Reduce code repetition in failure exit from decrypt().

src/vmod_gcrypt.c

@@ -472,9 +472,7 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 		if (iv == NULL) {
 			VERR(ctx, "Required initialization vector is NULL in "
 			     "%s.decrypt()", symmetric->vcl_name);
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 		assert(iv->len >= 0);
 		/* A NULL iv of length 0 is permitted. */
@@ -485,18 +483,14 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 			VERR(ctx, "Cannot set initialization vector in "
 			     "%s.decrypt(): %s/%s", symmetric->vcl_name,
 			     gcry_strsource(err), gcry_strerror(err));
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 	}
 	if (need_ctr[symmetric->mode]) {
 		if (ctr == NULL || ctr->priv == NULL) {
 			VERR(ctx, "Required counter vector is NULL in "
 			     "%s.decrypt()", symmetric->vcl_name);
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 		assert(ctr->len >= 0);
 		if ((err = gcry_cipher_setctr(hd, ctr->priv, ctr->len))
@@ -504,9 +498,7 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 			VERR(ctx, "Cannot set counter vector in %s.decrypt(): "
 			     "%s/%s", symmetric->vcl_name, gcry_strsource(err),
 			     gcry_strerror(err));
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 	}
 	if ((err = gcry_cipher_decrypt(hd, plaintext->priv, ciphertext->len,
@@ -514,9 +506,7 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 	    != GPG_ERR_NO_ERROR) {
 		VERR(ctx, "in %s.decrypt(): %s/%s", symmetric->vcl_name,
 		     gcry_strsource(err), gcry_strerror(err));
-		WS_Release(ctx->ws, 0);
-		WS_Reset(ctx->ws, snap);
-		return NULL;
+		goto fail;
 	}
 	plaintext->len = ciphertext->len;
 	if (symmetric->padding != NONE) {
@@ -525,9 +515,7 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 			     "plaintext length %d is not a multiple of block "
 			     "length %d", symmetric->vcl_name, plaintext->len,
 			     symmetric->blocklen);
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 		plaintext->len =
 			(unpadlenf[symmetric->padding])(plaintext->priv,
@@ -536,14 +524,17 @@ vmod_symmetric_decrypt(VRT_CTX, struct vmod_gcrypt_symmetric *symmetric,
 		if (plaintext->len < 0) {
 			VERR(ctx, "in %s.decrypt(): incorrect padding",
 			     symmetric->vcl_name);
-			WS_Release(ctx->ws, 0);
-			WS_Reset(ctx->ws, snap);
-			return NULL;
+			goto fail;
 		}
 	}
 	WS_Release(ctx->ws, plaintext->len);
 	plaintext->free = NULL;
 	return plaintext;
+
+ fail:
+	WS_Release(ctx->ws, 0);
+	WS_Reset(ctx->ws, snap);
+	return NULL;
 }
 
 /* Function random */