linux-stable.git/include/net/ip6_fib.h, branch linux-5.4.y

ipv6: annotate accesses to fn->fn_sernum

2022-02-01T16:24:38+00:00

commit aafc2e3285c2d7a79b7ee15221c19fbeca7b1509 upstream.

struct fib6_node's fn_sernum field can be
read while other threads change it.

Add READ_ONCE()/WRITE_ONCE() annotations.

Do not change existing smp barriers in fib6_get_cookie_safe()
and __fib6_update_sernum_upto_root()

syzbot reported:

BUG: KCSAN: data-race in fib6_clean_node / inet6_csk_route_socket

write to 0xffff88813df62e2c of 4 bytes by task 1920 on cpu 1:
 fib6_clean_node+0xc2/0x260 net/ipv6/ip6_fib.c:2178
 fib6_walk_continue+0x38e/0x430 net/ipv6/ip6_fib.c:2112
 fib6_walk net/ipv6/ip6_fib.c:2160 [inline]
 fib6_clean_tree net/ipv6/ip6_fib.c:2240 [inline]
 __fib6_clean_all+0x1a9/0x2e0 net/ipv6/ip6_fib.c:2256
 fib6_flush_trees+0x6c/0x80 net/ipv6/ip6_fib.c:2281
 rt_genid_bump_ipv6 include/net/net_namespace.h:488 [inline]
 addrconf_dad_completed+0x57f/0x870 net/ipv6/addrconf.c:4230
 addrconf_dad_work+0x908/0x1170
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:359
 ret_from_fork+0x1f/0x30

read to 0xffff88813df62e2c of 4 bytes by task 15701 on cpu 0:
 fib6_get_cookie_safe include/net/ip6_fib.h:285 [inline]
 rt6_get_cookie include/net/ip6_fib.h:306 [inline]
 ip6_dst_store include/net/ip6_route.h:234 [inline]
 inet6_csk_route_socket+0x352/0x3c0 net/ipv6/inet6_connection_sock.c:109
 inet6_csk_xmit+0x91/0x1e0 net/ipv6/inet6_connection_sock.c:121
 __tcp_transmit_skb+0x1323/0x1840 net/ipv4/tcp_output.c:1402
 tcp_transmit_skb net/ipv4/tcp_output.c:1420 [inline]
 tcp_write_xmit+0x1450/0x4460 net/ipv4/tcp_output.c:2680
 __tcp_push_pending_frames+0x68/0x1c0 net/ipv4/tcp_output.c:2864
 tcp_push+0x2d9/0x2f0 net/ipv4/tcp.c:725
 mptcp_push_release net/mptcp/protocol.c:1491 [inline]
 __mptcp_push_pending+0x46c/0x490 net/mptcp/protocol.c:1578
 mptcp_sendmsg+0x9ec/0xa50 net/mptcp/protocol.c:1764
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:643
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 kernel_sendmsg+0x97/0xd0 net/socket.c:745
 sock_no_sendpage+0x84/0xb0 net/core/sock.c:3086
 inet_sendpage+0x9d/0xc0 net/ipv4/af_inet.c:834
 kernel_sendpage+0x187/0x200 net/socket.c:3492
 sock_sendpage+0x5a/0x70 net/socket.c:1007
 pipe_to_sendpage+0x128/0x160 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x207/0x500 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x94/0xd0 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000026f -> 0x00000271

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15701 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

The Fixes tag I chose is probably arbitrary, I do not think
we need to backport this patch to older kernels.

Fixes: c5cff8561d2d ("ipv6: add rcu grace period before freeing fib6_node")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Link: https://lore.kernel.org/r/20220120174112.1126644-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

net: ipv6: add fib6_nh_release_dsts stub

2021-12-01T08:23:33+00:00

[ Upstream commit 8837cbbf854246f5f4d565f21e6baa945d37aded ]

We need a way to release a fib6_nh's per-cpu dsts when replacing
nexthops otherwise we can end up with stale per-cpu dsts which hold net
device references, so add a new IPv6 stub called fib6_nh_release_dsts.
It must be used after an RCU grace period, so no new dsts can be created
through a group's nexthop entry.
Similar to fib6_nh_release it shouldn't be used if fib6_nh_init has failed
so it doesn't need a dummy stub when IPv6 is not enabled.

