3 files changed, 87 insertions, 4 deletions
diff --git a/sbin/ifconfig/tests/Makefile b/sbin/ifconfig/tests/Makefile
index 93967c705175..e902f262552a 100644
--- a/sbin/ifconfig/tests/Makefile
+++ b/sbin/ifconfig/tests/Makefile
@@ -1,7 +1,8 @@
-# $FreeBSD$
+NETBSD_ATF_TESTS_SH=	nonexistent_test
+ATF_TESTS_SH+=		inet6
 
-NETBSD_ATF_TESTS_SH=		nonexistent_test
+TEST_METADATA+=	execenv="jail"
+TEST_METADATA+=	execenv_jail_params="vnet allow.raw_sockets"
 
 .include <netbsd-tests.test.mk>
-
 .include <bsd.test.mk>
diff --git a/sbin/ifconfig/tests/Makefile.depend b/sbin/ifconfig/tests/Makefile.depend
index f80275d86ab1..11aba52f82cf 100644
--- a/sbin/ifconfig/tests/Makefile.depend
+++ b/sbin/ifconfig/tests/Makefile.depend
@@ -1,4 +1,3 @@
-# $FreeBSD$
 # Autogenerated - do NOT edit!
 
 DIRDEPS = \
diff --git a/sbin/ifconfig/tests/inet6.sh b/sbin/ifconfig/tests/inet6.sh
new file mode 100644
index 000000000000..edfd88d93af7
--- /dev/null
+++ b/sbin/ifconfig/tests/inet6.sh
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: ISC
+#
+# Copyright (c) 2025 Lexi Winter
+
+. $(atf_get_srcdir)/../../sys/common/vnet.subr
+
+# Bug 286910: adding 'netmask' or 'broadcast' to an IPv6 address crashed
+# ifconfig.
+
+atf_test_case "netmask" "cleanup"
+netmask_head()
+{
+	atf_set descr "Test invalid 'netmask' option"
+	atf_set require.user root
+}
+
+netmask_body()
+{
+	vnet_init
+
+	ep=$(vnet_mkepair)
+	vnet_mkjail ifcjail ${ep}a
+
+	# Add the address the wrong way
+	atf_check -s exit:1 \
+	    -e match:"ifconfig: netmask: invalid option for inet6" \
+	    jexec ifcjail ifconfig ${ep}a inet6 2001:db8:1::1 netmask 64
+
+	# Add the address the correct way
+	atf_check -s exit:0 \
+	    jexec ifcjail ifconfig ${ep}a inet6 2001:db8:1::1/64
+	atf_check -s exit:0 -o match:"2001:db8:1::1 prefixlen 64" \
+	    jexec ifcjail ifconfig ${ep}a
+
+	# Remove the address the wrong way
+	atf_check -s exit:1 \
+	    -e match:"ifconfig: netmask: invalid option for inet6" \
+	    jexec ifcjail ifconfig ${ep}a inet6 2001:db8:1::1 netmask 64 -alias
+}
+
+netmask_cleanup()
+{
+	vnet_cleanup
+}
+
+atf_test_case "broadcast" "cleanup"
+broadcast_head()
+{
+	atf_set descr "Test invalid 'broadcast' option"
+	atf_set require.user root
+}
+
+broadcast_body()
+{
+	vnet_init
+
+	ep=$(vnet_mkepair)
+	vnet_mkjail ifcjail ${ep}a
+
+	atf_check -s exit:1 \
+	    -e match:"ifconfig: broadcast: invalid option for inet6" \
+	    jexec ifcjail ifconfig ${ep}a \
+	        inet6 2001:db8:1::1 broadcast 2001:db8:1::ffff
+
+	atf_check -s exit:0 \
+	    jexec ifcjail ifconfig ${ep}a inet6 2001:db8:1::1/64
+
+	atf_check -s exit:1 \
+	    -e match:"ifconfig: broadcast: invalid option for inet6" \
+	    jexec ifcjail ifconfig ${ep}a \
+	        inet6 2001:db8:1::1 broadcast 2001:db:1::ffff -alias
+}
+
+broadcast_cleanup()
+{
+	vnet_cleanup
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case netmask
+	atf_add_test_case broadcast
+}