upstream: make Chacha20-POLY1305 context struct opaque; ok tb@ as

part of a larger diff at a2k20

OpenBSD-Commit-ID: a4609b7263284f95c9417ef60ed7cdbb7bf52cfd

1 files changed, 19 insertions, 6 deletions

diff --git a/cipher-chachapoly.c b/cipher-chachapoly.c
index 0899c5ad5..42e8d40b7 100644
--- a/cipher-chachapoly.c
+++ b/cipher-chachapoly.c
@@ -14,7 +14,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $OpenBSD: cipher-chachapoly.c,v 1.8 2016/08/03 05:41:57 djm Exp $ */
+/* $OpenBSD: cipher-chachapoly.c,v 1.9 2020/04/03 04:27:03 djm Exp $ */
 
 #include "includes.h"
 
@@ -28,15 +28,28 @@
 #include "ssherr.h"
 #include "cipher-chachapoly.h"
 
-int
-chachapoly_init(struct chachapoly_ctx *ctx,
-    const u_char *key, u_int keylen)
+struct chachapoly_ctx {
+        struct chacha_ctx main_ctx, header_ctx;
+};
+
+struct chachapoly_ctx *
+chachapoly_new(const u_char *key, u_int keylen)
 {
+        struct chachapoly_ctx *ctx;
+
         if (keylen != (32 + 32)) /* 2 x 256 bit keys */
-                return SSH_ERR_INVALID_ARGUMENT;
+                return NULL;
+        if ((ctx = calloc(1, sizeof(*ctx))) == NULL)
+                return NULL;
         chacha_keysetup(&ctx->main_ctx, key, 256);
         chacha_keysetup(&ctx->header_ctx, key + 32, 256);
-        return 0;
+        return ctx;
+}
+
+void
+chachapoly_free(struct chachapoly_ctx *cpctx)
+{
+        freezero(cpctx, sizeof(*cpctx));
 }
 
 /*