linux-stable.git/net/ipv6, branch v6.9.6

net/ipv6: Fix the RT cache flush via sysctl using a previous delay

2024-06-21T12:40:25+00:00

[ Upstream commit 14a20e5b4ad998793c5f43b0330d9e1388446cf3 ]

The net.ipv6.route.flush system parameter takes a value which specifies
a delay used during the flush operation for aging exception routes. The
written value is however not used in the currently requested flush and
instead utilized only in the next one.

A problem is that ipv6_sysctl_rtcache_flush() first reads the old value
of net->ipv6.sysctl.flush_delay into a local delay variable and then
calls proc_dointvec() which actually updates the sysctl based on the
provided input.

Fix the problem by switching the order of the two operations.

Fixes: 4990509f19e8 ("[NETNS][IPV6]: Make sysctls route per namespace.")
Signed-off-by: Petr Pavlu 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20240607112828.30285-1-petr.pavlu@suse.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

tcp: fix race in tcp_v6_syn_recv_sock()

2024-06-21T12:40:21+00:00

[ Upstream commit d37fe4255abe8e7b419b90c5847e8ec2b8debb08 ]

tcp_v6_syn_recv_sock() calls ip6_dst_store() before
inet_sk(newsk)->pinet6 has been set up.

This means ip6_dst_store() writes over the parent (listener)
np->dst_cookie.

This is racy because multiple threads could share the same
parent and their final np->dst_cookie could be wrong.

Move ip6_dst_store() call after inet_sk(newsk)->pinet6
has been changed and after the copy of parent ipv6_pinfo.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet 
Reviewed-by: Simon Horman 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: fix possible race in __fib6_drop_pcpu_from()

2024-06-21T12:40:10+00:00

[ Upstream commit b01e1c030770ff3b4fe37fc7cc6bca03f594133f ]

syzbot found a race in __fib6_drop_pcpu_from() [1]

If compiler reads more than once (*ppcpu_rt),
second read could read NULL, if another cpu clears
the value in rt6_get_pcpu_route().

Add a READ_ONCE() to prevent this race.

Also add rcu_read_lock()/rcu_read_unlock() because
we rely on RCU protection while dereferencing pcpu_rt.

[1]

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097]
CPU: 0 PID: 7543 Comm: kworker/u8:17 Not tainted 6.10.0-rc1-syzkaller-00013-g2bfcfd584ff5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: netns cleanup_net
 RIP: 0010:__fib6_drop_pcpu_from.part.0+0x10a/0x370 net/ipv6/ip6_fib.c:984
Code: f8 48 c1 e8 03 80 3c 28 00 0f 85 16 02 00 00 4d 8b 3f 4d 85 ff 74 31 e8 74 a7 fa f7 49 8d bf 90 00 00 00 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 1e 02 00 00 49 8b 87 90 00 00 00 48 8b 0c 24 48
RSP: 0018:ffffc900040df070 EFLAGS: 00010206
RAX: 0000000000000012 RBX: 0000000000000001 RCX: ffffffff89932e16
RDX: ffff888049dd1e00 RSI: ffffffff89932d7c RDI: 0000000000000091
RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000001 R11: 0000000000000006 R12: ffff88807fa080b8
R13: fffffbfff1a9a07d R14: ffffed100ff41022 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32c26000 CR3: 000000005d56e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 
  __fib6_drop_pcpu_from net/ipv6/ip6_fib.c:966 [inline]
  fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1027 [inline]
  fib6_purge_rt+0x7f2/0x9f0 net/ipv6/ip6_fib.c:1038
  fib6_del_route net/ipv6/ip6_fib.c:1998 [inline]
  fib6_del+0xa70/0x17b0 net/ipv6/ip6_fib.c:2043
  fib6_clean_node+0x426/0x5b0 net/ipv6/ip6_fib.c:2205
  fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2127
  fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2175
  fib6_clean_tree+0xd7/0x120 net/ipv6/ip6_fib.c:2255
  __fib6_clean_all+0x100/0x2d0 net/ipv6/ip6_fib.c:2271
  rt6_sync_down_dev net/ipv6/route.c:4906 [inline]
  rt6_disable_ip+0x7ed/0xa00 net/ipv6/route.c:4911
  addrconf_ifdown.isra.0+0x117/0x1b40 net/ipv6/addrconf.c:3855
  addrconf_notify+0x223/0x19e0 net/ipv6/addrconf.c:3778
  notifier_call_chain+0xb9/0x410 kernel/notifier.c:93
  call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:1992
  call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
  call_netdevice_notifiers net/core/dev.c:2044 [inline]
  dev_close_many+0x333/0x6a0 net/core/dev.c:1585
  unregister_netdevice_many_notify+0x46d/0x19f0 net/core/dev.c:11193
  unregister_netdevice_many net/core/dev.c:11276 [inline]
  default_device_exit_batch+0x85b/0xae0 net/core/dev.c:11759
  ops_exit_list+0x128/0x180 net/core/net_namespace.c:178
  cleanup_net+0x5b7/0xbf0 net/core/net_namespace.c:640
  process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
  process_scheduled_works kernel/workqueue.c:3312 [inline]
  worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
  kthread+0x2c1/0x3a0 kernel/kthread.c:389
  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Fixes: d52d3997f843 ("ipv6: Create percpu rt6_info")
Signed-off-by: Eric Dumazet 
Cc: Martin KaFai Lau 
Link: https://lore.kernel.org/r/20240604193549.981839-1-edumazet@google.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

ipv6: sr: block BH in seg6_output_core() and seg6_input_core()

2024-06-21T12:40:04+00:00

[ Upstream commit c0b98ac1cc104f48763cdb27b1e9ac25fd81fc90 ]

As explained in commit 1378817486d6 ("tipc: block BH
before using dst_cache"), net/core/dst_cache.c
helpers need to be called with BH disabled.

Disabling preemption in seg6_output_core() is not good enough,
because seg6_output_core() is called from process context,
lwtunnel_output() only uses rcu_read_lock().

We might be interrupted by a softirq, re-enter seg6_output_core()
and corrupt dst_cache data structures.

Fix the race by using local_bh_disable() instead of
preempt_disable().

Apply a similar change in seg6_input_core().

Fixes: fa79581ea66c ("ipv6: sr: fix several BUGs when preemption is enabled")
Fixes: 6c8702c60b88 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels")
Signed-off-by: Eric Dumazet 
Cc: David Lebrun 
Acked-by: Paolo Abeni 
Link: https://lore.kernel.org/r/20240531132636.2637995-4-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: ioam: block BH from ioam6_output()

2024-06-21T12:40:04+00:00

[ Upstream commit 2fe40483ec257de2a0d819ef88e3e76c7e261319 ]

As explained in commit 1378817486d6 ("tipc: block BH
before using dst_cache"), net/core/dst_cache.c
helpers need to be called with BH disabled.

Disabling preemption in ioam6_output() is not good enough,
because ioam6_output() is called from process context,
lwtunnel_output() only uses rcu_read_lock().

We might be interrupted by a softirq, re-enter ioam6_output()
and corrupt dst_cache data structures.

Fix the race by using local_bh_disable() instead of
preempt_disable().

Fixes: 8cb3bf8bff3c ("ipv6: ioam: Add support for the ip6ip6 encapsulation")
Signed-off-by: Eric Dumazet 
Cc: Justin Iurman 
Acked-by: Paolo Abeni 
Link: https://lore.kernel.org/r/20240531132636.2637995-2-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net/ipv6: Fix route deleting failure when metric equals 0

2024-06-16T11:51:05+00:00

commit bb487272380d120295e955ad8acfcbb281b57642 upstream.

Problem
=========
After commit 67f695134703 ("ipv6: Move setting default metric for routes"),
we noticed that the logic of assigning the default value of fc_metirc
changed in the ioctl process. That is, when users use ioctl(fd, SIOCADDRT,
rt) with a non-zero metric to add a route,  then they may fail to delete a
route with passing in a metric value of 0 to the kernel by ioctl(fd,
SIOCDELRT, rt). But iproute can succeed in deleting it.

As a reference, when using iproute tools by netlink to delete routes with
a metric parameter equals 0, like the command as follows:

	ip -6 route del fe80::/64 via fe81::5054:ff:fe11:3451 dev eth0 metric 0

the user can still succeed in deleting the route entry with the smallest
metric.

Root Reason
===========
After commit 67f695134703 ("ipv6: Move setting default metric for routes"),
When ioctl() pass in SIOCDELRT with a zero metric, rtmsg_to_fib6_config()
will set a defalut value (1024) to cfg->fc_metric in kernel, and in
ip6_route_del() and the line 4074 at net/ipv3/route.c, it will check by

	if (cfg->fc_metric && cfg->fc_metric != rt->fib6_metric)
		continue;

and the condition is true and skip the later procedure (deleting route)
because cfg->fc_metric != rt->fib6_metric. But before that commit,
cfg->fc_metric is still zero there, so the condition is false and it
will do the following procedure (deleting).

Solution
========
In order to keep a consistent behaviour across netlink() and ioctl(), we
should allow to delete a route with a metric value of 0. So we only do
the default setting of fc_metric in route adding.

CC: stable@vger.kernel.org # 5.4+
Fixes: 67f695134703 ("ipv6: Move setting default metric for routes")
Co-developed-by: Fan Yu 
Signed-off-by: Fan Yu 
Signed-off-by: xu xin 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20240514201102055dD2Ba45qKbLlUMxu_DTHP@zte.com.cn
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: fix __dst_negative_advice() race

2024-06-12T09:39:55+00:00

[ Upstream commit 92f1655aa2b2294d0b49925f3b875a634bd3b59e ]

__dst_negative_advice() does not enforce proper RCU rules when
sk->dst_cache must be cleared, leading to possible UAF.

RCU rules are that we must first clear sk->sk_dst_cache,
then call dst_release(old_dst).

Note that sk_dst_reset(sk) is implementing this protocol correctly,
while __dst_negative_advice() uses the wrong order.

Given that ip6_negative_advice() has special logic
against RTF_CACHE, this means each of the three ->negative_advice()
existing methods must perform the sk_dst_reset() themselves.

Note the check against NULL dst is centralized in
__dst_negative_advice(), there is no need to duplicate
it in various callbacks.

Many thanks to Clement Lecigne for tracking this issue.

This old bug became visible after the blamed commit, using UDP sockets.

Fixes: a87cb3e48ee8 ("net: Facility to report route quality of connected sockets")
Reported-by: Clement Lecigne 
Diagnosed-by: Clement Lecigne 
Signed-off-by: Eric Dumazet 
Cc: Tom Herbert 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20240528114353.1794151-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: introduce dst_rt6_info() helper

2024-06-12T09:39:54+00:00

[ Upstream commit e8dfd42c17faf183415323db1ef0c977be0d6489 ]

Instead of (struct rt6_info *)dst casts, we can use :

 #define dst_rt6_info(_ptr) \
         container_of_const(_ptr, struct rt6_info, dst)

Some places needed missing const qualifiers :

ip6_confirm_neigh(), ipv6_anycast_destination(),
ipv6_unicast_destination(), has_gateway()

v2: added missing parts (David Ahern)

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Stable-dep-of: 92f1655aa2b2 ("net: fix __dst_negative_advice() race")
Signed-off-by: Sasha Levin

ipv6: sr: fix memleak in seg6_hmac_init_algo

2024-06-12T09:39:40+00:00

[ Upstream commit efb9f4f19f8e37fde43dfecebc80292d179f56c6 ]

seg6_hmac_init_algo returns without cleaning up the previous allocations
if one fails, so it's going to leak all that memory and the crypto tfms.

Update seg6_hmac_exit to only free the memory when allocated, so we can
reuse the code directly.

Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support")
Reported-by: Sabrina Dubroca 
Closes: https://lore.kernel.org/netdev/Zj3bh-gE7eT6V6aH@hog/
Signed-off-by: Hangbin Liu 
Reviewed-by: Simon Horman 
Reviewed-by: Sabrina Dubroca 
Link: https://lore.kernel.org/r/20240517005435.2600277-1-liuhangbin@gmail.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

ipv6: sr: fix missing sk_buff release in seg6_input_core

2024-06-12T09:39:38+00:00

[ Upstream commit 5447f9708d9e4c17a647b16a9cb29e9e02820bd9 ]

The seg6_input() function is responsible for adding the SRH into a
packet, delegating the operation to the seg6_input_core(). This function
uses the skb_cow_head() to ensure that there is sufficient headroom in
the sk_buff for accommodating the link-layer header.
In the event that the skb_cow_header() function fails, the
seg6_input_core() catches the error but it does not release the sk_buff,
which will result in a memory leak.

This issue was introduced in commit af3b5158b89d ("ipv6: sr: fix BUG due
to headroom too small after SRH push") and persists even after commit
7a3f5b0de364 ("netfilter: add netfilter hooks to SRv6 data plane"),
where the entire seg6_input() code was refactored to deal with netfilter
hooks.

The proposed patch addresses the identified memory leak by requiring the
seg6_input_core() function to release the sk_buff in the event that
skb_cow_head() fails.

Fixes: af3b5158b89d ("ipv6: sr: fix BUG due to headroom too small after SRH push")
Signed-off-by: Andrea Mayer 
Reviewed-by: Simon Horman 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin