linux-stable.git/net/ipv6/addrconf.c, branch linux-5.4.y

ipv6: fix omitted netlink attributes when using RTEXT_FILTER_SKIP_STATS

2025-04-10T12:29:43+00:00

[ Upstream commit 7ac6ea4a3e0898db76aecccd68fb2c403eb7d24e ]

Using RTEXT_FILTER_SKIP_STATS is incorrectly skipping non-stats IPv6
netlink attributes on link dump. This causes issues on userspace tools,
e.g iproute2 is not rendering address generation mode as it should due
to missing netlink attribute.

Move the filling of IFLA_INET6_STATS and IFLA_INET6_ICMP6STATS to a
helper function guarded by a flag check to avoid hitting the same
situation in the future.

Fixes: d5566fd72ec1 ("rtnetlink: RTEXT_FILTER_SKIP_STATS support to avoid dumping inet/inet6 stats")
Signed-off-by: Fernando Fernandez Mancera 
Reviewed-by: Simon Horman 
Link: https://patch.msgid.link/20250402121751.3108-1-ffmancera@riseup.net
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: take care of scope when choosing the src addr

2024-08-19T03:33:35+00:00

commit abb9a68d2c64dd9b128ae1f2e635e4d805e7ce64 upstream.

When the source address is selected, the scope must be checked. For
example, if a loopback address is assigned to the vrf device, it must not
be chosen for packets sent outside.

CC: stable@vger.kernel.org
Fixes: afbac6010aec ("net: ipv6: Address selection needs to consider L3 domains")
Signed-off-by: Nicolas Dichtel 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20240710081521.3809742-4-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

ipv6: fix race condition between ipv6_get_ifaddr and ipv6_del_addr

2024-05-02T14:18:28+00:00

[ Upstream commit 7633c4da919ad51164acbf1aa322cc1a3ead6129 ]

Although ipv6_get_ifaddr walks inet6_addr_lst under the RCU lock, it
still means hlist_for_each_entry_rcu can return an item that got removed
from the list. The memory itself of such item is not freed thanks to RCU
but nothing guarantees the actual content of the memory is sane.

In particular, the reference count can be zero. This can happen if
ipv6_del_addr is called in parallel. ipv6_del_addr removes the entry
from inet6_addr_lst (hlist_del_init_rcu(&ifp->addr_lst)) and drops all
references (__in6_ifa_put(ifp) + in6_ifa_put(ifp)). With bad enough
timing, this can happen:

1. In ipv6_get_ifaddr, hlist_for_each_entry_rcu returns an entry.

2. Then, the whole ipv6_del_addr is executed for the given entry. The
   reference count drops to zero and kfree_rcu is scheduled.

3. ipv6_get_ifaddr continues and tries to increments the reference count
   (in6_ifa_hold).

4. The rcu is unlocked and the entry is freed.

5. The freed entry is returned.

Prevent increasing of the reference count in such case. The name
in6_ifa_hold_safe is chosen to mimic the existing fib6_info_hold_safe.

[   41.506330] refcount_t: addition on 0; use-after-free.
[   41.506760] WARNING: CPU: 0 PID: 595 at lib/refcount.c:25 refcount_warn_saturate+0xa5/0x130
[   41.507413] Modules linked in: veth bridge stp llc
[   41.507821] CPU: 0 PID: 595 Comm: python3 Not tainted 6.9.0-rc2.main-00208-g49563be82afa #14
[   41.508479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
[   41.509163] RIP: 0010:refcount_warn_saturate+0xa5/0x130
[   41.509586] Code: ad ff 90 0f 0b 90 90 c3 cc cc cc cc 80 3d c0 30 ad 01 00 75 a0 c6 05 b7 30 ad 01 01 90 48 c7 c7 38 cc 7a 8c e8 cc 18 ad ff 90 <0f> 0b 90 90 c3 cc cc cc cc 80 3d 98 30 ad 01 00 0f 85 75 ff ff ff
[   41.510956] RSP: 0018:ffffbda3c026baf0 EFLAGS: 00010282
[   41.511368] RAX: 0000000000000000 RBX: ffff9e9c46914800 RCX: 0000000000000000
[   41.511910] RDX: ffff9e9c7ec29c00 RSI: ffff9e9c7ec1c900 RDI: ffff9e9c7ec1c900
[   41.512445] RBP: ffff9e9c43660c9c R08: 0000000000009ffb R09: 00000000ffffdfff
[   41.512998] R10: 00000000ffffdfff R11: ffffffff8ca58a40 R12: ffff9e9c4339a000
[   41.513534] R13: 0000000000000001 R14: ffff9e9c438a0000 R15: ffffbda3c026bb48
[   41.514086] FS:  00007fbc4cda1740(0000) GS:ffff9e9c7ec00000(0000) knlGS:0000000000000000
[   41.514726] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   41.515176] CR2: 000056233b337d88 CR3: 000000000376e006 CR4: 0000000000370ef0
[   41.515713] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   41.516252] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   41.516799] Call Trace:
[   41.517037]  
[   41.517249]  ? __warn+0x7b/0x120
[   41.517535]  ? refcount_warn_saturate+0xa5/0x130
[   41.517923]  ? report_bug+0x164/0x190
[   41.518240]  ? handle_bug+0x3d/0x70
[   41.518541]  ? exc_invalid_op+0x17/0x70
[   41.520972]  ? asm_exc_invalid_op+0x1a/0x20
[   41.521325]  ? refcount_warn_saturate+0xa5/0x130
[   41.521708]  ipv6_get_ifaddr+0xda/0xe0
[   41.522035]  inet6_rtm_getaddr+0x342/0x3f0
[   41.522376]  ? __pfx_inet6_rtm_getaddr+0x10/0x10
[   41.522758]  rtnetlink_rcv_msg+0x334/0x3d0
[   41.523102]  ? netlink_unicast+0x30f/0x390
[   41.523445]  ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[   41.523832]  netlink_rcv_skb+0x53/0x100
[   41.524157]  netlink_unicast+0x23b/0x390
[   41.524484]  netlink_sendmsg+0x1f2/0x440
[   41.524826]  __sys_sendto+0x1d8/0x1f0
[   41.525145]  __x64_sys_sendto+0x1f/0x30
[   41.525467]  do_syscall_64+0xa5/0x1b0
[   41.525794]  entry_SYSCALL_64_after_hwframe+0x72/0x7a
[   41.526213] RIP: 0033:0x7fbc4cfcea9a
[   41.526528] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89
[   41.527942] RSP: 002b:00007ffcf54012a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   41.528593] RAX: ffffffffffffffda RBX: 00007ffcf5401368 RCX: 00007fbc4cfcea9a
[   41.529173] RDX: 000000000000002c RSI: 00007fbc4b9d9bd0 RDI: 0000000000000005
[   41.529786] RBP: 00007fbc4bafb040 R08: 00007ffcf54013e0 R09: 000000000000000c
[   41.530375] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[   41.530977] R13: ffffffffc4653600 R14: 0000000000000001 R15: 00007fbc4ca85d1b
[   41.531573]  

Fixes: 5c578aedcb21d ("IPv6: convert addrconf hash list to RCU")
Reviewed-by: Eric Dumazet 
Reviewed-by: David Ahern 
Signed-off-by: Jiri Benc 
Link: https://lore.kernel.org/r/8ab821e36073a4a406c50ec83c9e8dc586c539e4.1712585809.git.jbenc@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6: fix potential "struct net" leak in inet6_rtm_getaddr()

2024-03-06T14:36:08+00:00

[ Upstream commit 10bfd453da64a057bcfd1a49fb6b271c48653cdb ]

It seems that if userspace provides a correct IFA_TARGET_NETNSID value
but no IFA_ADDRESS and IFA_LOCAL attributes, inet6_rtm_getaddr()
returns -EINVAL with an elevated "struct net" refcount.

Fixes: 6ecf4c37eb3e ("ipv6: enable IFA_TARGET_NETNSID for RTM_GETADDR")
Signed-off-by: Eric Dumazet 
Cc: Christian Brauner 
Cc: David Ahern 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: properly combine dev_base_seq and ipv6.dev_addr_genid

2024-03-01T12:13:37+00:00

[ Upstream commit e898e4cd1aab271ca414f9ac6e08e4c761f6913c ]

net->dev_base_seq and ipv6.dev_addr_genid are monotonically increasing.

If we XOR their values, we could miss to detect if both values
were changed with the same amount.

Fixes: 63998ac24f83 ("ipv6: provide addr and netconf dump consistency info")
Signed-off-by: Eric Dumazet 
Cc: Nicolas Dichtel 

Signed-off-by: Eric Dumazet 
Acked-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: ipv6: support reporting otherwise unknown prefix flags in RTM_NEWPREFIX

2023-12-20T14:41:13+00:00

[ Upstream commit bd4a816752bab609dd6d65ae021387beb9e2ddbd ]

Lorenzo points out that we effectively clear all unknown
flags from PIO when copying them to userspace in the netlink
RTM_NEWPREFIX notification.

We could fix this one at a time as new flags are defined,
or in one fell swoop - I choose the latter.

We could either define 6 new reserved flags (reserved1..6) and handle
them individually (and rename them as new flags are defined), or we
could simply copy the entire unmodified byte over - I choose the latter.

This unfortunately requires some anonymous union/struct magic,
so we add a static assert on the struct size for a little extra safety.

