factor out common code in the agent client

Add a ssh_request_reply_decode() function that sends a message to
the agent, reads and parses a success/failure reply.
Use it for all requests that only expect success/failure

ok markus@

diff --git a/usr.bin/ssh/authfd.c b/usr.bin/ssh/authfd.c
index 19c49d6..a7fe2cc 100644 (file)
--- a/usr.bin/ssh/authfd.c
+++ b/usr.bin/ssh/authfd.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: authfd.c,v 1.126 2020/10/29 02:52:43 djm Exp $ */
+/* $OpenBSD: authfd.c,v 1.127 2021/01/26 00:46:17 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -176,6 +176,27 @@ ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply)
        return 0;
 }
 
+/* Communicate with agent: sent request, read and decode status reply */
+static int
+ssh_request_reply_decode(int sock, struct sshbuf *request)
+{
+       struct sshbuf *reply;
+       int r;
+       u_char type;
+
+       if ((reply = sshbuf_new()) == NULL)
+               return SSH_ERR_ALLOC_FAIL;
+       if ((r = ssh_request_reply(sock, request, reply)) != 0 ||
+           (r = sshbuf_get_u8(reply, &type)) != 0 ||
+           (r = decode_reply(type)) != 0)
+               goto out;
+       /* success */
+       r = 0;
+ out:
+       sshbuf_free(reply);
+       return r;
+}
+
 /*
  * Closes the agent socket if it should be closed (depends on how it was
  * obtained).  The argument must have been returned by
@@ -199,13 +220,11 @@ ssh_lock_agent(int sock, int lock, const char *password)
        if ((msg = sshbuf_new()) == NULL)
                return SSH_ERR_ALLOC_FAIL;
        if ((r = sshbuf_put_u8(msg, type)) != 0 ||
-           (r = sshbuf_put_cstring(msg, password)) != 0)
-               goto out;
-       if ((r = ssh_request_reply(sock, msg, msg)) != 0)
+           (r = sshbuf_put_cstring(msg, password)) != 0 ||
+           (r = ssh_request_reply_decode(sock, msg)) != 0)
                goto out;
-       if ((r = sshbuf_get_u8(msg, &type)) != 0)
-               goto out;
-       r = decode_reply(type);
+       /* success */
+       r = 0;
  out:
        sshbuf_free(msg);
        return r;
@@ -518,11 +537,10 @@ ssh_add_identity_constrained(int sock, struct sshkey *key,
            (r = encode_constraints(msg, life, confirm, maxsign,
            provider)) != 0)
                goto out;
-       if ((r = ssh_request_reply(sock, msg, msg)) != 0)
+       if ((r = ssh_request_reply_decode(sock, msg)) != 0)
                goto out;
-       if ((r = sshbuf_get_u8(msg, &type)) != 0)
-               goto out;
-       r = decode_reply(type);
+       /* success */
+       r = 0;
  out:
        sshbuf_free(msg);
        return r;
@@ -537,7 +555,7 @@ ssh_remove_identity(int sock, const struct sshkey *key)
 {
        struct sshbuf *msg;
        int r;
-       u_char type, *blob = NULL;
+       u_char *blob = NULL;
        size_t blen;
 
        if ((msg = sshbuf_new()) == NULL)
@@ -554,11 +572,10 @@ ssh_remove_identity(int sock, const struct sshkey *key)
                r = SSH_ERR_INVALID_ARGUMENT;
                goto out;
        }
-       if ((r = ssh_request_reply(sock, msg, msg)) != 0)
+       if ((r = ssh_request_reply_decode(sock, msg)) != 0)
                goto out;
-       if ((r = sshbuf_get_u8(msg, &type)) != 0)
-               goto out;
-       r = decode_reply(type);
+       /* success */
+       r = 0;
  out:
        if (blob != NULL)
                freezero(blob, blen);
@@ -594,11 +611,10 @@ ssh_update_card(int sock, int add, const char *reader_id, const char *pin,
        if (constrained &&
            (r = encode_constraints(msg, life, confirm, 0, NULL)) != 0)
                goto out;
-       if ((r = ssh_request_reply(sock, msg, msg)) != 0)
+       if ((r = ssh_request_reply_decode(sock, msg)) != 0)
                goto out;
-       if ((r = sshbuf_get_u8(msg, &type)) != 0)
-               goto out;
-       r = decode_reply(type);
+       /* success */
+       r = 0;
  out:
        sshbuf_free(msg);
        return r;
@@ -625,11 +641,10 @@ ssh_remove_all_identities(int sock, int version)
                return SSH_ERR_ALLOC_FAIL;
        if ((r = sshbuf_put_u8(msg, type)) != 0)
                goto out;
-       if ((r = ssh_request_reply(sock, msg, msg)) != 0)
+       if ((r = ssh_request_reply_decode(sock, msg)) != 0)
                goto out;
-       if ((r = sshbuf_get_u8(msg, &type)) != 0)
-               goto out;
-       r = decode_reply(type);
+       /* success */
+       r = 0;
  out:
        sshbuf_free(msg);
        return r;