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[ Upstream commit 9e30ecf23b1b8f091f7d08b27968dea83aae7908 ]
Currently, __mkroute_output overrules the MTU value configured for
broadcast routes.
This buggy behaviour can be reproduced with:
ip link set dev eth1 mtu 9000
ip route del broadcast 192.168.0.255 dev eth1 proto kernel scope link src 192.168.0.2
ip route add broadcast 192.168.0.255 dev eth1 proto kernel scope link src 192.168.0.2 mtu 1500
The maximum packet size should be 1500, but it is actually 8000:
ping -b 192.168.0.255 -s 8000
Fix __mkroute_output to allow MTU values to be configured for
for broadcast routes (to support a mixed-MTU local-area-network).
Signed-off-by: Oscar Maes <oscmaes92@gmail.com>
Link: https://patch.msgid.link/20250710142714.12986-1-oscmaes92@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 1118aaa3b35157777890fffab91d8c1da841b20b ]
Commit b40c5f4fde22 ("udp: disable inner UDP checksum offloads in
IPsec case") tried to fix checksumming in UFO when the packets are
going through IPsec, so that we can't rely on offloads because the UDP
header and payload will be encrypted.
But when doing a TCP test over VXLAN going through IPsec transport
mode with GSO enabled (esp4_offload module loaded), I'm seeing broken
UDP checksums on the encap after successful decryption.
The skbs get to udp4_ufo_fragment/__skb_udp_tunnel_segment via
__dev_queue_xmit -> validate_xmit_skb -> skb_gso_segment and at this
point we've already dropped the dst (unless the device sets
IFF_XMIT_DST_RELEASE, which is not common), so need_ipsec is false and
we proceed with checksum offload.
Make need_ipsec also check the secpath, which is not dropped on this
callpath.
Fixes: b40c5f4fde22 ("udp: disable inner UDP checksum offloads in IPsec case")
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>
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[ Upstream commit 38d7e444336567bae1c7b21fc18b7ceaaa5643a0 ]
tcp_measure_rcv_mss() is used to update icsk->icsk_ack.rcv_mss
(tcpi_rcv_mss in tcp_info) and tp->scaling_ratio.
Calling it from tcp_data_queue_ofo() makes sure these
fields are updated, and permits a better tuning
of sk->sk_rcvbuf, in the case a new flow receives many ooo
packets.
Fixes: dfa2f0483360 ("tcp: get rid of sysctl_tcp_adv_win_scale")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250711114006.480026-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 2dce8c52a98995c4719def6f88629ab1581c0b82 ]
dst_dev_put() can overwrite dst->output while other
cpus might read this field (for instance from dst_output())
Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.
We will likely need RCU protection in the future.
Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f1c5fd34891a1c242885f48c2e4dc52df180f311 ]
dst_dev_put() can overwrite dst->input while other
cpus might read this field (for instance from dst_input())
Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.
We will likely need full RCU protection later.
Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a041f70e573e185d5d5fdbba53f0db2fbe7257ad ]
If the new coming segment covers more than one skbs in the ofo queue,
and which seq is equal to rcv_nxt, then the sequence range
that is duplicated will be sent as DUP SACK, the detail as below,
in step6, the {501,2001} range is clearly including too much
DUP SACK range, in violation of RFC 2883 rules.
1. client > server: Flags [.], seq 501:1001, ack 1325288529, win 20000, length 500
2. server > client: Flags [.], ack 1, [nop,nop,sack 1 {501:1001}], length 0
3. client > server: Flags [.], seq 1501:2001, ack 1325288529, win 20000, length 500
4. server > client: Flags [.], ack 1, [nop,nop,sack 2 {1501:2001} {501:1001}], length 0
5. client > server: Flags [.], seq 1:2001, ack 1325288529, win 20000, length 2000
6. server > client: Flags [.], ack 2001, [nop,nop,sack 1 {501:2001}], length 0
After this fix, the final ACK is as below:
6. server > client: Flags [.], ack 2001, options [nop,nop,sack 1 {501:1001}], length 0
[edumazet] added a new packetdrill test in the following patch.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: xin.guo <guoxin0309@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250626123420.1933835-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3ac9e29211fa2df5539ba0d742c8fe9fe95fdc79 ]
The referenced commit replaced a call to __xfrm4|6_udp_encap_rcv() with
a custom check for non-ESP markers. But what the called function also
did was setting the transport header to the ESP header. The function
that follows, esp4|6_gro_receive(), relies on that being set when it calls
xfrm_parse_spi(). We have to set the full offset as the skb's head was
not moved yet so adding just the UDP header length won't work.
Fixes: e3fd05777685 ("xfrm: Fix UDP GRO handling for some corner cases")
Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9f735b6f8a77d7be7f8b0765dc93587774832cb1 ]
Since "net: gro: use cb instead of skb->network_header", the skb network
header is no longer set in the GRO path.
This breaks fraglist segmentation, which relies on ip_hdr()/tcp_hdr()
to check for address/port changes.
Fix this regression by selectively setting the network header for merged
segment skbs.
Fixes: 186b1ea73ad8 ("net: gro: use cb instead of skb->network_header")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250705150622.10699-1-nbd@nbd.name
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d3a5f2871adc0c61c61869f37f3e697d97f03d8c ]
Syzkaller reported a bug [1] where sk->sk_forward_alloc can overflow.
