linux-stable.git/drivers/net/ppp, branch v6.15

net: ppp: Add bound checking for skb data on ppp_sync_txmung

2025-04-10T09:24:17+00:00

Ensure we have enough data in linear buffer from skb before accessing
initial bytes. This prevents potential out-of-bounds accesses
when processing short packets.

When ppp_sync_txmung receives an incoming package with an empty
payload:
(remote) gef➤  p *(struct pppoe_hdr *) (skb->head + skb->network_header)
$18 = {
	type = 0x1,
	ver = 0x1,
	code = 0x0,
	sid = 0x2,
        length = 0x0,
	tag = 0xffff8880371cdb96
}

from the skb struct (trimmed)
      tail = 0x16,
      end = 0x140,
      head = 0xffff88803346f400 "4",
      data = 0xffff88803346f416 ":\377",
      truesize = 0x380,
      len = 0x0,
      data_len = 0x0,
      mac_len = 0xe,
      hdr_len = 0x0,

it is not safe to access data[2].

Reported-by: syzbot+29fc8991b0ecb186cf40@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=29fc8991b0ecb186cf40
Tested-by: syzbot+29fc8991b0ecb186cf40@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Arnaud Lecomte 
Link: https://patch.msgid.link/20250408-bound-checking-ppp_txmung-v2-1-94bb6e1b92d0@arnaud-lcm.com
[pabeni@redhat.com: fixed subj typo]
Signed-off-by: Paolo Abeni

net: move misc netdev_lock flavors to a separate header

2025-03-08T17:06:50+00:00

Move the more esoteric helpers for netdev instance lock to
a dedicated header. This avoids growing netdevice.h to infinity
and makes rebuilding the kernel much faster (after touching
the header with the helpers).

The main netdev_lock() / netdev_unlock() functions are used
in static inlines in netdevice.h and will probably be used
most commonly, so keep them in netdevice.h.

Acked-by: Stanislav Fomichev 
Link: https://patch.msgid.link/20250307183006.2312761-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2025-03-06T21:03:35+00:00

Cross-merge networking fixes after downstream PR (net-6.14-rc6).

Conflicts:

net/ethtool/cabletest.c
  2bcf4772e45a ("net: ethtool: try to protect all callback with netdev instance lock")
  637399bf7e77 ("net: ethtool: netlink: Allow NULL nlattrs when getting a phy_device")

No Adjacent changes.

Signed-off-by: Jakub Kicinski

ppp: use IFF_NO_QUEUE in virtual interfaces

2025-03-05T01:11:17+00:00

For PPPoE, PPTP, and PPPoL2TP, the start_xmit() function directly
forwards packets to the underlying network stack and never returns
anything other than 1. So these interfaces do not require a qdisc,
and the IFF_NO_QUEUE flag should be set.

Introduces a direct_xmit flag in struct ppp_channel to indicate when
IFF_NO_QUEUE should be applied. The flag is set in ppp_connect_channel()
for relevant protocols.

While at it, remove the usused latency member from struct ppp_channel.

Signed-off-by: Qingfang Deng 
Reviewed-by: Toke Høiland-Jørgensen 
Link: https://patch.msgid.link/20250301135517.695809-1-dqfext@gmail.com
Signed-off-by: Jakub Kicinski

ppp: Fix KMSAN uninit-value warning with bpf

2025-03-05T00:56:41+00:00

Syzbot caught an "KMSAN: uninit-value" warning [1], which is caused by the
ppp driver not initializing a 2-byte header when using socket filter.

The following code can generate a PPP filter BPF program:
'''
struct bpf_program fp;
pcap_t *handle;
handle = pcap_open_dead(DLT_PPP_PPPD, 65535);
pcap_compile(handle, &fp, "ip and outbound", 0, 0);
bpf_dump(&fp, 1);
'''
Its output is:
'''
(000) ldh [2]
(001) jeq #0x21 jt 2 jf 5
(002) ldb [0]
(003) jeq #0x1 jt 4 jf 5
(004) ret #65535
(005) ret #0
'''
Wen can find similar code at the following link:
https://github.com/ppp-project/ppp/blob/master/pppd/options.c#L1680
The maintainer of this code repository is also the original maintainer
of the ppp driver.

As you can see the BPF program skips 2 bytes of data and then reads the
'Protocol' field to determine if it's an IP packet. Then it read the first
byte of the first 2 bytes to determine the direction.

The issue is that only the first byte indicating direction is initialized
in current ppp driver code while the second byte is not initialized.

For normal BPF programs generated by libpcap, uninitialized data won't be
used, so it's not a problem. However, for carefully crafted BPF programs,
such as those generated by syzkaller [2], which start reading from offset
0, the uninitialized data will be used and caught by KMSAN.

[1] https://syzkaller.appspot.com/bug?extid=853242d9c9917165d791
[2] https://syzkaller.appspot.com/text?tag=ReproC&x=11994913980000

Cc: Paul Mackerras 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+853242d9c9917165d791@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/bpf/000000000000dea025060d6bc3bc@google.com/
Signed-off-by: Jiayuan Chen 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250228141408.393864-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski

net: Use link/peer netns in newlink() of rtnl_link_ops

2025-02-21T23:28:02+00:00

Add two helper functions - rtnl_newlink_link_net() and
rtnl_newlink_peer_net() for netns fallback logic. Peer netns falls back
to link netns, and link netns falls back to source netns.

Convert the use of params->net in netdevice drivers to one of the helper
functions for clarity.

Signed-off-by: Xiao Liang 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250219125039.18024-4-shaw.leon@gmail.com
Signed-off-by: Jakub Kicinski

rtnetlink: Pack newlink() params into struct

2025-02-21T23:28:02+00:00

There are 4 net namespaces involved when creating links:

 - source netns - where the netlink socket resides,
 - target netns - where to put the device being created,
 - link netns - netns associated with the device (backend),
 - peer netns - netns of peer device.

Currently, two nets are passed to newlink() callback - "src_net"
parameter and "dev_net" (implicitly in net_device). They are set as
follows, depending on netlink attributes in the request.

 +------------+-------------------+---------+---------+
 | peer netns | IFLA_LINK_NETNSID | src_net | dev_net |
 +------------+-------------------+---------+---------+
 |            | absent            | source  | target  |
 | absent     +-------------------+---------+---------+
 |            | present           | link    | link    |
 +------------+-------------------+---------+---------+
 |            | absent            | peer    | target  |
 | present    +-------------------+---------+---------+
 |            | present           | peer    | link    |
 +------------+-------------------+---------+---------+

When IFLA_LINK_NETNSID is present, the device is created in link netns
first and then moved to target netns. This has some side effects,
including extra ifindex allocation, ifname validation and link events.
These could be avoided if we create it in target netns from
the beginning.

On the other hand, the meaning of src_net parameter is ambiguous. It
varies depending on how parameters are passed. It is the effective
link (or peer netns) by design, but some drivers ignore it and use
dev_net instead.

To provide more netns context for drivers, this patch packs existing
newlink() parameters, along with the source netns, link netns and peer
netns, into a struct. The old "src_net" is renamed to "net" to avoid
confusion with real source netns, and will be deprecated later. The use
of src_net are converted to params->net trivially.

Signed-off-by: Xiao Liang 
Reviewed-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20250219125039.18024-3-shaw.leon@gmail.com
Signed-off-by: Jakub Kicinski

ppp: fix ppp_async_encode() illegal access

2024-10-10T15:47:13+00:00

syzbot reported an issue in ppp_async_encode() [1]

In this case, pppoe_sendmsg() is called with a zero size.
Then ppp_async_encode() is called with an empty skb.

BUG: KMSAN: uninit-value in ppp_async_encode drivers/net/ppp/ppp_async.c:545 [inline]
 BUG: KMSAN: uninit-value in ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675
  ppp_async_encode drivers/net/ppp/ppp_async.c:545 [inline]
  ppp_async_push+0xb4f/0x2660 drivers/net/ppp/ppp_async.c:675
  ppp_async_send+0x130/0x1b0 drivers/net/ppp/ppp_async.c:634
  ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2280 [inline]
  ppp_input+0x1f1/0xe60 drivers/net/ppp/ppp_generic.c:2304
  pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379
  sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113
  __release_sock+0x1da/0x330 net/core/sock.c:3072
  release_sock+0x6b/0x250 net/core/sock.c:3626
  pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903
  sock_sendmsg_nosec net/socket.c:729 [inline]
  __sock_sendmsg+0x30f/0x380 net/socket.c:744
  ____sys_sendmsg+0x903/0xb60 net/socket.c:2602
  ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656
  __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742
  __do_sys_sendmmsg net/socket.c:2771 [inline]
  __se_sys_sendmmsg net/socket.c:2768 [inline]
  __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768
  x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
  slab_post_alloc_hook mm/slub.c:4092 [inline]
  slab_alloc_node mm/slub.c:4135 [inline]
  kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4187
  kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
  __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
  alloc_skb include/linux/skbuff.h:1322 [inline]
  sock_wmalloc+0xfe/0x1a0 net/core/sock.c:2732
  pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867
  sock_sendmsg_nosec net/socket.c:729 [inline]
  __sock_sendmsg+0x30f/0x380 net/socket.c:744
  ____sys_sendmsg+0x903/0xb60 net/socket.c:2602
  ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656
  __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742
  __do_sys_sendmmsg net/socket.c:2771 [inline]
  __se_sys_sendmmsg net/socket.c:2768 [inline]
  __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768
  x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 5411 Comm: syz.1.14 Not tainted 6.12.0-rc1-syzkaller-00165-g360c1f1f24c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+1d121645899e7692f92a@syzkaller.appspotmail.com
Signed-off-by: Eric Dumazet 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20241009185802.3763282-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

Merge tag 'net-6.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-10-03T16:44:00+00:00

Pull networking fixes from Paolo Abeni:
 "Including fixes from ieee802154, bluetooth and netfilter.

  Current release - regressions:

   - eth: mlx5: fix wrong reserved field in hca_cap_2 in mlx5_ifc

   - eth: am65-cpsw: fix forever loop in cleanup code

  Current release - new code bugs:

   - eth: mlx5: HWS, fixed double-free in error flow of creating SQ

  Previous releases - regressions:

   - core: avoid potential underflow in qdisc_pkt_len_init() with UFO

   - core: test for not too small csum_start in virtio_net_hdr_to_skb()

   - vrf: revert "vrf: remove unnecessary RCU-bh critical section"

   - bluetooth:
       - fix uaf in l2cap_connect
       - fix possible crash on mgmt_index_removed

   - dsa: improve shutdown sequence

   - eth: mlx5e: SHAMPO, fix overflow of hd_per_wq

   - eth: ip_gre: fix drops of small packets in ipgre_xmit

  Previous releases - always broken:

   - core: fix gso_features_check to check for both
     dev->gso_{ipv4_,}max_size

   - core: fix tcp fraglist segmentation after pull from frag_list

   - netfilter: nf_tables: prevent nf_skb_duplicated corruption

   - sctp: set sk_state back to CLOSED if autobind fails in
     sctp_listen_start

   - mac802154: fix potential RCU dereference issue in
     mac802154_scan_worker

   - eth: fec: restart PPS after link state change"

* tag 'net-6.12-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (48 commits)
  sctp: set sk_state back to CLOSED if autobind fails in sctp_listen_start
  dt-bindings: net: xlnx,axi-ethernet: Add missing reg minItems
  doc: net: napi: Update documentation for napi_schedule_irqoff
  net/ncsi: Disable the ncsi work before freeing the associated structure
  net: phy: qt2025: Fix warning: unused import DeviceId
  gso: fix udp gso fraglist segmentation after pull from frag_list
  bridge: mcast: Fail MDB get request on empty entry
  vrf: revert "vrf: Remove unnecessary RCU-bh critical section"
  net: ethernet: ti: am65-cpsw: Fix forever loop in cleanup code
  net: phy: realtek: Check the index value in led_hw_control_get
  ppp: do not assume bh is held in ppp_channel_bridge_input()
  selftests: rds: move include.sh to TEST_FILES
  net: test for not too small csum_start in virtio_net_hdr_to_skb()
  net: gso: fix tcp fraglist segmentation after pull from frag_list
  ipv4: ip_gre: Fix drops of small packets in ipgre_xmit
  net: stmmac: dwmac4: extend timeout for VLAN Tag register busy bit check
  net: add more sanity checks to qdisc_pkt_len_init()
  net: avoid potential underflow in qdisc_pkt_len_init() with UFO
  net: ethernet: ti: cpsw_ale: Fix warning on some platforms
  net: microchip: Make FDMA config symbol invisible
  ...

ppp: do not assume bh is held in ppp_channel_bridge_input()

2024-10-03T00:24:10+00:00

Networking receive path is usually handled from BH handler.
However, some protocols need to acquire the socket lock, and
packets might be stored in the socket backlog is the socket was
owned by a user process.

In this case, release_sock(), __release_sock(), and sk_backlog_rcv()
might call the sk->sk_backlog_rcv() handler in process context.

sybot caught ppp was not considering this case in
ppp_channel_bridge_input() :

WARNING: inconsistent lock state
6.11.0-rc7-syzkaller-g5f5673607153 #0 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/1/24 [HC0[0]:SC1[1]:HE1:SE0] takes:
 ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]
 ffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
{SOFTIRQ-ON-W} state was registered at:
   lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
   __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
   _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
   spin_lock include/linux/spinlock.h:351 [inline]
   ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]
   ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
   pppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379
   sk_backlog_rcv include/net/sock.h:1111 [inline]
   __release_sock+0x1a8/0x3d8 net/core/sock.c:3004
   release_sock+0x68/0x1b8 net/core/sock.c:3558
   pppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903
   sock_sendmsg_nosec net/socket.c:730 [inline]
   __sock_sendmsg net/socket.c:745 [inline]
   __sys_sendto+0x374/0x4f4 net/socket.c:2204
   __do_sys_sendto net/socket.c:2216 [inline]
   __se_sys_sendto net/socket.c:2212 [inline]
   __arm64_sys_sendto+0xd8/0xf8 net/socket.c:2212
   __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
   invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
   el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
   do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
   el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
   el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
   el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
irq event stamp: 282914
 hardirqs last  enabled at (282914): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
 hardirqs last  enabled at (282914): [] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194
 hardirqs last disabled at (282913): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
 hardirqs last disabled at (282913): [] _raw_spin_lock_irqsave+0x2c/0x7c kernel/locking/spinlock.c:162
 softirqs last  enabled at (282904): [] softirq_handle_end kernel/softirq.c:400 [inline]
 softirqs last  enabled at (282904): [] handle_softirqs+0xa3c/0xbfc kernel/softirq.c:582
 softirqs last disabled at (282909): [] run_ksoftirqd+0x70/0x158 kernel/softirq.c:928

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&pch->downl);
  
    lock(&pch->downl);

 *** DEADLOCK ***

1 lock held by ksoftirqd/1/24:
  #0: ffff80008f74dfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:325

stack backtrace:
CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.11.0-rc7-syzkaller-g5f5673607153 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call trace:
  dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:319
  show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:326
  __dump_stack lib/dump_stack.c:93 [inline]
  dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:119
  dump_stack+0x1c/0x28 lib/dump_stack.c:128
  print_usage_bug+0x698/0x9ac kernel/locking/lockdep.c:4000
 mark_lock_irq+0x980/0xd2c
  mark_lock+0x258/0x360 kernel/locking/lockdep.c:4677
  __lock_acquire+0xf48/0x779c kernel/locking/lockdep.c:5096
  lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759
  __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
  _raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154
  spin_lock include/linux/spinlock.h:351 [inline]
  ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]
  ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304
  ppp_async_process+0x98/0x150 drivers/net/ppp/ppp_async.c:495
  tasklet_action_common+0x318/0x3f4 kernel/softirq.c:785
  tasklet_action+0x68/0x8c kernel/softirq.c:811
  handle_softirqs+0x2e4/0xbfc kernel/softirq.c:554
  run_ksoftirqd+0x70/0x158 kernel/softirq.c:928
  smpboot_thread_fn+0x4b0/0x90c kernel/smpboot.c:164
  kthread+0x288/0x310 kernel/kthread.c:389
  ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860

Fixes: 4cf476ced45d ("ppp: add PPPIOCBRIDGECHAN and PPPIOCUNBRIDGECHAN ioctls")
Reported-by: syzbot+bd8d55ee2acd0a71d8ce@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/66f661e2.050a0220.38ace9.000f.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet 
Cc: Tom Parkin 
Cc: James Chapman 
Link: https://patch.msgid.link/20240927074553.341910-1-edumazet@google.com
Signed-off-by: Jakub Kicinski