Use bitmap_zalloc() and bitmap_free() instead of hand-writing them. It is less verbose and it improves the type checking and semantic. While at it, add missing header inclusion (should be bitops.h, but with the above change it becomes bitmap.h). Suggested-by: Sergey Ryazanov <ryazanov.s.a@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230911154534.4174265-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
When a PTP ethernet raw frame with a size of more than 256 bytes followed
by a 0xff pattern is sent to __skb_flow_dissect, nhoff value calculation
is wrong. For example: hdr->message_length takes the wrong value (0xffff)
and it does not replicate real header length. In this case, 'nhoff' value
was overridden and the PTP header was badly dissected. This leads to a
kernel crash.
net/core: flow_dissector
net/core flow dissector nhoff = 0x0000000e
net/core flow dissector hdr->message_length = 0x0000ffff
net/core flow dissector nhoff = 0x0001000d (u16 overflow)
...
skb linear: 00000000: 00 a0 c9 00 00 00 00 a0 c9 00 00 00 88
skb frag: 00000000: f7 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Using the size of the ptp_header struct will allow the corrected
calculation of the nhoff value.
net/core flow dissector nhoff = 0x0000000e
net/core flow dissector nhoff = 0x00000030 (sizeof ptp_header)
...
skb linear: 00000000: 00 a0 c9 00 00 00 00 a0 c9 00 00 00 88 f7 ff ff
skb linear: 00000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
skb linear: 00000020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
skb frag: 00000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
Kernel trace:
[ 74.984279] ------------[ cut here ]------------
[ 74.989471] kernel BUG at include/linux/skbuff.h:2440!
[ 74.995237] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 75.001098] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G U 5.15.85-intel-ese-standard-lts #1
[ 75.011629] Hardware name: Intel Corporation A-Island (CPU:AlderLake)/A-Island (ID:06), BIOS SB_ADLP.01.01.00.01.03.008.D-6A9D9E73-dirty Mar 30 2023
[ 75.026507] RIP: 0010:eth_type_trans+0xd0/0x130
[ 75.031594] Code: 03 88 47 78 eb c7 8b 47 68 2b 47 6c 48 8b 97 c0 00 00 00 83 f8 01 7e 1b 48 85 d2 74 06 66 83 3a ff 74 09 b8 00 04 00 00 eb ab <0f> 0b b8 00 01 00 00 eb a2 48 85 ff 74 eb 48 8d 54 24 06 31 f6 b9
[ 75.052612] RSP: 0018:ffff9948c0228de0 EFLAGS: 00010297
[ 75.058473] RAX: 00000000000003f2 RBX: ffff8e47047dc300 RCX: 0000000000001003
[ 75.066462] RDX: ffff8e4e8c9ea040 RSI: ffff8e4704e0a000 RDI: ffff8e47047dc300
[ 75.074458] RBP: ffff8e4704e2acc0 R08: 00000000000003f3 R09: 0000000000000800
[ 75.082466] R10: 000000000000000d R11: ffff9948c0228dec R12: ffff8e4715e4e010
[ 75.090461] R13: ffff9948c0545018 R14: 0000000000000001 R15: 0000000000000800
[ 75.098464] FS: 0000000000000000(0000) GS:ffff8e4e8fb00000(0000) knlGS:0000000000000000
[ 75.107530] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.113982] CR2: 00007f5eb35934a0 CR3: 0000000150e0a002 CR4: 0000000000770ee0
[ 75.121980] PKRU: 55555554
[ 75.125035] Call Trace:
[ 75.127792] <IRQ>
[ 75.130063] ? eth_get_headlen+0xa4/0xc0
[ 75.134472] igc_process_skb_fields+0xcd/0x150
[ 75.139461] igc_poll+0xc80/0x17b0
[ 75.143272] __napi_poll+0x27/0x170
[ 75.147192] net_rx_action+0x234/0x280
[ 75.151409] __do_softirq+0xef/0x2f4
[ 75.155424] irq_exit_rcu+0xc7/0x110
[ 75.159432] common_interrupt+0xb8/0xd0
[ 75.163748] </IRQ>
[ 75.166112] <TASK>
[ 75.168473] asm_common_interrupt+0x22/0x40
[ 75.173175] RIP: 0010:cpuidle_enter_state+0xe2/0x350
[ 75.178749] Code: 85 c0 0f 8f 04 02 00 00 31 ff e8 39 6c 67 ff 45 84 ff 74 12 9c 58 f6 c4 02 0f 85 50 02 00 00 31 ff e8 52 b0 6d ff fb 45 85 f6 <0f> 88 b1 00 00 00 49 63 ce 4c 2b 2c 24 48 89 c8 48 6b d1 68 48 c1
[ 75.199757] RSP: 0018:ffff9948c013bea8 EFLAGS: 00000202
[ 75.205614] RAX: ffff8e4e8fb00000 RBX: ffffb948bfd23900 RCX: 000000000000001f
[ 75.213619] RDX: 0000000000000004 RSI: ffffffff94206161 RDI: ffffffff94212e20
[ 75.221620] RBP: 0000000000000004 R08: 000000117568973a R09: 0000000000000001
[ 75.229622] R10: 000000000000afc8 R11: ffff8e4e8fb29ce4 R12: ffffffff945ae980
[ 75.237628] R13: 000000117568973a R14: 0000000000000004 R15: 0000000000000000
[ 75.245635] ? cpuidle_enter_state+0xc7/0x350
[ 75.250518] cpuidle_enter+0x29/0x40
[ 75.254539] do_idle+0x1d9/0x260
[ 75.258166] cpu_startup_entry+0x19/0x20
[ 75.262582] secondary_startup_64_no_verify+0xc2/0xcb
[ 75.268259] </TASK>
[ 75.270721] Modules linked in: 8021q snd_sof_pci_intel_tgl snd_sof_intel_hda_common tpm_crb snd_soc_hdac_hda snd_sof_intel_hda snd_hda_ext_core snd_sof_pci snd_sof snd_sof_xtensa_dsp snd_soc_acpi_intel_match snd_soc_acpi snd_soc_core snd_compress iTCO_wdt ac97_bus intel_pmc_bxt mei_hdcp iTCO_vendor_support snd_hda_codec_hdmi pmt_telemetry intel_pmc_core pmt_class snd_hda_intel x86_pkg_temp_thermal snd_intel_dspcfg snd_hda_codec snd_hda_core kvm_intel snd_pcm snd_timer kvm snd mei_me soundcore tpm_tis irqbypass i2c_i801 mei tpm_tis_core pcspkr intel_rapl_msr tpm i2c_smbus intel_pmt thermal sch_fq_codel uio uhid i915 drm_buddy video drm_display_helper drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm fuse configfs
[ 75.342736] ---[ end trace 3785f9f360400e3a ]---
[ 75.347913] RIP: 0010:eth_type_trans+0xd0/0x130
[ 75.352984] Code: 03 88 47 78 eb c7 8b 47 68 2b 47 6c 48 8b 97 c0 00 00 00 83 f8 01 7e 1b 48 85 d2 74 06 66 83 3a ff 74 09 b8 00 04 00 00 eb ab <0f> 0b b8 00 01 00 00 eb a2 48 85 ff 74 eb 48 8d 54 24 06 31 f6 b9
[ 75.373994] RSP: 0018:ffff9948c0228de0 EFLAGS: 00010297
[ 75.379860] RAX: 00000000000003f2 RBX: ffff8e47047dc300 RCX: 0000000000001003
[ 75.387856] RDX: ffff8e4e8c9ea040 RSI: ffff8e4704e0a000 RDI: ffff8e47047dc300
[ 75.395864] RBP: ffff8e4704e2acc0 R08: 00000000000003f3 R09: 0000000000000800
[ 75.403857] R10: 000000000000000d R11: ffff9948c0228dec R12: ffff8e4715e4e010
[ 75.411863] R13: ffff9948c0545018 R14: 0000000000000001 R15: 0000000000000800
[ 75.419875] FS: 0000000000000000(0000) GS:ffff8e4e8fb00000(0000) knlGS:0000000000000000
[ 75.428946] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.435403] CR2: 00007f5eb35934a0 CR3: 0000000150e0a002 CR4: 0000000000770ee0
[ 75.443410] PKRU: 55555554
[ 75.446477] Kernel panic - not syncing: Fatal exception in interrupt
[ 75.453738] Kernel Offset: 0x11c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 75.465794] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
Fixes: 4f1cc51f3488 ("net: flow_dissector: Parse PTP L2 packet header")
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking updates from Jakub Kicinski:
"Including fixes from netfilter and bpf.
Current release - regressions:
- eth: stmmac: fix failure to probe without MAC interface specified
Current release - new code bugs:
- docs: netlink: fix missing classic_netlink doc reference
Previous releases - regressions:
- deal with integer overflows in kmalloc_reserve()
- use sk_forward_alloc_get() in sk_get_meminfo()
- bpf_sk_storage: fix the missing uncharge in sk_omem_alloc
- fib: avoid warn splat in flow dissector after packet mangling
- skb_segment: call zero copy functions before using skbuff frags
- eth: sfc: check for zero length in EF10 RX prefix
Previous releases - always broken:
- af_unix: fix msg_controllen test in scm_pidfd_recv() for
MSG_CMSG_COMPAT
- xsk: fix xsk_build_skb() dereferencing possible ERR_PTR()
- netfilter:
- nft_exthdr: fix non-linear header modification
- xt_u32, xt_sctp: validate user space input
- nftables: exthdr: fix 4-byte stack OOB write
- nfnetlink_osf: avoid OOB read
- one more fix for the garbage collection work from last release
- igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU
- bpf, sockmap: fix preempt_rt splat when using raw_spin_lock_t
- handshake: fix null-deref in handshake_nl_done_doit()
- ip: ignore dst hint for multipath routes to ensure packets are
hashed across the nexthops
- phy: micrel:
- correct bit assignments for cable test errata
- disable EEE according to the KSZ9477 errata
Misc:
- docs/bpf: document compile-once-run-everywhere (CO-RE) relocations
- Revert "net: macsec: preserve ingress frame ordering", it appears
to have been developed against an older kernel, problem doesn't
exist upstream"
* tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits)
net: enetc: distinguish error from valid pointers in enetc_fixup_clear_rss_rfs()
Revert "net: team: do not use dynamic lockdep key"
net: hns3: remove GSO partial feature bit
net: hns3: fix the port information display when sfp is absent
net: hns3: fix invalid mutex between tc qdisc and dcb ets command issue
net: hns3: fix debugfs concurrency issue between kfree buffer and read
net: hns3: fix byte order conversion issue in hclge_dbg_fd_tcam_read()
net: hns3: Support query tx timeout threshold by debugfs
net: hns3: fix tx timeout issue
net: phy: Provide Module 4 KSZ9477 errata (DS80000754C)
netfilter: nf_tables: Unbreak audit log reset
netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c
netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction
netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID
netfilter: nfnetlink_osf: avoid OOB read
netfilter: nftables: exthdr: fix 4-byte stack OOB write
selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc
bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc
bpf: bpf_sk_storage: Fix invalid wait context lockdep report
s390/bpf: Pass through tail call counter in trampolines
...
Daniel Borkmann says:
====================
pull-request: bpf 2023-09-06
We've added 9 non-merge commits during the last 6 day(s) which contain
a total of 12 files changed, 189 insertions(+), 44 deletions(-).
The main changes are:
1) Fix bpf_sk_storage to address an invalid wait context lockdep
report and another one to address missing omem uncharge,
from Martin KaFai Lau.
2) Two BPF recursion detection related fixes,
from Sebastian Andrzej Siewior.
3) Fix tailcall limit enforcement in trampolines for s390 JIT,
from Ilya Leoshkevich.
4) Fix a sockmap refcount race where skbs in sk_psock_backlog can
be referenced after user space side has already skb_consumed them,
from John Fastabend.
5) Fix BPF CI flake/race wrt sockmap vsock write test where
the transport endpoint is not connected, from Xu Kuohai.
6) Follow-up doc fix to address a cross-link warning,
from Eduard Zingerman.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc
bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc
bpf: bpf_sk_storage: Fix invalid wait context lockdep report
s390/bpf: Pass through tail call counter in trampolines
bpf: Assign bpf_tramp_run_ctx::saved_run_ctx before recursion check.
bpf: Invoke __bpf_prog_exit_sleepable_recur() on recursion in kern_sys_bpf().
bpf, sockmap: Fix skb refcnt race after locking changes
docs/bpf: Fix "file doesn't exist" warnings in {llvm_reloc,btf}.rst
selftests/bpf: Fix a CI failure caused by vsock write
====================
Link: https://lore.kernel.org/r/20230906095117.16941-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
__skb_get_hash_symmetric() was added to compute a symmetric hash over
the protocol, addresses and transport ports, by commit eb70db875671
("packet: Use symmetric hash for PACKET_FANOUT_HASH."). It uses
flow_keys_dissector_symmetric_keys as the flow_dissector to incorporate
IPv4 addresses, IPv6 addresses and ports. However, it should not specify
the flag as FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL, which stops further
dissection when an IPv6 flow label is encountered, making transport
ports not being incorporated in such case.
As a consequence, the symmetric hash is based on 5-tuple for IPv4 but
3-tuple for IPv6 when flow label is present. It caused a few problems,
e.g. when nft symhash and openvswitch l4_sym rely on the symmetric hash
to perform load balancing as different L4 flows between two given IPv6
addresses would always get the same symmetric hash, leading to uneven
traffic distribution.
Removing the use of FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL makes sure the
symmetric hash is based on 5-tuple for both IPv4 and IPv6 consistently.
Fixes: eb70db875671 ("packet: Use symmetric hash for PACKET_FANOUT_HASH.")
Reported-by: Lars Ekman <uablrek@gmail.com>
Closes: https://github.com/antrea-io/antrea/issues/5457
Signed-off-by: Quan Tian <qtian@vmware.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As with sk->sk_shutdown shown in the previous patch, sk->sk_err can be
read locklessly by unix_dgram_sendmsg().
Let's use READ_ONCE() for sk_err as well.
Note that the writer side is marked by commit cc04410af7de ("af_unix:
annotate lockless accesses to sk->sk_err").
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk->sk_shutdown is changed under unix_state_lock(sk), but
unix_dgram_sendmsg() calls two functions to read sk_shutdown locklessly.
sock_alloc_send_pskb
`- sock_wait_for_wmem
Let's use READ_ONCE() there.
Note that the writer side was marked by commit e1d09c2c2f57 ("af_unix:
Fix data races around sk->sk_shutdown.").
BUG: KCSAN: data-race in sock_alloc_send_pskb / unix_release_sock
write (marked) to 0xffff8880069af12c of 1 bytes by task 1 on cpu 1:
unix_release_sock+0x75c/0x910 net/unix/af_unix.c:631
unix_release+0x59/0x80 net/unix/af_unix.c:1053
__sock_release+0x7d/0x170 net/socket.c:654
sock_close+0x19/0x30 net/socket.c:1386
__fput+0x2a3/0x680 fs/file_table.c:384
____fput+0x15/0x20 fs/file_table.c:412
task_work_run+0x116/0x1a0 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x174/0x180 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:297
do_syscall_64+0x4b/0x90 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
read to 0xffff8880069af12c of 1 bytes by task 28650 on cpu 0:
sock_alloc_send_pskb+0xd2/0x620 net/core/sock.c:2767
unix_dgram_sendmsg+0x2f8/0x14f0 net/unix/af_unix.c:1944
unix_seqpacket_sendmsg net/unix/af_unix.c:2308 [inline]
unix_seqpacket_sendmsg+0xba/0x130 net/unix/af_unix.c:2292
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0x148/0x160 net/socket.c:748
____sys_sendmsg+0x4e4/0x610 net/socket.c:2494
___sys_sendmsg+0xc6/0x140 net/socket.c:2548
__sys_sendmsg+0x94/0x140 net/socket.c:2577
__do_sys_sendmsg net/socket.c:2586 [inline]
__se_sys_sendmsg net/socket.c:2584 [inline]
__x64_sys_sendmsg+0x45/0x50 net/socket.c:2584
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
value changed: 0x00 -> 0x03
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28650 Comm: systemd-coredum Not tainted 6.4.0-11989-g6843306689af #6
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a race where skb's from the sk_psock_backlog can be referenced
after userspace side has already skb_consumed() the sk_buff and its refcnt
dropped to zer0 causing use after free.
The flow is the following:
while ((skb = skb_peek(&psock->ingress_skb))
sk_psock_handle_Skb(psock, skb, ..., ingress)
if (!ingress) ...
sk_psock_skb_ingress
sk_psock_skb_ingress_enqueue(skb)
msg->skb = skb
sk_psock_queue_msg(psock, msg)
skb_dequeue(&psock->ingress_skb)
The sk_psock_queue_msg() puts the msg on the ingress_msg queue. This is
what the application reads when recvmsg() is called. An application can
read this anytime after the msg is placed on the queue. The recvmsg hook
will also read msg->skb and then after user space reads the msg will call
consume_skb(skb) on it effectively free'ing it.
But, the race is in above where backlog queue still has a reference to
the skb and calls skb_dequeue(). If the skb_dequeue happens after the
user reads and free's the skb we have a use after free.
The !ingress case does not suffer from this problem because it uses
sendmsg_*(sk, msg) which does not pass the sk_buff further down the
stack.
The following splat was observed with 'test_progs -t sockmap_listen':
[ 1022.710250][ T2556] general protection fault, ...
[...]
[ 1022.712830][ T2556] Workqueue: events sk_psock_backlog
[ 1022.713262][ T2556] RIP: 0010:skb_dequeue+0x4c/0x80
[ 1022.713653][ T2556] Code: ...
[...]
[ 1022.720699][ T2556] Call Trace:
[ 1022.720984][ T2556] <TASK>
[ 1022.721254][ T2556] ? die_addr+0x32/0x80^M
[ 1022.721589][ T2556] ? exc_general_protection+0x25a/0x4b0
[ 1022.722026][ T2556] ? asm_exc_general_protection+0x22/0x30
[ 1022.722489][ T2556] ? skb_dequeue+0x4c/0x80
[ 1022.722854][ T2556] sk_psock_backlog+0x27a/0x300
[ 1022.723243][ T2556] process_one_work+0x2a7/0x5b0
[ 1022.723633][ T2556] worker_thread+0x4f/0x3a0
[ 1022.723998][ T2556] ? __pfx_worker_thread+0x10/0x10
[ 1022.724386][ T2556] kthread+0xfd/0x130
[ 1022.724709][ T2556] ? __pfx_kthread+0x10/0x10
[ 1022.725066][ T2556] ret_from_fork+0x2d/0x50
[ 1022.725409][ T2556] ? __pfx_kthread+0x10/0x10
[ 1022.725799][ T2556] ret_from_fork_asm+0x1b/0x30
[ 1022.726201][ T2556] </TASK>
To fix we add an skb_get() before passing the skb to be enqueued in the
engress queue. This bumps the skb->users refcnt so that consume_skb()
and kfree_skb will not immediately free the sk_buff. With this we can
be sure the skb is still around when we do the dequeue. Then we just
need to decrement the refcnt or free the skb in the backlog case which
we do by calling kfree_skb() on the ingress case as well as the sendmsg
case.
Before locking change from fixes tag we had the sock locked so we
couldn't race with user and there was no issue here.
Fixes: 799aa7f98d53e ("skmsg: Avoid lock_sock() in sk_psock_backlog()")
Reported-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Xu Kuohai <xukuohai@huawei.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230901202137.214666-1-john.fastabend@gmail.com
Blamed commit changed:
ptr = kmalloc(size);
if (ptr)
size = ksize(ptr);
to:
size = kmalloc_size_roundup(size);
ptr = kmalloc(size);
This allowed various crash as reported by syzbot [1]
and Kyle Zeng.
Problem is that if @size is bigger than 0x80000001,
kmalloc_size_roundup(size) returns 2^32.
kmalloc_reserve() uses a 32bit variable (obj_size),
so 2^32 is truncated to 0.
kmalloc(0) returns ZERO_SIZE_PTR which is not handled by
skb allocations.
Following trace can be triggered if a netdev->mtu is set
close to 0x7fffffff
We might in the future limit netdev->mtu to more sensible
limit (like KMALLOC_MAX_SIZE).
This patch is based on a syzbot report, and also a report
and tentative fix from Kyle Zeng.
[1]
BUG: KASAN: user-memory-access in __build_skb_around net/core/skbuff.c:294 [inline]
BUG: KASAN: user-memory-access in __alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527
Write of size 32 at addr 00000000fffffd10 by task syz-executor.4/22554
CPU: 1 PID: 22554 Comm: syz-executor.4 Not tainted 6.1.39-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call trace:
dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:279
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:286
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x120/0x1a0 lib/dump_stack.c:106
print_report+0xe4/0x4b4 mm/kasan/report.c:398
kasan_report+0x150/0x1ac mm/kasan/report.c:495
kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:189
memset+0x40/0x70 mm/kasan/shadow.c:44
__build_skb_around net/core/skbuff.c:294 [inline]
__alloc_skb+0x3c4/0x6e8 net/core/skbuff.c:527
alloc_skb include/linux/skbuff.h:1316 [inline]
igmpv3_newpack+0x104/0x1088 net/ipv4/igmp.c:359
add_grec+0x81c/0x1124 net/ipv4/igmp.c:534
igmpv3_send_cr net/ipv4/igmp.c:667 [inline]
igmp_ifc_timer_expire+0x1b0/0x1008 net/ipv4/igmp.c:810
call_timer_fn+0x1c0/0x9f0 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers+0x54c/0x710 kernel/time/timer.c:1790
run_timer_softirq+0x28/0x4c kernel/time/timer.c:1803
_stext+0x380/0xfbc
____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:79
call_on_irq_stack+0x24/0x4c arch/arm64/kernel/entry.S:891
do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:84
invoke_softirq kernel/softirq.c:437 [inline]
__irq_exit_rcu+0x1c0/0x4cc kernel/softirq.c:683
irq_exit_rcu+0x14/0x78 kernel/softirq.c:695
el0_interrupt+0x7c/0x2e0 arch/arm64/kernel/entry-common.c:717
__el0_irq_handler_common+0x18/0x24 arch/arm64/kernel/entry-common.c:724
el0t_64_irq_handler+0x10/0x1c arch/arm64/kernel/entry-common.c:729
el0t_64_irq+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Fixes: 12d6c1d3a2ad ("skbuff: Proactively round up to kmalloc bucket size")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: Kyle Zeng <zengyhkyle@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit bf5c25d60861 ("skbuff: in skb_segment, call zerocopy functions
once per nskb") added the call to zero copy functions in skb_segment().
The change introduced a bug in skb_segment() because skb_orphan_frags()
may possibly change the number of fragments or allocate new fragments
altogether leaving nrfrags and frag to point to the old values. This can
cause a panic with stacktrace like the one below.
[ 193.894380] BUG: kernel NULL pointer dereference, address: 00000000000000bc
[ 193.895273] CPU: 13 PID: 18164 Comm: vh-net-17428 Kdump: loaded Tainted: G O 5.15.123+ #26
[ 193.903919] RIP: 0010:skb_segment+0xb0e/0x12f0
[ 194.021892] Call Trace:
[ 194.027422] <TASK>
[ 194.072861] tcp_gso_segment+0x107/0x540
[ 194.082031] inet_gso_segment+0x15c/0x3d0
[ 194.090783] skb_mac_gso_segment+0x9f/0x110
[ 194.095016] __skb_gso_segment+0xc1/0x190
[ 194.103131] netem_enqueue+0x290/0xb10 [sch_netem]
[ 194.107071] dev_qdisc_enqueue+0x16/0x70
[ 194.110884] __dev_queue_xmit+0x63b/0xb30
[ 194.121670] bond_start_xmit+0x159/0x380 [bonding]
[ 194.128506] dev_hard_start_xmit+0xc3/0x1e0
[ 194.131787] __dev_queue_xmit+0x8a0/0xb30
[ 194.138225] macvlan_start_xmit+0x4f/0x100 [macvlan]
[ 194.141477] dev_hard_start_xmit+0xc3/0x1e0
[ 194.144622] sch_direct_xmit+0xe3/0x280
[ 194.147748] __dev_queue_xmit+0x54a/0xb30
[ 194.154131] tap_get_user+0x2a8/0x9c0 [tap]
[ 194.157358] tap_sendmsg+0x52/0x8e0 [tap]
[ 194.167049] handle_tx_zerocopy+0x14e/0x4c0 [vhost_net]
[ 194.173631] handle_tx+0xcd/0xe0 [vhost_net]
[ 194.176959] vhost_worker+0x76/0xb0 [vhost]
[ 194.183667] kthread+0x118/0x140
[ 194.190358] ret_from_fork+0x1f/0x30
[ 194.193670] </TASK>
In this case calling skb_orphan_frags() updated nr_frags leaving nrfrags
local variable in skb_segment() stale. This resulted in the code hitting
i >= nrfrags prematurely and trying to move to next frag_skb using
list_skb pointer, which was NULL, and caused kernel panic. Move the call
to zero copy functions before using frags and nr_frags.
Fixes: bf5c25d60861 ("skbuff: in skb_segment, call zerocopy functions once per nskb")
Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
Reported-by: Amit Goyal <agoyal@purestorage.com>
Cc: stable@vger.kernel.org
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>