linux.git/drivers/net/netdevsim/bpf.c, branch v6.12.80

netdevsim: fix a race issue related to the operation on bpf_bound_progs list

2026-01-30T09:28:42+00:00

[ Upstream commit b97d5eedf4976cc94321243be83b39efe81a0e15 ]

The netdevsim driver lacks a protection mechanism for operations on the
bpf_bound_progs list. When the nsim_bpf_create_prog() performs
list_add_tail, it is possible that nsim_bpf_destroy_prog() is
simultaneously performs list_del. Concurrent operations on the list may
lead to list corruption and trigger a kernel crash as follows:

[  417.290971] kernel BUG at lib/list_debug.c:62!
[  417.290983] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[  417.290992] CPU: 10 PID: 168 Comm: kworker/10:1 Kdump: loaded Not tainted 6.19.0-rc5 #1
[  417.291003] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[  417.291007] Workqueue: events bpf_prog_free_deferred
[  417.291021] RIP: 0010:__list_del_entry_valid_or_report+0xa7/0xc0
[  417.291034] Code: a8 ff 0f 0b 48 89 fe 48 89 ca 48 c7 c7 48 a1 eb ae e8 ed fb a8 ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 80 a1 eb ae e8 d9 fb a8 ff <0f> 0b 48 89 d1 48 c7 c7 d0 a1 eb ae 48 89 f2 48 89 c6 e8 c2 fb a8
[  417.291040] RSP: 0018:ffffb16a40807df8 EFLAGS: 00010246
[  417.291046] RAX: 000000000000006d RBX: ffff8e589866f500 RCX: 0000000000000000
[  417.291051] RDX: 0000000000000000 RSI: ffff8e59f7b23180 RDI: ffff8e59f7b23180
[  417.291055] RBP: ffffb16a412c9000 R08: 0000000000000000 R09: 0000000000000003
[  417.291059] R10: ffffb16a40807c80 R11: ffffffffaf9edce8 R12: ffff8e594427ac20
[  417.291063] R13: ffff8e59f7b44780 R14: ffff8e58800b7a05 R15: 0000000000000000
[  417.291074] FS:  0000000000000000(0000) GS:ffff8e59f7b00000(0000) knlGS:0000000000000000
[  417.291079] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  417.291083] CR2: 00007fc4083efe08 CR3: 00000001c3626006 CR4: 0000000000770ee0
[  417.291088] PKRU: 55555554
[  417.291091] Call Trace:
[  417.291096]  
[  417.291103]  nsim_bpf_destroy_prog+0x31/0x80 [netdevsim]
[  417.291154]  __bpf_prog_offload_destroy+0x2a/0x80
[  417.291163]  bpf_prog_dev_bound_destroy+0x6f/0xb0
[  417.291171]  bpf_prog_free_deferred+0x18e/0x1a0
[  417.291178]  process_one_work+0x18a/0x3a0
[  417.291188]  worker_thread+0x27b/0x3a0
[  417.291197]  ? __pfx_worker_thread+0x10/0x10
[  417.291207]  kthread+0xe5/0x120
[  417.291214]  ? __pfx_kthread+0x10/0x10
[  417.291221]  ret_from_fork+0x31/0x50
[  417.291230]  ? __pfx_kthread+0x10/0x10
[  417.291236]  ret_from_fork_asm+0x1a/0x30
[  417.291246]  

Add a mutex lock, to prevent simultaneous addition and deletion operations
on the list.

Fixes: 31d3ad832948 ("netdevsim: add bpf offload support")
Reported-by: Yinhao Hu 
Reported-by: Kaiyan Mei 
Signed-off-by: Yun Lu 
Link: https://patch.msgid.link/20260116095308.11441-1-luyun_611@163.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

netdevsim: Don't accept device bound programs

2023-11-23T21:04:04+00:00

Commit 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs") introduced
device-bound programs by largely reusing existing offloading infrastructure.
This changed the semantics of 'prog->aux->offload' a bit. Now, it's non-NULL
for both offloaded and device-bound programs.

Instead of looking at 'prog->aux->offload' let's call bpf_prog_is_offloaded
which should be true iff the program is offloaded and not merely device-bound.

Fixes: 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs")
Reported-by: syzbot+44c2416196b7c607f226@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Jakub Kicinski 
Cc: Dipendra Khadka 
Link: https://lore.kernel.org/bpf/20231114045453.1816995-2-sdf@google.com
Signed-off-by: Alexei Starovoitov

bpf: Introduce device-bound XDP programs

2023-01-23T17:38:10+00:00

New flag BPF_F_XDP_DEV_BOUND_ONLY plus all the infra to have a way
to associate a netdev with a BPF program at load time.

netdevsim checks are dropped in favor of generic check in dev_xdp_attach.

Cc: John Fastabend 
Cc: David Ahern 
Cc: Martin KaFai Lau 
Cc: Jakub Kicinski 
Cc: Willem de Bruijn 
Cc: Jesper Dangaard Brouer 
Cc: Anatoly Burakov 
Cc: Alexander Lobakin 
Cc: Magnus Karlsson 
Cc: Maryam Tahhan 
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev 
Link: https://lore.kernel.org/r/20230119221536.3349901-6-sdf@google.com
Signed-off-by: Martin KaFai Lau

netdevsim: Avoid allocation warnings triggered from user space

2022-07-29T21:57:26+00:00

We need to suppress warnings from sily map sizes. Also switch
from GFP_USER to GFP_KERNEL_ACCOUNT, I'm pretty sure I misunderstood
the flags when writing this code.

Fixes: 395cacb5f1a0 ("netdevsim: bpf: support fake map offload")
Reported-by: syzbot+ad24705d3fd6463b18c6@syzkaller.appspotmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20220726213605.154204-1-kuba@kernel.org

netdevsim: Zero-initialize memory for new map's value in function nsim_bpf_map_alloc

2021-12-16T01:49:13+00:00

Zero-initialize memory for new map's value in function nsim_bpf_map_alloc
since it may cause a potential kernel information leak issue, as follows:
1. nsim_bpf_map_alloc calls nsim_map_alloc_elem to allocate elements for
a new map.
2. nsim_map_alloc_elem uses kmalloc to allocate map's value, but doesn't
zero it.
3. A user application can use IOCTL BPF_MAP_LOOKUP_ELEM to get specific
element's information in the map.
4. The kernel function map_lookup_elem will call bpf_map_copy_value to get
the information allocated at step-2, then use copy_to_user to copy to the
user buffer.
This can only leak information for an array map.

Fixes: 395cacb5f1a0 ("netdevsim: bpf: support fake map offload")
Suggested-by: Jakub Kicinski 
Acked-by: Jakub Kicinski 
Signed-off-by: Haimin Zhang 
Link: https://lore.kernel.org/r/20211215111530.72103-1-tcs.kernel@gmail.com
Signed-off-by: Jakub Kicinski

netdevsim: Add debugfs toggle to reject BPF programs in verifier

2020-12-09T15:27:42+00:00

This adds a new debugfs toggle ('bpf_bind_verifier_accept') that can be
used to make netdevsim reject BPF programs from being accepted by the
verifier. If this toggle (which defaults to true) is set to false,
nsim_bpf_verify_insn() will return EOPNOTSUPP on the last
instruction (after outputting the 'Hello from netdevsim' verifier message).

This makes it possible to check the verification callback in the driver
from test_offload.py in selftests, since the verifier now clears the
verifier log on a successful load, hiding the message from the driver.

Fixes: 6f8a57ccf851 ("bpf: Make verifier log more relevant by default")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Daniel Borkmann 
Acked-by: Jakub Kicinski 
Link: https://lore.kernel.org/bpf/160752225964.110217.12584017165318065332.stgit@toke.dk

xdp: Remove the xdp_attachment_flags_ok() callback

2020-12-09T15:27:42+00:00

Since commit 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF
programs in net_device"), the XDP program attachment info is now maintained
in the core code. This interacts badly with the xdp_attachment_flags_ok()
check that prevents unloading an XDP program with different load flags than
it was loaded with. In practice, two kinds of failures are seen:

- An XDP program loaded without specifying a mode (and which then ends up
  in driver mode) cannot be unloaded if the program mode is specified on
  unload.

- The dev_xdp_uninstall() hook always calls the driver callback with the
  mode set to the type of the program but an empty flags argument, which
  means the flags_ok() check prevents the program from being removed,
  leading to bpf prog reference leaks.

The original reason this check was added was to avoid ambiguity when
multiple programs were loaded. With the way the checks are done in the core
now, this is quite simple to enforce in the core code, so let's add a check
there and get rid of the xdp_attachment_flags_ok() callback entirely.

Fixes: 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device")
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: Daniel Borkmann 
Acked-by: Jakub Kicinski 
Link: https://lore.kernel.org/bpf/160752225751.110217.10267659521308669050.stgit@toke.dk

bpf, xdp: Remove XDP_QUERY_PROG and XDP_QUERY_PROG_HW XDP commands

2020-07-26T03:37:02+00:00

Now that BPF program/link management is centralized in generic net_device
code, kernel code never queries program id from drivers, so
XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary.

This patch removes all the implementations of those commands in kernel, along
the xdp_attachment_query().

This patch was compile-tested on allyesconfig.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

netdevsim: use IS_ERR instead of IS_ERR_OR_NULL for debugfs

2020-02-03T23:32:20+00:00

Debugfs APIs return valid pointer or error pointer. it doesn't return NULL.
So, using IS_ERR is enough, not using IS_ERR_OR_NULL.

Reviewed-by: Jakub Kicinski 
Reported-by: kbuild test robot 
Reported-by: Dan Carpenter 
Signed-off-by: Taehee Yoo 
Signed-off-by: Jakub Kicinski

netdevsim: move netdev creation/destruction to dev probe

2019-04-26T05:52:03+00:00

Remove the existing way to create netdevsim over rtnetlink and move the
netdev creation/destruction to dev probe, so for every probed port,
a netdevsim-netdev instance is created.

Adjust selftests to work with new interface.

Signed-off-by: Jiri Pirko 
Signed-off-by: David S. Miller