lwn.git/net/sched, branch docs-4.16

net_sched: use macvlan real dev trans_start in dev_trans_start()

2017-12-06T20:34:10+00:00

Macvlan devices are similar to vlans and do not update their own trans_start. In order for arp monitoring to work for a bond device when the slaves are macvlans, obtain its real device. Signed-off-by: Chris Dion Signed-off-by: David S. Miller

net_sched: red: Avoid illegal values

2017-12-05T19:37:13+00:00

Check the qmin & qmax values doesn't overflow for the given Wlog value. Check that qmin <= qmax. Fixes: a783474591f2 ("[PKT_SCHED]: Generic RED layer") Signed-off-by: Nogah Frankel Signed-off-by: David S. Miller

act_sample: get rid of tcf_sample_cleanup_rcu()

2017-11-30T15:19:17+00:00

Similar to commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu"), TC actions don't need to respect RCU grace period, because it is either just detached from tc filter (standalone case) or it is removed together with tc filter (bound case) in which case RCU grace period is already respected at filter layer. Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action") Reported-by: Eric Dumazet Cc: Jamal Hadi Salim Cc: Jiri Pirko Cc: Yotam Gigi Signed-off-by: Cong Wang Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

net: sched: cbq: create block for q->link.block

2017-11-28T21:04:26+00:00

q->link.block is not initialized, that leads to EINVAL when one tries to add filter there. So initialize it properly. This can be reproduced by: $ tc qdisc add dev eth0 root handle 1: cbq avpkt 1000 rate 1000Mbit bandwidth 1000Mbit $ tc filter add dev eth0 parent 1: protocol ip prio 100 u32 match ip protocol 0 0x00 flowid 1:1 Reported-by: Jaroslav Aster Reported-by: Ivan Vecera Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure") Signed-off-by: Jiri Pirko Acked-by: Eelco Chaudron Reviewed-by: Ivan Vecera Signed-off-by: David S. Miller

sch_sfq: fix null pointer dereference at timer expiration

2017-11-28T20:54:05+00:00

While converting sch_sfq to use timer_setup(), the commit cdeabbb88134 ("net: sched: Convert timers to use timer_setup()") forgot to initialize the 'sch' field. As a result, the timer callback tries to dereference a NULL pointer, and the kernel does oops. Fix it initializing such field at qdisc creation time. Fixes: cdeabbb88134 ("net: sched: Convert timers to use timer_setup()") Signed-off-by: Paolo Abeni Acked-by: Cong Wang Acked-by: Kees Cook Signed-off-by: David S. Miller

cls_bpf: don't decrement net's refcount when offload fails

2017-11-28T20:49:44+00:00

When cls_bpf offload was added it seemed like a good idea to call cls_bpf_delete_prog() instead of extending the error handling path, since the software state is fully initialized at that point. This handling of errors without jumping to the end of the function is error prone, as proven by later commit missing that extra call to __cls_bpf_delete_prog(). __cls_bpf_delete_prog() is now expected to be invoked with a reference on exts->net or the field zeroed out. The call on the offload's error patch does not fullfil this requirement, leading to each error stealing a reference on net namespace. Create a function undoing what cls_bpf_set_parms() did and use it from __cls_bpf_delete_prog() and the error path. Fixes: aae2c35ec892 ("cls_bpf: use tcf_exts_get_net() before call_rcu()") Signed-off-by: Jakub Kicinski Reviewed-by: Simon Horman Acked-by: Daniel Borkmann Acked-by: Cong Wang Signed-off-by: David S. Miller

net: sched: crash on blocks with goto chain action

2017-11-25T14:57:20+00:00

tcf_block_put_ext has assumed that all filters (and thus their goto actions) are destroyed in RCU callback and thus can not race with our list iteration. However, that is not true during netns cleanup (see tcf_exts_get_net comment). Prevent the user after free by holding all chains (except 0, that one is already held). foreach_safe is not enough in this case. To reproduce, run the following in a netns and then delete the ns: ip link add dtest type dummy tc qdisc add dev dtest ingress tc filter add dev dtest chain 1 parent ffff: handle 1 prio 1 flower action goto chain 2 Fixes: 822e86d997 ("net_sched: remove tcf_block_put_deferred()") Signed-off-by: Roman Kapl Acked-by: Jiri Pirko Signed-off-by: David S. Miller

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

2017-11-23T17:33:01+00:00

Daniel Borkmann says: ==================== pull-request: bpf 2017-11-23 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Several BPF offloading fixes, from Jakub. Among others: - Limit offload to cls_bpf and XDP program types only. - Move device validation into the driver and don't make any assumptions about the device in the classifier due to shared blocks semantics. - Don't pass offloaded XDP program into the driver when it should be run in native XDP instead. Offloaded ones are not JITed for the host in such cases. - Don't destroy device offload state when moved to another namespace. - Revert dumping offload info into user space for now, since ifindex alone is not sufficient. This will be redone properly for bpf-next tree. 2) Fix test_verifier to avoid using bpf_probe_write_user() helper in test cases, since it's dumping a warning into kernel log which may confuse users when only running tests. Switch to use bpf_trace_printk() instead, from Yonghong. 3) Several fixes for correcting ARG_CONST_SIZE_OR_ZERO semantics before it becomes uabi, from Gianluca. More specifically: - Add a type ARG_PTR_TO_MEM_OR_NULL that is used only by bpf_csum_diff(), where the argument is either a valid pointer or NULL. The subsequent ARG_CONST_SIZE_OR_ZERO then enforces a valid pointer in case of non-0 size or a valid pointer or NULL in case of size 0. Given that, the semantics for ARG_PTR_TO_MEM in combination with ARG_CONST_SIZE_OR_ZERO are now such that in case of size 0, the pointer must always be valid and cannot be NULL. This fix in semantics allows for bpf_probe_read() to drop the recently added size == 0 check in the helper that would become part of uabi otherwise once released. At the same time we can then fix bpf_probe_read_str() and bpf_perf_event_output() to use ARG_CONST_SIZE_OR_ZERO instead of ARG_CONST_SIZE in order to fix recently reported issues by Arnaldo et al, where LLVM optimizes two boundary checks into a single one for unknown variables where the verifier looses track of the variable bounds and thus rejects valid programs otherwise. 4) A fix for the verifier for the case when it detects comparison of two constants where the branch is guaranteed to not be taken at runtime. Verifier will rightfully prune the exploration of such paths, but we still pass the program to JITs, where they would complain about using reserved fields, etc. Track such dead instructions and sanitize them with mov r0,r0. Rejection is not possible since LLVM may generate them for valid C code and doesn't do as much data flow analysis as verifier. For bpf-next we might implement removal of such dead code and adjust branches instead. Fix from Alexei. ==================== Signed-off-by: David S. Miller

net: accept UFO datagrams from tuntap and packet

2017-11-23T16:37:35+00:00

Tuntap and similar devices can inject GSO packets. Accept type VIRTIO_NET_HDR_GSO_UDP, even though not generating UFO natively. Processes are expected to use feature negotiation such as TUNSETOFFLOAD to detect supported offload types and refrain from injecting other packets. This process breaks down with live migration: guest kernels do not renegotiate flags, so destination hosts need to expose all features that the source host does. Partially revert the UFO removal from 182e0b6b5846~1..d9d30adf5677. This patch introduces nearly(*) no new code to simplify verification. It brings back verbatim tuntap UFO negotiation, VIRTIO_NET_HDR_GSO_UDP insertion and software UFO segmentation. It does not reinstate protocol stack support, hardware offload (NETIF_F_UFO), SKB_GSO_UDP tunneling in SKB_GSO_SOFTWARE or reception of VIRTIO_NET_HDR_GSO_UDP packets in tuntap. To support SKB_GSO_UDP reappearing in the stack, also reinstate logic in act_csum and openvswitch. Achieve equivalence with v4.13 HEAD by squashing in commit 939912216fa8 ("net: skb_needs_check() removes CHECKSUM_UNNECESSARY check for tx.") and reverting commit 8d63bee643f1 ("net: avoid skb_warn_bad_offload false positives on UFO"). (*) To avoid having to bring back skb_shinfo(skb)->ip6_frag_id, ipv6_proxy_select_ident is changed to return a __be32 and this is assigned directly to the frag_hdr. Also, SKB_GSO_UDP is inserted at the end of the enum to minimize code churn. Tested Booted a v4.13 guest kernel with QEMU. On a host kernel before this patch `ethtool -k eth0` shows UFO disabled. After the patch, it is enabled, same as on a v4.13 host kernel. A UFO packet sent from the guest appears on the tap device: host: nc -l -p -u 8000 & tcpdump -n -i tap0 guest: dd if=/dev/zero of=payload.txt bs=1 count=2000 nc -u 192.16.1.1 8000 < payload.txt Direct tap to tap transmission of VIRTIO_NET_HDR_GSO_UDP succeeds, packets arriving fragmented: ./with_tap_pair.sh ./tap_send_ufo tap0 tap1 (from https://github.com/wdebruij/kerneltools/tree/master/tests) Changes v1 -> v2 - simplified set_offload change (review comment) - documented test procedure Link: http://lkml.kernel.org/r/ Fixes: fb652fdfe837 ("macvlan/macvtap: Remove NETIF_F_UFO advertisement.") Reported-by: Michal Kubecek Signed-off-by: Willem de Bruijn Acked-by: Jason Wang Signed-off-by: David S. Miller

net: sched: fix crash when deleting secondary chains

2017-11-23T16:25:37+00:00

If you flush (delete) a filter chain other than chain 0 (such as when deleting the device), the kernel may run into a use-after-free. The chain refcount must not be decremented unless we are sure we are done with the chain. To reproduce the bug, run: ip link add dtest type dummy tc qdisc add dev dtest ingress tc filter add dev dtest chain 1 parent ffff: flower ip link del dtest Introduced in: commit f93e1cdcf42c ("net/sched: fix filter flushing"), but unless you have KAsan or luck, you won't notice it until commit 0dadc117ac8b ("cls_flower: use tcf_exts_get_net() before call_rcu()") Fixes: f93e1cdcf42c ("net/sched: fix filter flushing") Acked-by: Jiri Pirko Signed-off-by: Roman Kapl Signed-off-by: David S. Miller