better bounds check on iovcnt (we only ever use fixed, positive values)

diff --git a/usr.bin/ssh/atomicio.c b/usr.bin/ssh/atomicio.c
index 4a39195..5891638 100644 (file)
--- a/usr.bin/ssh/atomicio.c
+++ b/usr.bin/ssh/atomicio.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: atomicio.c,v 1.27 2015/01/16 06:40:12 deraadt Exp $ */
+/* $OpenBSD: atomicio.c,v 1.28 2016/07/27 23:18:12 djm Exp $ */
 /*
  * Copyright (c) 2006 Damien Miller. All rights reserved.
  * Copyright (c) 2005 Anil Madhavapeddy. All rights reserved.
@@ -94,12 +94,12 @@ atomiciov6(ssize_t (*f) (int, const struct iovec *, int), int fd,
        struct iovec iov_array[IOV_MAX], *iov = iov_array;
        struct pollfd pfd;
 
-       if (iovcnt > IOV_MAX) {
+       if (iovcnt < 0 || iovcnt > IOV_MAX) {
                errno = EINVAL;
                return 0;
        }
        /* Make a copy of the iov array because we may modify it below */
-       memcpy(iov, _iov, iovcnt * sizeof(*_iov));
+       memcpy(iov, _iov, (size_t)iovcnt * sizeof(*_iov));
 
        pfd.fd = fd;
        pfd.events = f == readv ? POLLIN : POLLOUT;