When we send data, if an skb exists at the tail of the write queue, the
kernel will attempt to append the new data to that skb. However, the code
that checks for available space in the skb is flawed:
'''
copy = size_goal - skb->len
'''
The types of the variables involved are:
'''
copy: ssize_t (s64 on 64-bit systems)
size_goal: int
skb->len: unsigned int
'''
Due to C's type promotion rules, the signed size_goal is converted to an
unsigned int to match skb->len before the subtraction. The result is an
unsigned int.
When this unsigned int result is then assigned to the s64 copy variable,
it is zero-extended, preserving its non-negative value. Consequently, copy
is always >= 0.
Assume we are sending 2GB of data and size_goal has been adjusted to a
value smaller than skb->len. The subtraction will result in copy holding a
very large positive integer. In the subsequent logic, this large value is
used to update sk->sk_forward_alloc, which can easily cause it to overflow.
The syzkaller reproducer uses TCP_REPAIR to reliably create this
condition. However, this can also occur in real-world scenarios. The
tcp_bound_to_half_wnd() function can also reduce size_goal to a small
value. This would cause the subsequent tcp_wmem_schedule() to set
sk->sk_forward_alloc to a value close to INT_MAX. Further memory
allocation requests would then cause sk_forward_alloc to wrap around and
become negative.
[1]: https://syzkaller.appspot.com/bug?extid=de6565462ab540f50e47
Reported-by: syzbot+de6565462ab540f50e47@syzkaller.appspotmail.com
Fixes: 270a1c3de47e ("tcp: Support MSG_SPLICE_PAGES")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20250707054112.101081-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c2a2ff6b4db55647575260bf2227b0e09d46addb ]
udp_v4_early_demux now returns drop reasons as it either returns 0 or
ip_mc_validate_source, which returns itself a drop reason. However its
use was not converted in ip_rcv_finish_core and the drop reason is
ignored, leading to potentially skipping increasing LINUX_MIB_IPRPFILTER
if the drop reason is SKB_DROP_REASON_IP_RPFILTER.
This is a fix and we're not converting udp_v4_early_demux to explicitly
return a drop reason to ease backports; this can be done as a follow-up.
Fixes: d46f827016d8 ("net: ip: make ip_mc_validate_source() return drop reason")
Cc: Menglong Dong <menglong8.dong@gmail.com>
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/20250701074935.144134-1-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit dbe0ca8da1f62b6252e7be6337209f4d86d4a914 ]
There is a bug with passive TFO sockets returning an invalid NAPI ID 0
from SO_INCOMING_NAPI_ID. Normally this is not an issue, but zero copy
receive relies on a correct NAPI ID to process sockets on the right
queue.
Fix by adding a sk_mark_napi_id_set().
Fixes: e5907459ce7e ("tcp: Record Rx hash and NAPI ID in tcp_child_process")
Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250617212102.175711-5-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d0fa59897e049e84432600e86df82aab3dce7aa5 ]
After the following commit from 2024:
commit e37ab7373696 ("tcp: fix to allow timestamp undo if no retransmits were sent")
...there was buggy behavior where TCP connections without SACK support
could easily see erroneous undo events at the end of fast recovery or
RTO recovery episodes. The erroneous undo events could cause those
connections to suffer repeated loss recovery episodes and high
retransmit rates.
The problem was an interaction between the non-SACK behavior on these
connections and the undo logic. The problem is that, for non-SACK
connections at the end of a loss recovery episode, if snd_una ==
high_seq, then tcp_is_non_sack_preventing_reopen() holds steady in
CA_Recovery or CA_Loss, but clears tp->retrans_stamp to 0. Then upon
the next ACK the "tcp: fix to allow timestamp undo if no retransmits
were sent" logic saw the tp->retrans_stamp at 0 and erroneously
concluded that no data was retransmitted, and erroneously performed an
undo of the cwnd reduction, restoring cwnd immediately to the value it
had before loss recovery. This caused an immediate burst of traffic
and build-up of queues and likely another immediate loss recovery
episode.
This commit fixes tcp_packet_delayed() to ignore zero retrans_stamp
values for non-SACK connections when snd_una is at or above high_seq,
because tcp_is_non_sack_preventing_reopen() clears retrans_stamp in
this case, so it's not a valid signal that we can undo.
Note that the commit named in the Fixes footer restored long-present
behavior from roughly 2005-2019, so apparently this bug was present
for a while during that era, and this was simply not caught.
Fixes: e37ab7373696 ("tcp: fix to allow timestamp undo if no retransmits were sent")
Reported-by: Eric Wheeler <netdev@lists.ewheeler.net>
Closes: https://lore.kernel.org/netdev/64ea9333-e7f9-0df-b0f2-8d566143acab@ewheeler.net/
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Co-developed-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 1c0829788a6e6e165846b9bedd0b908ef16260b6 ]
The statistics are incremented with raw_cpu_inc() assuming it always
happens with bottom half disabled. Without per-CPU locking in
local_bh_disable() on PREEMPT_RT this is no longer true.
Use this_cpu_inc() on PREEMPT_RT for the increment to not worry about
preemption.
Cc: David Ahern <dsahern@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-4-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit ea33537d82921e71f852ea2ed985acc562125efe ]
If the application can not drain fast enough a TCP socket queue,
tcp_rcv_space_adjust() can overestimate tp->rcvq_space.space.
Then sk->sk_rcvbuf can grow and hit tcp_rmem[2] for no good reason.
Fix this by taking into acount the number of available bytes.