Cc: David Ahern 
Cc: Lorenzo Colitti 
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Maciej Żenczykowski 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: ipv6/addrconf: avoid integer underflow in ipv6_create_tempaddr

2023-09-23T08:59:58+00:00

[ Upstream commit f31867d0d9d82af757c1e0178b659438f4c1ea3c ]

The existing code incorrectly casted a negative value (the result of a
subtraction) to an unsigned value without checking. For example, if
/proc/sys/net/ipv6/conf/*/temp_prefered_lft was set to 1, the preferred
lifetime would jump to 4 billion seconds. On my machine and network the
shortest lifetime that avoided underflow was 3 seconds.

Fixes: 76506a986dc3 ("IPv6: fix DESYNC_FACTOR")
Signed-off-by: Alex Henrie 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6 addrconf: fix bug where deleting a mngtmpaddr can create a new temporary address

2023-08-11T09:53:47+00:00

[ Upstream commit 69172f0bcb6a09110c5d2a6d792627f5095a9018 ]

currently on 6.4 net/main:

  # ip link add dummy1 type dummy
  # echo 1 > /proc/sys/net/ipv6/conf/dummy1/use_tempaddr
  # ip link set dummy1 up
  # ip -6 addr add 2000::1/64 mngtmpaddr dev dummy1
  # ip -6 addr show dev dummy1

  11: dummy1:  mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
      inet6 2000::44f3:581c:8ca:3983/64 scope global temporary dynamic
         valid_lft 604800sec preferred_lft 86172sec
      inet6 2000::1/64 scope global mngtmpaddr
         valid_lft forever preferred_lft forever
      inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
         valid_lft forever preferred_lft forever

  # ip -6 addr del 2000::44f3:581c:8ca:3983/64 dev dummy1

  (can wait a few seconds if you want to, the above delete isn't [directly] the problem)

  # ip -6 addr show dev dummy1

  11: dummy1:  mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
      inet6 2000::1/64 scope global mngtmpaddr
         valid_lft forever preferred_lft forever
      inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
         valid_lft forever preferred_lft forever

  # ip -6 addr del 2000::1/64 mngtmpaddr dev dummy1
  # ip -6 addr show dev dummy1

  11: dummy1:  mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
      inet6 2000::81c9:56b7:f51a:b98f/64 scope global temporary dynamic
         valid_lft 604797sec preferred_lft 86169sec
      inet6 fe80::e8a8:a6ff:fed5:56d4/64 scope link
         valid_lft forever preferred_lft forever

This patch prevents this new 'global temporary dynamic' address from being
created by the deletion of the related (same subnet prefix) 'mngtmpaddr'
(which is triggered by there already being no temporary addresses).

Cc: Jiri Pirko 
Fixes: 53bd67491537 ("ipv6 addrconf: introduce IFA_F_MANAGETEMPADDR to tell kernel to manage temporary addresses")
Reported-by: Xiao Ma 
Signed-off-by: Maciej Żenczykowski 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20230720160022.1887942-1-maze@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv6/addrconf: fix a potential refcount underflow for idev

2023-07-27T06:37:32+00:00

[ Upstream commit 06a0716949c22e2aefb648526580671197151acc ]

Now in addrconf_mod_rs_timer(), reference idev depends on whether
rs_timer is not pending. Then modify rs_timer timeout.

There is a time gap in [1], during which if the pending rs_timer
becomes not pending. It will miss to hold idev, but the rs_timer
is activated. Thus rs_timer callback function addrconf_rs_timer()
will be executed and put idev later without holding idev. A refcount
underflow issue for idev can be caused by this.

	if (!timer_pending(&idev->rs_timer))
		in6_dev_hold(idev);
		  <--------------[1]
	mod_timer(&idev->rs_timer, jiffies + when);

To fix the issue, hold idev if mod_timer() return 0.

Fixes: b7b1bfce0bb6 ("ipv6: split duplicate address detection and router solicitation timer")
Suggested-by: Eric Dumazet 
Signed-off-by: Ziyang Xuan 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: take care of disable_policy when restoring routes

2022-07-07T15:36:47+00:00

commit 3b0dc529f56b5f2328244130683210be98f16f7f upstream.

When routes corresponding to addresses are restored by
fixup_permanent_addr(), the dst_nopolicy parameter was not set.
The typical use case is a user that configures an address on a down
interface and then put this interface up.

Let's take care of this flag in addrconf_f6i_alloc(), so that every callers
benefit ont it.

CC: stable@kernel.org
CC: David Forster 
Fixes: df789fe75206 ("ipv6: Provide ipv6 version of "disable_policy" sysctl")
Reported-by: Siwar Zitouni 
Signed-off-by: Nicolas Dichtel 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20220623120015.32640-1-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman