From d612c3f3fae221e7ea736d196581c2217304bbbc Mon Sep 17 00:00:00 2001 From: Nanyong Sun Date: Tue, 8 Jun 2021 09:51:58 +0800 Subject: net: ipv4: fix memory leak in netlbl_cipsov4_add_std 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/ipv4/cipso_ipv4.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/ipv4') diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index bfaf327e9d12..e0480c6cebaa 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c @@ -472,6 +472,7 @@ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def) kfree(doi_def->map.std->lvl.local); kfree(doi_def->map.std->cat.cipso); kfree(doi_def->map.std->cat.local); + kfree(doi_def->map.std); break; } kfree(doi_def); -- cgit v1.2.3-70-g09d2 From 5ac6b198d7e312bd10ebe7d58c64690dc59cc49a Mon Sep 17 00:00:00 2001 From: Zheng Yongjun Date: Tue, 8 Jun 2021 09:53:15 +0800 Subject: net: ipv4: Remove unneed BUG() function 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/devinet.c | 2 +- net/ipv6/addrconf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 2e35f68da40a..1c6429c353a9 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1989,7 +1989,7 @@ static int inet_set_link_af(struct net_device *dev, const struct nlattr *nla, return -EAFNOSUPPORT; if (nla_parse_nested_deprecated(tb, IFLA_INET_MAX, nla, NULL, NULL) < 0) - BUG(); + return -EINVAL; if (tb[IFLA_INET_CONF]) { nla_for_each_nested(a, tb[IFLA_INET_CONF], rem) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index b0ef65eb9bd2..701eb82acd1c 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -5827,7 +5827,7 @@ static int inet6_set_link_af(struct net_device *dev, const struct nlattr *nla, return -EAFNOSUPPORT; if (nla_parse_nested_deprecated(tb, IFLA_INET6_MAX, nla, NULL, NULL) < 0) - BUG(); + return -EINVAL; if (tb[IFLA_INET6_TOKEN]) { err = inet6_set_iftoken(idev, nla_data(tb[IFLA_INET6_TOKEN]), -- cgit v1.2.3-70-g09d2 From dcd01eeac14486b56a790f5cce9b823440ba5b34 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Jun 2021 00:59:45 -0700 Subject: inet: annotate data race in inet_send_prepare() and inet_dgram_connect() 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/af_inet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index f17870ee558b..2f94d221c00e 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -575,7 +575,7 @@ int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr, return err; } - if (!inet_sk(sk)->inet_num && inet_autobind(sk)) + if (data_race(!inet_sk(sk)->inet_num) && inet_autobind(sk)) return -EAGAIN; return sk->sk_prot->connect(sk, uaddr, addr_len); } @@ -803,7 +803,7 @@ int inet_send_prepare(struct sock *sk) sock_rps_record_flow(sk); /* We may need to bind the socket. */ - if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind && + if (data_race(!inet_sk(sk)->inet_num) && !sk->sk_prot->no_autobind && inet_autobind(sk)) return -EAGAIN; -- cgit v1.2.3-70-g09d2 From a8b897c7bcd47f4147d066e22cc01d1026d7640e Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 9 Jun 2021 11:49:01 +0200 Subject: udp: fix race between close() and udp_abort() 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 --- net/ipv4/udp.c | 10 ++++++++++ net/ipv6/udp.c | 3 +++ 2 files changed, 13 insertions(+) (limited to 'net/ipv4') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 15f5504adf5b..1307ad0d3b9e 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2607,6 +2607,9 @@ void udp_destroy_sock(struct sock *sk) { struct udp_sock *up = udp_sk(sk); bool slow = lock_sock_fast(sk); + + /* protects from races with udp_abort() */ + sock_set_flag(sk, SOCK_DEAD); udp_flush_pending_frames(sk); unlock_sock_fast(sk, slow); if (static_branch_unlikely(&udp_encap_needed_key)) { @@ -2857,10 +2860,17 @@ int udp_abort(struct sock *sk, int err) { lock_sock(sk); + /* udp{v6}_destroy_sock() sets it under the sk lock, avoid racing + * with close() + */ + if (sock_flag(sk, SOCK_DEAD)) + goto out; + sk->sk_err = err; sk->sk_error_report(sk); __udp_disconnect(sk, 0); +out: release_sock(sk); return 0; diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 199b080d418a..3fcd86f4dfdc 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1598,6 +1598,9 @@ void udpv6_destroy_sock(struct sock *sk) { struct udp_sock *up = udp_sk(sk); lock_sock(sk); + + /* protects from races with udp_abort() */ + sock_set_flag(sk, SOCK_DEAD); udp_v6_flush_pending_frames(sk); release_sock(sk); -- cgit v1.2.3-70-g09d2 From 9d44fa3e50cc91691896934d106c86e4027e61ca Mon Sep 17 00:00:00 2001 From: Zheng Yongjun Date: Thu, 10 Jun 2021 09:41:36 +0800 Subject: ping: Check return value of function 'ping_queue_rcv_skb' 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 --- net/ipv4/ping.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 1c9f71a37258..95a718397fd1 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -954,6 +954,7 @@ bool ping_rcv(struct sk_buff *skb) struct sock *sk; struct net *net = dev_net(skb->dev); struct icmphdr *icmph = icmp_hdr(skb); + bool rc = false; /* We assume the packet has already been checked by icmp_rcv */ @@ -968,14 +969,15 @@ bool ping_rcv(struct sk_buff *skb) struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); pr_debug("rcv on socket %p\n", sk); - if (skb2) - ping_queue_rcv_skb(sk, skb2); + if (skb2 && !ping_queue_rcv_skb(sk, skb2)) + rc = true; sock_put(sk); - return true; } - pr_debug("no socket, dropping\n"); - return false; + if (!rc) + pr_debug("no socket, dropping\n"); + + return rc; } EXPORT_SYMBOL_GPL(ping_rcv); -- cgit v1.2.3-70-g09d2 From b87b04f5019e821c8c6c7761f258402e43500a1f Mon Sep 17 00:00:00 2001 From: David Ahern Date: Sat, 12 Jun 2021 18:24:59 -0600 Subject: ipv4: Fix device used for dst_alloc with local routes 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 --- net/ipv4/route.c | 15 ++++++++++++++- tools/testing/selftests/net/fib_tests.sh | 25 +++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/route.c b/net/ipv4/route.c index f6787c55f6ab..6a36ac98476f 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2056,6 +2056,19 @@ martian_source: return err; } +/* get device for dst_alloc with local routes */ +static struct net_device *ip_rt_get_dev(struct net *net, + const struct fib_result *res) +{ + struct fib_nh_common *nhc = res->fi ? res->nhc : NULL; + struct net_device *dev = NULL; + + if (nhc) + dev = l3mdev_master_dev_rcu(nhc->nhc_dev); + + return dev ? : net->loopback_dev; +} + /* * NOTE. We drop all the packets that has local source * addresses, because every properly looped back packet @@ -2212,7 +2225,7 @@ local_input: } } - rth = rt_dst_alloc(l3mdev_master_dev_rcu(dev) ? : net->loopback_dev, + rth = rt_dst_alloc(ip_rt_get_dev(net, res), flags | RTCF_LOCAL, res->type, IN_DEV_ORCONF(in_dev, NOPOLICY), false); if (!rth) diff --git a/tools/testing/selftests/net/fib_tests.sh b/tools/testing/selftests/net/fib_tests.sh index 76d9487fb03c..5abe92d55b69 100755 --- a/tools/testing/selftests/net/fib_tests.sh +++ b/tools/testing/selftests/net/fib_tests.sh @@ -1384,12 +1384,37 @@ ipv4_rt_replace() ipv4_rt_replace_mpath } +# checks that cached input route on VRF port is deleted +# when VRF is deleted +ipv4_local_rt_cache() +{ + run_cmd "ip addr add 10.0.0.1/32 dev lo" + run_cmd "ip netns add test-ns" + run_cmd "ip link add veth-outside type veth peer name veth-inside" + run_cmd "ip link add vrf-100 type vrf table 1100" + run_cmd "ip link set veth-outside master vrf-100" + run_cmd "ip link set veth-inside netns test-ns" + run_cmd "ip link set veth-outside up" + run_cmd "ip link set vrf-100 up" + run_cmd "ip route add 10.1.1.1/32 dev veth-outside table 1100" + run_cmd "ip netns exec test-ns ip link set veth-inside up" + run_cmd "ip netns exec test-ns ip addr add 10.1.1.1/32 dev veth-inside" + run_cmd "ip netns exec test-ns ip route add 10.0.0.1/32 dev veth-inside" + run_cmd "ip netns exec test-ns ip route add default via 10.0.0.1" + run_cmd "ip netns exec test-ns ping 10.0.0.1 -c 1 -i 1" + run_cmd "ip link delete vrf-100" + + # if we do not hang test is a success + log_test $? 0 "Cached route removed from VRF port device" +} + ipv4_route_test() { route_setup ipv4_rt_add ipv4_rt_replace + ipv4_local_rt_cache route_cleanup } -- cgit v1.2.3-70-g09d2 From d8e2973029b8b2ce477b564824431f3385c77083 Mon Sep 17 00:00:00 2001 From: Chengyang Fan Date: Wed, 16 Jun 2021 17:59:25 +0800 Subject: net: ipv4: fix memory leak in ip_mc_add1_src 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 --- net/ipv4/igmp.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/ipv4') diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 7b272bbed2b4..6b3c558a4f23 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -1801,6 +1801,7 @@ void ip_mc_destroy_dev(struct in_device *in_dev) while ((i = rtnl_dereference(in_dev->mc_list)) != NULL) { in_dev->mc_list = i->next_rcu; in_dev->mc_count--; + ip_mc_clear_src(i); ip_ma_put(i); } } -- cgit v1.2.3-70-g09d2 From 321827477360934dc040e9d3c626bf1de6c3ab3c Mon Sep 17 00:00:00 2001 From: Toke Høiland-Jørgensen Date: Fri, 18 Jun 2021 13:04:35 +0200 Subject: icmp: don't send out ICMP messages with a source address of 0.0.0.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- include/uapi/linux/in.h | 3 +++ net/ipv4/icmp.c | 7 +++++++ 2 files changed, 10 insertions(+) (limited to 'net/ipv4') diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h index 7d6687618d80..d1b327036ae4 100644 --- a/include/uapi/linux/in.h +++ b/include/uapi/linux/in.h @@ -289,6 +289,9 @@ struct sockaddr_in { /* Address indicating an error return. */ #define INADDR_NONE ((unsigned long int) 0xffffffff) +/* Dummy address for src of ICMP replies if no real address is set (RFC7600). */ +#define INADDR_DUMMY ((unsigned long int) 0xc0000008) + /* Network number for local host loopback. */ #define IN_LOOPBACKNET 127 diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 7b6931a4d775..752e392083e6 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -759,6 +759,13 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, icmp_param.data_len = room; icmp_param.head_len = sizeof(struct icmphdr); + /* if we don't have a source address at this point, fall back to the + * dummy address instead of sending out a packet with a source address + * of 0.0.0.0 + */ + if (!fl4.saddr) + fl4.saddr = htonl(INADDR_DUMMY); + icmp_push_reply(&icmp_param, &fl4, &ipc, &rt); ende: ip_rt_put(rt); -- cgit v1.2.3-70-g09d2