ( \
+    ((st)->template ? (st)->template->field : 0) \
+)
+
+EVP_MD *GOST_init_digest(GOST_digest *d)
 {
-    if (_hidden_GostR3411_94_md == NULL) {
-        EVP_MD *md;
+    if (d->digest)
+        return d->digest;
 
-        if ((md = EVP_MD_meth_new(NID_id_GostR3411_94, NID_undef)) == NULL
-            || !EVP_MD_meth_set_result_size(md, 32)
-            || !EVP_MD_meth_set_input_blocksize(md, 32)
-            || !EVP_MD_meth_set_app_datasize(md,
-                                             sizeof(struct
-                                                    ossl_gost_digest_ctx))
-            || !EVP_MD_meth_set_init(md, gost_digest_init)
-            || !EVP_MD_meth_set_update(md, gost_digest_update)
-            || !EVP_MD_meth_set_final(md, gost_digest_final)
-            || !EVP_MD_meth_set_copy(md, gost_digest_copy)
-            || !EVP_MD_meth_set_cleanup(md, gost_digest_cleanup)) {
-            EVP_MD_meth_free(md);
-            md = NULL;
-        }
-        _hidden_GostR3411_94_md = md;
+    EVP_MD *md;
+    if (!(md = EVP_MD_meth_new(d->nid, NID_undef))
+        || !EVP_MD_meth_set_result_size(md, TPL(d, result_size))
+        || !EVP_MD_meth_set_input_blocksize(md, TPL(d, input_blocksize))
+        || !EVP_MD_meth_set_app_datasize(md, TPL(d, app_datasize))
+        || !EVP_MD_meth_set_flags(md, d->flags | TPL_VAL(d, flags))
+        || !EVP_MD_meth_set_init(md, TPL(d, init))
+        || !EVP_MD_meth_set_update(md, TPL(d, update))
+        || !EVP_MD_meth_set_final(md, TPL(d, final))
+        || !EVP_MD_meth_set_copy(md, TPL(d, copy))
+        || !EVP_MD_meth_set_cleanup(md, TPL(d, cleanup))
+        || !EVP_MD_meth_set_ctrl(md, TPL(d, ctrl))) {
+        EVP_MD_meth_free(md);
+        md = NULL;
     }
-    return _hidden_GostR3411_94_md;
+    d->digest = md;
+    return md;
+}
+
+void GOST_deinit_digest(GOST_digest *d)
+{
+    EVP_MD_meth_free(d->digest);
+    d->digest = NULL;
+}
+
+EVP_MD *digest_gost(void)
+{
+    return GOST_init_digest(&GostR3411_94_digest);
 }
 
 void digest_gost_destroy(void)
 {
-    EVP_MD_meth_free(_hidden_GostR3411_94_md);
-    _hidden_GostR3411_94_md = NULL;
+    GOST_deinit_digest(&GostR3411_94_digest);
 }
 
 int gost_digest_init(EVP_MD_CTX *ctx)
@@ -89,3 +121,4 @@ int gost_digest_cleanup(EVP_MD_CTX *ctx)
                sizeof(struct ossl_gost_digest_ctx));
     return 1;
 }
+/* vim: set expandtab cinoptions=\:0,l1,t0,g0,(0 sw=4 : */
-- 
2.39.5