linux-stable.git/net/ipv4/fib_semantics.c, branch linux-5.4.y

ipv4: fib: annotate races around nh->nh_saddr_genid and nh->nh_saddr

2023-10-25T09:53:21+00:00

commit 195374d893681da43a39796e53b30ac4f20400c4 upstream.

syzbot reported a data-race while accessing nh->nh_saddr_genid [1]

Add annotations, but leave the code lazy as intended.

[1]
BUG: KCSAN: data-race in fib_select_path / fib_select_path

write to 0xffff8881387166f0 of 4 bytes by task 6778 on cpu 1:
fib_info_update_nhc_saddr net/ipv4/fib_semantics.c:1334 [inline]
fib_result_prefsrc net/ipv4/fib_semantics.c:1354 [inline]
fib_select_path+0x292/0x330 net/ipv4/fib_semantics.c:2269
ip_route_output_key_hash_rcu+0x659/0x12c0 net/ipv4/route.c:2810
ip_route_output_key_hash net/ipv4/route.c:2644 [inline]
__ip_route_output_key include/net/route.h:134 [inline]
ip_route_output_flow+0xa6/0x150 net/ipv4/route.c:2872
send4+0x1f5/0x520 drivers/net/wireguard/socket.c:61
wg_socket_send_skb_to_peer+0x94/0x130 drivers/net/wireguard/socket.c:175
wg_socket_send_buffer_to_peer+0xd6/0x100 drivers/net/wireguard/socket.c:200
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x10c/0x150 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:2630 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
worker_thread+0x525/0x730 kernel/workqueue.c:2784
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

read to 0xffff8881387166f0 of 4 bytes by task 6759 on cpu 0:
fib_result_prefsrc net/ipv4/fib_semantics.c:1350 [inline]
fib_select_path+0x1cb/0x330 net/ipv4/fib_semantics.c:2269
ip_route_output_key_hash_rcu+0x659/0x12c0 net/ipv4/route.c:2810
ip_route_output_key_hash net/ipv4/route.c:2644 [inline]
__ip_route_output_key include/net/route.h:134 [inline]
ip_route_output_flow+0xa6/0x150 net/ipv4/route.c:2872
send4+0x1f5/0x520 drivers/net/wireguard/socket.c:61
wg_socket_send_skb_to_peer+0x94/0x130 drivers/net/wireguard/socket.c:175
wg_socket_send_buffer_to_peer+0xd6/0x100 drivers/net/wireguard/socket.c:200
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x10c/0x150 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:2630 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
worker_thread+0x525/0x730 kernel/workqueue.c:2784
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

value changed: 0x959d3217 -> 0x959d3218

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6759 Comm: kworker/u4:15 Not tainted 6.6.0-rc4-syzkaller-00029-gcbf3a2cb156a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Workqueue: wg-kex-wg1 wg_packet_handshake_send_worker

Fixes: 436c3b66ec98 ("ipv4: Invalidate nexthop cache nh_saddr more correctly.")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Reviewed-by: Simon Horman 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20231017192304.82626-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

ipv4: annotate data-races around fi->fib_dead

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

[ Upstream commit fce92af1c29d90184dfec638b5738831097d66e9 ]

syzbot complained about a data-race in fib_table_lookup() [1]

Add appropriate annotations to document it.

[1]
BUG: KCSAN: data-race in fib_release_info / fib_table_lookup

write to 0xffff888150f31744 of 1 bytes by task 1189 on cpu 0:
fib_release_info+0x3a0/0x460 net/ipv4/fib_semantics.c:281
fib_table_delete+0x8d2/0x900 net/ipv4/fib_trie.c:1777
fib_magic+0x1c1/0x1f0 net/ipv4/fib_frontend.c:1106
fib_del_ifaddr+0x8cf/0xa60 net/ipv4/fib_frontend.c:1317
fib_inetaddr_event+0x77/0x200 net/ipv4/fib_frontend.c:1448
notifier_call_chain kernel/notifier.c:93 [inline]
blocking_notifier_call_chain+0x90/0x200 kernel/notifier.c:388
__inet_del_ifa+0x4df/0x800 net/ipv4/devinet.c:432
inet_del_ifa net/ipv4/devinet.c:469 [inline]
inetdev_destroy net/ipv4/devinet.c:322 [inline]
inetdev_event+0x553/0xaf0 net/ipv4/devinet.c:1606
notifier_call_chain kernel/notifier.c:93 [inline]
raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461
call_netdevice_notifiers_info net/core/dev.c:1962 [inline]
call_netdevice_notifiers_mtu+0xd2/0x130 net/core/dev.c:2037
dev_set_mtu_ext+0x30b/0x3e0 net/core/dev.c:8673
do_setlink+0x5be/0x2430 net/core/rtnetlink.c:2837
rtnl_setlink+0x255/0x300 net/core/rtnetlink.c:3177
rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6445
netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2549
rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6463
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x56f/0x640 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x665/0x770 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg net/socket.c:748 [inline]
sock_write_iter+0x1aa/0x230 net/socket.c:1129
do_iter_write+0x4b4/0x7b0 fs/read_write.c:860
vfs_writev+0x1a8/0x320 fs/read_write.c:933
do_writev+0xf8/0x220 fs/read_write.c:976
__do_sys_writev fs/read_write.c:1049 [inline]
__se_sys_writev fs/read_write.c:1046 [inline]
__x64_sys_writev+0x45/0x50 fs/read_write.c:1046
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888150f31744 of 1 bytes by task 21839 on cpu 1:
fib_table_lookup+0x2bf/0xd50 net/ipv4/fib_trie.c:1585
fib_lookup include/net/ip_fib.h:383 [inline]
ip_route_output_key_hash_rcu+0x38c/0x12c0 net/ipv4/route.c:2751
ip_route_output_key_hash net/ipv4/route.c:2641 [inline]
__ip_route_output_key include/net/route.h:134 [inline]
ip_route_output_flow+0xa6/0x150 net/ipv4/route.c:2869
send4+0x1e7/0x500 drivers/net/wireguard/socket.c:61
wg_socket_send_skb_to_peer+0x94/0x130 drivers/net/wireguard/socket.c:175
wg_socket_send_buffer_to_peer+0xd6/0x100 drivers/net/wireguard/socket.c:200
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x10c/0x150 drivers/net/wireguard/send.c:51
process_one_work+0x434/0x860 kernel/workqueue.c:2600
worker_thread+0x5f2/0xa10 kernel/workqueue.c:2751
kthread+0x1d7/0x210 kernel/kthread.c:389
ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21839 Comm: kworker/u4:18 Tainted: G W 6.5.0-syzkaller #0

Fixes: dccd9ecc3744 ("ipv4: Do not use dead fib_info entries.")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20230830095520.1046984-1-edumazet@google.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

ipv4: Fix incorrect route flushing when source address is deleted

2023-02-22T11:50:38+00:00

[ Upstream commit f96a3d74554df537b6db5c99c27c80e7afadc8d1 ]

Cited commit added the table ID to the FIB info structure, but did not
prevent structures with different table IDs from being consolidated.
This can lead to routes being flushed from a VRF when an address is
deleted from a different VRF.

Fix by taking the table ID into account when looking for a matching FIB
info. This is already done for FIB info structures backed by a nexthop
object in fib_find_info_nh().

Add test cases that fail before the fix:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [FAIL]
     TEST: Route in default VRF not removed                              [ OK ]
 RTNETLINK answers: File exists
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [FAIL]

 Tests passed:   6
 Tests failed:   2

And pass after:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]

 Tests passed:   8
 Tests failed:   0

Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs")
Signed-off-by: Ido Schimmel 
Reviewed-by: David Ahern 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Shaoying Xu 
Signed-off-by: Greg Kroah-Hartman

Revert "ipv4: Fix incorrect route flushing when source address is deleted"

2023-02-22T11:50:38+00:00

This reverts commit 2537b637eac0bd546f63e1492a34edd30878e8d4 that
deleted the whole fib_tests.sh by mistake and caused fib_tests failure
in kselftests run.

Signed-off-by: Shaoying Xu 
Signed-off-by: Greg Kroah-Hartman

ipv4: prevent potential spectre v1 gadget in fib_metrics_match()

2023-02-06T06:52:45+00:00

[ Upstream commit 5e9398a26a92fc402d82ce1f97cc67d832527da0 ]

if (!type)
        continue;
    if (type > RTAX_MAX)
        return false;
    ...
    fi_val = fi->fib_metrics->metrics[type - 1];

@type being used as an array index, we need to prevent
cpu speculation or risk leaking kernel memory content.

Fixes: 5f9ae3d9e7e4 ("ipv4: do metrics match when looking up and deleting a route")
Signed-off-by: Eric Dumazet 
Link: https://lore.kernel.org/r/20230120133140.3624204-1-edumazet@google.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv4: Fix incorrect route flushing when source address is deleted

2022-12-14T10:30:47+00:00

[ Upstream commit f96a3d74554df537b6db5c99c27c80e7afadc8d1 ]

Cited commit added the table ID to the FIB info structure, but did not
prevent structures with different table IDs from being consolidated.
This can lead to routes being flushed from a VRF when an address is
deleted from a different VRF.

Fix by taking the table ID into account when looking for a matching FIB
info. This is already done for FIB info structures backed by a nexthop
object in fib_find_info_nh().

Add test cases that fail before the fix:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [FAIL]
     TEST: Route in default VRF not removed                              [ OK ]
 RTNETLINK answers: File exists
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [FAIL]

 Tests passed:   6
 Tests failed:   2

And pass after:

 # ./fib_tests.sh -t ipv4_del_addr

 IPv4 delete address route tests
     Regular FIB info
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]
     Identical FIB info with different table ID
     TEST: Route removed from VRF when source address deleted            [ OK ]
     TEST: Route in default VRF not removed                              [ OK ]
     TEST: Route removed in default VRF when source address deleted      [ OK ]
     TEST: Route in VRF is not removed by address delete                 [ OK ]

 Tests passed:   8
 Tests failed:   0

Fixes: 5a56a0b3a45d ("net: Don't delete routes in different VRFs")
Signed-off-by: Ido Schimmel 
Reviewed-by: David Ahern 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv4: Fix route deletion when nexthop info is not specified

2022-12-08T10:23:05+00:00

[ Upstream commit d5082d386eee7e8ec46fa8581932c81a4961dcef ]

When the kernel receives a route deletion request from user space it
tries to delete a route that matches the route attributes specified in
the request.

If only prefix information is specified in the request, the kernel
should delete the first matching FIB alias regardless of its associated
FIB info. However, an error is currently returned when the FIB info is
backed by a nexthop object:

 # ip nexthop add id 1 via 192.0.2.2 dev dummy10
 # ip route add 198.51.100.0/24 nhid 1
 # ip route del 198.51.100.0/24
 RTNETLINK answers: No such process

Fix by matching on such a FIB info when legacy nexthop attributes are
not specified in the request. An earlier check already covers the case
where a nexthop ID is specified in the request.

Add tests that cover these flows. Before the fix:

 # ./fib_nexthops.sh -t ipv4_fcnal
 ...
 TEST: Delete route when not specifying nexthop attributes           [FAIL]

 Tests passed:  11
 Tests failed:   1

After the fix:

 # ./fib_nexthops.sh -t ipv4_fcnal
 ...
 TEST: Delete route when not specifying nexthop attributes           [ OK ]

 Tests passed:  12
 Tests failed:   0

No regressions in other tests:

 # ./fib_nexthops.sh
 ...
 Tests passed: 228
 Tests failed:   0

 # ./fib_tests.sh
 ...
 Tests passed: 186
 Tests failed:   0

Cc: stable@vger.kernel.org
Reported-by: Jonas Gorski 
Tested-by: Jonas Gorski 
Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects")
Fixes: 6bf92d70e690 ("net: ipv4: fix route with nexthop object delete warning")
Fixes: 61b91eb33a69 ("ipv4: Handle attempt to delete multipath route when fib_info contains an nh reference")
Signed-off-by: Ido Schimmel 
Reviewed-by: Nikolay Aleksandrov 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20221124210932.2470010-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

ipv4: Handle attempt to delete multipath route when fib_info contains an nh reference

2022-12-08T10:23:05+00:00

[ Upstream commit 61b91eb33a69c3be11b259c5ea484505cd79f883 ]

Gwangun Jung reported a slab-out-of-bounds access in fib_nh_match:
    fib_nh_match+0xf98/0x1130 linux-6.0-rc7/net/ipv4/fib_semantics.c:961
    fib_table_delete+0x5f3/0xa40 linux-6.0-rc7/net/ipv4/fib_trie.c:1753
    inet_rtm_delroute+0x2b3/0x380 linux-6.0-rc7/net/ipv4/fib_frontend.c:874

Separate nexthop objects are mutually exclusive with the legacy
multipath spec. Fix fib_nh_match to return if the config for the
to be deleted route contains a multipath spec while the fib_info
is using a nexthop object.

Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects")
Fixes: 6bf92d70e690 ("net: ipv4: fix route with nexthop object delete warning")
Reported-by: Gwangun Jung 
Signed-off-by: David Ahern 
Reviewed-by: Ido Schimmel 
Tested-by: Ido Schimmel 
Signed-off-by: David S. Miller 
Stable-dep-of: d5082d386eee ("ipv4: Fix route deletion when nexthop info is not specified")
Signed-off-by: Sasha Levin

ipv4: Fix a data-race around sysctl_fib_multipath_use_neigh.

2022-07-29T15:14:14+00:00

[ Upstream commit 87507bcb4f5de16bb419e9509d874f4db6c0ad0f ]

While reading sysctl_fib_multipath_use_neigh, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its reader.

Fixes: a6db4494d218 ("net: ipv4: Consider failed nexthops in multipath routes")
Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

ip: fix dflt addr selection for connected nexthop

2022-07-21T18:59:17+00:00

commit 747c14307214b55dbd8250e1ab44cad8305756f1 upstream.

When a nexthop is added, without a gw address, the default scope was set
to 'host'. Thus, when a source address is selected, 127.0.0.1 may be chosen
but rejected when the route is used.

When using a route without a nexthop id, the scope can be configured in the
route, thus the problem doesn't exist.

To explain more deeply: when a user creates a nexthop, it cannot specify
the scope. To create it, the function nh_create_ipv4() calls fib_check_nh()
with scope set to 0. fib_check_nh() calls fib_check_nh_nongw() wich was
setting scope to 'host'. Then, nh_create_ipv4() calls
fib_info_update_nhc_saddr() with scope set to 'host'. The src addr is
chosen before the route is inserted.

When a 'standard' route (ie without a reference to a nexthop) is added,
fib_create_info() calls fib_info_update_nhc_saddr() with the scope set by
the user. iproute2 set the scope to 'link' by default.

Here is a way to reproduce the problem:
ip netns add foo
ip -n foo link set lo up
ip netns add bar
ip -n bar link set lo up
sleep 1

ip -n foo link add name eth0 type dummy
ip -n foo link set eth0 up
ip -n foo address add 192.168.0.1/24 dev eth0

ip -n foo link add name veth0 type veth peer name veth1 netns bar
ip -n foo link set veth0 up
ip -n bar link set veth1 up

ip -n bar address add 192.168.1.1/32 dev veth1
ip -n bar route add default dev veth1

ip -n foo nexthop add id 1 dev veth0
ip -n foo route add 192.168.1.1 nhid 1

Try to get/use the route:
> $ ip -n foo route get 192.168.1.1
> RTNETLINK answers: Invalid argument
> $ ip netns exec foo ping -c1 192.168.1.1
> ping: connect: Invalid argument

Try without nexthop group (iproute2 sets scope to 'link' by dflt):
ip -n foo route del 192.168.1.1
ip -n foo route add 192.168.1.1 dev veth0

Try to get/use the route:
> $ ip -n foo route get 192.168.1.1
> 192.168.1.1 dev veth0 src 192.168.0.1 uid 0
>     cache
> $ ip netns exec foo ping -c1 192.168.1.1
> PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
> 64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.039 ms
>
> --- 192.168.1.1 ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> rtt min/avg/max/mdev = 0.039/0.039/0.039/0.000 ms

CC: stable@vger.kernel.org
Fixes: 597cfe4fc339 ("nexthop: Add support for IPv4 nexthops")
Reported-by: Edwin Brossette 
Signed-off-by: Nicolas Dichtel 
Link: https://lore.kernel.org/r/20220713114853.29406-1-nicolas.dichtel@6wind.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman