linux.git/net/ipv4, branch v5.13

icmp: don't send out ICMP messages with a source address of 0.0.0.0

2021-06-18T19:13:24+00:00

When constructing ICMP response messages, the kernel will try to pick a
suitable source address for the outgoing packet. However, if no IPv4
addresses are configured on the system at all, this will fail and we end up
producing an ICMP message with a source address of 0.0.0.0. This can happen
on a box routing IPv4 traffic via v6 nexthops, for instance.

Since 0.0.0.0 is not generally routable on the internet, there's a good
chance that such ICMP messages will never make it back to the sender of the
original packet that the ICMP message was sent in response to. This, in
turn, can create connectivity and PMTUd problems for senders. Fortunately,
RFC7600 reserves a dummy address to be used as a source for ICMP
messages (192.0.0.8/32), so let's teach the kernel to substitute that
address as a last resort if the regular source address selection procedure
fails.

Below is a quick example reproducing this issue with network namespaces:

ip netns add ns0
ip l add type veth peer netns ns0
ip l set dev veth0 up
ip a add 10.0.0.1/24 dev veth0
ip a add fc00:dead:cafe:42::1/64 dev veth0
ip r add 10.1.0.0/24 via inet6 fc00:dead:cafe:42::2
ip -n ns0 l set dev veth0 up
ip -n ns0 a add fc00:dead:cafe:42::2/64 dev veth0
ip -n ns0 r add 10.0.0.0/24 via inet6 fc00:dead:cafe:42::1
ip netns exec ns0 sysctl -w net.ipv4.icmp_ratelimit=0
ip netns exec ns0 sysctl -w net.ipv4.ip_forward=1
tcpdump -tpni veth0 -c 2 icmp &
ping -w 1 10.1.0.1 > /dev/null
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on veth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 29, seq 1, length 64
IP 0.0.0.0 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92
2 packets captured
2 packets received by filter
0 packets dropped by kernel

With this patch the above capture changes to:
IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 31127, seq 1, length 64
IP 192.0.0.8 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Juliusz Chroboczek 
Reviewed-by: David Ahern 
Signed-off-by: Toke Høiland-Jørgensen 
Signed-off-by: David S. Miller

net: ipv4: fix memory leak in ip_mc_add1_src

2021-06-16T19:41:01+00:00

BUG: memory leak
unreferenced object 0xffff888101bc4c00 (size 32):
  comm "syz-executor527", pid 360, jiffies 4294807421 (age 19.329s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
    01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................
  backtrace:
    [<00000000f17c5244>] kmalloc include/linux/slab.h:558 [inline]
    [<00000000f17c5244>] kzalloc include/linux/slab.h:688 [inline]
    [<00000000f17c5244>] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline]
    [<00000000f17c5244>] ip_mc_add_src+0x95f/0xdb0 net/ipv4/igmp.c:2095
    [<000000001cb99709>] ip_mc_source+0x84c/0xea0 net/ipv4/igmp.c:2416
    [<0000000052cf19ed>] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline]
    [<0000000052cf19ed>] ip_setsockopt+0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423
    [<00000000477edfbc>] raw_setsockopt+0x13d/0x170 net/ipv4/raw.c:857
    [<00000000e75ca9bb>] __sys_setsockopt+0x158/0x270 net/socket.c:2117
    [<00000000bdb993a8>] __do_sys_setsockopt net/socket.c:2128 [inline]
    [<00000000bdb993a8>] __se_sys_setsockopt net/socket.c:2125 [inline]
    [<00000000bdb993a8>] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125
    [<000000006a1ffdbd>] do_syscall_64+0x40/0x80 arch/x86/entry/common.c:47
    [<00000000b11467c4>] entry_SYSCALL_64_after_hwframe+0x44/0xae

In commit 24803f38a5c0 ("igmp: do not remove igmp souce list info when set
link down"), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed,
because it was also called in igmpv3_clear_delrec().

Rough callgraph:

inetdev_destroy
-> ip_mc_destroy_dev
     -> igmpv3_clear_delrec
        -> ip_mc_clear_src
-> RCU_INIT_POINTER(dev->ip_ptr, NULL)

However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn't
release in_dev->mc_list->sources. And RCU_INIT_POINTER() assigns the
NULL to dev->ip_ptr. As a result, in_dev cannot be obtained through
inetdev_by_index() and then in_dev->mc_list->sources cannot be released
by ip_mc_del1_src() in the sock_close. Rough call sequence goes like:

sock_close
-> __sock_release
   -> inet_release
      -> ip_mc_drop_socket
         -> inetdev_by_index
         -> ip_mc_leave_src
            -> ip_mc_del_src
               -> ip_mc_del1_src

So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free
in_dev->mc_list->sources.

Fixes: 24803f38a5c0 ("igmp: do not remove igmp souce list info ...")
Reported-by: Hulk Robot 
Signed-off-by: Chengyang Fan 
Acked-by: Hangbin Liu 
Signed-off-by: David S. Miller

ipv4: Fix device used for dst_alloc with local routes

2021-06-14T19:30:53+00:00

Oliver reported a use case where deleting a VRF device can hang
waiting for the refcnt to drop to 0. The root cause is that the dst
is allocated against the VRF device but cached on the loopback
device.

The use case (added to the selftests) has an implicit VRF crossing
due to the ordering of the FIB rules (lookup local is before the
l3mdev rule, but the problem occurs even if the FIB rules are
re-ordered with local after l3mdev because the VRF table does not
have a default route to terminate the lookup). The end result is
is that the FIB lookup returns the loopback device as the nexthop,
but the ingress device is in a VRF. The mismatch causes the dst
alloc against the VRF device but then cached on the loopback.

The fix is to bring the trick used for IPv6 (see ip6_rt_get_dev_rcu):
pick the dst alloc device based the fib lookup result but with checks
that the result has a nexthop device (e.g., not an unreachable or
prohibit entry).

Fixes: f5a0aab84b74 ("net: ipv4: dst for local input routes should use l3mdev if relevant")
Reported-by: Oliver Herms 
Signed-off-by: David Ahern 
Signed-off-by: David S. Miller

ping: Check return value of function 'ping_queue_rcv_skb'

2021-06-10T20:44:55+00:00

Function 'ping_queue_rcv_skb' not always return success, which will
also return fail. If not check the wrong return value of it, lead to function
`ping_rcv` return success.

Signed-off-by: Zheng Yongjun 
Signed-off-by: David S. Miller

udp: fix race between close() and udp_abort()

2021-06-09T21:08:41+00:00

Kaustubh reported and diagnosed a panic in udp_lib_lookup().
The root cause is udp_abort() racing with close(). Both
racing functions acquire the socket lock, but udp{v6}_destroy_sock()
release it before performing destructive actions.

We can't easily extend the socket lock scope to avoid the race,
instead use the SOCK_DEAD flag to prevent udp_abort from doing
any action when the critical race happens.

Diagnosed-and-tested-by: Kaustubh Pandey 
Fixes: 5d77dca82839 ("net: diag: support SOCK_DESTROY for UDP sockets")
Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

inet: annotate data race in inet_send_prepare() and inet_dgram_connect()

2021-06-09T20:59:53+00:00

Both functions are known to be racy when reading inet_num
as we do not want to grab locks for the common case the socket
has been bound already. The race is resolved in inet_autobind()
by reading again inet_num under the socket lock.

syzbot reported:
BUG: KCSAN: data-race in inet_send_prepare / udp_lib_get_port

write to 0xffff88812cba150e of 2 bytes by task 24135 on cpu 0:
 udp_lib_get_port+0x4b2/0xe20 net/ipv4/udp.c:308
 udp_v6_get_port+0x5e/0x70 net/ipv6/udp.c:89
 inet_autobind net/ipv4/af_inet.c:183 [inline]
 inet_send_prepare+0xd0/0x210 net/ipv4/af_inet.c:807
 inet6_sendmsg+0x29/0x80 net/ipv6/af_inet6.c:639
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812cba150e of 2 bytes by task 24132 on cpu 1:
 inet_send_prepare+0x21/0x210 net/ipv4/af_inet.c:806
 inet6_sendmsg+0x29/0x80 net/ipv6/af_inet6.c:639
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000 -> 0x9db4

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24132 Comm: syz-executor.2 Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller

net: ipv4: Remove unneed BUG() function

2021-06-08T18:36:48+00:00

When 'nla_parse_nested_deprecated' failed, it's no need to
BUG() here, return -EINVAL is ok.

Signed-off-by: Zheng Yongjun 
Signed-off-by: David S. Miller

net: ipv4: fix memory leak in netlbl_cipsov4_add_std

2021-06-08T18:36:04+00:00

Reported by syzkaller:
BUG: memory leak
unreferenced object 0xffff888105df7000 (size 64):
comm "syz-executor842", pid 360, jiffies 4294824824 (age 22.546s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000e67ed558>] kmalloc include/linux/slab.h:590 [inline]
[<00000000e67ed558>] kzalloc include/linux/slab.h:720 [inline]
[<00000000e67ed558>] netlbl_cipsov4_add_std net/netlabel/netlabel_cipso_v4.c:145 [inline]
[<00000000e67ed558>] netlbl_cipsov4_add+0x390/0x2340 net/netlabel/netlabel_cipso_v4.c:416
[<0000000006040154>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320 net/netlink/genetlink.c:739
[<00000000204d7a1c>] genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
[<00000000204d7a1c>] genl_rcv_msg+0x2bf/0x4f0 net/netlink/genetlink.c:800
[<00000000c0d6a995>] netlink_rcv_skb+0x134/0x3d0 net/netlink/af_netlink.c:2504
[<00000000d78b9d2c>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
[<000000009733081b>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
[<000000009733081b>] netlink_unicast+0x4a0/0x6a0 net/netlink/af_netlink.c:1340
[<00000000d5fd43b8>] netlink_sendmsg+0x789/0xc70 net/netlink/af_netlink.c:1929
[<000000000a2d1e40>] sock_sendmsg_nosec net/socket.c:654 [inline]
[<000000000a2d1e40>] sock_sendmsg+0x139/0x170 net/socket.c:674
[<00000000321d1969>] ____sys_sendmsg+0x658/0x7d0 net/socket.c:2350
[<00000000964e16bc>] ___sys_sendmsg+0xf8/0x170 net/socket.c:2404
[<000000001615e288>] __sys_sendmsg+0xd3/0x190 net/socket.c:2433
[<000000004ee8b6a5>] do_syscall_64+0x37/0x90 arch/x86/entry/common.c:47
[<00000000171c7cee>] entry_SYSCALL_64_after_hwframe+0x44/0xae

The memory of doi_def->map.std pointing is allocated in
netlbl_cipsov4_add_std, but no place has freed it. It should be
freed in cipso_v4_doi_free which frees the cipso DOI resource.

Fixes: 96cb8e3313c7a ("[NetLabel]: CIPSOv4 and Unlabeled packet integration")
Reported-by: Hulk Robot 
Signed-off-by: Nanyong Sun 
Acked-by: Paul Moore 
Signed-off-by: David S. Miller

net: ipconfig: Don't override command-line hostnames or domains

2021-06-02T20:27:03+00:00

If the user specifies a hostname or domain name as part of the ip=
command-line option, preserve it and don't overwrite it with one
supplied by DHCP/BOOTP.

For instance, ip=::::myhostname::dhcp will use "myhostname" rather than
ignoring and overwriting it.

Fix the comment on ic_bootp_string that suggests it only copies a string
"if not already set"; it doesn't have any such logic.

Signed-off-by: Josh Triplett 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2021-05-11T23:05:56+00:00

Daniel Borkmann says:

====================
pull-request: bpf 2021-05-11

The following pull-request contains BPF updates for your *net* tree.

We've added 13 non-merge commits during the last 8 day(s) which contain
a total of 21 files changed, 817 insertions(+), 382 deletions(-).

The main changes are:

1) Fix multiple ringbuf bugs in particular to prevent writable mmap of
   read-only pages, from Andrii Nakryiko & Thadeu Lima de Souza Cascardo.

2) Fix verifier alu32 known-const subregister bound tracking for bitwise
   operations and/or/xor, from Daniel Borkmann.

3) Reject trampoline attachment for functions with variable arguments,
   and also add a deny list of other forbidden functions, from Jiri Olsa.

4) Fix nested bpf_bprintf_prepare() calls used by various helpers by
   switching to per-CPU buffers, from Florent Revest.

5) Fix kernel compilation with BTF debug info on ppc64 due to pahole
   missing TCP-CC functions like cubictcp_init, from Martin KaFai Lau.

6) Add a kconfig entry to provide an option to disallow unprivileged
   BPF by default, from Daniel Borkmann.

7) Fix libbpf compilation for older libelf when GELF_ST_VISIBILITY()
   macro is not available, from Arnaldo Carvalho de Melo.

8) Migrate test_tc_redirect to test_progs framework as prep work
   for upcoming skb_change_head() fix & selftest, from Jussi Maki.

9) Fix a libbpf segfault in add_dummy_ksym_var() if BTF is not
   present, from Ian Rogers.

10) Fix tx_only micro-benchmark in xdpsock BPF sample with proper frame
    size, from Magnus Karlsson.
====================

Signed-off-by: David S. Miller