linux-stable.git/tools/testing/selftests/net, branch v6.18.4

selftests: net: fix "buffer overflow detected" for tap.c

2026-01-08T09:16:46+00:00

[ Upstream commit 472c5dd6b95c02b3e5d7395acf542150e91165e7 ]

When the selftest 'tap.c' is compiled with '-D_FORTIFY_SOURCE=3',
the strcpy() in rtattr_add_strsz() is replaced with a checked
version which causes the test to consistently fail when compiled
with toolchains for which this option is enabled by default.

 TAP version 13
 1..3
 # Starting 3 tests from 1 test cases.
 #  RUN           tap.test_packet_valid_udp_gso ...
 *** buffer overflow detected ***: terminated
 # test_packet_valid_udp_gso: Test terminated by assertion
 #          FAIL  tap.test_packet_valid_udp_gso
 not ok 1 tap.test_packet_valid_udp_gso
 #  RUN           tap.test_packet_valid_udp_csum ...
 *** buffer overflow detected ***: terminated
 # test_packet_valid_udp_csum: Test terminated by assertion
 #          FAIL  tap.test_packet_valid_udp_csum
 not ok 2 tap.test_packet_valid_udp_csum
 #  RUN           tap.test_packet_crash_tap_invalid_eth_proto ...
 *** buffer overflow detected ***: terminated
 # test_packet_crash_tap_invalid_eth_proto: Test terminated by assertion
 #          FAIL  tap.test_packet_crash_tap_invalid_eth_proto
 not ok 3 tap.test_packet_crash_tap_invalid_eth_proto
 # FAILED: 0 / 3 tests passed.
 # Totals: pass:0 fail:3 xfail:0 xpass:0 skip:0 error:0

A buffer overflow is detected by the fortified glibc __strcpy_chk()
since the __builtin_object_size() of `RTA_DATA(rta)` is incorrectly
reported as 1, even though there is ample space in its bounding
buffer `req`.

Additionally, given that IFLA_IFNAME also expects a null-terminated
string, callers of rtaddr_add_str{,sz}() could simply use the
rtaddr_add_strsz() variant. (which has been renamed to remove the
trailing `sz`) memset() has been used for this function since it
is unchecked and thus circumvents the issue discussed in the
previous paragraph.

Fixes: 2e64fe4624d1 ("selftests: add few test cases for tap driver")
Signed-off-by: Alice C. Munduruca 
Reviewed-by: Cengiz Can 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20251216170641.250494-1-alice.munduruca@canonical.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

selftests: mptcp: pm: ensure unknown flags are ignored

2026-01-02T11:57:12+00:00

commit 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 upstream.

This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

selftests: netfilter: packetdrill: avoid failure on HZ=100 kernel

2026-01-02T11:56:47+00:00

[ Upstream commit fec7b0795548b43e2c3c46e3143c34ef6070341c ]

packetdrill --ip_version=ipv4 --mtu=1500 --tolerance_usecs=1000000 --non_fatal packet conntrack_syn_challenge_ack.pkt
conntrack v1.4.8 (conntrack-tools): 1 flow entries have been shown.
conntrack_syn_challenge_ack.pkt:32: error executing `conntrack -f $NFCT_IP_VERSION \
-L -p tcp --dport 8080 | grep UNREPLIED | grep -q SYN_SENT` command: non-zero status 1

Affected kernel had CONFIG_HZ=100; reset packet was still sitting in
backlog.

Reported-by: Yi Chen 
Fixes: a8a388c2aae4 ("selftests: netfilter: add packetdrill based conntrack tests")
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin

netfilter: nf_nat: remove bogus direction check

2026-01-02T11:56:47+00:00

[ Upstream commit 5ec8ca26fe93103577c904644b0957f069d0051a ]

Jakub reports spurious failures of the 'conntrack_reverse_clash.sh'
selftest.  A bogus test makes nat core resort to port rewrite even
though there is no need for this.

When the test is made, nf_nat_used_tuple() would already have caused us
to return if no other CPU had added a colliding entry.
Moreover, nf_nat_used_tuple() would have ignored the colliding entry if
their origin tuples had been the same.

All that is left to check is if the colliding entry in the hash table
is subject to NAT, and, if its not, if our entry matches in the reverse
direction, e.g. hash table has

addr1:1234 -> addr2:80, and we want to commit
addr2:80   -> addr1:1234.

Because we already checked that neither the new nor the committed entry is
subject to NAT we only have to check origin vs. reply tuple:
for non-nat entries, the reply tuple is always the inverted original.

Just in case there are more problems extend the error reporting
in the selftest while at it and dump conntrack table/stats on error.

Reported-by: Jakub Kicinski 
Closes: https://lore.kernel.org/netdev/20251206175135.4a56591b@kernel.org/
Fixes: d8f84a9bc7c4 ("netfilter: nf_nat: don't try nat source port reallocation for reverse dir clash")
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin

selftests: netfilter: prefer xfail in case race wasn't triggered

2026-01-02T11:56:47+00:00

[ Upstream commit b8a81b0ce539e021ac72825238aea1eb657000f0 ]

Jakub says: "We try to reserve SKIP for tests skipped because tool is
missing in env, something isn't built into the kernel etc."

use xfail, we can't force the race condition to appear at will
so its expected that the test 'fails' occasionally.

Fixes: 78a588363587 ("selftests: netfilter: add conntrack clash resolution test case")
Reported-by: Jakub Kicinski 
Closes: https://lore.kernel.org/netdev/20251206175647.5c32f419@kernel.org/
Signed-off-by: Florian Westphal 
Signed-off-by: Sasha Levin

selftests: net: tfo: Fix build warning

2026-01-02T11:56:46+00:00

[ Upstream commit 91dc09a609d9443e6b34bdb355a18d579a95e132 ]

Fix

tfo.c: In function ‘run_server’:
tfo.c:84:9: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’

by evaluating the return value from read() and displaying an error message
if it reports an error.

Fixes: c65b5bb2329e3 ("selftests: net: add passive TFO test binary")
Cc: David Wei 
Signed-off-by: Guenter Roeck 
Link: https://patch.msgid.link/20251205171010.515236-14-linux@roeck-us.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

selftests: net: Fix build warnings

2026-01-02T11:56:46+00:00

[ Upstream commit 59546e874403c1dd0cbc42df06fdf8c113f72022 ]

Fix

ksft.h: In function ‘ksft_ready’:
ksft.h:27:9: warning: ignoring return value of ‘write’ declared with attribute ‘warn_unused_result’

ksft.h: In function ‘ksft_wait’:
ksft.h:51:9: warning: ignoring return value of ‘read’ declared with attribute ‘warn_unused_result’

by checking the return value of the affected functions and displaying
an error message if an error is seen.

Fixes: 2b6d490b82668 ("selftests: drv-net: Factor out ksft C helpers")
Cc: Joe Damato 
Signed-off-by: Guenter Roeck 
Link: https://patch.msgid.link/20251205171010.515236-11-linux@roeck-us.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

selftest: af_unix: Support compilers without flex-array-member-not-at-end support

2026-01-02T11:56:46+00:00

[ Upstream commit 06f7cae92fe346fa49a8a9b161124b26cc5c3ed1 ]

Fix:

gcc: error: unrecognized command-line option ‘-Wflex-array-member-not-at-end’

by making the compiler option dependent on its support.

Fixes: 1838731f1072c ("selftest: af_unix: Add -Wall and -Wflex-array-member-not-at-end to CFLAGS.")
Cc: Kuniyuki Iwashima 
Signed-off-by: Guenter Roeck 
Link: https://patch.msgid.link/20251205171010.515236-7-linux@roeck-us.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

selftests/net: packetdrill: pass send_omit_free to MSG_ZEROCOPY tests

2025-12-18T13:03:22+00:00

[ Upstream commit c01a6e5b2e4f21d31cf725b9f3803cb0280b1b8d ]

The --send_omit_free flag is needed for TCP zero copy tests, to ensure
that packetdrill doesn't free the send() buffer after the send() call.

Fixes: 1e42f73fd3c2 ("selftests/net: packetdrill: import tcp/zerocopy")
Closes: https://lore.kernel.org/netdev/20251124071831.4cbbf412@kernel.org/
Suggested-by: Neal Cardwell 
Signed-off-by: Willem de Bruijn 
Link: https://patch.msgid.link/20251125234029.1320984-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

selftests: mptcp: add a check for 'add_addr_accepted'

2025-11-20T04:07:16+00:00

The previous patch fixed an issue with the 'add_addr_accepted' counter.
This was not spot by the test suite.

Check this counter and 'add_addr_signal' in MPTCP Join 'delete re-add
signal' test. This should help spotting similar regressions later on.
These counters are crucial for ensuring the MPTCP path manager correctly
handles the subflow creation via 'ADD_ADDR'.

Signed-off-by: Gang Yan 
Reviewed-by: Geliang Tang 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-11-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski