kernel.git/net/sched, branch linux-4.20.y

net: sched: flower: insert new filter to idr after setting its mask

2019-03-19T12:11:54Z

[ Upstream commit ecb3dea400d3beaf611ce76ac7a51d4230492cf2 ] When adding new filter to flower classifier, fl_change() inserts it to handle_idr before initializing filter extensions and assigning it a mask. Normally this ordering doesn't matter because all flower classifier ops callbacks assume rtnl lock protection. However, when filter has an action that doesn't have its kernel module loaded, rtnl lock is released before call to request_module(). During this time the filter can be accessed bu concurrent task before its initialization is completed, which can lead to a crash. Example case of NULL pointer dereference in concurrent dump: Task 1 Task 2 tc_new_tfilter() fl_change() idr_alloc_u32(fnew) fl_set_parms() tcf_exts_validate() tcf_action_init() tcf_action_init_1() rtnl_unlock() request_module() ... rtnl_lock() tc_dump_tfilter() tcf_chain_dump() fl_walk() idr_get_next_ul() tcf_node_dump() tcf_fill_node() fl_dump() mask = &f->mask->key; <- NULL ptr rtnl_lock() Extension initialization and mask assignment don't depend on fnew->handle that is allocated by idr_alloc_u32(). Move idr allocation code after action creation and mask assignment in fl_change() to prevent concurrent access to not fully initialized filter when rtnl lock is released to load action module. Fixes: 01683a146999 ("net: sched: refactor flower walk to iterate over idr") Signed-off-by: Vlad Buslov Reviewed-by: Roi Dayan Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: act_tunnel_key: fix NULL pointer dereference during init

2019-03-10T06:10:14Z

[ Upstream commit a3df633a3c92bb96b06552c3f828d7c267774379 ] Metadata pointer is only initialized for action TCA_TUNNEL_KEY_ACT_SET, but it is unconditionally dereferenced in tunnel_key_init() error handler. Verify that metadata pointer is not NULL before dereferencing it in tunnel_key_init error handling code. Fixes: ee28bb56ac5b ("net/sched: fix memory leak in act_tunnel_key_init()") Signed-off-by: Vlad Buslov Reviewed-by: Davide Caratti Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/sched: act_skbedit: fix refcount leak when replace fails

2019-03-10T06:10:14Z

[ Upstream commit 6191da98062d25276a3b88fb2a94dcbcfb3ea65d ] when act_skbedit was converted to use RCU in the data plane, we added an error path, but we forgot to drop the action refcount in case of failure during a 'replace' operation: # tc actions add action skbedit ptype otherhost pass index 100 # tc action show action skbedit total acts 1 action order 0: skbedit ptype otherhost pass index 100 ref 1 bind 0 # tc actions replace action skbedit ptype otherhost drop index 100 RTNETLINK answers: Cannot allocate memory We have an error talking to the kernel # tc action show action skbedit total acts 1 action order 0: skbedit ptype otherhost pass index 100 ref 2 bind 0 Ensure we call tcf_idr_release(), in case 'params_new' allocation failed, also when the action is being replaced. Fixes: c749cdda9089 ("net/sched: act_skbedit: don't use spinlock in the data path") Signed-off-by: Davide Caratti Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net/sched: act_ipt: fix refcount leak when replace fails

2019-03-10T06:10:14Z

[ Upstream commit 8f67c90ee9148eab3d2b4393c3cf76489b27f87c ] After commit 4e8ddd7f1758 ("net: sched: don't release reference on action overwrite"), the error path of all actions was converted to drop refcount also when the action was being overwritten. But we forgot act_ipt_init(), in case allocation of 'tname' was not successful: # tc action add action xt -j LOG --log-prefix hello index 100 tablename: mangle hook: NF_IP_POST_ROUTING target: LOG level warning prefix "hello" index 100 # tc action show action xt total acts 1 action order 0: tablename: mangle hook: NF_IP_POST_ROUTING target LOG level warning prefix "hello" index 100 ref 1 bind 0 # tc action replace action xt -j LOG --log-prefix world index 100 tablename: mangle hook: NF_IP_POST_ROUTING target: LOG level warning prefix "world" index 100 RTNETLINK answers: Cannot allocate memory We have an error talking to the kernel # tc action show action xt total acts 1 action order 0: tablename: mangle hook: NF_IP_POST_ROUTING target LOG level warning prefix "hello" index 100 ref 2 bind 0 Ensure we call tcf_idr_release(), in case 'tname' allocation failed, also when the action is being replaced. Fixes: 4e8ddd7f1758 ("net: sched: don't release reference on action overwrite") Signed-off-by: Davide Caratti Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: netem: fix skb length BUG_ON in __skb_to_sgvec

2019-03-10T06:10:12Z

[ Upstream commit 5845f706388a4cde0f6b80f9e5d33527e942b7d9 ] It can be reproduced by following steps: 1. virtio_net NIC is configured with gso/tso on 2. configure nginx as http server with an index file bigger than 1M bytes 3. use tc netem to produce duplicate packets and delay: tc qdisc add dev eth0 root netem delay 100ms 10ms 30% duplicate 90% 4. continually curl the nginx http server to get index file on client 5. BUG_ON is seen quickly [10258690.371129] kernel BUG at net/core/skbuff.c:4028! [10258690.371748] invalid opcode: 0000 [#1] SMP PTI [10258690.372094] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G W 5.0.0-rc6 #2 [10258690.372094] RSP: 0018:ffffa05797b43da0 EFLAGS: 00010202 [10258690.372094] RBP: 00000000000005ea R08: 0000000000000000 R09: 00000000000005ea [10258690.372094] R10: ffffa0579334d800 R11: 00000000000002c0 R12: 0000000000000002 [10258690.372094] R13: 0000000000000000 R14: ffffa05793122900 R15: ffffa0578f7cb028 [10258690.372094] FS: 0000000000000000(0000) GS:ffffa05797b40000(0000) knlGS:0000000000000000 [10258690.372094] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [10258690.372094] CR2: 00007f1a6dc00868 CR3: 000000001000e000 CR4: 00000000000006e0 [10258690.372094] Call Trace: [10258690.372094] [10258690.372094] skb_to_sgvec+0x11/0x40 [10258690.372094] start_xmit+0x38c/0x520 [virtio_net] [10258690.372094] dev_hard_start_xmit+0x9b/0x200 [10258690.372094] sch_direct_xmit+0xff/0x260 [10258690.372094] __qdisc_run+0x15e/0x4e0 [10258690.372094] net_tx_action+0x137/0x210 [10258690.372094] __do_softirq+0xd6/0x2a9 [10258690.372094] irq_exit+0xde/0xf0 [10258690.372094] smp_apic_timer_interrupt+0x74/0x140 [10258690.372094] apic_timer_interrupt+0xf/0x20 [10258690.372094] In __skb_to_sgvec(), the skb->len is not equal to the sum of the skb's linear data size and nonlinear data size, thus BUG_ON triggered. Because the skb is cloned and a part of nonlinear data is split off. Duplicate packet is cloned in netem_enqueue() and may be delayed some time in qdisc. When qdisc len reached the limit and returns NET_XMIT_DROP, the skb will be retransmit later in write queue. the skb will be fragmented by tso_fragment(), the limit size that depends on cwnd and mss decrease, the skb's nonlinear data will be split off. The length of the skb cloned by netem will not be updated. When we use virtio_net NIC and invoke skb_to_sgvec(), the BUG_ON trigger. To fix it, netem returns NET_XMIT_SUCCESS to upper stack when it clones a duplicate packet. Fixes: 35d889d1 ("sch_netem: fix skb leak in netem_enqueue()") Signed-off-by: Sheng Lan Reported-by: Qin Ji Suggested-by: Eric Dumazet Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: put back q.qlen into a single location

2019-03-10T06:10:11Z

[ Upstream commit 46b1c18f9deb326a7e18348e668e4c7ab7c7458b ] In the series fc8b81a5981f ("Merge branch 'lockless-qdisc-series'") John made the assumption that the data path had no need to read the qdisc qlen (number of packets in the qdisc). It is true when pfifo_fast is used as the root qdisc, or as direct MQ/MQPRIO children. But pfifo_fast can be used as leaf in class full qdiscs, and existing logic needs to access the child qlen in an efficient way. HTB breaks badly, since it uses cl->leaf.q->q.qlen in : htb_activate() -> WARN_ON() htb_dequeue_tree() to decide if a class can be htb_deactivated when it has no more packets. HFSC, DRR, CBQ, QFQ have similar issues, and some calls to qdisc_tree_reduce_backlog() also read q.qlen directly. Using qdisc_qlen_sum() (which iterates over all possible cpus) in the data path is a non starter. It seems we have to put back qlen in a central location, at least for stable kernels. For all qdisc but pfifo_fast, qlen is guarded by the qdisc lock, so the existing q.qlen{++|--} are correct. For 'lockless' qdisc (pfifo_fast so far), we need to use atomic_{inc|dec}() because the spinlock might be not held (for example from pfifo_fast_enqueue() and pfifo_fast_dequeue()) This patch adds atomic_qlen (in the same location than qlen) and renames the following helpers, since we want to express they can be used without qdisc lock, and that qlen is no longer percpu. - qdisc_qstats_cpu_qlen_dec -> qdisc_qstats_atomic_qlen_dec() - qdisc_qstats_cpu_qlen_inc -> qdisc_qstats_atomic_qlen_inc() Later (net-next) we might revert this patch by tracking all these qlen uses and replace them by a more efficient method (not having to access a precise qlen, but an empty/non_empty status that might be less expensive to maintain/track). Another possibility is to have a legacy pfifo_fast version that would be used when used a a child qdisc, since the parent qdisc needs a spinlock anyway. But then, future lockless qdiscs would also have the same problem. Fixes: 7e66016f2c65 ("net: sched: helpers to sum qlen and qlen for per cpu logic") Signed-off-by: Eric Dumazet Cc: John Fastabend Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net_sched: fix two more memory leaks in cls_tcindex

2019-02-27T09:09:54Z

[ Upstream commit 1db817e75f5b9387b8db11e37d5f0624eb9223e0 ] struct tcindex_filter_result contains two parts: struct tcf_exts and struct tcf_result. For the local variable 'cr', its exts part is never used but initialized without being released properly on success path. So just completely remove the exts part to fix this leak. For the local variable 'new_filter_result', it is never properly released if not used by 'r' on success path. Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net_sched: fix a memory leak in cls_tcindex

2019-02-27T09:09:54Z

[ Upstream commit 033b228e7f26b29ae37f8bfa1bc6b209a5365e9f ] When tcindex_destroy() destroys all the filter results in the perfect hash table, it invokes the walker to delete each of them. However, results with class==0 are skipped in either tcindex_walk() or tcindex_delete(), which causes a memory leak reported by kmemleak. This patch fixes it by skipping the walker and directly deleting these filter results so we don't miss any filter result. As a result of this change, we have to initialize exts->net properly in tcindex_alloc_perfect_hash(). For net-next, we need to consider whether we should initialize ->net in tcf_exts_init() instead, before that just directly test CONFIG_NET_CLS_ACT=y. Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net_sched: fix a race condition in tcindex_destroy()

2019-02-27T09:09:53Z

[ Upstream commit 8015d93ebd27484418d4952284fd02172fa4b0b2 ] tcindex_destroy() invokes tcindex_destroy_element() via a walker to delete each filter result in its perfect hash table, and tcindex_destroy_element() calls tcindex_delete() which schedules tcf RCU works to do the final deletion work. Unfortunately this races with the RCU callback __tcindex_destroy(), which could lead to use-after-free as reported by Adrian. Fix this by migrating this RCU callback to tcf RCU work too, as that workqueue is ordered, we will not have use-after-free. Note, we don't need to hold netns refcnt because we don't call tcf_exts_destroy() here. Fixes: 27ce4f05e2ab ("net_sched: use tcf_queue_work() in tcindex filter") Reported-by: Adrian Cc: Ben Hutchings Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: cls_flower: Remove filter from mask before freeing it

2019-02-12T19:02:34Z

[ Upstream commit c1f7e02979edd7a3a3e69fe04be60b1d650dc8a7 ] In fl_change(), when adding a new rule (i.e. fold == NULL), a driver may reject the new rule, for example due to resource exhaustion. By that point, the new rule was already assigned a mask, and it was added to that mask's hash table. The clean-up path that's invoked as a result of the rejection however neglects to undo the hash table addition, and proceeds to free the new rule, thus leaving a dangling pointer in the hash table. Fix by removing fnew from the mask's hash table before it is freed. Fixes: 35cc3cefc4de ("net/sched: cls_flower: Reject duplicated rules also under skip_sw") Signed-off-by: Petr Machata Acked-by: Jiri Pirko Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman