kernel/git/stable/linux-stable.git/tools/testing/selftests/net, branch master

selftests: mptcp: lib: get counters for the right test

2026-09-09T20:32:56+00:00

When the value for a MIB counter is required, mptcp_lib_get_counter is called. It tries to use the cache, if available. If not it falls back to calling 'nstat' directly by looking at the absolute counters. That's an issue for tests that don't recreate the netns for each subtest. In this case, 'nstat -a' will look at the counters for the netns. Instead, it should look at the increment for the current test, by using the history recorded in /tmp/.nstat, if available, and not using '-a' which was dumping the absolute values. While at it, rename the previous 'hist' variable to 'cache' as it was used to look at the cache, not the nstat history. Fixes: 71388a9f331d ("selftests: mptcp: lib: get counters from nstat history") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-12-df1de70348b6@kernel.org Signed-off-by: Jakub Kicinski

selftests: mptcp: lib: dump nstat for the right test

2026-09-09T20:32:56+00:00

In case of errors, mptcp_lib_pr_nstat is called to dump the nstat counters, but for some tests, it was dumping the counters for all subtests, not just the current one. That's an issue for tests that don't recreate the netns for each subtest, e.g. mptcp_connect.sh. In this case, 'nstat -a' will look at the absolute counters since the creation of the netns, making debugging harder. Instead, it should dump the counters for the current test, by using the history recorded in /tmp/.nstat if available, and not using '-a' which was dumping the absolute values instead of calculating increments. While at it, rename the previous 'hist' variable to 'cache' as it was used to look at the cache, not the nstat history. Fixes: 658e53141780 ("selftests: mptcp: join: dump stats from history") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-11-df1de70348b6@kernel.org Signed-off-by: Jakub Kicinski

selftests: mptcp: fix an UAF in mptcp_connect.c

2026-09-09T20:32:55+00:00

At the end of 'sock_connect_mptcp()', it calls 'freeaddrinfo(addr)', the 'peer' pointer (which points into 'addr') remains. Later, the main loop uses this peer pointer for reconnection attempts. If the memory has been freed and reused, the address data could be overwritten, resulting in an invalid remote address. This patch keeps the addrinfo list allocated for the whole process lifetime so "peer" remains valid across reconnects; the memory will be released at exit() time. Fixes: 05be5e273c84 ("selftests: mptcp: add disconnect tests") Cc: stable@vger.kernel.org Suggested-by: Paolo Abeni Signed-off-by: Gang Yan Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-7-df1de70348b6@kernel.org Signed-off-by: Jakub Kicinski

selftests: net: Test UDP length overflow with PMTU discover and big MTU

2026-09-08T00:13:55+00:00

Two previous commits fixed overflow of UDP length when setsockopt IP(V6)_MTU_DISCOVER is set to IPV6_PMTUDISC_DO or IP(V6)_PMTUDISC_PROBE, and a large packet is sent over a netdev with an unusually large MTU. This commit adds the selftests that replicate the described steps to reproduce for IPv6 and IPv4, and also one more test that ensures that sending UDP jumbograms over a raw socket is still possible after the fix. Signed-off-by: Alice Mikityanska Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260901195714.673548-4-alice.kernel@fastmail.im Signed-off-by: Jakub Kicinski

selftest: af_unix: Add zero-buffer test for msg_oob.c

2026-09-07T23:58:42+00:00

The previous patches fixed two issues related to zero-length buffer with MSG_PEEK for MSG_OOB skb. Let's add corresponding tests in msg_oob.c. Without this series: # FAILED: 50 / 60 tests passed. # Totals: pass:50 fail:10 xfail:0 xpass:0 skip:0 error:0 With this series: # PASSED: 60 / 60 tests passed. # Totals: pass:60 fail:0 xfail:0 xpass:0 skip:0 error:0 Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20260902202202.892676-4-kuniyu@google.com Signed-off-by: Jakub Kicinski

vxlan: reject dynamic fdb entries that reference a nexthop id

2026-09-04T23:14:52+00:00

The commit cited in the Fixes tag allowed VXLAN FDB entries to point to FDB nexthops so that overlay traffic could be load balanced across multiple VTEPs. Such entries can only be configured from user space, cannot be learned and cannot roam. They only make sense with a user space control plane such as E-VPN where data plane learning is disabled. Despite that, the VXLAN driver does not currently prevent such entries from being configured with the "dynamic" flag. The per-nexthop FDB list is only protected by the per-device hash lock, which is not sufficient when two VXLAN devices point to the same FDB nexthop and therefore share the list. Aging runs in softirq context without RTNL, so an entry deleted by one device can race with an addition or deletion from the other, leading to list corruption: list_del corruption. next->prev should be ffff8881069d9548, but was dead000000000122. (next=ffff8881069d9448) WARNING: CPU: 0 PID: 90 at lib/list_debug.c:65 __list_del_entry_valid_or_report+0x1aa/0x210 ... vxlan_fdb_destroy+0x5b8/0xad0 vxlan_cleanup+0x328/0x450 call_timer_fn+0x2a/0x1c0 run_timer_softirq+0x18c/0x210 BUG: KASAN: slab-use-after-free in vxlan_fdb_destroy Fix this by rejecting the bogus configuration of dynamic FDB entries that point to FDB nexthops, both when created and when an existing entry is updated. As such, the per-nexthop FDB list is only ever mutated under the RTNL lock. Add test cases to make sure that this does not regress in the future. Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") Suggested-by: Ido Schimmel Signed-off-by: Seungwon Bae Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260902155956.296699-1-qotmddnjs@ajou.ac.kr Signed-off-by: Jakub Kicinski

tunnels: Drop stale dst when building an ICMP error for PMTUD

2026-09-04T00:40:55+00:00

Bridged UDP tunnels such as VXLAN and GENEVE build an ICMP error packet around an overlay packet if the packet is going to exceed the underlay path MTU. The ICMP error packet is then injected back into the Rx path with the source and destination addresses swapped, so that it will be delivered to the overlay source. If the overlay packet was routed to the UDP tunnel or locally generated, then it is already carrying a valid dst entry and this entry is not dropped when transforming the packet to an ICMP error packet. This causes the IP layer to reuse the dst entry, leading to the ICMP error packet being dropped or routed out of the UDP tunnel interface in case of forwarding. Prior to the blamed commit this could not happen, as skb_tunnel_check_pmtu() did not build ICMP errors for PACKET_HOST packets. Such packets were instead encapsulated and, unless the DF bit was set in the outer header, fragmented by the underlay. Fix this by making sure that the ICMP error packet does not have a valid dst entry, thereby forcing the IP layer to perform a route lookup. Adjust the bridged PMTU exception selftests accordingly. When the local sender in ns_a pings the overlay destination with a deadline (-w), ping exits on the first socket error before any reply is received and returns a non-zero exit code. The test therefore only passed because the ICMP error was never delivered. Use a packet count (-c) like the ns_c line above it, so that the ICMP error counts against the packet budget and the exit code depends on whether echo replies were received. This passes with and without the fix. Fixes: 8930424777e4 ("tunnels: Accept PACKET_HOST in skb_tunnel_check_pmtu().") Cc: stable@vger.kernel.org Reported-by: Laika Price Closes: https://lore.kernel.org/netdev/20260614-master-v3-1-9f5060ba1ed1@gmail.com/ Reported-by: Yaroslav Dudkov Closes: https://lore.kernel.org/netdev/20260901081825.287173-1-aroslavdudkov622@gmail.com/ Reported-by: Charles Bordet Closes: https://lore.kernel.org/netdev/aHVhQLPJIhq-SYPM@eldamar.lan/ Signed-off-by: Ido Schimmel Tested-by: Yaroslav Dudkov Reviewed-by: David Ahern Reviewed-by: Stefano Brivio Reviewed-by: Guillaume Nault Link: https://patch.msgid.link/20260902190112.4126199-1-idosch@nvidia.com Signed-off-by: Jakub Kicinski

selftests: net: Add exception cache tests

2026-09-01T02:56:31+00:00

Add a test for the IPv4 and IPv6 exception caches, covering the exceptions that are created in response to ICMP errors quoting a UDP packet. The topology consists of a host (h1) that reaches a remote host (h2) via a router (r1), with a second router (r2) attached to the segment shared by h1 and r1. UDP packets are injected using a packet socket, so that an ICMP error quoting them is only matched to a socket when one was opened separately with the same source port. PMTU errors are provoked by lowering the MTU of the far end of the path and redirects by pointing r1's route towards h2 back over the segment it received the packet from. The following is tested for both address families and for both PMTU and redirect exceptions: * An error that is not matched to a socket creates an exception that carries the new MTU or gateway. * An error that is matched to a socket creates the same exception. The PMTU tests further verify that a lower PMTU replaces the one stored in the exception whereas a higher one does not, and that a socket which disabled PMTU discovery using IP{,V6}_PMTUDISC_OMIT gets the same exception as the other cases. Without "ipv4: udp: Create exceptions before socket matching" and "ipv6: udp: Create exceptions before socket matching", the tests that do not open a socket fail: # ./exception_cache.sh TEST: IPv4: PMTU: exception without a matching socket [FAIL] No socket: exception does not carry an MTU of 1400 TEST: IPv6: PMTU: exception without a matching socket [FAIL] No socket: exception does not carry an MTU of 1400 TEST: IPv4: PMTU: exception with a matching socket [ OK ] TEST: IPv6: PMTU: exception with a matching socket [ OK ] TEST: IPv4: PMTU: exception with a socket ignoring it [FAIL] PMTU discovery disabled: exception does not carry an MTU of 1400 TEST: IPv6: PMTU: exception with a socket ignoring it [FAIL] PMTU discovery disabled: exception does not carry an MTU of 1400 TEST: IPv4: Redirect: exception without a matching socket [FAIL] No socket: exception does not carry the new gateway TEST: IPv6: Redirect: exception without a matching socket [FAIL] No socket: exception does not carry the new gateway TEST: IPv4: Redirect: exception with a matching socket [ OK ] TEST: IPv6: Redirect: exception with a matching socket [ OK ] Signed-off-by: Ido Schimmel Link: https://patch.msgid.link/20260828192344.2596928-5-idosch@nvidia.com Signed-off-by: Jakub Kicinski

vxlan: mdb: Fix use-after-free in vxlan_mdb_remote_src_del()

2026-08-30T21:19:59+00:00

vxlan_mdb_is_valid_source(), which validates MDBE_ATTR_SOURCE and every MDBE_ATTR_SRC_LIST member, accepts the all-zeros address. A source list is only accepted on a (*, G) entry, whose source is the all-zeros address, and for each member of the list an (S, G) entry is derived from it by substituting the source. Entries are keyed by a plain memcmp() of struct vxlan_mdb_entry_key, so if MDBE_ATTR_SOURCE is present and holds the all-zeros address and the source list holds it as well, the derived (S, G) key is byte-identical to the (*, G) key and resolves to the same entry. Omitting MDBE_ATTR_SOURCE is not equivalent, as the key is then left with a zero address family. vxlan_mdb_remote_src_del() removes the forwarding entry of a source before freeing the source entry: vxlan_mdb_remote_src_fwd_del(vxlan, group, remote, &ent->addr); vxlan_mdb_remote_src_entry_del(ent); With the keys aliased, the first call deletes the remote of the entry that owns 'ent' instead of a separate (S, G) entry, and frees 'ent'. The second call then runs on the freed entry, and its hlist_del() reads ->pprev and ->next out of it and writes through them. Adding the (*, G) entry with NLM_F_REPLACE and no source list marks the all-zeros source for deletion and reaches this from the sweep at the end of vxlan_mdb_remote_srcs_replace(). BUG: KASAN: slab-use-after-free in __vxlan_mdb_add+0x1cd/0xd70 Read of size 8 at addr ffff888102852500 by task poc/84 __vxlan_mdb_add+0x1cd/0xd70 vxlan_mdb_add+0xc0/0x140 rtnl_mdb_add+0x157/0x2a0 rtnetlink_rcv_msg+0x207/0x5a0 Allocated by task 84: __kmalloc_cache_noprof+0x153/0x360 vxlan_mdb_remote_srcs_add+0x2eb/0x440 __vxlan_mdb_add+0x803/0xd70 Freed by task 84: kfree+0x14c/0x3b0 vxlan_mdb_remote_del+0x129/0x1a0 __vxlan_mdb_del+0x4f/0xe0 vxlan_mdb_remote_src_fwd_del.isra.0+0x162/0x1b0 __vxlan_mdb_add+0x1c5/0xd70 The MDB operations are netns-scoped, so an unprivileged user can perform them in a new user and network namespace. Reject the all-zeros address in vxlan_mdb_is_valid_source(), which covers both call sites. A (*, G) entry is expressed by omitting the source, so nothing legitimate is refused. Discovered by XBOW, triaged by Baul Lee Fixes: a3a48de5eade ("vxlan: mdb: Add MDB control path support") Signed-off-by: Baul Lee Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260826173604.90158-1-baul.lee@xbow.com Signed-off-by: Jakub Kicinski

Merge tag 'net-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-08-27T20:53:43+00:00

Pull networking fixes from Jakub Kicinski: "Including fixes from Bluetooth, IPSec and Netfilter. Current release - fix to a fix: - netfilter: ipset: remove need to allocate memory on delete operations Current release - regressions: - macb: drop CONFIG_OF #if block, fix build Previous releases - always broken: - stream of fixes for SCTP continues - inet: frags: strip GSO state from fragments before reassembly - virtio-net: ensure that TCP packets don't overflow gso_segs - tcp-ao: fix use-after-free of current_key on reconnect to another peer - page_pool: remove zone/policy GFP flags when allocating XArray entries - Bluetooth: L2CAP: reject accept queue add unless BT_LISTEN - tls: device: fix out-of-bounds write in tls_append_frag() - eth: bnxt: - ring the doorbell when SW USO exits early, avoid packets stuck in Tx - gate TPH enablement behind BNXT_SUPPORTS_QUEUE_API check, avoid users of older NICs seeing non-actionable warning messages - eth: qede: fix NULL pointer dereference in TPA fragment processing" * tag 'net-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (216 commits) inet: frags: strip GSO state from fragments before reassembly net/sched: sch_htb: limit htb_classify inner-class filter hops selftests/net: packetdrill: add tcp_urg_ptr_retransmit tcp: fix corruption of urgent data on multi-segment retransmit usb: atm: usbatm: fix invalid ci_range initialization net: fec: only stop PTP if it was initialized slip: remove slip_hangup() to fix use-after-free in slip_receive_buf() net: bridge: mcast: fix use-after-free of a master VLAN's multicast context net/sched: bound qdisc_pkt_len to prevent qdisc soft lockup net: dsa: mxl862xx: enable assisted learning on CPU port net: stmmac: restore NET_IP_ALIGN in the RX DMA offset net: stmmac: drop gso_enabled_types and rely on netdev features net: stmmac: selftests: Don't test flow control for small rx fifos net: stmmac: selftests: Account for the UC filter list for filtering tests net: stmmac: dwxgmac: Account for the primary MAC address for UC filtering net: stmmac: dwmac4: Account for the primary MAC address for UC filtering net: stmmac: dwmac1000: Account for the primary MAC address for UC filtering net: stmmac: selftests: Check multiple MMC counters selftests: net: Fix slow configurations in big_tcp_tunnels.sh selftests: net: Lower threshold with csum offload off in big_tcp_tunnels.sh ...