[ Upstream commit e4faaf65a7 ]
idev->mr_maxdelay is read and written locklessly,
add READ_ONCE()/WRITE_ONCE() annotations.
While we are at it, make this field an u32.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20260122172247.2429403-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 034bbd8062 ]
Following expression can overflow
if sysctl_icmp_msgs_per_sec is big enough.
sysctl_icmp_msgs_per_sec * delta / HZ;
Fixes: 4cdf507d54 ("icmp: add a global rate limitation")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260216142832.3834174-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ad5dfde2a5 ]
isk->inet_num, isk->inet_rcv_saddr and sk->sk_bound_dev_if
are read locklessly in ping_lookup().
Add READ_ONCE()/WRITE_ONCE() annotations.
The race on isk->inet_rcv_saddr is probably coming from IPv6 support,
but does not deserve a specific backport.
Fixes: dbca1596bb ("ping: convert to RCU lookups, get rid of rwlock")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260216100149.3319315-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 81b84de32b ]
icmp_route_lookup() performs multiple route lookups to find a suitable
route for sending ICMP error messages, with special handling for XFRM
(IPsec) policies.
The lookup sequence is:
1. First, lookup output route for ICMP reply (dst = original src)
2. Pass through xfrm_lookup() for policy check
3. If blocked (-EPERM) or dst is not local, enter "reverse path"
4. In reverse path, call xfrm_decode_session_reverse() to get fl4_dec
which reverses the original packet's flow (saddr<->daddr swapped)
5. If fl4_dec.saddr is local (we are the original destination), use
__ip_route_output_key() for output route lookup
6. If fl4_dec.saddr is NOT local (we are a forwarding node), use
ip_route_input() to simulate the reverse packet's input path
7. Finally, pass rt2 through xfrm_lookup() with XFRM_LOOKUP_ICMP flag
The bug occurs in step 6: ip_route_input() is called with fl4_dec.daddr
(original packet's source) as destination. If this address becomes local
between the initial check and ip_route_input() call (e.g., due to
concurrent "ip addr add"), ip_route_input() returns a LOCAL route with
dst.output set to ip_rt_bug.
This route is then used for ICMP output, causing dst_output() to call
ip_rt_bug(), triggering a WARN_ON:
------------[ cut here ]------------
WARNING: net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1
Call Trace:
<TASK>
ip_push_pending_frames+0x202/0x240
icmp_push_reply+0x30d/0x430
__icmp_send+0x1149/0x24f0
ip_options_compile+0xa2/0xd0
ip_rcv_finish_core+0x829/0x1950
ip_rcv+0x2d7/0x420
__netif_receive_skb_one_core+0x185/0x1f0
netif_receive_skb+0x90/0x450
tun_get_user+0x3413/0x3fb0
tun_chr_write_iter+0xe4/0x220
...
Fix this by checking rt2->rt_type after ip_route_input(). If it's
RTN_LOCAL, the route cannot be used for output, so treat it as an error.
The reproducer requires kernel modification to widen the race window,
making it unsuitable as a selftest. It is available at:
https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81
Reported-by: syzbot+e738404dcd14b620923c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000b1060905eada8881@google.com/T/
Closes: https://lore.kernel.org/r/20260128090523.356953-1-jiayuan.chen@linux.dev
Fixes: 8b7817f3a9 ("[IPSEC]: Add ICMP host relookup support")
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://patch.msgid.link/20260206050220.59642-1-jiayuan.chen@linux.dev
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e97e6a1830 ]
Going forward skb_dst_set will assert that skb dst_entry
is empty during skb_dst_set. skb_dstref_steal is added to reset
existing entry without doing refcnt. skb_dstref_restore should
be used to restore the previous entry. Convert icmp_route_lookup
and ip_options_rcv_srr to these helpers. Add extra call to
skb_dstref_reset to icmp_route_lookup to clear the ip_route_input
entry.
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250818154032.3173645-5-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 81b84de32b ("xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c89477ad79 ]
Yizhou Zhao reported that simply having one RAW socket on protocol
IPPROTO_RAW (255) was dangerous.
socket(AF_INET, SOCK_RAW, 255);
A malicious incoming ICMP packet can set the protocol field to 255
and match this socket, leading to FNHE cache changes.
inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST")
pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner
"man 7 raw" states:
A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able
to send any IP protocol that is specified in the passed header.
Receiving of all IP protocols via IPPROTO_RAW is not possible
using raw sockets.
Make sure we drop these malicious packets.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Yizhou Zhao <zhaoyz24@mails.tsinghua.edu.cn>
Link: https://lore.kernel.org/netdev/20251109134600.292125-1-zhaoyz24@mails.tsinghua.edu.cn/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260203192509.682208-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 838eb96876 ]
tcp_tx_timestamp() is only called at the end of tcp_sendmsg_locked()
before the final tcp_push().
By the time it is called, it is possible all the copied data
has been sent already (transmit queue is empty).
If this is the case, use the last skb in the rtx queue.
Fixes: 75c119afe1 ("tcp: implement rb-tree based retransmit queue")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20260127123828.4098577-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 929e30f931 ]
A socket using sockmap has its own independent receive queue: ingress_msg.
This queue may contain data from its own protocol stack or from other
sockets.
Therefore, for sockmap, relying solely on copied_seq and rcv_nxt to
calculate FIONREAD is not enough.
This patch adds a new msg_tot_len field in the psock structure to record
the data length in ingress_msg. Additionally, we implement new ioctl
interfaces for TCP and UDP to intercept FIONREAD operations.
Note that we intentionally do not include sk_receive_queue data in the
FIONREAD result. Data in sk_receive_queue has not yet been processed by
the BPF verdict program, and may be redirected to other sockets or
dropped. Including it would create semantic ambiguity since this data
may never be readable by the user.
Unix and VSOCK sockets have similar issues, but fixing them is outside
the scope of this patch as it would require more intrusive changes.
Previous work by John Fastabend made some efforts towards FIONREAD support:
commit e5c6de5fa0 ("bpf, sockmap: Incorrectly handling copied_seq")
Although the current patch is based on the previous work by John Fastabend,
it is acceptable for our Fixes tag to point to the same commit.
FD1:read()
-- FD1->copied_seq++
| [read data]
|
[enqueue data] v
[sockmap] -> ingress to self -> ingress_msg queue
FD1 native stack ------> ^
-- FD1->rcv_nxt++ -> redirect to other | [enqueue data]
| |
| ingress to FD1
v ^
... | [sockmap]
FD2 native stack
Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20260124113314.113584-3-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b40cc5adaa ]
A socket using sockmap has its own independent receive queue: ingress_msg.
This queue may contain data from its own protocol stack or from other
sockets.
The issue is that when reading from ingress_msg, we update tp->copied_seq
by default. However, if the data is not from its own protocol stack,
tcp->rcv_nxt is not increased. Later, if we convert this socket to a
native socket, reading from this socket may fail because copied_seq might
be significantly larger than rcv_nxt.
This fix also addresses the syzkaller-reported bug referenced in the
Closes tag.
This patch marks the skmsg objects in ingress_msg. When reading, we update
copied_seq only if the data is from its own protocol stack.
FD1:read()
-- FD1->copied_seq++
| [read data]
|
[enqueue data] v
[sockmap] -> ingress to self -> ingress_msg queue
FD1 native stack ------> ^
-- FD1->rcv_nxt++ -> redirect to other | [enqueue data]
| |
| ingress to FD1
v ^
... | [sockmap]
FD2 native stack
Closes: https://syzkaller.appspot.com/bug?extid=06dbd397158ec0ea4983
Fixes: 04919bed94 ("tcp: Introduce tcp_read_skb()")
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260124113314.113584-2-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 426ca15c7f upstream.
This patch enhances GSO segment handling by properly checking
the SKB_GSO_DODGY flag for frag_list GSO packets, addressing
low throughput issues observed when a station accesses IPv4
servers via hotspots with an IPv6-only upstream interface.
Specifically, it fixes a bug in GSO segmentation when forwarding
GRO packets containing a frag_list. The function skb_segment_list
cannot correctly process GRO skbs that have been converted by XLAT,
since XLAT only translates the header of the head skb. Consequently,
skbs in the frag_list may remain untranslated, resulting in protocol
inconsistencies and reduced throughput.
To address this, the patch explicitly sets the SKB_GSO_DODGY flag
for GSO packets in XLAT's IPv4/IPv6 protocol translation helpers
(bpf_skb_proto_4_to_6 and bpf_skb_proto_6_to_4). This marks GSO
packets as potentially modified after protocol translation. As a
result, GSO segmentation will avoid using skb_segment_list and
instead falls back to skb_segment for packets with the SKB_GSO_DODGY
flag. This ensures that only safe and fully translated frag_list
packets are processed by skb_segment_list, resolving protocol
inconsistencies and improving throughput when forwarding GRO packets
converted by XLAT.
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Fixes: 9fd1ff5d2a ("udp: Support UDP fraglist GRO/GSO.")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260126152114.1211-1-jibin.zhang@mediatek.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 7a9bc9e3f4 ]
fou_udp_recv() has the same problem mentioned in the previous
patch.
If FOU_ATTR_IPPROTO is set to 0, skb is not freed by
fou_udp_recv() nor "resubmit"-ted in ip_protocol_deliver_rcu().
Let's forbid 0 for FOU_ATTR_IPPROTO.
Fixes: 23461551c0 ("fou: Support for foo-over-udp RX path")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260115172533.693652-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e67c577d89 ]
Analog to commit db5b4e39c4 ("ip6_gre: make ip6gre_header() robust")
Over the years, syzbot found many ways to crash the kernel
in ipgre_header() [1].
This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ipgre device.
[1]
skbuff: skb_under_panic: text:ffffffff89ea3cb7 len:2030915468 put:2030915372 head:ffff888058b43000 data:ffff887fdfa6e194 tail:0x120 end:0x6c0 dev:team0
kernel BUG at net/core/skbuff.c:213 !
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 1322 Comm: kworker/1:9 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: mld mld_ifc_work
RIP: 0010:skb_panic+0x157/0x160 net/core/skbuff.c:213
Call Trace:
<TASK>
skb_under_panic net/core/skbuff.c:223 [inline]
skb_push+0xc3/0xe0 net/core/skbuff.c:2641
ipgre_header+0x67/0x290 net/ipv4/ip_gre.c:897
dev_hard_header include/linux/netdevice.h:3436 [inline]
neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Fixes: c544193214 ("GRE: Refactor GRE tunneling code.")
Reported-by: syzbot+7c134e1c3aa3283790b9@syzkaller.appspotmail.com
Closes: https://www.spinics.net/lists/netdev/msg1147302.html
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260108190214.1667040-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3d5221af9c ]
Commit 61fafbee6c ("xfrm: Determine inner GSO type from packet inner
protocol") attempted to fix GSO segmentation by reading the inner
protocol from XFRM_MODE_SKB_CB(skb)->protocol. This was incorrect
because the field holds the inner L4 protocol (TCP/UDP) instead of the
required tunnel protocol. Also, the memory location (shared by
XFRM_SKB_CB(skb) which could be overwritten by xfrm_replay_overflow())
is prone to corruption. This combination caused the kernel to select
the wrong inner mode and get the wrong address family.
The correct value is in xfrm_offload(skb)->proto, which is set from
the outer tunnel header's protocol field by esp[4|6]_gso_encap(). It
is initialized by xfrm[4|6]_tunnel_encap_add() to either IPPROTO_IPIP
or IPPROTO_IPV6, using xfrm_af2proto() and correctly reflects the
inner packet's address family.
Fixes: 61fafbee6c ("xfrm: Determine inner GSO type from packet inner protocol")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c92510f5e3 ]
arp_create() is the only dev_hard_header() caller
making assumption about skb->head being unchanged.
A recent commit broke this assumption.
Initialize @arp pointer after dev_hard_header() call.
Fixes: db5b4e39c4 ("ip6_gre: make ip6gre_header() robust")
Reported-by: syzbot+58b44a770a1585795351@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260107212250.384552-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4c0856c225 ]
When the ping program uses an IPPROTO_ICMP socket to send ICMP_ECHO
messages, ICMP_MIB_OUTMSGS is counted twice.
ping_v4_sendmsg
ping_v4_push_pending_frames
ip_push_pending_frames
ip_finish_skb
__ip_make_skb
icmp_out_count(net, icmp_type); // first count
icmp_out_count(sock_net(sk), user_icmph.type); // second count
However, when the ping program uses an IPPROTO_RAW socket,
ICMP_MIB_OUTMSGS is counted correctly only once.
Therefore, the first count should be removed.
Fixes: c319b4d76b ("net: ipv4: add IPPROTO_ICMP socket kind")
Signed-off-by: yuan.gao <yuan.gao@ucloud.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20251224063145.3615282-1-yuan.gao@ucloud.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ac782f4e3b ]
When a nexthop object is deleted, it is marked as dead and then
fib_table_flush() is called to flush all the routes that are using the
dead nexthop.
The current logic in fib_table_flush() is to only flush error routes
(e.g., blackhole) when it is called as part of network namespace
dismantle (i.e., with flush_all=true). Therefore, error routes are not
flushed when their nexthop object is deleted:
# ip link add name dummy1 up type dummy
# ip nexthop add id 1 dev dummy1
# ip route add 198.51.100.1/32 nhid 1
# ip route add blackhole 198.51.100.2/32 nhid 1
# ip nexthop del id 1
# ip route show
blackhole 198.51.100.2 nhid 1 dev dummy1
As such, they keep holding a reference on the nexthop object which in
turn holds a reference on the nexthop device, resulting in a reference
count leak:
# ip link del dev dummy1
[ 70.516258] unregister_netdevice: waiting for dummy1 to become free. Usage count = 2
Fix by flushing error routes when their nexthop is marked as dead.
IPv6 does not suffer from this problem.
Fixes: 493ced1ac4 ("ipv4: Allow routes to use nexthop objects")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Closes: https://lore.kernel.org/netdev/d943f806-4da6-4970-ac28-b9373b0e63ac@I-love.SAKURA.ne.jp/
Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20251221144829.197694-1-idosch@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 50c127a69c ]
Replace three dst_dev() with a lockdep enabled helper.
Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250828195823.3958522-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Gyokhan Kochmarla <gyokhan@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit caedcc5b6d ]
Followup of commit 88fe14253e ("net: dst: add four helpers
to annotate data-races around dst->dev").
We want to gradually add explicit RCU protection to dst->dev,
including lockdep support.
Add an union to alias dst->dev_rcu and dst->dev.
Add dst_dev_net_rcu() helper.
Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250828195823.3958522-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 50c127a69c ("Replace three dst_dev() with a lockdep enabled helper.")
Signed-off-by: Gyokhan Kochmarla <gyokhan@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b8ec80b130 ]
Since ehash lookups are lockless, if another CPU is converting sk to tw
concurrently, fetching the newly inserted tw with tw->tw_refcnt == 0 cause
lookup failure.
The call trace map is drawn as follows:
CPU 0 CPU 1
----- -----
inet_twsk_hashdance_schedule()
spin_lock()
inet_twsk_add_node_rcu(tw, ...)
__inet_lookup_established()
(find tw, failure due to tw_refcnt = 0)
__sk_nulls_del_node_init_rcu(sk)
refcount_set(&tw->tw_refcnt, 3)
spin_unlock()
By replacing sk with tw atomically via hlist_nulls_replace_init_rcu() after
setting tw_refcnt, we ensure that tw is either fully initialized or not
visible to other CPUs, eliminating the race.
It's worth noting that we held lock_sock() before the replacement, so
there's no need to check if sk is hashed. Thanks to Kuniyuki Iwashima!
Fixes: 3ab5aee7fe ("net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls")
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251015020236.431822-4-xuanqiang.luo@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1532ed0d07 ]
Since ehash lookups are lockless, if one CPU performs a lookup while
another concurrently deletes and inserts (removing reqsk and inserting sk),
the lookup may fail to find the socket, an RST may be sent.
The call trace map is drawn as follows:
CPU 0 CPU 1
----- -----
inet_ehash_insert()
spin_lock()
sk_nulls_del_node_init_rcu(osk)
__inet_lookup_established()
(lookup failed)
__sk_nulls_add_node_rcu(sk, list)
spin_unlock()
As both deletion and insertion operate on the same ehash chain, this patch
introduces a new sk_nulls_replace_node_init_rcu() helper functions to
implement atomic replacement.
Fixes: 5e0724d027 ("tcp/dccp: fix hashdance race for passive sessions")
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251015020236.431822-3-xuanqiang.luo@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b441cf3f8c ]
The ipcomp fallback tunnels currently get deleted (from the various
lists and hashtables) as the last user state that needed that fallback
is destroyed (not deleted). If a reference to that user state still
exists, the fallback state will remain on the hashtables/lists,
triggering the WARN in xfrm_state_fini. Because of those remaining
references, the fix in commit f75a2804da ("xfrm: destroy xfrm_state
synchronously on net exit path") is not complete.
We recently fixed one such situation in TCP due to defered freeing of
skbs (commit 9b6412e697 ("tcp: drop secpath at the same time as we
currently drop dst")). This can also happen due to IP reassembly: skbs
with a secpath remain on the reassembly queue until netns
destruction. If we can't guarantee that the queues are flushed by the
time xfrm_state_fini runs, there may still be references to a (user)
xfrm_state, preventing the timely deletion of the corresponding
fallback state.
Instead of chasing each instance of skbs holding a secpath one by one,
this patch fixes the issue directly within xfrm, by deleting the
fallback state as soon as the last user state depending on it has been
deleted. Destruction will still happen when the final reference is
dropped.
A separate lockdep class for the fallback state is required since
we're going to lock x->tunnel while x is locked.
Fixes: 9d4139c769 ("netns xfrm: per-netns xfrm_state_all list")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 61fafbee6c ]
The GSO segmentation functions for ESP tunnel mode
(xfrm4_tunnel_gso_segment and xfrm6_tunnel_gso_segment) were
determining the inner packet's L2 protocol type by checking the static
x->inner_mode.family field from the xfrm state.
This is unreliable. In tunnel mode, the state's actual inner family
could be defined by x->inner_mode.family or by
x->inner_mode_iaf.family. Checking only the former can lead to a
mismatch with the actual packet being processed, causing GSO to create
segments with the wrong L2 header type.
This patch fixes the bug by deriving the inner mode directly from the
packet's inner protocol stored in XFRM_MODE_SKB_CB(skb)->protocol.
Instead of replicating the code, this patch modifies the
xfrm_ip2inner_mode helper function. It now correctly returns
&x->inner_mode if the selector family (x->sel.family) is already
specified, thereby handling both specific and AF_UNSPEC cases
appropriately.
With this change, ESP GSO can use xfrm_ip2inner_mode to get the
correct inner mode. It doesn't affect existing callers, as the updated
logic now mirrors the checks they were already performing externally.
Fixes: 26dbd66eab ("esp: choose the correct inner protocol for GSO on inter address family tunnels")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ac1499fcd4 upstream.
The sit driver's packet transmission path calls: sit_tunnel_xmit() ->
update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called
to delete entries exceeding FNHE_RECLAIM_DEPTH+random.
The race window is between fnhe_remove_oldest() selecting fnheX for
deletion and the subsequent kfree_rcu(). During this time, the
concurrent path's __mkroute_output() -> find_exception() can fetch the
soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a
new dst using a dst_hold(). When the original fnheX is freed via RCU,
the dst reference remains permanently leaked.
CPU 0 CPU 1
__mkroute_output()
find_exception() [fnheX]
update_or_create_fnhe()
fnhe_remove_oldest() [fnheX]
rt_bind_exception() [bind dst]
RCU callback [fnheX freed, dst leak]
This issue manifests as a device reference count leak and a warning in
dmesg when unregistering the net device:
unregister_netdevice: waiting for sitX to become free. Usage count = N
Ido Schimmel provided the simple test validation method [1].
The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes().
Since rt_bind_exception() checks this field, setting it to zero prevents
the stale fnhe from being reused and bound to a new dst just before it
is freed.
[1]
ip netns add ns1
ip -n ns1 link set dev lo up
ip -n ns1 address add 192.0.2.1/32 dev lo
ip -n ns1 link add name dummy1 up type dummy
ip -n ns1 route add 192.0.2.2/32 dev dummy1
ip -n ns1 link add name gretap1 up arp off type gretap \
local 192.0.2.1 remote 192.0.2.2
ip -n ns1 route add 198.51.0.0/16 dev gretap1
taskset -c 0 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
taskset -c 2 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
sleep 10
ip netns pids ns1 | xargs kill
ip netns del ns1
Cc: stable@vger.kernel.org
Fixes: 67d6d681e1 ("ipv4: make exception cache less predictible")
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251111064328.24440-1-nashuiliang@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit dc2f650f7e ]
netdev_WARN() uses WARN/WARN_ON to print a backtrace along with
file and line information. In this case, udp_tunnel_nic_register()
returning an error is just a failed operation, not a kernel bug.
udp_tunnel_nic_register() can fail due to a memory allocation
failure (kzalloc() or udp_tunnel_nic_alloc()).
This is a normal runtime error and not a kernel bug.
Replace netdev_WARN() with netdev_warn() accordingly.
Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250910195031.3784748-1-alok.a.tiwari@oracle.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 18282100d7 ]
tcp_recvmsg_dmabuf can export the following errors:
- EFAULT when linear copy fails
- ETOOSMALL when cmsg put fails
- ENODEV if one of the frags is readable
- ENOMEM on xarray failures
But they are all ignored and replaced by EFAULT in the caller
(tcp_recvmsg_locked). Expose real error to the userspace to
add more transparency on what specifically fails.
In non-devmem case (skb_copy_datagram_msg) doing `if (!copied)
copied=-EFAULT` is ok because skb_copy_datagram_msg can return only EFAULT.
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250910162429.4127997-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit db99b2f2b3 ]
tcp reject code won't reply to a tcp reset.
But the icmp reject 'netdev' family versions will reply to icmp
dst-unreach errors, unlike icmp_send() and icmp6_send() which are used
by the inet family implementation (and internally by the REJECT target).
Check for the icmp(6) type and do not respond if its an unreachable error.
Without this, something like 'ip protocol icmp reject', when used
in a netdev chain attached to 'lo', cause a packet loop.
Same for two hosts that both use such a rule: each error packet
will be replied to.
Such situation persist until the (bogus) rule is amended to ratelimit or
checks the icmp type before the reject statement.
As the inet versions don't do this make the netdev ones follow along.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b62a59c18b ]
Use RCU to avoid a pair of atomic operations and a potential
UAF on dst_dev()->flags.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250828195823.3958522-8-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1b8c5fa0cb ]
Currently, ip_extract_route_hint uses RTN_BROADCAST to decide
whether to use the route dst hint mechanism.
This check is too strict, as it prevents directed broadcast
routes from using the hint, resulting in poor performance
during bursts of directed broadcast traffic.
Fix this in ip_extract_route_hint and modify ip_route_use_hint
to preserve the intended behaviour.
Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250819174642.5148-2-oscmaes92@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b0ac6d3b56 ]
When removing a nexthop, commit
90f33bffa3 ("nexthops: don't modify published nexthop groups") added a
call to synchronize_rcu() (later changed to _net()) to make sure
everyone sees the new nexthop-group before the rtnl-lock is released.
When one wants to delete a large number of groups and nexthops, it is
fastest to first flush the groups (ip nexthop flush groups) and then
flush the nexthops themselves (ip -6 nexthop flush). As that way the
groups don't need to be rebalanced.
However, `ip -6 nexthop flush` will still take a long time if there is
a very large number of nexthops because of the call to
synchronize_net(). Now, if there are no more groups, there is no point
in calling synchronize_net(). So, let's skip that entirely by checking
if nh->grp_list is empty.
This gives us a nice speedup:
BEFORE:
=======
$ time sudo ip -6 nexthop flush
Dump was interrupted and may be inconsistent.
Flushed 2097152 nexthops
real 1m45.345s
user 0m0.001s
sys 0m0.005s
$ time sudo ip -6 nexthop flush
Dump was interrupted and may be inconsistent.
Flushed 4194304 nexthops
real 3m10.430s
user 0m0.002s
sys 0m0.004s
AFTER:
======
$ time sudo ip -6 nexthop flush
Dump was interrupted and may be inconsistent.
Flushed 2097152 nexthops
real 0m17.545s
user 0m0.003s
sys 0m0.003s
$ time sudo ip -6 nexthop flush
Dump was interrupted and may be inconsistent.
Flushed 4194304 nexthops
real 0m35.823s
user 0m0.002s
sys 0m0.004s
Signed-off-by: Christoph Paasch <cpaasch@openai.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250816-nexthop_dump-v2-2-491da3462118@openai.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1dbf1d590d ]
In ip_output() skb->dev is updated from the skb_dst(skb)->dev
this can become invalid when the interface is unregistered and freed,
Introduced new skb_dst_dev_rcu() function to be used instead of
skb_dst_dev() within rcu_locks in ip_output.This will ensure that
all the skb's associated with the dev being deregistered will
be transnmitted out first, before freeing the dev.
Given that ip_output() is called within an rcu_read_lock()
critical section or from a bottom-half context, it is safe to introduce
an RCU read-side critical section within it.
Multiple panic call stacks were observed when UL traffic was run
in concurrency with device deregistration from different functions,
pasting one sample for reference.
[496733.627565][T13385] Call trace:
[496733.627570][T13385] bpf_prog_ce7c9180c3b128ea_cgroupskb_egres+0x24c/0x7f0
[496733.627581][T13385] __cgroup_bpf_run_filter_skb+0x128/0x498
[496733.627595][T13385] ip_finish_output+0xa4/0xf4
[496733.627605][T13385] ip_output+0x100/0x1a0
[496733.627613][T13385] ip_send_skb+0x68/0x100
[496733.627618][T13385] udp_send_skb+0x1c4/0x384
[496733.627625][T13385] udp_sendmsg+0x7b0/0x898
[496733.627631][T13385] inet_sendmsg+0x5c/0x7c
[496733.627639][T13385] __sys_sendto+0x174/0x1e4
[496733.627647][T13385] __arm64_sys_sendto+0x28/0x3c
[496733.627653][T13385] invoke_syscall+0x58/0x11c
[496733.627662][T13385] el0_svc_common+0x88/0xf4
[496733.627669][T13385] do_el0_svc+0x2c/0xb0
[496733.627676][T13385] el0_svc+0x2c/0xa4
[496733.627683][T13385] el0t_64_sync_handler+0x68/0xb4
[496733.627689][T13385] el0t_64_sync+0x1a4/0x1a8
Changes in v3:
- Replaced WARN_ON() with WARN_ON_ONCE(), as suggested by Willem de Bruijn.
- Dropped legacy lines mistakenly pulled in from an outdated branch.
Changes in v2:
- Addressed review comments from Eric Dumazet
- Used READ_ONCE() to prevent potential load/store tearing
- Added skb_dst_dev_rcu() and used along with rcu_read_lock() in ip_output
Signed-off-by: Sharath Chandra Vurukala <quic_sharathv@quicinc.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 833d4313bc ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit a74fc62eec ]
Use the new helpers as a first step to deal with
potential dst->dev races.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-8-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 833d4313bc ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 15492700ac ]
tcp_in_quickack_mode() is called from input path for small packets.
It calls __sk_dst_get() which reads sk->sk_dst_cache which has been
put in sock_read_tx group (for good reasons).
Then dst_metric(dst, RTAX_QUICKACK) also needs extra cache line misses.
Cache RTAX_QUICKACK in icsk->icsk_ack.dst_quick_ack to no longer pull
these cache lines for the cases a delayed ACK is scheduled.
After this patch TCP receive path does not longer access sock_read_tx
group.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250312083907.1931644-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Stable-dep-of: 833d4313bc ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e7b9ecce56 ]
TCP uses of dev_net() are under RCU protection, change them
to dev_net_rcu() to get LOCKDEP support.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 833d4313bc ("mptcp: reset blackhole on success with non-loopback ifaces")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 295ce1eb36 ]
Neal reported that using neper tcp_stream with TCP_TX_DELAY
set to 50ms would often lead to flows stuck in a small cwnd mode,
regardless of the congestion control.
While tcp_stream sets TCP_TX_DELAY too late after the connect(),
it highlighted two kernel bugs.
The following heuristic in tcp_tso_should_defer() seems wrong
for large RTT:
delta = tp->tcp_clock_cache - head->tstamp;
/* If next ACK is likely to come too late (half srtt), do not defer */
if ((s64)(delta - (u64)NSEC_PER_USEC * (tp->srtt_us >> 4)) < 0)
goto send_now;
If next ACK is expected to come in more than 1 ms, we should
not defer because we prefer a smooth ACK clocking.
While blamed commit was a step in the good direction, it was not
generic enough.
Another patch fixing TCP_TX_DELAY for established flows
will be proposed when net-next reopens.
Fixes: 50c8339e92 ("tcp: tso: restore IW10 after TSO autosizing")
Reported-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251011115742.1245771-1-edumazet@google.com
[pabeni@redhat.com: fixed whitespace issue]
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 21f4d45eba ]
Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too.
While ipv4 tunnel headroom adjustment growth was limited in
commit 5ae1e9922b ("net: ip_tunnel: prevent perpetual headroom growth"),
ipv6 tunnel yet increases the headroom without any ceiling.
Reflect ipv4 tunnel headroom adjustment limit on ipv6 version.
Credits to Francesco Ruggeri, who was originally debugging this issue
and wrote local Arista-specific patch and a reproducer.
Fixes: 8eb30be035 ("ipv6: Create ip6_tnl_xmit")
Cc: Florian Westphal <fw@strlen.de>
Cc: Francesco Ruggeri <fruggeri05@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://patch.msgid.link/20251009-ip6_tunnel-headroom-v2-1-8e4dbd8f7e35@arista.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 21b29e74ff ]
Some applications (like selftests/net/tcp_mmap.c) call SO_RCVLOWAT
on their listener, before accept().
This has an unfortunate effect on wscale selection in
tcp_select_initial_window() during 3WHS.
For instance, tcp_mmap was negotiating wscale 4, regardless
of tcp_rmem[2] and sysctl_rmem_max.
Do not change tp->window_clamp if it is zero
or bigger than our computed value.
Zero value is special, it allows tcp_select_initial_window()
to enable autotuning.
Note that SO_RCVLOWAT use on listener is probably not wise,
because tp->scaling_ratio has a default value, possibly wrong.
Fixes: d1361840f8 ("tcp: fix SO_RCVLOWAT and RCVBUF autotuning")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20251003184119.2526655-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5f92385309 ]
If the receive queue contains payload that was already
received, __tcp_close() can send an unexpected RST.
Refine the code to take tp->copied_seq into account,
as we already do in tcp recvmsg().
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20250903084720.1168904-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 59f26d86b2 ]
We need to check socket netns before considering them in ping_get_port().
Otherwise, one malicious netns could 'consume' all ports.
Add corresponding check in ping_lookup().
Fixes: c319b4d76b ("net: ipv4: add IPPROTO_ICMP socket kind")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://patch.msgid.link/20250829153054.474201-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 390b3a300d ]
The kernel forbids the creation of non-FDB nexthop groups with FDB
nexthops:
# ip nexthop add id 1 via 192.0.2.1 fdb
# ip nexthop add id 2 group 1
Error: Non FDB nexthop group cannot have fdb nexthops.
And vice versa:
# ip nexthop add id 3 via 192.0.2.2 dev dummy1
# ip nexthop add id 4 group 3 fdb
Error: FDB nexthop group can only have fdb nexthops.
However, as long as no routes are pointing to a non-FDB nexthop group,
the kernel allows changing the type of a nexthop from FDB to non-FDB and
vice versa:
# ip nexthop add id 5 via 192.0.2.2 dev dummy1
# ip nexthop add id 6 group 5
# ip nexthop replace id 5 via 192.0.2.2 fdb
# echo $?
0
This configuration is invalid and can result in a NPD [1] since FDB
nexthops are not associated with a nexthop device:
# ip route add 198.51.100.1/32 nhid 6
# ping 198.51.100.1
Fix by preventing nexthop FDB status change while the nexthop is in a
group:
# ip nexthop add id 7 via 192.0.2.2 dev dummy1
# ip nexthop add id 8 group 7
# ip nexthop replace id 7 via 192.0.2.2 fdb
Error: Cannot change nexthop FDB status while in a group.
[1]
BUG: kernel NULL pointer dereference, address: 00000000000003c0
[...]
Oops: Oops: 0000 [#1] SMP
CPU: 6 UID: 0 PID: 367 Comm: ping Not tainted 6.17.0-rc6-virtme-gb65678cacc03 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
RIP: 0010:fib_lookup_good_nhc+0x1e/0x80
[...]
Call Trace:
<TASK>
fib_table_lookup+0x541/0x650
ip_route_output_key_hash_rcu+0x2ea/0x970
ip_route_output_key_hash+0x55/0x80
__ip4_datagram_connect+0x250/0x330
udp_connect+0x2b/0x60
__sys_connect+0x9c/0xd0
__x64_sys_connect+0x18/0x20
do_syscall_64+0xa4/0x2a0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Fixes: 38428d6871 ("nexthop: support for fdb ecmp nexthops")
Reported-by: syzbot+6596516dd2b635ba2350@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68c9a4d2.050a0220.3c6139.0e63.GAE@google.com/
Tested-by: syzbot+6596516dd2b635ba2350@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250921150824.149157-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2e7bba0892 ]
A NULL pointer dereference can occur in tcp_ao_finish_connect() during a
connect() system call on a socket with a TCP-AO key added and TCP_REPAIR
enabled.
The function is called with skb being NULL and attempts to dereference it
on tcp_hdr(skb)->seq without a prior skb validation.
Fix this by checking if skb is NULL before dereferencing it.
The commentary is taken from bpf_skops_established(), which is also called
in the same flow. Unlike the function being patched,
bpf_skops_established() validates the skb before dereferencing it.
int main(void){
struct sockaddr_in sockaddr;
struct tcp_ao_add tcp_ao;
int sk;
int one = 1;
memset(&sockaddr,'\0',sizeof(sockaddr));
memset(&tcp_ao,'\0',sizeof(tcp_ao));
sk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
sockaddr.sin_family = AF_INET;
memcpy(tcp_ao.alg_name,"cmac(aes128)",12);
memcpy(tcp_ao.key,"ABCDEFGHABCDEFGH",16);
tcp_ao.keylen = 16;
memcpy(&tcp_ao.addr,&sockaddr,sizeof(sockaddr));
setsockopt(sk, IPPROTO_TCP, TCP_AO_ADD_KEY, &tcp_ao,
sizeof(tcp_ao));
setsockopt(sk, IPPROTO_TCP, TCP_REPAIR, &one, sizeof(one));
sockaddr.sin_family = AF_INET;
sockaddr.sin_port = htobe16(123);
inet_aton("127.0.0.1", &sockaddr.sin_addr);
connect(sk,(struct sockaddr *)&sockaddr,sizeof(sockaddr));
return 0;
}
$ gcc tcp-ao-nullptr.c -o tcp-ao-nullptr -Wall
$ unshare -Urn
BUG: kernel NULL pointer dereference, address: 00000000000000b6
PGD 1f648d067 P4D 1f648d067 PUD 1982e8067 PMD 0
Oops: Oops: 0000 [#1] SMP NOPTI
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop
Reference Platform, BIOS 6.00 11/12/2020
RIP: 0010:tcp_ao_finish_connect (net/ipv4/tcp_ao.c:1182)
Fixes: 7c2ffaf21b ("net/tcp: Calculate TCP-AO traffic keys")
Signed-off-by: Anderson Nascimento <anderson@allelesecurity.com>
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250911230743.2551-3-anderson@allelesecurity.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e3c674db35 ]
If a GSO skb is sent through a Geneve tunnel and if Geneve options are
added, the split GSO skb might not fit in the MTU anymore and an ICMP
frag needed packet can be generated. In such case the ICMP packet might
go through the segmentation logic (and dropped) later if it reaches a
path were the GSO status is checked and segmentation is required.
This is especially true when an OvS bridge is used with a Geneve tunnel
attached to it. The following set of actions could lead to the ICMP
packet being wrongfully segmented:
1. An skb is constructed by the TCP layer (e.g. gso_type SKB_GSO_TCPV4,
segs >= 2).
2. The skb hits the OvS bridge where Geneve options are added by an OvS
action before being sent through the tunnel.
3. When the skb is xmited in the tunnel, the split skb does not fit
anymore in the MTU and iptunnel_pmtud_build_icmp is called to
generate an ICMP fragmentation needed packet. This is done by reusing
the original (GSO!) skb. The GSO metadata is not cleared.
4. The ICMP packet being sent back hits the OvS bridge again and because
skb_is_gso returns true, it goes through queue_gso_packets...
5. ...where __skb_gso_segment is called. The skb is then dropped.
6. Note that in the above example on re-transmission the skb won't be a
GSO one as it would be segmented (len > MSS) and the ICMP packet
should go through.
Fix this by resetting the GSO information before reusing an skb in
iptunnel_pmtud_build_icmp and iptunnel_pmtud_build_icmpv6.
Fixes: 4cb47a8644 ("tunnels: PMTU discovery support for directly bridged IP packets")
Reported-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Link: https://patch.msgid.link/20250904125351.159740-1-atenart@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a3967baad4 ]
syzbot reported the splat below. [0]
The repro does the following:
1. Load a sk_msg prog that calls bpf_msg_cork_bytes(msg, cork_bytes)
2. Attach the prog to a SOCKMAP
3. Add a socket to the SOCKMAP
4. Activate fault injection
5. Send data less than cork_bytes
At 5., the data is carried over to the next sendmsg() as it is
smaller than the cork_bytes specified by bpf_msg_cork_bytes().
Then, tcp_bpf_send_verdict() tries to allocate psock->cork to hold
the data, but this fails silently due to fault injection + __GFP_NOWARN.
If the allocation fails, we need to revert the sk->sk_forward_alloc
change done by sk_msg_alloc().
Let's call sk_msg_free() when tcp_bpf_send_verdict fails to allocate
psock->cork.
The "*copied" also needs to be updated such that a proper error can
be returned to the caller, sendmsg. It fails to allocate psock->cork.
Nothing has been corked so far, so this patch simply sets "*copied"
to 0.
[0]:
WARNING: net/ipv4/af_inet.c:156 at inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156, CPU#1: syz-executor/5983
Modules linked in:
CPU: 1 UID: 0 PID: 5983 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:inet_sock_destruct+0x623/0x730 net/ipv4/af_inet.c:156
Code: 0f 0b 90 e9 62 fe ff ff e8 7a db b5 f7 90 0f 0b 90 e9 95 fe ff ff e8 6c db b5 f7 90 0f 0b 90 e9 bb fe ff ff e8 5e db b5 f7 90 <0f> 0b 90 e9 e1 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 9f fc
RSP: 0018:ffffc90000a08b48 EFLAGS: 00010246
RAX: ffffffff8a09d0b2 RBX: dffffc0000000000 RCX: ffff888024a23c80
RDX: 0000000000000100 RSI: 0000000000000fff RDI: 0000000000000000
RBP: 0000000000000fff R08: ffff88807e07c627 R09: 1ffff1100fc0f8c4
R10: dffffc0000000000 R11: ffffed100fc0f8c5 R12: ffff88807e07c380
R13: dffffc0000000000 R14: ffff88807e07c60c R15: 1ffff1100fc0f872
FS: 00005555604c4500(0000) GS:ffff888125af1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555604df5c8 CR3: 0000000032b06000 CR4: 00000000003526f0
Call Trace:
<IRQ>
__sk_destruct+0x86/0x660 net/core/sock.c:2339
rcu_do_batch kernel/rcu/tree.c:2605 [inline]
rcu_core+0xca8/0x1770 kernel/rcu/tree.c:2861
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
</IRQ>
Fixes: 4f738adba3 ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data")
Reported-by: syzbot+4cabd1d2fa917a456db8@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/68c0b6b5.050a0220.3c6139.0013.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250909232623.4151337-1-kuniyu@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a51160f8da ]
The inetdev_init() function never returns NULL. Check for error
pointers instead.
Fixes: 22600596b6 ("ipv4: give an IPv4 dev to blackhole_netdev")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/aLaQWL9NguWmeM1i@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c6dd1aa2cb ]
The icmp_ndo_send function was originally introduced to ensure proper
rate limiting when icmp_send is called by a network device driver,
where the packet's source address may have already been transformed
by SNAT.
However, the original implementation only considers the
IP_CT_DIR_ORIGINAL direction for SNAT and always replaced the packet's
source address with that of the original-direction tuple. This causes
two problems:
1. For SNAT:
Reply-direction packets were incorrectly translated using the source
address of the CT original direction, even though no translation is
required.
2. For DNAT:
Reply-direction packets were not handled at all. In DNAT, the original
direction's destination is translated. Therefore, in the reply
direction the source address must be set to the reply-direction
source, so rate limiting works as intended.
Fix this by using the connection direction to select the correct tuple
for source address translation, and adjust the pre-checks to handle
reply-direction packets in case of DNAT.
Additionally, wrap the `ct->status` access in READ_ONCE(). This avoids
possible KCSAN reports about concurrent updates to `ct->status`.
Fixes: 0b41713b60 ("icmp: introduce helper for nat'd source address in network device context")
Signed-off-by: Fabian Bläse <fabian@blaese.de>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5189446ba9 ]
Commit 9e30ecf23b ("net: ipv4: fix incorrect MTU in broadcast routes")
introduced a regression where local-broadcast packets would have their
gateway set in __mkroute_output, which was caused by fi = NULL being
removed.
Fix this by resetting the fib_info for local-broadcast packets. This
preserves the intended changes for directed-broadcast packets.
Cc: stable@vger.kernel.org
Fixes: 9e30ecf23b ("net: ipv4: fix incorrect MTU in broadcast routes")
Reported-by: Brett A C Sheffield <bacs@librecast.net>
Closes: https://lore.kernel.org/regressions/20250822165231.4353-4-bacs@librecast.net
Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20250827062322.4807-1-oscmaes92@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
