Yiming Qian reported:
<quote>
ipmr_cache_report()` allocates a report skb with `alloc_skb(128,
GFP_ATOMIC)` and appends a `struct igmphdr` using `skb_put()`. In the
non-`IGMPMSG_WHOLEPKT` path it initializes only:
- `igmp->type`
- `igmp->code`
but does not initialize:
- `igmp->csum`
- `igmp->group`
Later, `igmpmsg_netlink_event()` copies the bytes after `sizeof(struct
igmpmsg)` into the `IPMRA_CREPORT_PKT` netlink attribute and emits
`RTM_NEWCACHEREPORT` on `RTNLGRP_IPV4_MROUTE_R`.
As a result, 6 bytes of stale heap data from the skb head are
disclosed to userspace.
</quote>
Let's use skb_put_zero() instead of skb_put() to fix this bug.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260430070611.4004529-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
With CONFIG_IP_MROUTE_MULTIPLE_TABLES=n, ipmr_fib_lookup()
does not check if net->ipv4.mrt is NULL.
Since default_device_exit_batch() is called after ->exit_rtnl(),
a device could receive IGMP packets and access net->ipv4.mrt
during/after ipmr_rules_exit_rtnl().
If ipmr_rules_exit_rtnl() had already cleared it and freed the
memory, the access would trigger null-ptr-deref or use-after-free.
Let's fix it by using RCU helper and free mrt after RCU grace
period.
In addition, check_net(net) is added to mroute_clean_tables()
and ipmr_cache_unresolved() to synchronise via mfc_unres_lock.
This prevents ipmr_cache_unresolved() from putting skb into
c->_c.mfc_un.unres.unresolved after mroute_clean_tables()
purges it.
For the same reason, timer_shutdown_sync() is moved after
mroute_clean_tables().
Since rhltable_destroy() holds mutex internally, rcu_work is
used, and it is placed as the first member because rcu_head
must be placed within <4K offset. mr_table is alraedy 3864
bytes without rcu_work.
Note that IP6MR is not yet converted to ->exit_rtnl(), so this
change is not needed for now but will be.
Fixes: b22b018674 ("ipmr: Convert ipmr_net_exit_batch() to ->exit_rtnl().")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260423053456.4097409-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipmr_mfc_add() and ipmr_mfc_delete() are already protected
by a dedicated mutex.
rtm_to_ipmr_mfcc() calls __ipmr_get_table(), __dev_get_by_index(),
amd ipmr_find_vif().
Once __dev_get_by_index() is converted to dev_get_by_index_rcu(),
we can move the other two functions under that same RCU section
and drop RTNL for ipmr_rtm_route().
Let's do that conversion and drop ASSERT_RTNL() in
mr_call_mfc_notifiers().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-16-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We will no longer hold RTNL for ipmr_rtm_route() to modify the
MFC hash table.
Only __dev_get_by_index() in rtm_to_ipmr_mfcc() is the RTNL
dependant, otherwise, we just need protection for mrt->mfc_hash
and mrt->mfc_cache_list.
Let's add a new mutex for ipmr_mfc_add(), ipmr_mfc_delete(),
and mroute_clean_tables() (setsockopt(MRT_FLUSH or MRT_DONE)).
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-15-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We will no longer hold RTNL for ipmr_mfc_add() and ipmr_mfc_delete().
MFC entry can be loosely connected with VIF by its index for
mrt->vif_table[] (stored in mfc_parent), but the two tables are
not synchronised. i.e. Even if VIF 1 is removed, MFC for VIF 1
is not automatically removed.
The only field that the MFC/VIF interfaces share is
net->ipv[46].ipmr_seq, which is protected by RTNL.
Adding a new mutex for both just to protect a single field is overkill.
Let's convert the field to atomic_t.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-14-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
fib_rules_unregister() removes ops from net->rules_ops under
spinlock, calls ops->delete() for each rule, and frees the ops.
ipmr_rules_ops_template does not have ->delete(), and any
operation does not require RTNL there.
Let's move fib_rules_unregister() from ipmr_rules_exit_rtnl()
to ipmr_net_exit().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-12-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When ipmr_free_table() is called from ipmr_rules_init() or
ipmr_net_init(), the netns is not yet published.
Thus, no device should have been registered, and
mroute_clean_tables() will not call vif_delete(), so
unregister_netdevice_many() is unnecessary.
unregister_netdevice_many() does nothing if the list is empty,
but it requires RTNL due to the unconditional ASSERT_RTNL()
at the entry of unregister_netdevice_many_notify().
Let's remove unnecessary RTNL and ASSERT_RTNL() and instead
add WARN_ON_ONCE() in ipmr_free_table().
Note that we use a local list for the new WARN_ON_ONCE() because
dev_kill_list passed from ipmr_rules_exit_rtnl() may have some
devices when other ops->init() fails after ipmr durnig setup_net().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-11-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipmr_net_ops uses ->exit_batch() to acquire RTNL only once
for dying network namespaces.
ipmr does not depend on the ordering of ->exit_rtnl() and
->exit_batch() of other pernet_operations (unlike fib_net_ops).
Once ipmr_free_table() is called and all devices are
queued for destruction in ->exit_rtnl(), later during
NETDEV_UNREGISTER, ipmr_device_event() will not see anything
in vif table and just do nothing.
Let's convert ipmr_net_exit_batch() to ->exit_rtnl().
Note that fib_rules_unregister() does not need RTNL and
we will remove RTNL and unregister_netdevice_many() in
ipmr_net_init().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-10-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a prep commit to convert ipmr_net_exit_batch() to
->exit_rtnl().
Let's move unregister_netdevice_many() in ipmr_free_table()
to its callers.
Now ipmr_rules_exit() can do batching all tables per netns.
Note that later we will remove RTNL and unregister_netdevice_many()
in ipmr_rules_init().
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-9-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipmr_rtm_dumproute() calls mr_table_dump() or mr_rtm_dumproute(),
and mr_rtm_dumproute() finally calls mr_table_dump().
mr_table_dump() calls the passed function, _ipmr_fill_mroute().
_ipmr_fill_mroute() is a wrapper of ipmr_fill_mroute() to cast
struct mr_mfc * to struct mfc_cache *.
ipmr_fill_mroute() can be already called safely under RCU.
Let's convert ipmr_rtm_dumproute() to RCU.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-7-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ipmr_rtm_getroute() calls __ipmr_get_table(), ipmr_cache_find(),
and ipmr_fill_mroute().
The table is not removed until netns dismantle, and net->ipv4.mr_tables
is managed with RCU list API, so __ipmr_get_table() is safe under RCU.
struct mfc_cache is freed by mr_cache_put() after RCU grace period,
so we can use ipmr_cache_find() under RCU. rcu_read_lock() around
it was just to avoid lockdep splat for rhl_for_each_entry_rcu().
ipmr_fill_mroute() calls mr_fill_mroute(), which properly uses RCU.
Let's drop RTNL for ipmr_rtm_getroute() and use RCU instead.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-6-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
mroute_msgsize() calculates skb size needed for ipmr_fill_mroute().
The size differs based on mrt->maxvif.
We will drop RTNL for ipmr_rtm_getroute() and mrt->maxvif may
change under RCU.
To avoid -EMSGSIZE, let's calculate the size with the maximum
value of mrt->maxvif, MAXVIFS.
struct rtnexthop is 8 bytes and MAXVIFS is 32, so the maximum delta
is 256 bytes, which is small enough.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net->ipv4.mr_tables is updated under RTNL and can be read
safely under RCU.
Once created, the multicast route tables are not removed
until netns dismantle.
ipmr_rtm_dumplink() does not need RTNL protection for
ipmr_for_each_table() and ipmr_fill_table() if RCU is held.
Even if mrt->maxvif changes concurrently, ipmr_fill_vif()
returns true to continue dumping the next table.
Let's convert it to RCU.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-4-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These fields in struct mr_table are updated in ip_mroute_setsockopt()
under RTNL:
* mroute_do_pim
* mroute_do_assert
* mroute_do_wrvifwhole
However, ip_mroute_getsockopt() does not hold RTNL and read the first
two fields locklessly, and ip_mr_forward() reads all the three under
RCU. pim_rcv_v1() also reads mroute_do_pim locklessly.
Let's use WRITE_ONCE() and READ_ONCE() for them.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert the ->flowic_tos field of struct flowi_common from __u8 to
dscp_t, rename it ->flowic_dscp and propagate these changes to struct
flowi and struct flowi4.
We've had several bugs in the past where ECN bits could interfere with
IPv4 routing, because these bits were not properly cleared when setting
->flowi4_tos. These bugs should be fixed now and the dscp_t type has
been introduced to ensure that variables carrying DSCP values don't
accidentally have any ECN bits set. Several variables and structure
fields have been converted to dscp_t already, but the main IPv4 routing
structure, struct flowi4, is still using a __u8. To avoid any future
regression, this patch converts it to dscp_t.
There are many users to convert at once. Fortunately, around half of
->flowi4_tos users already have a dscp_t value at hand, which they
currently convert to __u8 using inet_dscp_to_dsfield(). For all of
these users, we just need to drop that conversion.
But, although we try to do the __u8 <-> dscp_t conversions at the
boundaries of the network or of user space, some places still store
TOS/DSCP variables as __u8 in core networking code. Those can hardly be
converted either because the data structure is part of UAPI or because
the same variable or field is also used for handling ECN in other parts
of the code. In all of these cases where we don't have a dscp_t
variable at hand, we need to use inet_dsfield_to_dscp() when
interacting with ->flowi4_dscp.
Changes since v1:
* Fix space alignment in __bpf_redirect_neigh_v4() (Ido).
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/29acecb45e911d17446b9a3dbdb1ab7b821ea371.1756128932.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit cc34acd577 ("docs: net: document new locking reality")
introduced netif_ vs dev_ function semantics: the former expects locked
netdev, the latter takes care of the locking. We don't strictly
follow this semantics on either side, but there are more dev_xxx handlers
now that don't fit. Rename them to netif_xxx where appropriate.
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250717172333.1288349-2-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code today. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. Thus MC
routing configuration needs to be kept in sync with the VXLAN FDB and MDB.
Ideally, the VXLAN packets would be routed by the MC routing code instead.
To that end, this patch adds support to route locally generated multicast
packets. The newly-added routines do largely what ip_mr_input() and
ip_mr_forward() do: make an MR cache lookup to find where to send the
packets, and use ip_mc_output() to send each of them. When no cache entry
is found, the packet is punted to the daemon for resolution.
However, an installation that uses a VXLAN underlay netdevice for which it
also has matching MC routes, would get a different routing with this patch.
Previously, the MC packets would be delivered directly to the underlay
port, whereas now they would be MC-routed. In order to avoid this change in
behavior, introduce an IPCB flag. Only if the flag is set will
ip_mr_output() actually engage, otherwise it reverts to ip_mc_output().
This code is based on work by Roopa Prabhu and Nikolay Aleksandrov.
Signed-off-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/0aadbd49330471c0f758d54afb05eb3b6e3a6b65.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Some of the work of ipmr_queue_xmit() is specific to IPMR forwarding, and
should not take place on the output path. In order to allow reuse of the
common parts, split the function into two: the ipmr_prepare_xmit() helper
that takes care of the common bits, and the ipmr_queue_fwd_xmit(), which
invokes the former and encapsulates the whole forwarding algorithm.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/4e8db165572a4f8bd29a723a801e854e9d20df4d.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The variable is used for caching of rt->dst.dev. The netdevice referenced
therein does not change during the scope of validity of that local. At the
same time, the local is only used twice, and each of these uses will end up
in a different function in the following patches, further eliminating any
use the local could have had.
Drop the local altogether and inline the uses.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/c80600a4b51679fe78f429ccb6d60892c2f9e4de.1750113335.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
