diff --git a/bin/dd/position.c b/bin/dd/position.c
index 71153f04fe6a..d816716456fe 100644
--- a/bin/dd/position.c
+++ b/bin/dd/position.c
@@ -70,7 +70,7 @@ seek_offset(IO *io)
 	 *
 	 * Bail out if the calculation of a file offset would overflow.
 	 */
-	if ((io->flags & ISCHR) == 0 && n > OFF_MAX / (ssize_t)sz)
+	if ((io->flags & ISCHR) == 0 && (n < 0 || n > OFF_MAX / (ssize_t)sz))
 		errx(1, "seek offsets cannot be larger than %jd",
 		    (intmax_t)OFF_MAX);
 	else if ((io->flags & ISCHR) != 0 && (uint64_t)n > UINT64_MAX / sz)
diff --git a/bin/dd/tests/Makefile b/bin/dd/tests/Makefile
index dd04af915887..4e1f7859f605 100644
--- a/bin/dd/tests/Makefile
+++ b/bin/dd/tests/Makefile
@@ -1,5 +1,10 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
+.PATH: ${.CURDIR}/..
+
+ATF_TESTS_SH=	dd2_test
 NETBSD_ATF_TESTS_SH=	dd_test
 
 .include <netbsd-tests.test.mk>
diff --git a/bin/dd/tests/dd2_test.sh b/bin/dd/tests/dd2_test.sh
new file mode 100755
index 000000000000..8e19ab2f8847
--- /dev/null
+++ b/bin/dd/tests/dd2_test.sh
@@ -0,0 +1,50 @@
+#
+# Copyright (c) 2017 Spectra Logic Corporation
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+# $FreeBSD$
+
+
+atf_test_case seek_overflow
+seek_overflow_head() {
+	atf_set "descr" "dd(1) should reject too-large seek values"
+}
+seek_overflow_body() {
+	touch f.in
+	# Positive tests
+	seek=`echo "2^63 / 4096 - 1" | bc`
+	atf_check -s exit:0 -e ignore dd if=f.in of=f.out bs=4096 seek=$seek
+
+	# Negative tests
+	seek=`echo "2^63 / 4096" | bc`
+	atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
+		dd if=f.in of=f.out bs=4096 seek=$seek
+	atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
+		dd if=f.in of=f.out bs=4096 seek=-1
+}
+
+atf_init_test_cases()
+{
+        atf_add_test_case seek_overflow
+}