Keeping sk->sk_rcvbuf at the right size allows better cache efficiency.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Wei Wang <weiwan@google.com>
Link: https://patch.msgid.link/20250513193919.1089692-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit cd171461b90a2d2cf230943df60d580174633718 ]
tcp_rcv_state_process() must tweak tp->advmss for TS enabled flows
before the call to tcp_init_transfer() / tcp_init_buffer_space().
Otherwise tp->rcvq_space.space is off by 120 bytes
(TCP_INIT_CWND * TCPOLEN_TSTAMP_ALIGNED).
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Wei Wang <weiwan@google.com>
Link: https://patch.msgid.link/20250513193919.1089692-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d59fc95be9d0fd05ed3ccc11b4a2f832bdf2ee03 ]
For TCP flows using ms RFC 7323 timestamp granularity
tcp_rcv_rtt_update() can be fed with 1 ms samples, breaking
TCP autotuning for data center flows with sub ms RTT.
Instead, rely on the window based samples, fed by tcp_rcv_rtt_measure()
tcp_rcvbuf_grow() for a 10 second TCP_STREAM sesssion now looks saner.
We can see rcvbuf is kept at a reasonable value.
222.234976: tcp:tcp_rcvbuf_grow: time=348 rtt_us=330 copied=110592 inq=0 space=40960 ooo=0 scaling_ratio=230 rcvbuf=131072 ...
222.235276: tcp:tcp_rcvbuf_grow: time=300 rtt_us=288 copied=126976 inq=0 space=110592 ooo=0 scaling_ratio=230 rcvbuf=246187 ...
222.235569: tcp:tcp_rcvbuf_grow: time=294 rtt_us=288 copied=184320 inq=0 space=126976 ooo=0 scaling_ratio=230 rcvbuf=282659 ...
222.235833: tcp:tcp_rcvbuf_grow: time=264 rtt_us=244 copied=373760 inq=0 space=184320 ooo=0 scaling_ratio=230 rcvbuf=410312 ...
222.236142: tcp:tcp_rcvbuf_grow: time=308 rtt_us=219 copied=424960 inq=20480 space=373760 ooo=0 scaling_ratio=230 rcvbuf=832022 ...
222.236378: tcp:tcp_rcvbuf_grow: time=236 rtt_us=219 copied=692224 inq=49152 space=404480 ooo=0 scaling_ratio=230 rcvbuf=900407 ...
222.236602: tcp:tcp_rcvbuf_grow: time=225 rtt_us=219 copied=730112 inq=49152 space=643072 ooo=0 scaling_ratio=230 rcvbuf=1431534 ...
222.237050: tcp:tcp_rcvbuf_grow: time=229 rtt_us=219 copied=1160192 inq=49152 space=680960 ooo=0 scaling_ratio=230 rcvbuf=1515876 ...
222.237618: tcp:tcp_rcvbuf_grow: time=305 rtt_us=218 copied=2228224 inq=49152 space=1111040 ooo=0 scaling_ratio=230 rcvbuf=2473271 ...
222.238591: tcp:tcp_rcvbuf_grow: time=224 rtt_us=218 copied=3063808 inq=360448 space=2179072 ooo=0 scaling_ratio=230 rcvbuf=4850803 ...
222.240647: tcp:tcp_rcvbuf_grow: time=260 rtt_us=218 copied=2752512 inq=0 space=2703360 ooo=0 scaling_ratio=230 rcvbuf=6017914 ...
222.243535: tcp:tcp_rcvbuf_grow: time=224 rtt_us=218 copied=2834432 inq=49152 space=2752512 ooo=0 scaling_ratio=230 rcvbuf=6127331 ...
222.245108: tcp:tcp_rcvbuf_grow: time=240 rtt_us=218 copied=2883584 inq=49152 space=2785280 ooo=0 scaling_ratio=230 rcvbuf=6200275 ...
222.245333: tcp:tcp_rcvbuf_grow: time=224 rtt_us=218 copied=2859008 inq=0 space=2834432 ooo=0 scaling_ratio=230 rcvbuf=6309692 ...
222.301021: tcp:tcp_rcvbuf_grow: time=222 rtt_us=218 copied=2883584 inq=0 space=2859008 ooo=0 scaling_ratio=230 rcvbuf=6364400 ...
222.989242: tcp:tcp_rcvbuf_grow: time=225 rtt_us=218 copied=2899968 inq=0 space=2883584 ooo=0 scaling_ratio=230 rcvbuf=6419108 ...
224.139553: tcp:tcp_rcvbuf_grow: time=224 rtt_us=218 copied=3014656 inq=65536 space=2899968 ooo=0 scaling_ratio=230 rcvbuf=6455580 ...
224.584608: tcp:tcp_rcvbuf_grow: time=232 rtt_us=218 copied=3014656 inq=49152 space=2949120 ooo=0 scaling_ratio=230 rcvbuf=6564997 ...
230.145560: tcp:tcp_rcvbuf_grow: time=223 rtt_us=218 copied=2981888 inq=0 space=2965504 ooo=0 scaling_ratio=230 rcvbuf=6601469 ...
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Wei Wang <weiwan@google.com>
Link: https://patch.msgid.link/20250513193919.1089692-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b879dcb1aeeca278eacaac0b1e2425b1c7599f9f ]
tcp_rcv_rtt_update() goal is to maintain an estimation of the RTT
in tp->rcv_rtt_est.rtt_us, used by tcp_rcv_space_adjust()
When TCP TS are enabled, tcp_rcv_rtt_update() is using
EWMA to smooth the samples.
Change this to immediately latch the incoming value if it
is lower than tp->rcv_rtt_est.rtt_us, so that tcp_rcv_space_adjust()
does not overshoot tp->rcvq_space.space and sk->sk_rcvbuf.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250513193919.1089692-8-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3382a1ed7f778db841063f5d7e317ac55f9e7f72 ]
Commit a1e40ac5b5e9 ("net: gso: fix udp gso fraglist segmentation after
pull from frag_list") detected invalid geometry in frag_list skbs and
redirects them from skb_segment_list to more robust skb_segment. But some
packets with modified geometry can also hit bugs in that code. We don't
know how many such cases exist. Addressing each one by one also requires
touching the complex skb_segment code, which risks introducing bugs for
other types of skbs. Instead, linearize all these packets that fail the
basic invariants on gso fraglist skbs. That is more robust.
If only part of the fraglist payload is pulled into head_skb, it will
always cause exception when splitting skbs by skb_segment. For detailed
call stack information, see below.
Valid SKB_GSO_FRAGLIST skbs
- consist of two or more segments
- the head_skb holds the protocol headers plus first gso_size
- one or more frag_list skbs hold exactly one segment
- all but the last must be gso_size
Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can
modify fraglist skbs, breaking these invariants.
In extreme cases they pull one part of data into skb linear. For UDP,
this causes three payloads with lengths of (11,11,10) bytes were
pulled tail to become (12,10,10) bytes.
The skbs no longer meets the above SKB_GSO_FRAGLIST conditions because
payload was pulled into head_skb, it needs to be linearized before pass
to regular skb_segment.
skb_segment+0xcd0/0xd14
__udp_gso_segment+0x334/0x5f4
udp4_ufo_fragment+0x118/0x15c
inet_gso_segment+0x164/0x338
skb_mac_gso_segment+0xc4/0x13c
__skb_gso_segment+0xc4/0x124
validate_xmit_skb+0x9c/0x2c0
validate_xmit_skb_list+0x4c/0x80
sch_direct_xmit+0x70/0x404
__dev_queue_xmit+0x64c/0xe5c
neigh_resolve_output+0x178/0x1c4
ip_finish_output2+0x37c/0x47c
__ip_finish_output+0x194/0x240
ip_finish_output+0x20/0xf4
ip_output+0x100/0x1a0
NF_HOOK+0xc4/0x16c
ip_forward+0x314/0x32c
ip_rcv+0x90/0x118
__netif_receive_skb+0x74/0x124
process_backlog+0xe8/0x1a4
__napi_poll+0x5c/0x1f8
net_rx_action+0x154/0x314
handle_softirqs+0x154/0x4b8
[118.376811] [C201134] rxq0_pus: [name:bug&]kernel BUG at net/core/skbuff.c:4278!
[118.376829] [C201134] rxq0_pus: [name:traps&]Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
[118.470774] [C201134] rxq0_pus: [name:mrdump&]Kernel Offset: 0x178cc00000 from 0xffffffc008000000
[118.470810] [C201134] rxq0_pus: [name:mrdump&]PHYS_OFFSET: 0x40000000
[118.470827] [C201134] rxq0_pus: [name:mrdump&]pstate: 60400005 (nZCv daif +PAN -UAO)
[118.470848] [C201134] rxq0_pus: [name:mrdump&]pc : [0xffffffd79598aefc] skb_segment+0xcd0/0xd14
[118.470900] [C201134] rxq0_pus: [name:mrdump&]lr : [0xffffffd79598a5e8] skb_segment+0x3bc/0xd14
[118.470928] [C201134] rxq0_pus: [name:mrdump&]sp : ffffffc008013770
Fixes: a1e40ac5b5e9 ("gso: fix udp gso fraglist segmentation after pull from frag_list")
Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 9a119669fb1924cd9658c16da39a5a585e129e50 ]
fib has two modes:
1. Obtain output device according to source or destination address
2. Obtain the type of the address, e.g. local, unicast, multicast.
'fib daddr type' should return 'local' if the address is configured
in this netns or unicast otherwise.
'fib daddr . iif type' should return 'local' if the address is configured
on the input interface or unicast otherwise, i.e. more restrictive.
However, if the interface is part of a VRF, then 'fib daddr type'
returns unicast even if the address is configured on the incoming
interface.
This is broken for both ipv4 and ipv6.
In the ipv4 case, inet_dev_addr_type must only be used if the
'iif' or 'oif' (strict mode) was requested.
Else inet_addr_type_dev_table() needs to be used and the correct
dev argument must be passed as well so the correct fib (vrf) table
is used.
In the ipv6 case, the bug is similar, without strict mode, dev is NULL
so .flowi6_l3mdev will be set to 0.
Add a new 'nft_fib_l3mdev_master_ifindex_rcu()' helper and use that
to init the .l3mdev structure member.
For ipv6, use it from nft_fib6_flowi_init() which gets called from
both the 'type' and the 'route' mode eval functions.
This provides consistent behaviour for all modes for both ipv4 and ipv6:
If strict matching is requested, the input respectively output device
of the netfilter hooks is used.
Otherwise, use skb->dev to obtain the l3mdev ifindex.
Without this, most type checks in updated nft_fib.sh selftest fail:
FAIL: did not find veth0 . 10.9.9.1 . local in fibtype4
FAIL: did not find veth0 . dead:1::1 . local in fibtype6
FAIL: did not find veth0 . dead:9::1 . local in fibtype6
FAIL: did not find tvrf . 10.0.1.1 . local in fibtype4
FAIL: did not find tvrf . 10.9.9.1 . local in fibtype4
FAIL: did not find tvrf . dead:1::1 . local in fibtype6
FAIL: did not find tvrf . dead:9::1 . local in fibtype6
FAIL: fib expression address types match (iif in vrf)
(fib errounously returns 'unicast' for all of them, even
though all of these addresses are local to the vrf).
Fixes: f6d0cbcf09c5 ("netfilter: nf_tables: add fib expression")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec
Steffen Klassert says:
====================
pull request (net): ipsec 2025-05-21
1) Fix some missing kfree_skb in the error paths of espintcp.
From Sabrina Dubroca.
2) Fix a reference leak in espintcp.
From Sabrina Dubroca.
3) Fix UDP GRO handling for ESPINUDP.
From Tobias Brunner.
4) Fix ipcomp truesize computation on the receive path.
From Sabrina Dubroca.
5) Sanitize marks before policy/state insertation.
From Paul Chaignon.
* tag 'ipsec-2025-05-21' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec:
xfrm: Sanitize marks before insert
xfrm: ipcomp: fix truesize computation on receive
xfrm: Fix UDP GRO handling for some corner cases
espintcp: remove encap socket caching to avoid reference leak
espintcp: fix skb leaks
====================
Link: https://patch.msgid.link/20250521054348.4057269-1-steffen.klassert@secunet.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Guoyu Yin reported a splat in the ipmr netns cleanup path:
WARNING: CPU: 2 PID: 14564 at net/ipv4/ipmr.c:440 ipmr_free_table net/ipv4/ipmr.c:440 [inline]
WARNING: CPU: 2 PID: 14564 at net/ipv4/ipmr.c:440 ipmr_rules_exit+0x135/0x1c0 net/ipv4/ipmr.c:361
Modules linked in:
CPU: 2 UID: 0 PID: 14564 Comm: syz.4.838 Not tainted 6.14.0 #1
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:ipmr_free_table net/ipv4/ipmr.c:440 [inline]
RIP: 0010:ipmr_rules_exit+0x135/0x1c0 net/ipv4/ipmr.c:361
Code: ff df 48 c1 ea 03 80 3c 02 00 75 7d 48 c7 83 60 05 00 00 00 00 00 00 5b 5d 41 5c 41 5d 41 5e e9 71 67 7f 00 e8 4c 2d 8a fd 90 <0f> 0b 90 eb 93 e8 41 2d 8a fd 0f b6 2d 80 54 ea 01 31 ff 89 ee e8
RSP: 0018:ffff888109547c58 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888108c12dc0 RCX: ffffffff83e09868
RDX: ffff8881022b3300 RSI: ffffffff83e098d4 RDI: 0000000000000005
RBP: ffff888104288000 R08: 0000000000000000 R09: ffffed10211825c9
R10: 0000000000000001 R11: ffff88801816c4a0 R12: 0000000000000001
R13: ffff888108c13320 R14: ffff888108c12dc0 R15: fffffbfff0b74058
FS: 00007f84f39316c0(0000) GS:ffff88811b100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f84f3930f98 CR3: 0000000113b56000 CR4: 0000000000350ef0
Call Trace:
<TASK>
ipmr_net_exit_batch+0x50/0x90 net/ipv4/ipmr.c:3160
ops_exit_list+0x10c/0x160 net/core/net_namespace.c:177
setup_net+0x47d/0x8e0 net/core/net_namespace.c:394
copy_net_ns+0x25d/0x410 net/core/net_namespace.c:516
create_new_namespaces+0x3f6/0xaf0 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0xc3/0x180 kernel/nsproxy.c:228
ksys_unshare+0x78d/0x9a0 kernel/fork.c:3342
__do_sys_unshare kernel/fork.c:3413 [inline]
__se_sys_unshare kernel/fork.c:3411 [inline]
__x64_sys_unshare+0x31/0x40 kernel/fork.c:3411
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xa6/0x1a0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f84f532cc29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f84f3931038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f84f5615fa0 RCX: 00007f84f532cc29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000400
RBP: 00007f84f53fba18 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f84f5615fa0 R15: 00007fff51c5f328
</TASK>
The running kernel has CONFIG_IP_MROUTE_MULTIPLE_TABLES disabled, and
the sanity check for such build is still too loose.
Address the issue consolidating the relevant sanity check in a single
helper regardless of the kernel configuration. Also share it between
the ipv4 and ipv6 code.
Reported-by: Guoyu Yin <y04609127@gmail.com>
Fixes: 50b94204446e ("ipmr: tune the ipmr_can_free_table() checks.")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/372dc261e1bf12742276e1b984fc5a071b7fc5a8.1747321903.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
It is possible for a pointer of type struct inet_timewait_sock to be
returned from the functions __inet_lookup_established() and
__inet6_lookup_established(). This can cause a crash when the
returned pointer is of type struct inet_timewait_sock and
sock_put() is called on it. The following is a crash call stack that
shows sk->sk_wmem_alloc being accessed in sk_free() during the call to
sock_put() on a struct inet_timewait_sock pointer. To avoid this issue,
use sock_gen_put() instead of sock_put() when sk->sk_state
is TCP_TIME_WAIT.
mrdump.ko ipanic() + 120
vmlinux notifier_call_chain(nr_to_call=-1, nr_calls=0) + 132
vmlinux atomic_notifier_call_chain(val=0) + 56
vmlinux panic() + 344
vmlinux add_taint() + 164
vmlinux end_report() + 136
vmlinux kasan_report(size=0) + 236
vmlinux report_tag_fault() + 16
vmlinux do_tag_recovery() + 16
vmlinux __do_kernel_fault() + 88
vmlinux do_bad_area() + 28
vmlinux do_tag_check_fault() + 60
vmlinux do_mem_abort() + 80
vmlinux el1_abort() + 56
vmlinux el1h_64_sync_handler() + 124
vmlinux > 0xFFFFFFC080011294()
vmlinux __lse_atomic_fetch_add_release(v=0xF2FFFF82A896087C)
vmlinux __lse_atomic_fetch_sub_release(v=0xF2FFFF82A896087C)
vmlinux arch_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C)
+ 8
vmlinux raw_atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C)
+ 8
vmlinux atomic_fetch_sub_release(i=1, v=0xF2FFFF82A896087C) + 8
vmlinux __refcount_sub_and_test(i=1, r=0xF2FFFF82A896087C,
oldp=0) + 8
vmlinux __refcount_dec_and_test(r=0xF2FFFF82A896087C, oldp=0) + 8
vmlinux refcount_dec_and_test(r=0xF2FFFF82A896087C) + 8
vmlinux sk_free(sk=0xF2FFFF82A8960700) + 28
vmlinux sock_put() + 48
vmlinux tcp6_check_fraglist_gro() + 236
vmlinux tcp6_gro_receive() + 624
vmlinux ipv6_gro_receive() + 912
vmlinux dev_gro_receive() + 1116
vmlinux napi_gro_receive() + 196
ccmni.ko ccmni_rx_callback() + 208
ccmni.ko ccmni_queue_recv_skb() + 388
ccci_dpmaif.ko dpmaif_rxq_push_thread() + 1088
vmlinux kthread() + 268
vmlinux 0xFFFFFFC08001F30C()
Fixes: c9d1d23e5239 ("net: add heuristic for enabling TCP fraglist GRO")
Signed-off-by: Jibin Zhang <jibin.zhang@mediatek.com>
Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250429020412.14163-1-shiming.cheng@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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If any address or port is changed, update it in all packets and recalculate
checksum.
Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250426153210.14044-1-nbd@nbd.name
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
This fixes an issue that's caused if there is a mismatch between the data
offset in the GRO header and the length fields in the regular sk_buff due
to the pskb_pull()/skb_push() calls. That's because the UDP GRO layer
stripped off the UDP header via skb_gro_pull() already while the UDP
header was explicitly not pulled/pushed in this function.
For example, an IKE packet that triggered this had len=data_len=1268 and
the data_offset in the GRO header was 28 (IPv4 + UDP). So pskb_pull()
was called with an offset of 28-8=20, which reduced len to 1248 and via
pskb_may_pull() and __pskb_pull_tail() it also set data_len to 1248.
As the ESP offload module was not loaded, the function bailed out and
called skb_push(), which restored len to 1268, however, data_len remained
at 1248.
So while skb_headlen() was 0 before, it was now 20. The latter caused a
difference of 8 instead of 28 (or 0 if pskb_pull()/skb_push() was called
with the complete GRO data_offset) in gro_try_pull_from_frag0() that
triggered a call to gro_pull_from_frag0() that corrupted the packet.
This change uses a more GRO-like approach seen in other GRO receivers
via skb_gro_header() to just read the actual data we are interested in
and does not try to "restore" the UDP header at this point to call the
existing function. If the offload module is not loaded, it immediately
bails out, otherwise, it only does a quick check to see if the packet
is an IKE or keepalive packet instead of calling the existing function.
Fixes: 172bf009c18d ("xfrm: Support GRO for IPv4 ESP in UDP encapsulation")
Fixes: 221ddb723d90 ("xfrm: Support GRO for IPv6 ESP in UDP encapsulation")
Signed-off-by: Tobias Brunner <tobias@strongswan.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
The current scheme for caching the encap socket can lead to reference
leaks when we try to delete the netns.
The reference chain is: xfrm_state -> enacp_sk -> netns
Since the encap socket is a userspace socket, it holds a reference on
the netns. If we delete the espintcp state (through flush or
individual delete) before removing the netns, the reference on the
socket is dropped and the netns is correctly deleted. Otherwise, the
netns may not be reachable anymore (if all processes within the ns
have terminated), so we cannot delete the xfrm state to drop its
reference on the socket.
This patch results in a small (~2% in my tests) performance
regression.
A GC-type mechanism could be added for the socket cache, to clear
references if the state hasn't been used "recently", but it's a lot
more complex than just not caching the socket.
Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
A few error paths are missing a kfree_skb.
Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
|
|
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
struct geneve_opt uses 5 bit length for each single option, which
means every vary size option should be smaller than 128 bytes.
However, all current related Netlink policies cannot promise this
length condition and the attacker can exploit a exact 128-byte size
option to *fake* a zero length option and confuse the parsing logic,
further achieve heap out-of-bounds read.
One example crash log is like below:
[ 3.905425] ==================================================================
[ 3.905925] BUG: KASAN: slab-out-of-bounds in nla_put+0xa9/0xe0
[ 3.906255] Read of size 124 at addr ffff888005f291cc by task poc/177
[ 3.906646]
[ 3.906775] CPU: 0 PID: 177 Comm: poc-oob-read Not tainted 6.1.132 #1
[ 3.907131] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[ 3.907784] Call Trace:
[ 3.907925] <TASK>
[ 3.908048] dump_stack_lvl+0x44/0x5c
[ 3.908258] print_report+0x184/0x4be
[ 3.909151] kasan_report+0xc5/0x100
[ 3.909539] kasan_check_range+0xf3/0x1a0
[ 3.909794] memcpy+0x1f/0x60
[ 3.909968] nla_put+0xa9/0xe0
[ 3.910147] tunnel_key_dump+0x945/0xba0
[ 3.911536] tcf_action_dump_1+0x1c1/0x340
[ 3.912436] tcf_action_dump+0x101/0x180
[ 3.912689] tcf_exts_dump+0x164/0x1e0
[ 3.912905] fw_dump+0x18b/0x2d0
[ 3.913483] tcf_fill_node+0x2ee/0x460
[ 3.914778] tfilter_notify+0xf4/0x180
[ 3.915208] tc_new_tfilter+0xd51/0x10d0
[ 3.918615] rtnetlink_rcv_msg+0x4a2/0x560
[ 3.919118] netlink_rcv_skb+0xcd/0x200
[ 3.919787] netlink_unicast+0x395/0x530
[ 3.921032] netlink_sendmsg+0x3d0/0x6d0
[ 3.921987] __sock_sendmsg+0x99/0xa0
[ 3.922220] __sys_sendto+0x1b7/0x240
[ 3.922682] __x64_sys_sendto+0x72/0x90
[ 3.922906] do_syscall_64+0x5e/0x90
[ 3.923814] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[ 3.924122] RIP: 0033:0x7e83eab84407
[ 3.924331] Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 faf
[ 3.925330] RSP: 002b:00007ffff505e370 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
[ 3.925752] RAX: ffffffffffffffda RBX: 00007e83eaafa740 RCX: 00007e83eab84407
[ 3.926173] RDX: 00000000000001a8 RSI: 00007ffff505e3c0 RDI: 0000000000000003
[ 3.926587] RBP: 00007ffff505f460 R08: 00007e83eace1000 R09: 000000000000000c
[ 3.926977] R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffff505f3c0
[ 3.927367] R13: 00007ffff505f5c8 R14: 00007e83ead1b000 R15: 00005d4fbbe6dcb8
Fix these issues by enforing correct length condition in related
policies.
Fixes: 925d844696d9 ("netfilter: nft_tunnel: add support for geneve opts")
Fixes: 4ece47787077 ("lwtunnel: add options setting and dumping for geneve")
Fixes: 0ed5269f9e41 ("net/sched: add tunnel option support to act_tunnel_key")
Fixes: 0a6e77784f49 ("net/sched: allow flower to match tunnel options")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://patch.msgid.link/20250402165632.6958-1-linma@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Cosmin reports the following deadlock:
dump_stack_lvl+0x62/0x90
print_deadlock_bug+0x274/0x3b0
__lock_acquire+0x1229/0x2470
lock_acquire+0xb7/0x2b0
__mutex_lock+0xa6/0xd20
dev_disable_lro+0x20/0x80
inetdev_init+0x12f/0x1f0
inetdev_event+0x48b/0x870
notifier_call_chain+0x38/0xf0
netif_change_net_namespace+0x72e/0x9f0
do_setlink.isra.0+0xd5/0x1220
rtnl_newlink+0x7ea/0xb50
rtnetlink_rcv_msg+0x459/0x5e0
netlink_rcv_skb+0x54/0x100
netlink_unicast+0x193/0x270
netlink_sendmsg+0x204/0x450
Switch to netif_disable_lro which assumes the caller holds the instance
lock. inetdev_init is called for blackhole device (which sw device and
doesn't grab instance lock) and from REGISTER/UNREGISTER notifiers.
We already hold the instance lock for REGISTER notifier during
netns change and we'll soon hold the lock during other paths.
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Reported-by: Cosmin Ratiu <cratiu@nvidia.com>
Fixes: ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250401163452.622454-2-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Because skb_tunnel_check_pmtu() doesn't handle PACKET_HOST packets,
commit 30a92c9e3d6b ("openvswitch: Set the skbuff pkt_type for proper
pmtud support.") forced skb->pkt_type to PACKET_OUTGOING for
openvswitch packets that are sent using the OVS_ACTION_ATTR_OUTPUT
action. This allowed such packets to invoke the
iptunnel_pmtud_check_icmp() or iptunnel_pmtud_check_icmpv6() helpers
and thus trigger PMTU update on the input device.
However, this also broke other parts of PMTU discovery. Since these
packets don't have the PACKET_HOST type anymore, they won't trigger the
sending of ICMP Fragmentation Needed or Packet Too Big messages to
remote hosts when oversized (see the skb_in->pkt_type condition in
__icmp_send() for example).
These two skb->pkt_type checks are therefore incompatible as one
requires skb->pkt_type to be PACKET_HOST, while the other requires it
to be anything but PACKET_HOST.
It makes sense to not trigger ICMP messages for non-PACKET_HOST packets
as these messages should be generated only for incoming l2-unicast
packets. However there doesn't seem to be any reason for
skb_tunnel_check_pmtu() to ignore PACKET_HOST packets.
Allow both cases to work by allowing skb_tunnel_check_pmtu() to work on
PACKET_HOST packets and not overriding skb->pkt_type in openvswitch
anymore.
Fixes: 30a92c9e3d6b ("openvswitch: Set the skbuff pkt_type for proper pmtud support.")
Fixes: 4cb47a8644cc ("tunnels: PMTU discovery support for directly bridged IP packets")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Tested-by: Aaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/eac941652b86fddf8909df9b3bf0d97bc9444793.1743208264.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Matt Dowling reported a weird UDP memory usage issue.
Under normal operation, the UDP memory usage reported in /proc/net/sockstat
remains close to zero. However, it occasionally spiked to 524,288 pages
and never dropped. Moreover, the value doubled when the application was
terminated. Finally, it caused intermittent packet drops.
We can reproduce the issue with the script below [0]:
1. /proc/net/sockstat reports 0 pages
# cat /proc/net/sockstat | grep UDP:
UDP: inuse 1 mem 0
2. Run the script till the report reaches 524,288
# python3 test.py & sleep 5
# cat /proc/net/sockstat | grep UDP:
UDP: inuse 3 mem 524288 <-- (INT_MAX + 1) >> PAGE_SHIFT
3. Kill the socket and confirm the number never drops
# pkill python3 && sleep 5
# cat /proc/net/sockstat | grep UDP:
UDP: inuse 1 mem 524288
4. (necessary since v6.0) Trigger proto_memory_pcpu_drain()
# python3 test.py & sleep 1 && pkill python3
5. The number doubles
# cat /proc/net/sockstat | grep UDP:
UDP: inuse 1 mem 1048577
The application set INT_MAX to SO_RCVBUF, which triggered an integer
overflow in udp_rmem_release().
When a socket is close()d, udp_destruct_common() purges its receive
queue and sums up skb->truesize in the queue. This total is calculated
and stored in a local unsigned integer variable.
The total size is then passed to udp_rmem_release() to adjust memory
accounting. However, because the function takes a signed integer
argument, the total size can wrap around, causing an overflow.
Then, the released amount is calculated as follows:
1) Add size to sk->sk_forward_alloc.
2) Round down sk->sk_forward_alloc to the nearest lower multiple of
PAGE_SIZE and assign it to amount.
3) Subtract amount from sk->sk_forward_alloc.
4) Pass amount >> PAGE_SHIFT to __sk_mem_reduce_allocated().
When the issue occurred, the total in udp_destruct_common() was 2147484480
(INT_MAX + 833), which was cast to -2147482816 in udp_rmem_release().
At 1) sk->sk_forward_alloc is changed from 3264 to -2147479552, and
2) sets -2147479552 to amount. 3) reverts the wraparound, so we don't
see a warning in inet_sock_destruct(). However, udp_memory_allocated
ends up doubling at 4).
Since commit 3cd3399dd7a8 ("net: implement per-cpu reserves for
memory_allocated"), memory usage no longer doubles immediately after
a socket is close()d because __sk_mem_reduce_allocated() caches the
amount in udp_memory_per_cpu_fw_alloc. However, the next time a UDP
socket receives a packet, the subtraction takes effect, causing UDP
memory usage to double.
This issue makes further memory allocation fail once the socket's
sk->sk_rmem_alloc exceeds net.ipv4.udp_rmem_min, resulting in packet
drops.
To prevent this issue, let's use unsigned int for the calculation and
call sk_forward_alloc_add() only once for the small delta.
Note that first_packet_length() also potentially has the same problem.
[0]:
from socket import *
SO_RCVBUFFORCE = 33
INT_MAX = (2 ** 31) - 1
s = socket(AF_INET, SOCK_DGRAM)
s.bind(('', 0))
s.setsockopt(SOL_SOCKET, SO_RCVBUFFORCE, INT_MAX)
c = socket(AF_INET, SOCK_DGRAM)
c.connect(s.getsockname())
data = b'a' * 100
while True:
c.send(data)
Fixes: f970bd9e3a06 ("udp: implement memory accounting helpers")
Reported-by: Matt Dowling <madowlin@amazon.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250401184501.67377-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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__udp_enqueue_schedule_skb() has the following condition:
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
goto drop;
sk->sk_rcvbuf is initialised by net.core.rmem_default and later can
be configured by SO_RCVBUF, which is limited by net.core.rmem_max,
or SO_RCVBUFFORCE.
If we set INT_MAX to sk->sk_rcvbuf, the condition is always false
as sk->sk_rmem_alloc is also signed int.
Then, the size of the incoming skb is added to sk->sk_rmem_alloc
unconditionally.
This results in integer overflow (possibly multiple times) on
sk->sk_rmem_alloc and allows a single socket to have skb up to
net.core.udp_mem[1].
For example, if we set a large value to udp_mem[1] and INT_MAX to
sk->sk_rcvbuf and flood packets to the socket, we can see multiple
overflows:
# cat /proc/net/sockstat | grep UDP:
UDP: inuse 3 mem 7956736 <-- (7956736 << 12) bytes > INT_MAX * 15
^- PAGE_SHIFT
# ss -uam
State Recv-Q ...
UNCONN -1757018048 ... <-- flipping the sign repeatedly
skmem:(r2537949248,rb2147483646,t0,tb212992,f1984,w0,o0,bl0,d0)
Previously, we had a boundary check for INT_MAX, which was removed by
commit 6a1f12dd85a8 ("udp: relax atomic operation on sk->sk_rmem_alloc").
A complete fix would be to re |
