Описание
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put()
syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending
garbage on the four reserved tcp bits (th->res1)
Use skb_put_zero() to clear the whole TCP header,
as done in nf_reject_ip_tcphdr_put()
BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255
nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255
nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344
nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48
expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288
nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310
__netif_receive_skb_one_core net/core/dev.c:5661 [inline]
__netif_receive_skb+0x1da/0xa00 net/core/dev.c:5775
process_backlog+0x4ad/0xa50 net/core/dev.c:6108
__napi_poll+0xe7/0x980 net/core/dev.c:6772
napi_poll net/core/dev.c:6841 [inline]
net_rx_action+0xa5a/0x19b0 net/core/dev.c:6963
handle_softirqs+0x1ce/0x800 kernel/softirq.c:554
__do_softirq+0x14/0x1a kernel/softirq.c:588
do_softirq+0x9a/0x100 kernel/softirq.c:455
__local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:908 [inline]
__dev_queue_xmit+0x2692/0x5610 net/core/dev.c:4450
dev_queue_xmit include/linux/netdevice.h:3105 [inline]
neigh_resolve_output+0x9ca/0xae0 net/core/neighbour.c:1565
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x2347/0x2ba0 net/ipv6/ip6_output.c:141
__ip6_finish_output net/ipv6/ip6_output.c:215 [inline]
ip6_finish_output+0xbb8/0x14b0 net/ipv6/ip6_output.c:226
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x356/0x620 net/ipv6/ip6_output.c:247
dst_output include/net/dst.h:450 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip6_xmit+0x1ba6/0x25d0 net/ipv6/ip6_output.c:366
inet6_csk_xmit+0x442/0x530 net/ipv6/inet6_connection_sock.c:135
__tcp_transmit_skb+0x3b07/0x4880 net/ipv4/tcp_output.c:1466
tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline]
tcp_connect+0x35b6/0x7130 net/ipv4/tcp_output.c:4143
tcp_v6_connect+0x1bcc/0x1e40 net/ipv6/tcp_ipv6.c:333
__inet_stream_connect+0x2ef/0x1730 net/ipv4/af_inet.c:679
inet_stream_connect+0x6a/0xd0 net/ipv4/af_inet.c:750
__sys_connect_file net/socket.c:2061 [inline]
__sys_connect+0x606/0x690 net/socket.c:2078
__do_sys_connect net/socket.c:2088 [inline]
__se_sys_connect net/socket.c:2085 [inline]
__x64_sys_connect+0x91/0xe0 net/socket.c:2085
x64_sys_call+0x27a5/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:43
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 stored to memory at:
nf_reject_ip6_tcphdr_put+0x60c/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:249
nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344
nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48
expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288
nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:269 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ipv6_rcv+0x29b/0x390 net/ipv6/ip6_input.c:310
__netif_receive_skb_one_core
---truncated---
A flaw was found in the Netfilter and IPV6 functionality in the Linux kernel leading to a leak of 4 random bits. This issue may allow a remote user to preform an unauthorized read of random bits from the server.
Отчет
This issue is considered to be a moderate impact flaw, as the leaked data is a tcp stack and not the whole kernel. It does not seem to affect the availability. A remote user can potentially read 4 bits of random data from the server memory, but has no control of what is in the 4 bits and cannot bring any harm to the server from it.
Меры по смягчению последствий
If IPV6 or netfilter is not being used, then the issue is not applicable. In order to trigger this issue, the local user needs to enable Netfilter and IPV6 (that requires the ability to create user/net namespaces). On non-containerized deployments of Red Hat Enterprise Linux 8, you can disable user namespaces by setting user.max_user_namespaces to 0:
echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf
sysctl -p /etc/sysctl.d/userns.conf
On containerized deployments, such as Red Hat OpenShift Container Platform, do not use this mitigation as this functionality needs to be enabled.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
Показывать по
Дополнительная информация
Статус:
6.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending garbage on the four reserved tcp bits (th->res1) Use skb_put_zero() to clear the whole TCP header, as done in nf_reject_ip_tcphdr_put() BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inlin...
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending garbage on the four reserved tcp bits (th->res1) Use skb_put_zero() to clear the whole TCP header, as done in nf_reject_ip_tcphdr_put() BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netfilt
In the Linux kernel, the following vulnerability has been resolved: n ...
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_reject_ipv6: fix nf_reject_ip6_tcphdr_put() syzbot reported that nf_reject_ip6_tcphdr_put() was possibly sending garbage on the four reserved tcp bits (th->res1) Use skb_put_zero() to clear the whole TCP header, as done in nf_reject_ip_tcphdr_put() BUG: KMSAN: uninit-value in nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_reject_ip6_tcphdr_put+0x688/0x6c0 net/ipv6/netfilter/nf_reject_ipv6.c:255 nf_send_reset6+0xd84/0x15b0 net/ipv6/netfilter/nf_reject_ipv6.c:344 nft_reject_inet_eval+0x3c1/0x880 net/netfilter/nft_reject_inet.c:48 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x438/0x22a0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x41a/0x4f0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xf4/0x400 net/netfilter/core.c:626 nf_hook include/linux/netf...
6.5 Medium
CVSS3