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Message-ID: <20241106015235.2458807-2-kuba@kernel.org>
Date: Tue, 5 Nov 2024 17:52:35 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
johannes@...solutions.net,
pablo@...filter.org,
Jakub Kicinski <kuba@...nel.org>,
Kuniyuki Iwashima <kuniyu@...zon.com>
Subject: [PATCH net v2 2/2] selftests: net: add a test for closing a netlink socket ith dump in progress
Close a socket with dump in progress. We need a dump which generates
enough info not to fit into a single skb. Policy dump fits the bill.
Use the trick discovered by syzbot for keeping a ref on the socket
longer than just close, with mqueue.
TAP version 13
1..3
# Starting 3 tests from 1 test cases.
# RUN global.test_sanity ...
# OK global.test_sanity
ok 1 global.test_sanity
# RUN global.close_in_progress ...
# OK global.close_in_progress
ok 2 global.close_in_progress
# RUN global.close_with_ref ...
# OK global.close_with_ref
ok 3 global.close_with_ref
# PASSED: 3 / 3 tests passed.
# Totals: pass:3 fail:0 xfail:0 xpass:0 skip:0 error:0
Note that this test is not expected to fail but rather crash
the kernel if we get the cleanup wrong.
Reviewed-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
v2:
- fix the Makefile inclusion
v1: https://lore.kernel.org/20241105010347.2079981-2-kuba@kernel.org
---
tools/testing/selftests/net/Makefile | 1 +
tools/testing/selftests/net/netlink-dumps.c | 110 ++++++++++++++++++++
2 files changed, 111 insertions(+)
create mode 100644 tools/testing/selftests/net/netlink-dumps.c
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 649f1fe0dc46..5e86f7a51b43 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -78,6 +78,7 @@ TEST_PROGS += test_vxlan_vnifiltering.sh
TEST_GEN_FILES += io_uring_zerocopy_tx
TEST_PROGS += io_uring_zerocopy_tx.sh
TEST_GEN_FILES += bind_bhash
+TEST_GEN_PROGS += netlink-dumps
TEST_GEN_PROGS += sk_bind_sendto_listen
TEST_GEN_PROGS += sk_connect_zero_addr
TEST_GEN_PROGS += sk_so_peek_off
diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c
new file mode 100644
index 000000000000..7ee6dcd334df
--- /dev/null
+++ b/tools/testing/selftests/net/netlink-dumps.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <linux/genetlink.h>
+#include <linux/netlink.h>
+#include <linux/mqueue.h>
+
+#include "../kselftest_harness.h"
+
+static const struct {
+ struct nlmsghdr nlhdr;
+ struct genlmsghdr genlhdr;
+ struct nlattr ahdr;
+ __u16 val;
+ __u16 pad;
+} dump_policies = {
+ .nlhdr = {
+ .nlmsg_len = sizeof(dump_policies),
+ .nlmsg_type = GENL_ID_CTRL,
+ .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_DUMP,
+ .nlmsg_seq = 1,
+ },
+ .genlhdr = {
+ .cmd = CTRL_CMD_GETPOLICY,
+ .version = 2,
+ },
+ .ahdr = {
+ .nla_len = 6,
+ .nla_type = CTRL_ATTR_FAMILY_ID,
+ },
+ .val = GENL_ID_CTRL,
+ .pad = 0,
+};
+
+// Sanity check for the test itself, make sure the dump doesn't fit in one msg
+TEST(test_sanity)
+{
+ int netlink_sock;
+ char buf[8192];
+ ssize_t n;
+
+ netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
+ ASSERT_GE(netlink_sock, 0);
+
+ n = send(netlink_sock, &dump_policies, sizeof(dump_policies), 0);
+ ASSERT_EQ(n, sizeof(dump_policies));
+
+ n = recv(netlink_sock, buf, sizeof(buf), MSG_DONTWAIT);
+ ASSERT_GE(n, sizeof(struct nlmsghdr));
+
+ n = recv(netlink_sock, buf, sizeof(buf), MSG_DONTWAIT);
+ ASSERT_GE(n, sizeof(struct nlmsghdr));
+
+ close(netlink_sock);
+}
+
+TEST(close_in_progress)
+{
+ int netlink_sock;
+ ssize_t n;
+
+ netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
+ ASSERT_GE(netlink_sock, 0);
+
+ n = send(netlink_sock, &dump_policies, sizeof(dump_policies), 0);
+ ASSERT_EQ(n, sizeof(dump_policies));
+
+ close(netlink_sock);
+}
+
+TEST(close_with_ref)
+{
+ char cookie[NOTIFY_COOKIE_LEN] = {};
+ int netlink_sock, mq_fd;
+ struct sigevent sigev;
+ ssize_t n;
+
+ netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
+ ASSERT_GE(netlink_sock, 0);
+
+ n = send(netlink_sock, &dump_policies, sizeof(dump_policies), 0);
+ ASSERT_EQ(n, sizeof(dump_policies));
+
+ mq_fd = syscall(__NR_mq_open, "sed", O_CREAT | O_WRONLY, 0600, 0);
+ ASSERT_GE(mq_fd, 0);
+
+ memset(&sigev, 0, sizeof(sigev));
+ sigev.sigev_notify = SIGEV_THREAD;
+ sigev.sigev_value.sival_ptr = cookie;
+ sigev.sigev_signo = netlink_sock;
+
+ syscall(__NR_mq_notify, mq_fd, &sigev);
+
+ close(netlink_sock);
+
+ // give mqueue time to fire
+ usleep(100 * 1000);
+}
+
+TEST_HARNESS_MAIN
--
2.47.0
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