Fixes: 7bf4796dd099 ("nexthops: add support for replace")
Signed-off-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ipv6: Use global sernum for dst validation with nexthop objects

2020-05-14T05:58:20+00:00

[ Upstream commit 8f34e53b60b337e559f1ea19e2780ff95ab2fa65 ]

Nik reported a bug with pcpu dst cache when nexthop objects are
used illustrated by the following:
    $ ip netns add foo
    $ ip -netns foo li set lo up
    $ ip -netns foo addr add 2001:db8:11::1/128 dev lo
    $ ip netns exec foo sysctl net.ipv6.conf.all.forwarding=1
    $ ip li add veth1 type veth peer name veth2
    $ ip li set veth1 up
    $ ip addr add 2001:db8:10::1/64 dev veth1
    $ ip li set dev veth2 netns foo
    $ ip -netns foo li set veth2 up
    $ ip -netns foo addr add 2001:db8:10::2/64 dev veth2
    $ ip -6 nexthop add id 100 via 2001:db8:10::2 dev veth1
    $ ip -6 route add 2001:db8:11::1/128 nhid 100

    Create a pcpu entry on cpu 0:
    $ taskset -a -c 0 ip -6 route get 2001:db8:11::1

    Re-add the route entry:
    $ ip -6 ro del 2001:db8:11::1
    $ ip -6 route add 2001:db8:11::1/128 nhid 100

    Route get on cpu 0 returns the stale pcpu:
    $ taskset -a -c 0 ip -6 route get 2001:db8:11::1
    RTNETLINK answers: Network is unreachable

    While cpu 1 works:
    $ taskset -a -c 1 ip -6 route get 2001:db8:11::1
    2001:db8:11::1 from :: via 2001:db8:10::2 dev veth1 src 2001:db8:10::1 metric 1024 pref medium

Conversion of FIB entries to work with external nexthop objects
missed an important difference between IPv4 and IPv6 - how dst
entries are invalidated when the FIB changes. IPv4 has a per-network
namespace generation id (rt_genid) that is bumped on changes to the FIB.
Checking if a dst_entry is still valid means comparing rt_genid in the
rtable to the current value of rt_genid for the namespace.

IPv6 also has a per network namespace counter, fib6_sernum, but the
count is saved per fib6_node. With the per-node counter only dst_entries
based on fib entries under the node are invalidated when changes are
made to the routes - limiting the scope of invalidations. IPv6 uses a
reference in the rt6_info, 'from', to track the corresponding fib entry
used to create the dst_entry. When validating a dst_entry, the 'from'
is used to backtrack to the fib6_node and check the sernum of it to the
cookie passed to the dst_check operation.

With the inline format (nexthop definition inline with the fib6_info),
dst_entries cached in the fib6_nh have a 1:1 correlation between fib
entries, nexthop data and dst_entries. With external nexthops, IPv6
looks more like IPv4 which means multiple fib entries across disparate
fib6_nodes can all reference the same fib6_nh. That means validation
of dst_entries based on external nexthops needs to use the IPv4 format
- the per-network namespace counter.

Add sernum to rt6_info and set it when creating a pcpu dst entry. Update
rt6_get_cookie to return sernum if it is set and update dst_check for
IPv6 to look for sernum set and based the check on it if so. Finally,
rt6_get_pcpu_route needs to validate the cached entry before returning
a pcpu entry (similar to the rt_cache_valid calls in __mkroute_input and
__mkroute_output for IPv4).

This problem only affects routes using the new, external nexthops.

Thanks to the kbuild test robot for catching the IS_ENABLED needed
around rt_genid_ipv6 before I sent this out.

Fixes: 5b98324ebe29 ("ipv6: Allow routes to use nexthop objects")
Reported-by: Nikolay Aleksandrov 
Signed-off-by: David Ahern 
Reviewed-by: Nikolay Aleksandrov 
Tested-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ipv6: Dump route exceptions if requested

2019-06-24T17:18:49+00:00

Since commit 2b760fcf5cfb ("ipv6: hook up exception table to store dst
cache"), route exceptions reside in a separate hash table, and won't be
found by walking the FIB, so they won't be dumped to userspace on a
RTM_GETROUTE message.

This causes 'ip -6 route list cache' and 'ip -6 route flush cache' to
have no function anymore:

 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 539sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 536sec mtu 1500 pref medium
 # ip -6 route list cache
 # ip -6 route flush cache
 # ip -6 route get fc00:3::1
 fc00:3::1 via fc00:1::2 dev veth_A-R1 src fc00:1::1 metric 1024 expires 520sec mtu 1400 pref medium
 # ip -6 route get fc00:4::1
 fc00:4::1 via fc00:2::2 dev veth_A-R2 src fc00:2::1 metric 1024 expires 519sec mtu 1500 pref medium

because iproute2 lists cached routes using RTM_GETROUTE, and flushes them
by listing all the routes, and deleting them with RTM_DELROUTE one by one.

If cached routes are requested using the RTM_F_CLONED flag together with
strict checking, or if no strict checking is requested (and hence we can't
consistently apply filters), look up exceptions in the hash table
associated with the current fib6_info in rt6_dump_route(), and, if present
and not expired, add them to the dump.

We might be unable to dump all the entries for a given node in a single
message, so keep track of how many entries were handled for the current
node in fib6_walker, and skip that amount in case we start from the same
partially dumped node.

When a partial dump restarts, as the starting node might change when
'sernum' changes, we have no guarantee that we need to skip the same
amount of in-node entries. Therefore, we need two counters, and we need to
zero the in-node counter if the node from which the dump is resumed
differs.

Note that, with the current version of iproute2, this only fixes the
'ip -6 route list cache': on a flush command, iproute2 doesn't pass
RTM_F_CLONED and, due to this inconsistency, 'ip -6 route flush cache' is
still unable to fetch the routes to be flushed. This will be addressed in
a patch for iproute2.

To flush cached routes, a procfs entry could be introduced instead: that's
how it works for IPv4. We already have a rt6_flush_exception() function
ready to be wired to it. However, this would not solve the issue for
listing.

Versions of iproute2 and kernel tested:

                    iproute2
kernel             4.14.0   4.15.0   4.19.0   5.0.0   5.1.0    5.1.0, patched
 3.18    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.4     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.9     list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.14    list        +        +        +        +       +            +
         flush       +        +        +        +       +            +
 4.15    list
         flush
 4.19    list
         flush
 5.0     list
         flush
 5.1     list
         flush
 with    list        +        +        +        +       +            +
 fix     flush       +        +        +                             +

v7:
  - Explain usage of "skip" counters in commit message (suggested by
    David Ahern)

v6:
  - Rebase onto net-next, use recently introduced nexthop walker
  - Make rt6_nh_dump_exceptions() a separate function (suggested by David
    Ahern)

v5:
  - Use dump_routes and dump_exceptions from filter, ignore NLM_F_MATCH,
    update test results (flushing works with iproute2 < 5.0.0 now)

v4:
  - Split NLM_F_MATCH and strict check handling in separate patches
  - Filter routes using RTM_F_CLONED: if it's not set, only return
    non-cached routes, and if it's set, only return cached routes:
    change requested by David Ahern and Martin Lau. This implies that
    iproute2 needs a separate patch to be able to flush IPv6 cached
    routes. This is not ideal because we can't fix the breakage caused
    by 2b760fcf5cfb entirely in kernel. However, two years have passed
    since then, and this makes it more tolerable

v3:
  - More descriptive comment about expired exceptions in rt6_dump_route()
  - Swap return values of rt6_dump_route() (suggested by Martin Lau)
  - Don't zero skip_in_node in case we don't dump anything in a given pass
    (also suggested by Martin Lau)
  - Remove check on RTM_F_CLONED altogether: in the current UAPI semantic,
    it's just a flag to indicate the route was cloned, not to filter on
    routes

v2: Add tracking of number of entries to be skipped in current node after
    a partial dump. As we restart from the same node, if not all the
    exceptions for a given node fit in a single message, the dump will
    not terminate, as suggested by Martin Lau. This is a concrete
    possibility, setting up a big number of exceptions for the same route
    actually causes the issue, suggested by David Ahern.

Reported-by: Jianlin Shi 
Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache")
Signed-off-by: Stefano Brivio 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: Stop sending in-kernel notifications for each nexthop

2019-06-18T16:45:37+00:00

Both listeners - mlxsw and netdevsim - of IPv6 FIB notifications are now
ready to handle IPv6 multipath notifications.

Therefore, stop ignoring such notifications in both drivers and stop
sending notification for each added / deleted nexthop.

v2:
* Remove 'multipath_rt' from 'struct fib6_entry_notifier_info'

Signed-off-by: Ido Schimmel 
Acked-by: Jiri Pirko 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: Extend notifier info for multipath routes

2019-06-18T16:45:36+00:00

Extend the IPv6 FIB notifier info with number of sibling routes being
notified.

This will later allow listeners to process one notification for a
multipath routes instead of N, where N is the number of nexthops.

Signed-off-by: Ido Schimmel 
Acked-by: Jiri Pirko 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: Allow routes to use nexthop objects

2019-06-10T17:44:57+00:00

Add support for RTA_NH_ID attribute to allow a user to specify a
nexthop id to use with a route. fc_nh_id is added to fib6_config to
hold the value passed in the RTA_NH_ID attribute. If a nexthop id
is given, the gateway, device, encap and multipath attributes can
not be set.

Update ip6_route_del to check metric and protocol before nexthop
specs. If fc_nh_id is set, then it must match the id in the route
entry. Since IPv6 allows delete of a cached entry (an exception),
add ip6_del_cached_rt_nh to cycle through all of the fib6_nh in
a fib entry if it is using a nexthop.

Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-07T18:00:14+00:00

Some ISDN files that got removed in net-next had some changes
done in mainline, take the removals.

Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2019-06-07T16:29:14+00:00

Pull networking fixes from David Miller:

1) Free AF_PACKET po->rollover properly, from Willem de Bruijn.

2) Read SFP eeprom in max 16 byte increments to avoid problems with
some SFP modules, from Russell King.

3) Fix UDP socket lookup wrt. VRF, from Tim Beale.

4) Handle route invalidation properly in s390 qeth driver, from Julian
Wiedmann.

5) Memory leak on unload in RDS, from Zhu Yanjun.

6) sctp_process_init leak, from Neil HOrman.

7) Fix fib_rules rule insertion semantic change that broke Android,
from Hangbin Liu.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (33 commits)
pktgen: do not sleep with the thread lock held.
net: mvpp2: Use strscpy to handle stat strings
net: rds: fix memory leak in rds_ib_flush_mr_pool
ipv6: fix EFAULT on sendto with icmpv6 and hdrincl
ipv6: use READ_ONCE() for inet->hdrincl as in ipv4
Revert "fib_rules: return 0 directly if an exactly same rule exists when NLM_F_EXCL not supplied"
net: aquantia: fix wol configuration not applied sometimes
ethtool: fix potential userspace buffer overflow
Fix memory leak in sctp_process_init
net: rds: fix memory leak when unload rds_rdma
ipv6: fix the check before getting the cookie in rt6_get_cookie
ipv4: not do cache for local delivery if bc_forwarding is enabled
s390/qeth: handle error when updating TX queue count
s390/qeth: fix VLAN attribute in bridge_hostnotify udev event
s390/qeth: check dst entry before use
s390/qeth: handle limited IPv4 broadcast in L3 TX path
net: fix indirect calls helpers for ptype list hooks.
net: ipvlan: Fix ipvlan device tso disabled while NETIF_F_IP_CSUM is set
udp: only choose unbound UDP socket for multicast when not in a VRF
net/tls: replace the sleeping lock around RX resync with a bit lock
...

ipv6: fix the check before getting the cookie in rt6_get_cookie

2019-06-06T00:00:29+00:00

In Jianlin's testing, netperf was broken with 'Connection reset by peer',
as the cookie check failed in rt6_check() and ip6_dst_check() always
returned NULL.

It's caused by Commit 93531c674315 ("net/ipv6: separate handling of FIB
entries from dst based routes"), where the cookie can be got only when
'c1'(see below) for setting dst_cookie whereas rt6_check() is called
when !'c1' for checking dst_cookie, as we can see in ip6_dst_check().

Since in ip6_dst_check() both rt6_dst_from_check() (c1) and rt6_check()
(!c1) will check the 'from' cookie, this patch is to remove the c1 check
in rt6_get_cookie(), so that the dst_cookie can always be set properly.

c1:
  (rt->rt6i_flags & RTF_PCPU || unlikely(!list_empty(&rt->rt6i_uncached)))

Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes")
Reported-by: Jianlin Shi 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller