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2020-07-26bpf: Refactor to provide aux info to bpf_iter_init_seq_priv_tYonghong Song1-2/+2
This patch refactored target bpf_iter_init_seq_priv_t callback function to accept additional information. This will be needed in later patches for map element targets since a particular map should be passed to traverse elements for that particular map. In the future, other information may be passed to target as well, e.g., pid, cgroup id, etc. to customize the iterator. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200723184110.590156-1-yhs@fb.com
2020-07-26bpf: Refactor bpf_iter_reg to have separate seq_info memberYonghong Song1-2/+6
There is no functionality change for this patch. Struct bpf_iter_reg is used to register a bpf_iter target, which includes information for both prog_load, link_create and seq_file creation. This patch puts fields related seq_file creation into a different structure. This will be useful for map elements iterator where one iterator covers different map types and different map types may have different seq_ops, init/fini private_data function and private_data size. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200723184109.590030-1-yhs@fb.com
2020-07-25net/tcp: switch ->md5_parse to sockptr_tChristoph Hellwig1-2/+2
Pass a sockptr_t to prepare for set_fs-less handling of the kernel pointer from bpf-cgroup. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller1-1/+3
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-07-21 The following pull-request contains BPF updates for your *net-next* tree. We've added 46 non-merge commits during the last 6 day(s) which contain a total of 68 files changed, 4929 insertions(+), 526 deletions(-). The main changes are: 1) Run BPF program on socket lookup, from Jakub. 2) Introduce cpumap, from Lorenzo. 3) s390 JIT fixes, from Ilya. 4) teach riscv JIT to emit compressed insns, from Luke. 5) use build time computed BTF ids in bpf iter, from Yonghong. ==================== Purely independent overlapping changes in both filter.h and xdp.h Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-21bpf: net: Use precomputed btf_id for bpf iteratorsYonghong Song1-1/+3
One additional field btf_id is added to struct bpf_ctx_arg_aux to store the precomputed btf_ids. The btf_id is computed at build time with BTF_ID_LIST or BTF_ID_LIST_GLOBAL macro definitions. All existing bpf iterators are changed to used pre-compute btf_ids. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200720163403.1393551-1-yhs@fb.com
2020-07-20net/ipv6: remove compat_ipv6_{get,set}sockoptChristoph Hellwig1-4/+0
Handle the few cases that need special treatment in-line using in_compat_syscall(). This also removes all the now unused compat_{get,set}sockopt methods. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-20net/ipv4: remove compat_ip_{get,set}sockoptChristoph Hellwig1-4/+0
Handle the few cases that need special treatment in-line using in_compat_syscall(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-4/+16
All conflicts seemed rather trivial, with some guidance from Saeed Mameed on the tc_ct.c one. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-02tcp: md5: refine tcp_md5_do_add()/tcp_md5_hash_key() barriersEric Dumazet1-5/+14
My prior fix went a bit too far, according to Herbert and Mathieu. Since we accept that concurrent TCP MD5 lookups might see inconsistent keys, we can use READ_ONCE()/WRITE_ONCE() instead of smp_rmb()/smp_wmb() Clearing all key->key[] is needed to avoid possible KMSAN reports, if key->keylen is increased. Since tcp_md5_do_add() is not fast path, using __GFP_ZERO to clear all struct tcp_md5sig_key is simpler. data_race() was added in linux-5.8 and will prevent KCSAN reports, this can safely be removed in stable backports, if data_race() is not yet backported. v2: use data_race() both in tcp_md5_hash_key() and tcp_md5_do_add() Fixes: 6a2febec338d ("tcp: md5: add missing memory barriers in tcp_md5_do_add()/tcp_md5_hash_key()") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Marco Elver <elver@google.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-01tcp: md5: add missing memory barriers in tcp_md5_do_add()/tcp_md5_hash_key()Eric Dumazet1-0/+3
MD5 keys are read with RCU protection, and tcp_md5_do_add() might update in-place a prior key. Normally, typical RCU updates would allocate a new piece of memory. In this case only key->key and key->keylen might be updated, and we do not care if an incoming packet could see the old key, the new one, or some intermediate value, since changing the key on a live flow is known to be problematic anyway. We only want to make sure that in the case key->keylen is changed, cpus in tcp_md5_hash_key() wont try to use uninitialized data, or crash because key->keylen was read twice to feed sg_init_one() and ahash_request_set_crypt() Fixes: 9ea88a153001 ("tcp: md5: check md5 signature without socket lock") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-25net: bpf: Implement bpf iterator for tcpYonghong Song1-0/+123
The bpf iterator for tcp is implemented. Both tcp4 and tcp6 sockets will be traversed. It is up to bpf program to filter for tcp4 or tcp6 only, or both families of sockets. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230805.3987959-1-yhs@fb.com
2020-06-25net: bpf: Add bpf_seq_afinfo in tcp_iter_stateYonghong Song1-6/+24
A new field bpf_seq_afinfo is added to tcp_iter_state to provide bpf tcp iterator afinfo. There are two reasons on why we did this. First, the current way to get afinfo from PDE_DATA does not work for bpf iterator as its seq_file inode does not conform to /proc/net/{tcp,tcp6} inode structures. More specifically, anonymous bpf iterator will use an anonymous inode which is shared in the system and we cannot change inode private data structure at all. Second, bpf iterator for tcp/tcp6 wants to traverse all tcp and tcp6 sockets in one pass and bpf program can control whether they want to skip one sk_family or not. Having a different afinfo with family AF_UNSPEC make it easier to understand in the code. This patch does not change /proc/net/{tcp,tcp6} behavior as the bpf_seq_afinfo will be NULL for these two proc files. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230804.3987829-1-yhs@fb.com
2020-05-28tcp: ipv6: support RFC 6069 (TCP-LD)Eric Dumazet1-1/+2
Make tcp_ld_RTO_revert() helper available to IPv6, and implement RFC 6069 : Quoting this RFC : 3. Connectivity Disruption Indication For Internet Protocol version 6 (IPv6) [RFC2460], the counterpart of the ICMP destination unreachable message of code 0 (net unreachable) and of code 1 (host unreachable) is the ICMPv6 destination unreachable message of code 0 (no route to destination) [RFC4443]. As with IPv4, a router should generate an ICMPv6 destination unreachable message of code 0 in response to a packet that cannot be delivered to its destination address because it lacks a matching entry in its routing table. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-28tcp: rename tcp_v4_err() skb parameterEric Dumazet1-9/+9
This essentially reverts 4d1a2d9ec1c1 ("Revert Backoff [v3]: Rename skb to icmp_skb in tcp_v4_err()") Now we have tcp_ld_RTO_revert() helper, we can use the usual name for sk_buff parameter, so that tcp_v4_err() and tcp_v6_err() use similar names. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-28tcp: add tcp_ld_RTO_revert() helperEric Dumazet1-40/+45
RFC 6069 logic has been implemented for IPv4 only so far, right in the middle of tcp_v4_err() and was error prone. Move this code to one helper, to make tcp_v4_err() more readable and to eventually expand RFC 6069 to IPv6 in the future. Also perform sock_owned_by_user() check a bit sooner. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-27tcp: tcp_v4_err() icmp skb is named icmp_skbEric Dumazet1-1/+1
I missed the fact that tcp_v4_err() differs from tcp_v6_err(). After commit 4d1a2d9ec1c1 ("Rename skb to icmp_skb in tcp_v4_err()") the skb argument has been renamed to icmp_skb only in one function. I will in a future patch reconciliate these functions to avoid this kind of confusion. Fixes: 45af29ca761c ("tcp: allow traceroute -Mtcp for unpriv users") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-26tcp: allow traceroute -Mtcp for unpriv usersEric Dumazet1-0/+2
Unpriv users can use traceroute over plain UDP sockets, but not TCP ones. $ traceroute -Mtcp 8.8.8.8 You do not have enough privileges to use this traceroute method. $ traceroute -n -Mudp 8.8.8.8 traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets 1 192.168.86.1 3.631 ms 3.512 ms 3.405 ms 2 10.1.10.1 4.183 ms 4.125 ms 4.072 ms 3 96.120.88.125 20.621 ms 19.462 ms 20.553 ms 4 96.110.177.65 24.271 ms 25.351 ms 25.250 ms 5 69.139.199.197 44.492 ms 43.075 ms 44.346 ms 6 68.86.143.93 27.969 ms 25.184 ms 25.092 ms 7 96.112.146.18 25.323 ms 96.112.146.22 25.583 ms 96.112.146.26 24.502 ms 8 72.14.239.204 24.405 ms 74.125.37.224 16.326 ms 17.194 ms 9 209.85.251.9 18.154 ms 209.85.247.55 14.449 ms 209.85.251.9 26.296 ms^C We can easily support traceroute over TCP, by queueing an error message into socket error queue. Note that applications need to set IP_RECVERR/IPV6_RECVERR option to enable this feature, and that the error message is only queued while in SYN_SNT state. socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0 setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0 setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0 connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host) recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}], msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}}, {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}], msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144 Suggested-by: Maciej Żenczykowski <maze@google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-30tcp: add hrtimer slack to sack compressionEric Dumazet1-0/+1
Add a sysctl to control hrtimer slack, default of 100 usec. This gives the opportunity to reduce system overhead, and help very short RTT flows. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-13inet: Use fallthrough;Joe Perches1-2/+2
Convert the various uses of fallthrough comments to fallthrough; Done via script Link: https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/ And by hand: net/ipv6/ip6_fib.c has a fallthrough comment outside of an #ifdef block that causes gcc to emit a warning if converted in-place. So move the new fallthrough; inside the containing #ifdef/#endif too. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-25tcp: ipv4: Pass lockdep expression to RCU listsAmol Grover1-2/+4
md5sig->head maybe traversed using hlist_for_each_entry_rcu outside an RCU read-side critical section but under the protection of socket lock. Hence, add corresponding lockdep expression to silence false-positive warnings, and harden RCU lists. Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller1-2/+4
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-01-22 The following pull-request contains BPF updates for your *net-next* tree. We've added 92 non-merge commits during the last 16 day(s) which contain a total of 320 files changed, 7532 insertions(+), 1448 deletions(-). The main changes are: 1) function by function verification and program extensions from Alexei. 2) massive cleanup of selftests/bpf from Toke and Andrii. 3) batched bpf map operations from Brian and Yonghong. 4) tcp congestion control in bpf from Martin. 5) bulking for non-map xdp_redirect form Toke. 6) bpf_send_signal_thread helper from Yonghong. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-10tcp: Export TCP functions and ops structMat Martineau1-1/+1
MPTCP will make use of tcp_send_mss() and tcp_push() when sending data to specific TCP subflows. tcp_request_sock_ipvX_ops and ipvX_specific will be referenced during TCP subflow creation. Co-developed-by: Peter Krystad <peter.krystad@linux.intel.com> Signed-off-by: Peter Krystad <peter.krystad@linux.intel.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-09bpf: tcp: Support tcp_congestion_ops in bpfMartin KaFai Lau1-2/+4
This patch makes "struct tcp_congestion_ops" to be the first user of BPF STRUCT_OPS. It allows implementing a tcp_congestion_ops in bpf. The BPF implemented tcp_congestion_ops can be used like regular kernel tcp-cc through sysctl and setsockopt. e.g. [root@arch-fb-vm1 bpf]# sysctl -a | egrep congestion net.ipv4.tcp_allowed_congestion_control = reno cubic bpf_cubic net.ipv4.tcp_available_congestion_control = reno bic cubic bpf_cubic net.ipv4.tcp_congestion_control = bpf_cubic There has been attempt to move the TCP CC to the user space (e.g. CCP in TCP). The common arguments are faster turn around, get away from long-tail kernel versions in production...etc, which are legit points. BPF has been the continuous effort to join both kernel and userspace upsides together (e.g. XDP to gain the performance advantage without bypassing the kernel). The recent BPF advancements (in particular BTF-aware verifier, BPF trampoline, BPF CO-RE...) made implementing kernel struct ops (e.g. tcp cc) possible in BPF. It allows a faster turnaround for testing algorithm in the production while leveraging the existing (and continue growing) BPF feature/framework instead of building one specifically for userspace TCP CC. This patch allows write access to a few fields in tcp-sock (in bpf_tcp_ca_btf_struct_access()). The optional "get_info" is unsupported now. It can be added later. One possible way is to output the info with a btf-id to describe the content. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200109003508.3856115-1-kafai@fb.com
2020-01-03net: Add device index to tcp_md5sigDavid Ahern1-0/+18
Add support for userspace to specify a device index to limit the scope of an entry via the TCP_MD5SIG_EXT setsockopt. The existing __tcpm_pad is renamed to tcpm_ifindex and the new field is only checked if the new TCP_MD5SIG_FLAG_IFINDEX is set in tcpm_flags. For now, the device index must point to an L3 master device (e.g., VRF). The API and error handling are setup to allow the constraint to be relaxed in the future to any device index. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-03tcp: Add l3index to tcp_md5sig_key and md5 functionsDavid Ahern1-20/+48
Add l3index to tcp_md5sig_key to represent the L3 domain of a key, and add l3index to tcp_md5_do_add and tcp_md5_do_del to fill in the key. With the key now based on an l3index, add the new parameter to the lookup functions and consider the l3index when looking for a match. The l3index comes from the skb when processing ingress packets leveraging the helpers created for socket lookups, tcp_v4_sdif and inet_iif (and the v6 variants). When the sdif index is set it means the packet ingressed a device that is part of an L3 domain and inet_iif points to the VRF device. For egress, the L3 domain is determined from the socket binding and sk_bound_dev_if. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-03ipv4/tcp: Pass dif and sdif to tcp_v4_inbound_md5_hashDavid Ahern1-5/+8
The original ingress device index is saved to the cb space of the skb and the cb is moved during tcp processing. Since tcp_v4_inbound_md5_hash can be called before and after the cb move, pass dif and sdif to it so the caller can save both prior to the cb move. Both are used by a later patch. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-01-03ipv4/tcp: Use local variable for tcp_md5_addrDavid Ahern1-17/+26
Extract the typecast to (union tcp_md5_addr *) to a local variable rather than the current long, inline declaration with function calls. No functional change intended. Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-3/+4
Mere overlapping changes in the conflicts here. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-14tcp/dccp: fix possible race __inet_lookup_established()Eric Dumazet1-3/+4
Michal Kubecek and Firo Yang did a very nice analysis of crashes happening in __inet_lookup_established(). Since a TCP socket can go from TCP_ESTABLISH to TCP_LISTEN (via a close()/socket()/listen() cycle) without a RCU grace period, I should not have changed listeners linkage in their hash table. They must use the nulls protocol (Documentation/RCU/rculist_nulls.txt), so that a lookup can detect a socket in a hash list was moved in another one. Since we added code in commit d296ba60d8e2 ("soreuseport: Resolve merge conflict for v4/v6 ordering fix"), we have to add hlist_nulls_add_tail_rcu() helper. Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Michal Kubecek <mkubecek@suse.cz> Reported-by: Firo Yang <firo.yang@suse.com> Reviewed-by: Michal Kubecek <mkubecek@suse.cz> Link: https://lore.kernel.org/netdev/20191120083919.GH27852@unicorn.suse.cz/ Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-12-10net-tcp: Disable TCP ssthresh metrics cache by defaultKevin(Yudong) Yang1-0/+1
This patch introduces a sysctl knob "net.ipv4.tcp_no_ssthresh_metrics_save" that disables TCP ssthresh metrics cache by default. Other parts of TCP metrics cache, e.g. rtt, cwnd, remain unchanged. As modern networks becoming more and more dynamic, TCP metrics cache today often causes more harm than benefits. For example, the same IP address is often shared by different subscribers behind NAT in residential networks. Even if the IP address is not shared by different users, caching the slow-start threshold of a previous short flow using loss-based congestion control (e.g. cubic) often causes the future longer flows of the same network path to exit slow-start prematurely with abysmal throughput. Caching ssthresh is very risky and can lead to terrible performance. Therefore it makes sense to make disabling ssthresh caching by default and opt-in for specific networks by the administrators. This practice also has worked well for several years of deployment with CUBIC congestion control at Google. Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Kevin(Yudong) Yang <yyd@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-07net: annotate lockless accesses to sk->sk_ack_backlogEric Dumazet1-1/+1
sk->sk_ack_backlog can be read without any lock being held. We need to use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing and/or potential KCSAN warnings. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-3/+3
The only slightly tricky merge conflict was the netdevsim because the mutex locking fix overlapped a lot of driver reload reorganization. The rest were (relatively) trivial in nature. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-02inet: stop leaking jiffies on the wireEric Dumazet1-2/+2
Historically linux tried to stick to RFC 791, 1122, 2003 for IPv4 ID field generation. RFC 6864 made clear that no matter how hard we try, we can not ensure unicity of IP ID within maximum lifetime for all datagrams with a given source address/destination address/protocol tuple. Linux uses a per socket inet generator (inet_id), initialized at connection startup with a XOR of 'jiffies' and other fields that appear clear on the wire. Thiemo Nagel pointed that this strategy is a privacy concern as this provides 16 bits of entropy to fingerprint devices. Let's switch to a random starting point, this is just as good as far as RFC 6864 is concerned and does not leak anything critical. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Thiemo Nagel <tnagel@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-01tcp: increase tcp_max_syn_backlog max valueEric Dumazet1-1/+1
tcp_max_syn_backlog default value depends on memory size and TCP ehash size. Before this patch, the max value was 2048 [1], which is considered too small nowadays. Increase it to 4096 to match the recent SOMAXCONN change. [1] This is with TCP ehash size being capped to 524288 buckets. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Yue Cao <ycao009@ucr.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-13/+17
Several cases of overlapping changes which were for the most part trivially resolvable. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-13tcp: annotate tp->write_seq lockless readsEric Dumazet1-9/+12
There are few places where we fetch tp->write_seq while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-13tcp: annotate tp->copied_seq lockless readsEric Dumazet1-1/+1
There are few places where we fetch tp->copied_seq while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Note that tcp_inq_hint() was already using READ_ONCE(tp->copied_seq) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-13tcp: annotate tp->rcv_nxt lockless readsEric Dumazet1-1/+2
There are few places where we fetch tp->rcv_nxt while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Note that tcp_inq_hint() was already using READ_ONCE(tp->rcv_nxt) syzbot reported : BUG: KCSAN: data-race in tcp_poll / tcp_queue_rcv write to 0xffff888120425770 of 4 bytes by interrupt on cpu 0: tcp_rcv_nxt_update net/ipv4/tcp_input.c:3365 [inline] tcp_queue_rcv+0x180/0x380 net/ipv4/tcp_input.c:4638 tcp_rcv_established+0xbf1/0xf50 net/ipv4/tcp_input.c:5616 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1542 tcp_v4_rcv+0x1a03/0x1bf0 net/ipv4/tcp_ipv4.c:1923 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 read to 0xffff888120425770 of 4 bytes by task 7254 on cpu 1: tcp_stream_is_readable net/ipv4/tcp.c:480 [inline] tcp_poll+0x204/0x6b0 net/ipv4/tcp.c:554 sock_poll+0xed/0x250 net/socket.c:1256 vfs_poll include/linux/poll.h:90 [inline] ep_item_poll.isra.0+0x90/0x190 fs/eventpoll.c:892 ep_send_events_proc+0x113/0x5c0 fs/eventpoll.c:1749 ep_scan_ready_list.constprop.0+0x189/0x500 fs/eventpoll.c:704 ep_send_events fs/eventpoll.c:1793 [inline] ep_poll+0xe3/0x900 fs/eventpoll.c:1930 do_epoll_wait+0x162/0x180 fs/eventpoll.c:2294 __do_sys_epoll_pwait fs/eventpoll.c:2325 [inline] __se_sys_epoll_pwait fs/eventpoll.c:2311 [inline] __x64_sys_epoll_pwait+0xcd/0x170 fs/eventpoll.c:2311 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 7254 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-13tcp: add rcu protection around tp->fastopen_rskEric Dumazet1-2/+2
Both tcp_v4_err() and tcp_v6_err() do the following operations while they do not own the socket lock : fastopen = tp->fastopen_rsk; snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; The problem is that without appropriate barrier, the compiler might reload tp->fastopen_rsk and trigger a NULL deref. request sockets are protected by RCU, we can simply add the missing annotations and barriers to solve the issue. Fixes: 168a8f58059a ("tcp: TCP Fast Open Server - main code path") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-10net: silence KCSAN warnings around sk_add_backlog() callsEric Dumazet1-1/+1
sk_add_backlog() callers usually read sk->sk_rcvbuf without owning the socket lock. This means sk_rcvbuf value can be changed by other cpus, and KCSAN complains. Add READ_ONCE() annotations to document the lockless nature of these reads. Note that writes over sk_rcvbuf should also use WRITE_ONCE(), but this will be done in separate patches to ease stable backports (if we decide this is relevant for stable trees). BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1: __sk_add_backlog include/net/sock.h:902 [inline] sk_add_backlog include/net/sock.h:933 [inline] tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x3ae/0xa50 net/core/dev.c:6418 read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0: tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-10-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-1/+1
2019-10-01tcp: add ipv6_addr_v4mapped_loopback() helperEric Dumazet1-4/+2
tcp_twsk_unique() has a hard coded assumption about ipv4 loopback being 127/8 Lets instead use the standard ipv4_is_loopback() method, in a new ipv6_addr_v4mapped_loopback() helper. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-01netfilter: drop bridge nf reset from nf_resetFlorian Westphal1-1/+1
commit 174e23810cd31 ("sk_buff: drop all skb extensions on free and skb scrubbing") made napi recycle always drop skb extensions. The additional skb_ext_del() that is performed via nf_reset on napi skb recycle is not needed anymore. Most nf_reset() calls in the stack are there so queued skb won't block 'rmmod nf_conntrack' indefinitely. This removes the skb_ext_del from nf_reset, and renames it to a more fitting nf_reset_ct(). In a few selected places, add a call to skb_ext_reset to make sure that no active extensions remain. I am submitting this for "net", because we're still early in the release cycle. The patch applies to net-next too, but I think the rename causes needless divergence between those trees. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2019-09-27tcp: honor SO_PRIORITY in TIME_WAIT stateEric Dumazet1-0/+4
ctl packets sent on behalf of TIME_WAIT sockets currently have a zero skb->priority, which can cause various problems. In this patch we : - add a tw_priority field in struct inet_timewait_sock. - populate it from sk->sk_priority when a TIME_WAIT is created. - For IPv4, change ip_send_unicast_reply() and its two callers to propagate tw_priority correctly. ip_send_unicast_reply() no longer changes sk->sk_priority. - For IPv6, make sure TIME_WAIT sockets pass their tw_priority field to tcp_v6_send_response() and tcp_v6_send_ack(). Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-08-14Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski1-0/+15
Daniel Borkmann says: ==================== The following pull-request contains BPF updates for your *net-next* tree. There is a small merge conflict in libbpf (Cc Andrii so he's in the loop as well): for (i = 1; i <= btf__get_nr_types(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); if (!has_datasec && btf_is_var(t)) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); <<<<<<< HEAD /* * using size = 1 is the safest choice, 4 will be too * big and cause kernel BTF validation failure if * original variable took less than 4 bytes */ t->size = 1; *(int *)(t+1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && kind == BTF_KIND_DATASEC) { ======= t->size = sizeof(int); *(int *)(t + 1) = BTF_INT_ENC(0, 0, 32); } else if (!has_datasec && btf_is_datasec(t)) { >>>>>>> 72ef80b5ee131e96172f19e74b4f98fa3404efe8 /* replace DATASEC with STRUCT */ Conflict is between the two commits 1d4126c4e119 ("libbpf: sanitize VAR to conservative 1-byte INT") and b03bc6853c0e ("libbpf: convert libbpf code to use new btf helpers"), so we need to pick the sanitation fixup as well as use the new btf_is_datasec() helper and the whitespace cleanup. Looks like the following: [...] if (!has_datasec && btf_is_var(t)) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); /* * using size = 1 is the safest choice, 4 will be too * big and cause kernel BTF validation failure if * original variable took less than 4 bytes */ t->size = 1; *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && btf_is_datasec(t)) { /* replace DATASEC with STRUCT */ [...] The main changes are: 1) Addition of core parts of compile once - run everywhere (co-re) effort, that is, relocation of fields offsets in libbpf as well as exposure of kernel's own BTF via sysfs and loading through libbpf, from Andrii. More info on co-re: http://vger.kernel.org/bpfconf2019.html#session-2 and http://vger.kernel.org/lpc-bpf2018.html#session-2 2) Enable passing input flags to the BPF flow dissector to customize parsing and allowing it to stop early similar to the C based one, from Stanislav. 3) Add a BPF helper function that allows generating SYN cookies from XDP and tc BPF, from Petar. 4) Add devmap hash-based map type for more flexibility in device lookup for redirects, from Toke. 5) Improvements to XDP forwarding sample code now utilizing recently enabled devmap lookups, from Jesper. 6) Add support for reporting the effective cgroup progs in bpftool, from Jakub and Takshak. 7) Fix reading kernel config from bpftool via /proc/config.gz, from Peter. 8) Fix AF_XDP umem pages mapping for 32 bit architectures, from Ivan. 9) Follow-up to add two more BPF loop tests for the selftest suite, from Alexei. 10) Add perf event output helper also for other skb-based program types, from Allan. 11) Fix a co-re related compilation error in selftests, from Yonghong. ==================== Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-08-09tcp: add new tcp_mtu_probe_floor sysctlJosh Hunt1-0/+1
The current implementation of TCP MTU probing can considerably underestimate the MTU on lossy connections allowing the MSS to get down to 48. We have found that in almost all of these cases on our networks these paths can handle much larger MTUs meaning the connections are being artificially limited. Even though TCP MTU probing can raise the MSS back up we have seen this not to be the case causing connections to be "stuck" with an MSS of 48 when heavy loss is present. Prior to pushing out this change we could not keep TCP MTU probing enabled b/c of the above reasons. Now with a reasonble floor set we've had it enabled for the past 6 months. The new sysctl will still default to TCP_MIN_SND_MSS (48), but gives administrators the ability to control the floor of MSS probing. Signed-off-by: Josh Hunt <johunt@akamai.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-31tcp: add skb-less helpers to retrieve SYN cookiePetar Penkov1-0/+15
This patch allows generation of a SYN cookie before an SKB has been allocated, as is the case at XDP. Signed-off-by: Petar Penkov <ppenkov@google.com> Reviewed-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+1
Honestly all the conflicts were simple overlapping changes, nothing really interesting to report. Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-16tcp: add tcp_min_snd_mss sysctlEric Dumazet1-0/+1
Some TCP peers announce a very small MSS option in their SYN and/or SYN/ACK messages. This forces the stack to send packets with a very high network/cpu overhead. Linux has enforced a minimal value of 48. Since this value includes the size of TCP options, and that the options can consume up to 40 bytes, this means that each segment can include only 8 bytes of payload. In some cases, it can be useful to increase the minimal value to a saner value. We still let the default to 48 (TCP_MIN_SND_MSS), for compatibility reasons. Note that TCP_MAXSEG socket option enforces a minimal value of (TCP_MIN_MSS). David Miller increased this minimal value in commit c39508d6f118 ("tcp: Make TCP_MAXSEG minimum more correct.") from 64 to 88. We might in the future merge TCP_MIN_SND_MSS and TCP_MIN_MSS. CVE-2019-11479 -- tcp mss hardcoded to 48 Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Jonathan Looney <jtl@netflix.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Bruce Curtis <brucec@netflix.com> Cc: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-15ipv4: tcp: fix ACK/RST sent with a transmit delayEric Dumazet1-5/+9
If we want to set a EDT time for the skb we want to send via ip_send_unicast_reply(), we have to pass a new parameter and initialize ipc.sockc.transmit_time with it. This fixes the EDT time for ACK/RST packets sent on behalf of a TIME_WAIT socket. Fixes: a842fe1425cb ("tcp: add optional per socket transmit delay") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>