linux-stable.git/net, branch v6.14.2

ipv6: Do not consider link down nexthops in path selection

2025-04-10T12:44:42+00:00

[ Upstream commit 8b8e0dd357165e0258d9f9cdab5366720ed2f619 ]

Nexthops whose link is down are not supposed to be considered during
path selection when the "ignore_routes_with_linkdown" sysctl is set.
This is done by assigning them a negative region boundary.

However, when comparing the computed hash (unsigned) with the region
boundary (signed), the negative region boundary is treated as unsigned,
resulting in incorrect nexthop selection.

Fix by treating the computed hash as signed. Note that the computed hash
is always in range of [0, 2^31 - 1].

Fixes: 3d709f69a3e7 ("ipv6: Use hash-threshold instead of modulo-N")
Signed-off-by: Ido Schimmel 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250402114224.293392-3-idosch@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: Start path selection from the first nexthop

2025-04-10T12:44:41+00:00

[ Upstream commit 4d0ab3a6885e3e9040310a8d8f54503366083626 ]

Cited commit transitioned IPv6 path selection to use hash-threshold
instead of modulo-N. With hash-threshold, each nexthop is assigned a
region boundary in the multipath hash function's output space and a
nexthop is chosen if the calculated hash is smaller than the nexthop's
region boundary.

Hash-threshold does not work correctly if path selection does not start
with the first nexthop. For example, if fib6_select_path() is always
passed the last nexthop in the group, then it will always be chosen
because its region boundary covers the entire hash function's output
space.

Fix this by starting the selection process from the first nexthop and do
not consider nexthops for which rt6_score_route() provided a negative
score.

Fixes: 3d709f69a3e7 ("ipv6: Use hash-threshold instead of modulo-N")
Reported-by: Stanislav Fomichev 
Closes: https://lore.kernel.org/netdev/Z9RIyKZDNoka53EO@mini-arch/
Signed-off-by: Ido Schimmel 
Link: https://patch.msgid.link/20250402114224.293392-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: fix geneve_opt length integer overflow

2025-04-10T12:44:41+00:00

[ Upstream commit b27055a08ad4b415dcf15b63034f9cb236f7fb40 ]

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]  
[    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 
Reviewed-by: Xin Long 
Acked-by: Cong Wang 
Link: https://patch.msgid.link/20250402165632.6958-1-linma@zju.edu.cn
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: fix omitted netlink attributes when using RTEXT_FILTER_SKIP_STATS

2025-04-10T12:44:41+00:00

[ Upstream commit 7ac6ea4a3e0898db76aecccd68fb2c403eb7d24e ]

Using RTEXT_FILTER_SKIP_STATS is incorrectly skipping non-stats IPv6
netlink attributes on link dump. This causes issues on userspace tools,
e.g iproute2 is not rendering address generation mode as it should due
to missing netlink attribute.

Move the filling of IFLA_INET6_STATS and IFLA_INET6_ICMP6STATS to a
helper function guarded by a flag check to avoid hitting the same
situation in the future.

Fixes: d5566fd72ec1 ("rtnetlink: RTEXT_FILTER_SKIP_STATS support to avoid dumping inet/inet6 stats")
Signed-off-by: Fernando Fernandez Mancera 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250402121751.3108-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: nft_tunnel: fix geneve_opt type confusion addition

2025-04-10T12:44:41+00:00

[ Upstream commit 1b755d8eb1ace3870789d48fbd94f386ad6e30be ]

When handling multiple NFTA_TUNNEL_KEY_OPTS_GENEVE attributes, the
parsing logic should place every geneve_opt structure one by one
compactly. Hence, when deciding the next geneve_opt position, the
pointer addition should be in units of char *.

However, the current implementation erroneously does type conversion
before the addition, which will lead to heap out-of-bounds write.

[    6.989857] ==================================================================
[    6.990293] BUG: KASAN: slab-out-of-bounds in nft_tunnel_obj_init+0x977/0xa70
[    6.990725] Write of size 124 at addr ffff888005f18974 by task poc/178
[    6.991162]
[    6.991259] CPU: 0 PID: 178 Comm: poc-oob-write Not tainted 6.1.132 #1
[    6.991655] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[    6.992281] Call Trace:
[    6.992423]  
[    6.992586]  dump_stack_lvl+0x44/0x5c
[    6.992801]  print_report+0x184/0x4be
[    6.993790]  kasan_report+0xc5/0x100
[    6.994252]  kasan_check_range+0xf3/0x1a0
[    6.994486]  memcpy+0x38/0x60
[    6.994692]  nft_tunnel_obj_init+0x977/0xa70
[    6.995677]  nft_obj_init+0x10c/0x1b0
[    6.995891]  nf_tables_newobj+0x585/0x950
[    6.996922]  nfnetlink_rcv_batch+0xdf9/0x1020
[    6.998997]  nfnetlink_rcv+0x1df/0x220
[    6.999537]  netlink_unicast+0x395/0x530
[    7.000771]  netlink_sendmsg+0x3d0/0x6d0
[    7.001462]  __sock_sendmsg+0x99/0xa0
[    7.001707]  ____sys_sendmsg+0x409/0x450
[    7.002391]  ___sys_sendmsg+0xfd/0x170
[    7.003145]  __sys_sendmsg+0xea/0x170
[    7.004359]  do_syscall_64+0x5e/0x90
[    7.005817]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[    7.006127] RIP: 0033:0x7ec756d4e407
[    7.006339] 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
[    7.007364] RSP: 002b:00007ffed5d46760 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[    7.007827] RAX: ffffffffffffffda RBX: 00007ec756cc4740 RCX: 00007ec756d4e407
[    7.008223] RDX: 0000000000000000 RSI: 00007ffed5d467f0 RDI: 0000000000000003
[    7.008620] RBP: 00007ffed5d468a0 R08: 0000000000000000 R09: 0000000000000000
[    7.009039] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[    7.009429] R13: 00007ffed5d478b0 R14: 00007ec756ee5000 R15: 00005cbd4e655cb8

Fix this bug with correct pointer addition and conversion in parse
and dump code.

Fixes: 925d844696d9 ("netfilter: nft_tunnel: add support for geneve opts")
Signed-off-by: Lin Ma 
Signed-off-by: Pablo Neira Ayuso 
Signed-off-by: Sasha Levin

net: decrease cached dst counters in dst_release

2025-04-10T12:44:41+00:00

[ Upstream commit 3a0a3ff6593d670af2451ec363ccb7b18aec0c0a ]

Upstream fix ac888d58869b ("net: do not delay dst_entries_add() in
dst_release()") moved decrementing the dst count from dst_destroy to
dst_release to avoid accessing already freed data in case of netns
dismantle. However in case CONFIG_DST_CACHE is enabled and OvS+tunnels
are used, this fix is incomplete as the same issue will be seen for
cached dsts:

  Unable to handle kernel paging request at virtual address ffff5aabf6b5c000
  Call trace:
   percpu_counter_add_batch+0x3c/0x160 (P)
   dst_release+0xec/0x108
   dst_cache_destroy+0x68/0xd8
   dst_destroy+0x13c/0x168
   dst_destroy_rcu+0x1c/0xb0
   rcu_do_batch+0x18c/0x7d0
   rcu_core+0x174/0x378
   rcu_core_si+0x18/0x30

Fix this by invalidating the cache, and thus decrementing cached dst
counters, in dst_release too.

Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
Signed-off-by: Antoine Tenart 
Link: https://patch.msgid.link/20250326173634.31096-1-atenart@kernel.org
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

xsk: Fix __xsk_generic_xmit() error code when cq is full

2025-04-10T12:44:41+00:00

[ Upstream commit 5d0b204654de25615cf712be86c3192eca68ed80 ]

When the cq reservation is failed, the error code is not set which is
initialized to zero in __xsk_generic_xmit(). That means the packet is not
send successfully but sendto() return ok.

Considering the impact on uapi, return -EAGAIN is a good idea. The cq is
full usually because it is not released in time, try to send msg again is
appropriate.

The bug was at the very early implementation of xsk, so the Fixes tag
targets the commit that introduced the changes in
xsk_cq_reserve_addr_locked where this fix depends on.

Fixes: e6c4047f5122 ("xsk: Use xsk_buff_pool directly for cq functions")
Suggested-by: Magnus Karlsson 
Signed-off-by: Wang Liang 
Signed-off-by: Martin KaFai Lau 
Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250227081052.4096337-1-wangliang74@huawei.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

tunnels: Accept PACKET_HOST in skb_tunnel_check_pmtu().

2025-04-10T12:44:41+00:00

[ Upstream commit 8930424777e43257f5bf6f0f0f53defd0d30415c ]

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 
Reviewed-by: Stefano Brivio 
Reviewed-by: Aaron Conole 
Tested-by: Aaron Conole 
Link: https://patch.msgid.link/eac941652b86fddf8909df9b3bf0d97bc9444793.1743208264.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

vsock: avoid timeout during connect() if the socket is closing

2025-04-10T12:44:41+00:00

[ Upstream commit fccd2b711d9628c7ce0111d5e4938652101ee30a ]

When a peer attempts to establish a connection, vsock_connect() contains
a loop that waits for the state to be TCP_ESTABLISHED. However, the
other peer can be fast enough to accept the connection and close it
immediately, thus moving the state to TCP_CLOSING.

When this happens, the peer in the vsock_connect() is properly woken up,
but since the state is not TCP_ESTABLISHED, it goes back to sleep
until the timeout expires, returning -ETIMEDOUT.

If the socket state is TCP_CLOSING, waiting for the timeout is pointless.
vsock_connect() can return immediately without errors or delay since the
connection actually happened. The socket will be in a closing state,
but this is not an issue, and subsequent calls will fail as expected.

We discovered this issue while developing a test that accepts and
immediately closes connections to stress the transport switch between
two connect() calls, where the first one was interrupted by a signal
(see Closes link).

Reported-by: Luigi Leonardi 
Closes: https://lore.kernel.org/virtualization/bq6hxrolno2vmtqwcvb5bljfpb7mvwb3kohrvaed6auz5vxrfv@ijmd2f3grobn/
Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Signed-off-by: Stefano Garzarella 
Acked-by: Paolo Abeni 
Tested-by: Luigi Leonardi 
Reviewed-by: Luigi Leonardi 
Link: https://patch.msgid.link/20250328141528.420719-1-sgarzare@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

udp: Fix memory accounting leak.

2025-04-10T12:44:41+00:00

[ Upstream commit df207de9d9e7a4d92f8567e2c539d9c8c12fd99d ]

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 
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/20250401184501.67377-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin