kernel/net/ipv6, branch linux-5.1.y

ipv6: Unlink sibling route in case of failure

2019-07-28T06:28:25Z

[ Upstream commit 54851aa90cf27041d64b12f65ac72e9f97bd90fd ] When a route needs to be appended to an existing multipath route, fib6_add_rt2node() first appends it to the siblings list and increments the number of sibling routes on each sibling. Later, the function notifies the route via call_fib6_entry_notifiers(). In case the notification is vetoed, the route is not unlinked from the siblings list, which can result in a use-after-free. Fix this by unlinking the route from the siblings list before returning an error. Audited the rest of the call sites from which the FIB notification chain is called and could not find more problems. Fixes: 2233000cba40 ("net/ipv6: Move call_fib6_entry_notifiers up for route adds") Signed-off-by: Ido Schimmel Reported-by: Alexander Petrovskiy Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: rt6_check should return NULL if 'from' is NULL

2019-07-28T06:28:25Z

[ Upstream commit 49d05fe2c9d1b4a27761c9807fec39b8155bef9e ] Paul reported that l2tp sessions were broken after the commit referenced in the Fixes tag. Prior to this commit rt6_check returned NULL if the rt6_info 'from' was NULL - ie., the dst_entry was disconnected from a FIB entry. Restore that behavior. Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes") Reported-by: Paul Donohue Tested-by: Paul Donohue Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

netfilter: ipv6: nf_defrag: accept duplicate fragments again

2019-07-14T06:09:38Z

[ Upstream commit 8a3dca632538c550930ce8bafa8c906b130d35cf ] When fixing the skb leak introduced by the conversion to rbtree, I forgot about the special case of duplicate fragments. The condition under the 'insert_error' label isn't effective anymore as nf_ct_frg6_gather() doesn't override the returned value anymore. So duplicate fragments now get NF_DROP verdict. To accept duplicate fragments again, handle them specially as soon as inet_frag_queue_insert() reports them. Return -EINPROGRESS which will translate to NF_STOLEN verdict, like any accepted fragment. However, such packets don't carry any new information and aren't queued, so we just drop them immediately. Fixes: a0d56cb911ca ("netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments") Signed-off-by: Guillaume Nault Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

netfilter: ipv6: nf_defrag: fix leakage of unqueued fragments

2019-07-14T06:09:38Z

[ Upstream commit a0d56cb911ca301de81735f1d73c2aab424654ba ] With commit 997dd9647164 ("net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c"), nf_ct_frag6_reasm() is now called from nf_ct_frag6_queue(). With this change, nf_ct_frag6_queue() can fail after the skb has been added to the fragment queue and nf_ct_frag6_gather() was adapted to handle this case. But nf_ct_frag6_queue() can still fail before the fragment has been queued. nf_ct_frag6_gather() can't handle this case anymore, because it has no way to know if nf_ct_frag6_queue() queued the fragment before failing. If it didn't, the skb is lost as the error code is overwritten with -EINPROGRESS. Fix this by setting -EINPROGRESS directly in nf_ct_frag6_queue(), so that nf_ct_frag6_gather() can propagate the error as is. Fixes: 997dd9647164 ("net: IP6 defrag: use rbtrees in nf_conntrack_reasm.c") Signed-off-by: Guillaume Nault Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

bpf: udp: ipv6: Avoid running reuseport's bpf_prog from __udp6_lib_err

2019-07-03T11:13:43Z

commit 4ac30c4b3659efac031818c418beb51e630d512d upstream. __udp6_lib_err() may be called when handling icmpv6 message. For example, the icmpv6 toobig(type=2). __udp6_lib_lookup() is then called which may call reuseport_select_sock(). reuseport_select_sock() will call into a bpf_prog (if there is one). reuseport_select_sock() is expecting the skb->data pointing to the transport header (udphdr in this case). For example, run_bpf_filter() is pulling the transport header. However, in the __udp6_lib_err() path, the skb->data is pointing to the ipv6hdr instead of the udphdr. One option is to pull and push the ipv6hdr in __udp6_lib_err(). Instead of doing this, this patch follows how the original commit 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF") was done in IPv4, which has passed a NULL skb pointer to reuseport_select_sock(). Fixes: 538950a1b752 ("soreuseport: setsockopt SO_ATTACH_REUSEPORT_[CE]BPF") Cc: Craig Gallek Signed-off-by: Martin KaFai Lau Acked-by: Song Liu Acked-by: Craig Gallek Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman

bpf: udp: Avoid calling reuseport's bpf_prog from udp_gro

2019-07-03T11:13:43Z

commit 257a525fe2e49584842c504a92c27097407f778f upstream. When the commit a6024562ffd7 ("udp: Add GRO functions to UDP socket") added udp[46]_lib_lookup_skb to the udp_gro code path, it broke the reuseport_select_sock() assumption that skb->data is pointing to the transport header. This patch follows an earlier __udp6_lib_err() fix by passing a NULL skb to avoid calling the reuseport's bpf_prog. Fixes: a6024562ffd7 ("udp: Add GRO functions to UDP socket") Cc: Tom Herbert Signed-off-by: Martin KaFai Lau Acked-by: Song Liu Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman

bpf: fix unconnected udp hooks

2019-07-03T11:13:43Z

commit 983695fa676568fc0fe5ddd995c7267aabc24632 upstream. Intention of cgroup bind/connect/sendmsg BPF hooks is to act transparently to applications as also stated in original motivation in 7828f20e3779 ("Merge branch 'bpf-cgroup-bind-connect'"). When recently integrating the latter two hooks into Cilium to enable host based load-balancing with Kubernetes, I ran into the issue that pods couldn't start up as DNS got broken. Kubernetes typically sets up DNS as a service and is thus subject to load-balancing. Upon further debugging, it turns out that the cgroupv2 sendmsg BPF hooks API is currently insufficient and thus not usable as-is for standard applications shipped with most distros. To break down the issue we ran into with a simple example: # cat /etc/resolv.conf nameserver 147.75.207.207 nameserver 147.75.207.208 For the purpose of a simple test, we set up above IPs as service IPs and transparently redirect traffic to a different DNS backend server for that node: # cilium service list ID Frontend Backend 1 147.75.207.207:53 1 => 8.8.8.8:53 2 147.75.207.208:53 1 => 8.8.8.8:53 The attached BPF program is basically selecting one of the backends if the service IP/port matches on the cgroup hook. DNS breaks here, because the hooks are not transparent enough to applications which have built-in msg_name address checks: # nslookup 1.1.1.1 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.208#53 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53 [...] ;; connection timed out; no servers could be reached # dig 1.1.1.1 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.208#53 ;; reply from unexpected source: 8.8.8.8#53, expected 147.75.207.207#53 [...] ; <<>> DiG 9.11.3-1ubuntu1.7-Ubuntu <<>> 1.1.1.1 ;; global options: +cmd ;; connection timed out; no servers could be reached For comparison, if none of the service IPs is used, and we tell nslookup to use 8.8.8.8 directly it works just fine, of course: # nslookup 1.1.1.1 8.8.8.8 1.1.1.1.in-addr.arpa name = one.one.one.one. In order to fix this and thus act more transparent to the application, this needs reverse translation on recvmsg() side. A minimal fix for this API is to add similar recvmsg() hooks behind the BPF cgroups static key such that the program can track state and replace the current sockaddr_in{,6} with the original service IP. From BPF side, this basically tracks the service tuple plus socket cookie in an LRU map where the reverse NAT can then be retrieved via map value as one example. Side-note: the BPF cgroups static key should be converted to a per-hook static key in future. Same example after this fix: # cilium service list ID Frontend Backend 1 147.75.207.207:53 1 => 8.8.8.8:53 2 147.75.207.208:53 1 => 8.8.8.8:53 Lookups work fine now: # nslookup 1.1.1.1 1.1.1.1.in-addr.arpa name = one.one.one.one. Authoritative answers can be found from: # dig 1.1.1.1 ; <<>> DiG 9.11.3-1ubuntu1.7-Ubuntu <<>> 1.1.1.1 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 51550 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;1.1.1.1. IN A ;; AUTHORITY SECTION: . 23426 IN SOA a.root-servers.net. nstld.verisign-grs.com. 2019052001 1800 900 604800 86400 ;; Query time: 17 msec ;; SERVER: 147.75.207.207#53(147.75.207.207) ;; WHEN: Tue May 21 12:59:38 UTC 2019 ;; MSG SIZE rcvd: 111 And from an actual packet level it shows that we're using the back end server when talking via 147.75.207.20{7,8} front end: # tcpdump -i any udp [...] 12:59:52.698732 IP foo.42011 > google-public-dns-a.google.com.domain: 18803+ PTR? 1.1.1.1.in-addr.arpa. (38) 12:59:52.698735 IP foo.42011 > google-public-dns-a.google.com.domain: 18803+ PTR? 1.1.1.1.in-addr.arpa. (38) 12:59:52.701208 IP google-public-dns-a.google.com.domain > foo.42011: 18803 1/0/0 PTR one.one.one.one. (67) 12:59:52.701208 IP google-public-dns-a.google.com.domain > foo.42011: 18803 1/0/0 PTR one.one.one.one. (67) [...] In order to be flexible and to have same semantics as in sendmsg BPF programs, we only allow return codes in [1,1] range. In the sendmsg case the program is called if msg->msg_name is present which can be the case in both, connected and unconnected UDP. The former only relies on the sockaddr_in{,6} passed via connect(2) if passed msg->msg_name was NULL. Therefore, on recvmsg side, we act in similar way to call into the BPF program whenever a non-NULL msg->msg_name was passed independent of sk->sk_state being TCP_ESTABLISHED or not. Note that for TCP case, the msg->msg_name is ignored in the regular recvmsg path and therefore not relevant. For the case of ip{,v6}_recv_error() paths, picked up via MSG_ERRQUEUE, the hook is not called. This is intentional as it aligns with the same semantics as in case of TCP cgroup BPF hooks right now. This might be better addressed in future through a different bpf_attach_type such that this case can be distinguished from the regular recvmsg paths, for example. Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg") Signed-off-by: Daniel Borkmann Acked-by: Andrey Ignatov Acked-by: Martin KaFai Lau Acked-by: Martynas Pumputis Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

netfilter: nft_fib: Fix existence check support

2019-06-22T06:09:08Z

[ Upstream commit e633508a95289489d28faacb68b32c3e7e68ef6f ] NFTA_FIB_F_PRESENT flag was not always honored since eval functions did not call nft_fib_store_result in all cases. Given that in all callsites there is a struct net_device pointer available which holds the interface data to be stored in destination register, simplify nft_fib_store_result() to just accept that pointer instead of the nft_pktinfo pointer and interface index. This also allows to drop the index to interface lookup previously needed to get the name associated with given index. Fixes: 055c4b34b94f6 ("netfilter: nft_fib: Support existence check") Signed-off-by: Phil Sutter Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin

net: correct udp zerocopy refcnt also when zerocopy only on append

2019-06-22T06:09:07Z

[ Upstream commit 522924b583082f51b8a2406624a2f27c22119b20 ] The below patch fixes an incorrect zerocopy refcnt increment when appending with MSG_MORE to an existing zerocopy udp skb. send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt 1 send(.., MSG_ZEROCOPY | MSG_MORE); // refcnt still 1 (bar frags) But it missed that zerocopy need not be passed at the first send. The right test whether the uarg is newly allocated and thus has extra refcnt 1 is not !skb, but !skb_zcopy. send(.., MSG_MORE); // send(.., MSG_ZEROCOPY); // refcnt 1 Fixes: 100f6d8e09905 ("net: correct zerocopy refcnt with udp MSG_MORE") Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipv6: flowlabel: fl6_sock_lookup() must use atomic_inc_not_zero

2019-06-22T06:09:03Z

[ Upstream commit 65a3c497c0e965a552008db8bc2653f62bc925a1 ] Before taking a refcount, make sure the object is not already scheduled for deletion. Same fix is needed in ipv6_flowlabel_opt() Fixes: 18367681a10b ("ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.") Signed-off-by: Eric Dumazet Cc: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman