linux-stable.git/tools/testing/selftests/bpf, branch linux-6.8.y

selftests/bpf: Fix pointer arithmetic in test_xdp_do_redirect

2024-05-30T07:49:22+00:00

[ Upstream commit e549b39a0ab8880d7ae6c6495b00fc1cb8f36174 ]

Cast operation has a higher precedence than addition. The code here
wants to zero the 2nd half of the 64-bit metadata, but due to a pointer
arithmetic mistake, it writes the zero at offset 16 instead.

Just adding parentheses around "data + 4" would fix this, but I think
this will be slightly better readable with array syntax.

I was unable to test this with tools/testing/selftests/bpf/vmtest.sh,
because my glibc is newer than glibc in the provided VM image.
So I just checked the difference in the compiled code.
objdump -S tools/testing/selftests/bpf/xdp_do_redirect.test.o:
  -	*((__u32 *)data) = 0x42; /* metadata test value */
  +	((__u32 *)data)[0] = 0x42; /* metadata test value */
        be7:	48 8d 85 30 fc ff ff 	lea    -0x3d0(%rbp),%rax
        bee:	c7 00 42 00 00 00    	movl   $0x42,(%rax)
  -	*((__u32 *)data + 4) = 0;
  +	((__u32 *)data)[1] = 0;
        bf4:	48 8d 85 30 fc ff ff 	lea    -0x3d0(%rbp),%rax
  -     bfb:	48 83 c0 10          	add    $0x10,%rax
  +     bfb:	48 83 c0 04          	add    $0x4,%rax
        bff:	c7 00 00 00 00 00    	movl   $0x0,(%rax)

Fixes: 5640b6d89434 ("selftests/bpf: fix "metadata marker" getting overwritten by the netstack")
Signed-off-by: Michal Schmidt 
Signed-off-by: Andrii Nakryiko 
Reviewed-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/20240506145023.214248-1-mschmidt@redhat.com
Signed-off-by: Sasha Levin

selftests/bpf: Run cgroup1_hierarchy test in own mount namespace

2024-05-30T07:49:17+00:00

[ Upstream commit 19468ed51488dae19254e8a67c75d583b05fa5e3 ]

The cgroup1_hierarchy test uses setup_classid_environment to setup
cgroupv1 environment. The problem is that the environment is set in
/sys/fs/cgroup and therefore, if not run under an own mount namespace,
effectively deletes all system cgroups:

    $ ls /sys/fs/cgroup | wc -l
    27
    $ sudo ./test_progs -t cgroup1_hierarchy
    #41/1    cgroup1_hierarchy/test_cgroup1_hierarchy:OK
    #41/2    cgroup1_hierarchy/test_root_cgid:OK
    #41/3    cgroup1_hierarchy/test_invalid_level:OK
    #41/4    cgroup1_hierarchy/test_invalid_cgid:OK
    #41/5    cgroup1_hierarchy/test_invalid_hid:OK
    #41/6    cgroup1_hierarchy/test_invalid_cgrp_name:OK
    #41/7    cgroup1_hierarchy/test_invalid_cgrp_name2:OK
    #41/8    cgroup1_hierarchy/test_sleepable_prog:OK
    #41      cgroup1_hierarchy:OK
    Summary: 1/8 PASSED, 0 SKIPPED, 0 FAILED
    $ ls /sys/fs/cgroup | wc -l
    1

To avoid this, run setup_cgroup_environment first which will create an
own mount namespace. This only affects the cgroupv1_hierarchy test as
all other cgroup1 test progs already run setup_cgroup_environment prior
to running setup_classid_environment.

Also add a comment to the header of setup_classid_environment to warn
against this invalid usage in future.

Fixes: 360769233cc9 ("selftests/bpf: Add selftests for cgroup1 hierarchy")
Signed-off-by: Viktor Malik 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20240429112311.402497-1-vmalik@redhat.com
Signed-off-by: Sasha Levin

bpf: Fix verifier assumptions about socket->sk

2024-05-30T07:49:17+00:00

[ Upstream commit 0db63c0b86e981a1e97d2596d64ceceba1a5470e ]

The verifier assumes that 'sk' field in 'struct socket' is valid
and non-NULL when 'socket' pointer itself is trusted and non-NULL.
That may not be the case when socket was just created and
passed to LSM socket_accept hook.
Fix this verifier assumption and adjust tests.

Reported-by: Liam Wisehart 
Acked-by: Kumar Kartikeya Dwivedi 
Fixes: 6fcd486b3a0a ("bpf: Refactor RCU enforcement in the verifier.")
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/r/20240427002544.68803-1-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Sasha Levin

selftests/bpf: Fix a fd leak in error paths in open_netns

2024-05-30T07:49:15+00:00

[ Upstream commit 151f7442436658ee84076681d8f52e987fe147ea ]

As Martin mentioned in review comment, there is an existing bug that
orig_netns_fd will be leaked in the later "goto fail;" case after
open("/proc/self/ns/net") in open_netns() in network_helpers.c. This
patch adds "close(token->orig_netns_fd);" before "free(token);" to
fix it.

Fixes: a30338840fa5 ("selftests/bpf: Move open_netns() and close_netns() into network_helpers.c")
Signed-off-by: Geliang Tang 
Link: https://lore.kernel.org/r/a104040b47c3c34c67f3f125cdfdde244a870d3c.1713868264.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Sasha Levin

selftests/bpf: Fix umount cgroup2 error in test_sockmap

2024-05-30T07:49:11+00:00

[ Upstream commit d75142dbeb2bd1587b9cc19f841578f541275a64 ]

This patch fixes the following "umount cgroup2" error in test_sockmap.c:

 (cgroup_helpers.c:353: errno: Device or resource busy) umount cgroup2

Cgroup fd cg_fd should be closed before cleanup_cgroup_environment().

Fixes: 13a5f3ffd202 ("bpf: Selftests, sockmap test prog run without setting cgroup")
Signed-off-by: Geliang Tang 
Acked-by: Yonghong Song 
Link: https://lore.kernel.org/r/0399983bde729708773416b8488bac2cd5e022b8.1712639568.git.tanggeliang@kylinos.cn
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Sasha Levin

bpf: Check bloom filter map value size

2024-05-17T10:14:39+00:00

[ Upstream commit a8d89feba7e54e691ca7c4efc2a6264fa83f3687 ]

This patch adds a missing check to bloom filter creating, rejecting
values above KMALLOC_MAX_SIZE. This brings the bloom map in line with
many other map types.

The lack of this protection can cause kernel crashes for value sizes
that overflow int's. Such a crash was caught by syzkaller. The next
patch adds more guard-rails at a lower level.

Signed-off-by: Andrei Matei 
Acked-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20240327024245.318299-2-andreimatei1@gmail.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

selftests/bpf: trace_helpers.c: do not use poisoned type

2024-03-26T22:16:37+00:00

[ Upstream commit a68b50f47bec8bd6a33b07b7e1562db2553981a7 ]

After commit c698eaebdf47 ("selftests/bpf: trace_helpers.c: Optimize
kallsyms cache") trace_helpers.c now includes libbpf_internal.h, and
thus can no longer use the u32 type (among others) since they are poison
in libbpf_internal.h. Replace u32 with __u32 to fix the following error
when building trace_helpers.c on powerpc:

  error: attempt to use poisoned "u32"

Fixes: c698eaebdf47 ("selftests/bpf: trace_helpers.c: Optimize kallsyms cache")
Signed-off-by: Shung-Hsi Yu 
Acked-by: Jiri Olsa 
Link: https://lore.kernel.org/r/20240202095559.12900-1-shung-hsi.yu@suse.com
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Sasha Levin

selftests/bpf: Disable IPv6 for lwt_redirect test

2024-03-26T22:16:35+00:00

[ Upstream commit 2ef61296d2844c6a4211e07ab70ef2fb412b2c30 ]

After a recent change in the vmtest runner, this test started failing
sporadically.

Investigation showed that this test was subject to race condition which
got exacerbated after the vm runner change. The symptoms being that the
logic that waited for an ICMPv4 packet is naive and will break if 5 or
more non-ICMPv4 packets make it to tap0.
When ICMPv6 is enabled, the kernel will generate traffic such as ICMPv6
router solicitation...
On a system with good performance, the expected ICMPv4 packet would very
likely make it to the network interface promptly, but on a system with
poor performance, those "guarantees" do not hold true anymore.

Given that the test is IPv4 only, this change disable IPv6 in the test
netns by setting `net.ipv6.conf.all.disable_ipv6` to 1.
This essentially leaves "ping" as the sole generator of traffic in the
network namespace.
If this test was to be made IPv6 compatible, the logic in
`wait_for_packet` would need to be modified.

In more details...

At a high level, the test does:
- create a new namespace
- in `setup_redirect_target` set up lo, tap0, and link_err interfaces as
  well as add 2 routes that attaches ingress/egress sections of
  `test_lwt_redirect.bpf.o` to the xmit path.
- in `send_and_capture_test_packets` send an ICMP packet and read off
  the tap interface (using `wait_for_packet`) to check that a ICMP packet
  with the right size is read.

`wait_for_packet` will try to read `max_retry` (5) times from the tap0
fd looking for an ICMPv4 packet matching some criteria.

The problem is that when we set up the `tap0` interface, because IPv6 is
enabled by default, traffic such as Router solicitation is sent through
tap0, as in:

  # tcpdump -r /tmp/lwt_redirect.pc
  reading from file /tmp/lwt_redirect.pcap, link-type EN10MB (Ethernet)
  04:46:23.578352 IP6 :: > ff02::1:ffc0:4427: ICMP6, neighbor solicitation, who has fe80::fcba:dff:fec0:4427, length 32
  04:46:23.659522 IP6 :: > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
  04:46:24.389169 IP 10.0.0.1 > 20.0.0.9: ICMP echo request, id 122, seq 1, length 108
  04:46:24.618599 IP6 fe80::fcba:dff:fec0:4427 > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
  04:46:24.619985 IP6 fe80::fcba:dff:fec0:4427 > ff02::2: ICMP6, router solicitation, length 16
  04:46:24.767326 IP6 fe80::fcba:dff:fec0:4427 > ff02::16: HBH ICMP6, multicast listener report v2, 1 group record(s), length 28
  04:46:28.936402 IP6 fe80::fcba:dff:fec0:4427 > ff02::2: ICMP6, router solicitation, length 16

If `wait_for_packet` sees 5 non-ICMPv4 packets, it will return 0, which is what we see in:

  2024-01-31T03:51:25.0336992Z test_lwt_redirect_run:PASS:netns_create 0 nsec
  2024-01-31T03:51:25.0341309Z open_netns:PASS:malloc token 0 nsec
  2024-01-31T03:51:25.0344844Z open_netns:PASS:open /proc/self/ns/net 0 nsec
  2024-01-31T03:51:25.0350071Z open_netns:PASS:open netns fd 0 nsec
  2024-01-31T03:51:25.0353516Z open_netns:PASS:setns 0 nsec
  2024-01-31T03:51:25.0356560Z test_lwt_redirect_run:PASS:setns 0 nsec
  2024-01-31T03:51:25.0360140Z open_tuntap:PASS:open(/dev/net/tun) 0 nsec
  2024-01-31T03:51:25.0363822Z open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
  2024-01-31T03:51:25.0367402Z open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
  2024-01-31T03:51:25.0371167Z setup_redirect_target:PASS:open_tuntap 0 nsec
  2024-01-31T03:51:25.0375180Z setup_redirect_target:PASS:if_nametoindex 0 nsec
  2024-01-31T03:51:25.0379929Z setup_redirect_target:PASS:ip link add link_err type dummy 0 nsec
  2024-01-31T03:51:25.0384874Z setup_redirect_target:PASS:ip link set lo up 0 nsec
  2024-01-31T03:51:25.0389678Z setup_redirect_target:PASS:ip addr add dev lo 10.0.0.1/32 0 nsec
  2024-01-31T03:51:25.0394814Z setup_redirect_target:PASS:ip link set link_err up 0 nsec
  2024-01-31T03:51:25.0399874Z setup_redirect_target:PASS:ip link set tap0 up 0 nsec
  2024-01-31T03:51:25.0407731Z setup_redirect_target:PASS:ip route add 10.0.0.0/24 dev link_err encap bpf xmit obj test_lwt_redirect.bpf.o sec redir_ingress 0 nsec
  2024-01-31T03:51:25.0419105Z setup_redirect_target:PASS:ip route add 20.0.0.0/24 dev link_err encap bpf xmit obj test_lwt_redirect.bpf.o sec redir_egress 0 nsec
  2024-01-31T03:51:25.0427209Z test_lwt_redirect_normal:PASS:setup_redirect_target 0 nsec
  2024-01-31T03:51:25.0431424Z ping_dev:PASS:if_nametoindex 0 nsec
  2024-01-31T03:51:25.0437222Z send_and_capture_test_packets:FAIL:wait_for_epacket unexpected wait_for_epacket: actual 0 != expected 1
  2024-01-31T03:51:25.0448298Z (/tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/lwt_redirect.c:175: errno: Success) test_lwt_redirect_normal egress test fails
  2024-01-31T03:51:25.0457124Z close_netns:PASS:setns 0 nsec

When running in a VM which potential resource contrains, the odds that calling
`ping` is not scheduled very soon after bringing `tap0` up increases,
and with this the chances to get our ICMP packet pushed to position 6+
in the network trace.

To confirm this indeed solves the issue, I ran the test 100 times in a
row with:

  errors=0
  successes=0
  for i in `seq 1 100`
  do
    ./test_progs -t lwt_redirect/lwt_redirect_normal
    if [ $? -eq 0 ]; then
      successes=$((successes+1))
    else
      errors=$((errors+1))
    fi
  done
  echo "successes: $successes/errors: $errors"

While this test would at least fail a couple of time every 10 runs, here
it ran 100 times with no error.

Fixes: 43a7c3ef8a15 ("selftests/bpf: Add lwt_xmit tests for BPF_REDIRECT")
Signed-off-by: Manu Bretelle 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20240131053212.2247527-1-chantr4@gmail.com
Signed-off-by: Sasha Levin

selftests/bpf: Wait for the netstamp_needed_key static key to be turned on

2024-03-26T22:16:33+00:00

[ Upstream commit ce6f6cffaeaa0a3bcdafcae7fe03c68c3afae631 ]

After the previous patch that speeded up the test (by avoiding neigh
discovery in IPv6), the BPF CI occasionally hits this error:

rcv tstamp unexpected pkt rcv tstamp: actual 0 == expected 0

The test complains about the cmsg returned from the recvmsg() does not
have the rcv timestamp. Setting skb->tstamp or not is
controlled by a kernel static key "netstamp_needed_key". The static
key is enabled whenever this is at least one sk with the SOCK_TIMESTAMP
set.

The test_redirect_dtime does use setsockopt() to turn on
the SOCK_TIMESTAMP for the reading sk. In the kernel
net_enable_timestamp() has a delay to enable the "netstamp_needed_key"
when CONFIG_JUMP_LABEL is set. This potential delay is the likely reason
for packet missing rcv timestamp occasionally.

This patch is to create udp sockets with SOCK_TIMESTAMP set.
It sends and receives some packets until the received packet
has a rcv timestamp. It currently retries at most 5 times with 1s
in between. This should be enough to wait for the "netstamp_needed_key".
It then holds on to the socket and only closes it at the end of the test.
This guarantees that the test has the "netstamp_needed_key" key turned
on from the beginning.

To simplify the udp sockets setup, they are sending/receiving packets
in the same netns (ns_dst is used) and communicate over the "lo" dev.
Hence, the patch enables the "lo" dev in the ns_dst.

Fixes: c803475fd8dd ("bpf: selftests: test skb->tstamp in redirect_neigh")
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20240120060518.3604920-2-martin.lau@linux.dev
Signed-off-by: Sasha Levin

selftests/bpf: Fix the flaky tc_redirect_dtime test

2024-03-26T22:16:33+00:00

[ Upstream commit 177f1d083a19af58f4b1206d299ed73689249fd8 ]

BPF CI has been reporting the tc_redirect_dtime test failing
from time to time:

test_inet_dtime:PASS:setns src 0 nsec
(network_helpers.c:253: errno: No route to host) Failed to connect to server
close_netns:PASS:setns 0 nsec
test_inet_dtime:FAIL:connect_to_fd unexpected connect_to_fd: actual -1 < expected 0
test_tcp_clear_dtime:PASS:tcp ip6 clear dtime ingress_fwdns_p100 0 nsec

The connect_to_fd failure (EHOSTUNREACH) is from the
test_tcp_clear_dtime() test and it is the very first IPv6 traffic
after setting up all the links, addresses, and routes.

The symptom is this first connect() is always slow. In my setup, it
could take ~3s.

After some tracing and tcpdump, the slowness is mostly spent in
the neighbor solicitation in the "ns_fwd" namespace while
the "ns_src" and "ns_dst" are fine.

I forced the kernel to drop the neighbor solicitation messages.
I can then reproduce EHOSTUNREACH. What actually happen could be:
- the neighbor advertisement came back a little slow.
- the "ns_fwd" namespace concluded a neighbor discovery failure
  and triggered the ndisc_error_report() => ip6_link_failure() =>
  icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0)
- the client's connect() reports EHOSTUNREACH after receiving
  the ICMPV6_DEST_UNREACH message.

The neigh table of both "ns_src" and "ns_dst" namespace has already
been manually populated but not the "ns_fwd" namespace. This patch
fixes it by manually populating the neigh table also in the "ns_fwd"
namespace.

Although the namespace configuration part had been existed before
the tc_redirect_dtime test, still Fixes-tagging the patch when
the tc_redirect_dtime test was added since it is the only test
hitting it so far.

Fixes: c803475fd8dd ("bpf: selftests: test skb->tstamp in redirect_neigh")
Signed-off-by: Martin KaFai Lau 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20240120060518.3604920-1-martin.lau@linux.dev
Signed-off-by: Sasha Levin