Commit 55d42a0c authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

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: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241106015235.2458807-2-kuba@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 1904fb9e

tools/testing/selftests/net/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/net/netlink-dumps.c

0 → 100644
+110 −0
Original line number Diff line number Diff line 
// 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