implement dupctx for chacha20_poly1305

Same as chacha20 in the last commit, just clone the ctx and its
underlying tlsmac array if its allocated

Fixes #21887

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #21933)

(cherry picked from commit df93b3c)

providers/implementations/ciphers/cipher_chacha20_poly1305.c

@@ -23,6 +23,7 @@
 
 static OSSL_FUNC_cipher_newctx_fn chacha20_poly1305_newctx;
 static OSSL_FUNC_cipher_freectx_fn chacha20_poly1305_freectx;
+static OSSL_FUNC_cipher_dupctx_fn chacha20_poly1305_dupctx;
 static OSSL_FUNC_cipher_encrypt_init_fn chacha20_poly1305_einit;
 static OSSL_FUNC_cipher_decrypt_init_fn chacha20_poly1305_dinit;
 static OSSL_FUNC_cipher_get_params_fn chacha20_poly1305_get_params;
@@ -58,6 +59,25 @@ static void *chacha20_poly1305_newctx(void *provctx)
     return ctx;
 }
 
+static void *chacha20_poly1305_dupctx(void *provctx)
+{
+    PROV_CHACHA20_POLY1305_CTX *ctx = provctx;
+    PROV_CHACHA20_POLY1305_CTX *dctx = NULL;
+
+    if (ctx == NULL)
+        return NULL;
+    dctx = OPENSSL_memdup(ctx, sizeof(*ctx));
+    if (dctx != NULL && dctx->base.tlsmac != NULL && dctx->base.alloced) {
+        dctx->base.tlsmac = OPENSSL_memdup(dctx->base.tlsmac,
+                                           dctx->base.tlsmacsize);
+        if (dctx->base.tlsmac == NULL) {
+            OPENSSL_free(dctx);
+            dctx = NULL;
+        }
+    }
+    return dctx;
+}
+
 static void chacha20_poly1305_freectx(void *vctx)
 {
     PROV_CHACHA20_POLY1305_CTX *ctx = (PROV_CHACHA20_POLY1305_CTX *)vctx;
@@ -310,6 +330,7 @@ static int chacha20_poly1305_final(void *vctx, unsigned char *out, size_t *outl,
 const OSSL_DISPATCH ossl_chacha20_ossl_poly1305_functions[] = {
     { OSSL_FUNC_CIPHER_NEWCTX, (void (*)(void))chacha20_poly1305_newctx },
     { OSSL_FUNC_CIPHER_FREECTX, (void (*)(void))chacha20_poly1305_freectx },
+    { OSSL_FUNC_CIPHER_DUPCTX, (void (*)(void))chacha20_poly1305_dupctx },
     { OSSL_FUNC_CIPHER_ENCRYPT_INIT, (void (*)(void))chacha20_poly1305_einit },
     { OSSL_FUNC_CIPHER_DECRYPT_INIT, (void (*)(void))chacha20_poly1305_dinit },
     { OSSL_FUNC_CIPHER_UPDATE, (void (*)(void))chacha20_poly1305_update },