In the Linux kernel, the following vulnerability has been resolved:
icmp6: Fix null-ptr-deref of ip6_null_entry->rt6i_idev in icmp6_dev().
With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that
has the link-local address as src and dst IP and will be forwarded to
an external IP in the IPv6 Ext Hdr.
For example, the script below generates a packet whose src IP is the
link-local address and dst is updated to 11::.
# for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done
# python3
>>> from socket import *
>>> from scapy.all import *
>>>
>>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456"
>>>
>>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR)
>>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1)
>>>
>>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW)
>>> sk.sendto(bytes(pkt), (DST_ADDR, 0))
For such a packet, we call ip6_route_input() to look up a route for the
next destination in these three functions depending on the header type.
* ipv6_rthdr_rcv()
* ipv6_rpl_srh_rcv()
* ipv6_srh_rcv()
If no route is found, ip6_null_entry is set to skb, and the following
dst_input(skb) calls ip6_pkt_drop().
Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev
as the input device is the loopback interface. Then, we have to check if
skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref
for ip6_null_entry.
BUG: kernel NULL pointer dereference, address: 0000000000000000
PF: supervisor read access in kernel mode
PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503)
Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01
RSP: 0018:ffffc90000003c70 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0
RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18
RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001
R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10
R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0
FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0
PKRU: 55555554
Call Trace:
<IRQ>
ip6_pkt_drop (net/ipv6/route.c:4513)
ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686)
ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5))
ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483)
__netif_receive_skb_one_core (net/core/dev.c:5455)
process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895)
__napi_poll (net/core/dev.c:6460)
net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660)
__do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554)
do_softirq (kernel/softirq.c:454 kernel/softirq.c:441)
</IRQ>
<TASK>
__local_bh_enable_ip (kernel/softirq.c:381)
__dev_queue_xmit (net/core/dev.c:4231)
ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135)
rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914)
sock_sendmsg (net/socket.c:725 net/socket.c:748)
__sys_sendto (net/socket.c:2134)
__x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7f9dc751baea
Code: d8 64 89 02 48 c7 c0 ff f
---truncated---
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Handle pairing of E-switch via uplink un/load APIs
In case user switch a device from switchdev mode to legacy mode, mlx5
first unpair the E-switch and afterwards unload the uplink vport.
From the other hand, in case user remove or reload a device, mlx5
first unload the uplink vport and afterwards unpair the E-switch.
The latter is causing a bug[1], hence, handle pairing of E-switch as
part of uplink un/load APIs.
[1]
In case VF_LAG is used, every tc fdb flow is duplicated to the peer
esw. However, the original esw keeps a pointer to this duplicated
flow, not the peer esw.
e.g.: if user create tc fdb flow over esw0, the flow is duplicated
over esw1, in FW/HW, but in SW, esw0 keeps a pointer to the duplicated
flow.
During module unload while a peer tc fdb flow is still offloaded, in
case the first device to be removed is the peer device (esw1 in the
example above), the peer net-dev is destroyed, and so the mlx5e_priv
is memset to 0.
Afterwards, the peer device is trying to unpair himself from the
original device (esw0 in the example above). Unpair API invoke the
original device to clear peer flow from its eswitch (esw0), but the
peer flow, which is stored over the original eswitch (esw0), is
trying to use the peer mlx5e_priv, which is memset to 0 and result in
bellow kernel-oops.
[ 157.964081 ] BUG: unable to handle page fault for address: 000000000002ce60
[ 157.964662 ] #PF: supervisor read access in kernel mode
[ 157.965123 ] #PF: error_code(0x0000) - not-present page
[ 157.965582 ] PGD 0 P4D 0
[ 157.965866 ] Oops: 0000 [#1] SMP
[ 157.967670 ] RIP: 0010:mlx5e_tc_del_fdb_flow+0x48/0x460 [mlx5_core]
[ 157.976164 ] Call Trace:
[ 157.976437 ] <TASK>
[ 157.976690 ] __mlx5e_tc_del_fdb_peer_flow+0xe6/0x100 [mlx5_core]
[ 157.977230 ] mlx5e_tc_clean_fdb_peer_flows+0x67/0x90 [mlx5_core]
[ 157.977767 ] mlx5_esw_offloads_unpair+0x2d/0x1e0 [mlx5_core]
[ 157.984653 ] mlx5_esw_offloads_devcom_event+0xbf/0x130 [mlx5_core]
[ 157.985212 ] mlx5_devcom_send_event+0xa3/0xb0 [mlx5_core]
[ 157.985714 ] esw_offloads_disable+0x5a/0x110 [mlx5_core]
[ 157.986209 ] mlx5_eswitch_disable_locked+0x152/0x170 [mlx5_core]
[ 157.986757 ] mlx5_eswitch_disable+0x51/0x80 [mlx5_core]
[ 157.987248 ] mlx5_unload+0x2a/0xb0 [mlx5_core]
[ 157.987678 ] mlx5_uninit_one+0x5f/0xd0 [mlx5_core]
[ 157.988127 ] remove_one+0x64/0xe0 [mlx5_core]
[ 157.988549 ] pci_device_remove+0x31/0xa0
[ 157.988933 ] device_release_driver_internal+0x18f/0x1f0
[ 157.989402 ] driver_detach+0x3f/0x80
[ 157.989754 ] bus_remove_driver+0x70/0xf0
[ 157.990129 ] pci_unregister_driver+0x34/0x90
[ 157.990537 ] mlx5_cleanup+0xc/0x1c [mlx5_core]
[ 157.990972 ] __x64_sys_delete_module+0x15a/0x250
[ 157.991398 ] ? exit_to_user_mode_prepare+0xea/0x110
[ 157.991840 ] do_syscall_64+0x3d/0x90
[ 157.992198 ] entry_SYSCALL_64_after_hwframe+0x46/0xb0
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix BUG_ON condition in btrfs_cancel_balance
Pausing and canceling balance can race to interrupt balance lead to BUG_ON
panic in btrfs_cancel_balance. The BUG_ON condition in btrfs_cancel_balance
does not take this race scenario into account.
However, the race condition has no other side effects. We can fix that.
Reproducing it with panic trace like this:
kernel BUG at fs/btrfs/volumes.c:4618!
RIP: 0010:btrfs_cancel_balance+0x5cf/0x6a0
Call Trace:
<TASK>
? do_nanosleep+0x60/0x120
? hrtimer_nanosleep+0xb7/0x1a0
? sched_core_clone_cookie+0x70/0x70
btrfs_ioctl_balance_ctl+0x55/0x70
btrfs_ioctl+0xa46/0xd20
__x64_sys_ioctl+0x7d/0xa0
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Race scenario as follows:
> mutex_unlock(&fs_info->balance_mutex);
> --------------------
> .......issue pause and cancel req in another thread
> --------------------
> ret = __btrfs_balance(fs_info);
>
> mutex_lock(&fs_info->balance_mutex);
> if (ret == -ECANCELED && atomic_read(&fs_info->balance_pause_req)) {
> btrfs_info(fs_info, "balance: paused");
> btrfs_exclop_balance(fs_info, BTRFS_EXCLOP_BALANCE_PAUSED);
> }
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Collect command failures data only for known commands
DEVX can issue a general command, which is not used by mlx5 driver.
In case such command is failed, mlx5 is trying to collect the failure
data, However, mlx5 doesn't create a storage for this command, since
mlx5 doesn't use it. This lead to array-index-out-of-bounds error.
Fix it by checking whether the command is known before collecting the
failure data.
In the Linux kernel, the following vulnerability has been resolved:
media: ipu-bridge: Fix null pointer deref on SSDB/PLD parsing warnings
When ipu_bridge_parse_rotation() and ipu_bridge_parse_orientation() run
sensor->adev is not set yet.
So if either of the dev_warn() calls about unknown values are hit this
will lead to a NULL pointer deref.
Set sensor->adev earlier, with a borrowed ref to avoid making unrolling
on errors harder, to fix this.
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: do not write dirty data after degenerating to read-only
According to syzbot's report, mark_buffer_dirty() called from
nilfs_segctor_do_construct() outputs a warning with some patterns after
nilfs2 detects metadata corruption and degrades to read-only mode.
After such read-only degeneration, page cache data may be cleared through
nilfs_clear_dirty_page() which may also clear the uptodate flag for their
buffer heads. However, even after the degeneration, log writes are still
performed by unmount processing etc., which causes mark_buffer_dirty() to
be called for buffer heads without the "uptodate" flag and causes the
warning.
Since any writes should not be done to a read-only file system in the
first place, this fixes the warning in mark_buffer_dirty() by letting
nilfs_segctor_do_construct() abort early if in read-only mode.
This also changes the retry check of nilfs_segctor_write_out() to avoid
unnecessary log write retries if it detects -EROFS that
nilfs_segctor_do_construct() returned.
In the Linux kernel, the following vulnerability has been resolved:
lwt: Fix return values of BPF xmit ops
BPF encap ops can return different types of positive values, such like
NET_RX_DROP, NET_XMIT_CN, NETDEV_TX_BUSY, and so on, from function
skb_do_redirect and bpf_lwt_xmit_reroute. At the xmit hook, such return
values would be treated implicitly as LWTUNNEL_XMIT_CONTINUE in
ip(6)_finish_output2. When this happens, skbs that have been freed would
continue to the neighbor subsystem, causing use-after-free bug and
kernel crashes.
To fix the incorrect behavior, skb_do_redirect return values can be
simply discarded, the same as tc-egress behavior. On the other hand,
bpf_lwt_xmit_reroute returns useful errors to local senders, e.g. PMTU
information. Thus convert its return values to avoid the conflict with
LWTUNNEL_XMIT_CONTINUE.
In the Linux kernel, the following vulnerability has been resolved:
pstore/ram: Check start of empty przs during init
After commit 30696378f68a ("pstore/ram: Do not treat empty buffers as
valid"), initialization would assume a prz was valid after seeing that
the buffer_size is zero (regardless of the buffer start position). This
unchecked start value means it could be outside the bounds of the buffer,
leading to future access panics when written to:
sysdump_panic_event+0x3b4/0x5b8
atomic_notifier_call_chain+0x54/0x90
panic+0x1c8/0x42c
die+0x29c/0x2a8
die_kernel_fault+0x68/0x78
__do_kernel_fault+0x1c4/0x1e0
do_bad_area+0x40/0x100
do_translation_fault+0x68/0x80
do_mem_abort+0x68/0xf8
el1_da+0x1c/0xc0
__raw_writeb+0x38/0x174
__memcpy_toio+0x40/0xac
persistent_ram_update+0x44/0x12c
persistent_ram_write+0x1a8/0x1b8
ramoops_pstore_write+0x198/0x1e8
pstore_console_write+0x94/0xe0
...
To avoid this, also check if the prz start is 0 during the initialization
phase. If not, the next prz sanity check case will discover it (start >
size) and zap the buffer back to a sane state.
[kees: update commit log with backtrace and clarifications]