upstream: check access(ssh-sk-helper, X_OK) to provide friendly
error message for misconfigured helper paths
OpenBSD-Commit-ID: 061bcc262155d12e726305c91394ac0aaf1f8341
diff --git a/ssh-sk-client.c b/ssh-sk-client.c
index 9121570..359327b 100644
--- a/ssh-sk-client.c
+++ b/ssh-sk-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-sk-client.c,v 1.5 2020/01/10 23:43:26 djm Exp $ */
+/* $OpenBSD: ssh-sk-client.c,v 1.6 2020/01/21 07:07:31 djm Exp $ */
/*
* Copyright (c) 2019 Google LLC
*
@@ -21,6 +21,7 @@
#include <sys/socket.h>
#include <sys/wait.h>
+#include <fcntl.h>
#include <limits.h>
#include <errno.h>
#include <signal.h>
@@ -56,6 +57,13 @@
helper = getenv("SSH_SK_HELPER");
if (helper == NULL || strlen(helper) == 0)
helper = _PATH_SSH_SK_HELPER;
+ if (access(helper, X_OK) != 0) {
+ oerrno = errno;
+ error("%s: helper \"%s\" unusable: %s", __func__, helper,
+ strerror(errno));
+ errno = oerrno;
+ return SSH_ERR_SYSTEM_ERROR;
+ }
#ifdef DEBUG_SK
verbosity = "-vvv";
#endif