kernel.git/net/sched/sch_api.c, branch linux-4.1.y

net: sched: Fix one possible panic when no destroy callback

2017-07-31T17:37:54Z

[ Upstream commit c1a4872ebfb83b1af7144f7b29ac8c4b344a12a8 ] When qdisc fail to init, qdisc_create would invoke the destroy callback to cleanup. But there is no check if the callback exists really. So it would cause the panic if there is no real destroy callback like the qdisc codel, fq, and so on. Take codel as an example following: When a malicious user constructs one invalid netlink msg, it would cause codel_init->codel_change->nla_parse_nested failed. Then kernel would invoke the destroy callback directly but qdisc codel doesn't define one. It causes one panic as a result. Now add one the check for destroy to avoid the possible panic. Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Signed-off-by: Gao Feng Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net_sched: fix error recovery at qdisc creation

2017-07-31T17:37:54Z

[ Upstream commit 87b60cfacf9f17cf71933c6e33b66e68160af71d ] Dmitry reported uses after free in qdisc code [1] The problem here is that ops->init() can return an error. qdisc_create_dflt() then call ops->destroy(), while qdisc_create() does _not_ call it. Four qdisc chose to call their own ops->destroy(), assuming their caller would not. This patch makes sure qdisc_create() calls ops->destroy() and fixes the four qdisc to avoid double free. [1] BUG: KASAN: use-after-free in mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 at addr ffff8801d415d440 Read of size 8 by task syz-executor2/5030 CPU: 0 PID: 5030 Comm: syz-executor2 Not tainted 4.3.5-smp-DEV #119 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000046 ffff8801b435b870 ffffffff81bbbed4 ffff8801db000400 ffff8801d415d440 ffff8801d415dc40 ffff8801c4988510 ffff8801b435b898 ffffffff816682b1 ffff8801b435b928 ffff8801d415d440 ffff8801c49880c0 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0x6c/0x98 lib/dump_stack.c:51 [] kasan_object_err+0x21/0x70 mm/kasan/report.c:158 [] print_address_description mm/kasan/report.c:196 [inline] [] kasan_report_error+0x1b4/0x4b0 mm/kasan/report.c:285 [] kasan_report mm/kasan/report.c:305 [inline] [] __asan_report_load8_noabort+0x43/0x50 mm/kasan/report.c:326 [] mq_destroy+0x242/0x290 net/sched/sch_mq.c:33 [] qdisc_destroy+0x12d/0x290 net/sched/sch_generic.c:953 [] qdisc_create_dflt+0xf0/0x120 net/sched/sch_generic.c:848 [] attach_default_qdiscs net/sched/sch_generic.c:1029 [inline] [] dev_activate+0x6ad/0x880 net/sched/sch_generic.c:1064 [] __dev_open+0x221/0x320 net/core/dev.c:1403 [] __dev_change_flags+0x15e/0x3e0 net/core/dev.c:6858 [] dev_change_flags+0x8e/0x140 net/core/dev.c:6926 [] dev_ifsioc+0x446/0x890 net/core/dev_ioctl.c:260 [] dev_ioctl+0x1ba/0xb80 net/core/dev_ioctl.c:546 [] sock_do_ioctl+0x99/0xb0 net/socket.c:879 [] sock_ioctl+0x2a0/0x390 net/socket.c:958 [] vfs_ioctl fs/ioctl.c:44 [inline] [] do_vfs_ioctl+0x8a8/0xe50 fs/ioctl.c:611 [] SYSC_ioctl fs/ioctl.c:626 [inline] [] SyS_ioctl+0x94/0xc0 fs/ioctl.c:617 [] entry_SYSCALL_64_fastpath+0x12/0x17 Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net_sched: update hierarchical backlog too

2016-07-11T03:07:23Z

[ Upstream commit 2ccccf5fb43ff62b2b96cc58d95fc0b3596516e4 ] When the bottom qdisc decides to, for example, drop some packet, it calls qdisc_tree_decrease_qlen() to update the queue length for all its ancestors, we need to update the backlog too to keep the stats on root qdisc accurate. Cc: Jamal Hadi Salim Acked-by: Jamal Hadi Salim Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net_sched: make qdisc_tree_decrease_qlen() work for non mq

2016-01-23T04:54:15Z

[ Upstream commit 225734de70cd0a9e0b978f3583a4a87939271d5e ] Stas Nichiporovich reported a regression in his HFSC qdisc setup on a non multi queue device. It turns out I mistakenly added a TCQ_F_NOPARENT flag on all qdisc allocated in qdisc_create() for non multi queue devices, which was rather buggy. I was clearly mislead by the TCQ_F_ONETXQUEUE that is also set here for no good reason, since it only matters for the root qdisc. Fixes: 4eaf3b84f288 ("net_sched: fix qdisc_tree_decrease_qlen() races") Reported-by: Stas Nichiporovich Tested-by: Stas Nichiporovich Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net_sched: fix qdisc_tree_decrease_qlen() races

2015-12-15T05:24:33Z

[ Upstream commit 4eaf3b84f2881c9c028f1d5e76c52ab575fe3a66 ] qdisc_tree_decrease_qlen() suffers from two problems on multiqueue devices. One problem is that it updates sch->q.qlen and sch->qstats.drops on the mq/mqprio root qdisc, while it should not : Daniele reported underflows errors : [ 681.774821] PAX: sch->q.qlen: 0 n: 1 [ 681.774825] PAX: size overflow detected in function qdisc_tree_decrease_qlen net/sched/sch_api.c:769 cicus.693_49 min, count: 72, decl: qlen; num: 0; context: sk_buff_head; [ 681.774954] CPU: 2 PID: 19 Comm: ksoftirqd/2 Tainted: G O 4.2.6.201511282239-1-grsec #1 [ 681.774955] Hardware name: ASUSTeK COMPUTER INC. X302LJ/X302LJ, BIOS X302LJ.202 03/05/2015 [ 681.774956] ffffffffa9a04863 0000000000000000 0000000000000000 ffffffffa990ff7c [ 681.774959] ffffc90000d3bc38 ffffffffa95d2810 0000000000000007 ffffffffa991002b [ 681.774960] ffffc90000d3bc68 ffffffffa91a44f4 0000000000000001 0000000000000001 [ 681.774962] Call Trace: [ 681.774967] [] dump_stack+0x4c/0x7f [ 681.774970] [] report_size_overflow+0x34/0x50 [ 681.774972] [] qdisc_tree_decrease_qlen+0x152/0x160 [ 681.774976] [] fq_codel_dequeue+0x7b1/0x820 [sch_fq_codel] [ 681.774978] [] ? qdisc_peek_dequeued+0xa0/0xa0 [sch_fq_codel] [ 681.774980] [] __qdisc_run+0x4d/0x1d0 [ 681.774983] [] net_tx_action+0xc2/0x160 [ 681.774985] [] __do_softirq+0xf1/0x200 [ 681.774987] [] run_ksoftirqd+0x1e/0x30 [ 681.774989] [] smpboot_thread_fn+0x150/0x260 [ 681.774991] [] ? sort_range+0x40/0x40 [ 681.774992] [] kthread+0xe4/0x100 [ 681.774994] [] ? kthread_worker_fn+0x170/0x170 [ 681.774995] [] ret_from_fork+0x3e/0x70 mq/mqprio have their own ways to report qlen/drops by folding stats on all their queues, with appropriate locking. A second problem is that qdisc_tree_decrease_qlen() calls qdisc_lookup() without proper locking : concurrent qdisc updates could corrupt the list that qdisc_match_from_root() parses to find a qdisc given its handle. Fix first problem adding a TCQ_F_NOPARENT qdisc flag that qdisc_tree_decrease_qlen() can use to abort its tree traversal, as soon as it meets a mq/mqprio qdisc children. Second problem can be fixed by RCU protection. Qdisc are already freed after RCU grace period, so qdisc_list_add() and qdisc_list_del() simply have to use appropriate rcu list variants. A future patch will add a per struct netdev_queue list anchor, so that qdisc_tree_decrease_qlen() can have more efficient lookups. Reported-by: Daniele Fucini Signed-off-by: Eric Dumazet Cc: Cong Wang Cc: Jamal Hadi Salim Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net_sched: invoke ->attach() after setting dev->qdisc

2015-05-27T18:09:55Z

For mq qdisc, we add per tx queue qdisc to root qdisc for display purpose, however, that happens too early, before the new dev->qdisc is finally set, this causes q->list points to an old root qdisc which is going to be freed right before assigning with a new one. Fix this by moving ->attach() after setting dev->qdisc. For the record, this fixes the following crash: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 975 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98() list_del corruption. prev->next should be ffff8800d1998ae8, but was 6b6b6b6b6b6b6b6b CPU: 1 PID: 975 Comm: tc Not tainted 4.1.0-rc4+ #1019 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000009 ffff8800d73fb928 ffffffff81a44e7f 0000000047574756 ffff8800d73fb978 ffff8800d73fb968 ffffffff810790da ffff8800cfc4cd20 ffffffff814e725b ffff8800d1998ae8 ffffffff82381250 0000000000000000 Call Trace: [] dump_stack+0x4c/0x65 [] warn_slowpath_common+0x9c/0xb6 [] ? __list_del_entry+0x5a/0x98 [] warn_slowpath_fmt+0x46/0x48 [] ? dev_graft_qdisc+0x5e/0x6a [] __list_del_entry+0x5a/0x98 [] list_del+0xe/0x2d [] qdisc_list_del+0x1e/0x20 [] qdisc_destroy+0x30/0xd6 [] qdisc_graft+0x11d/0x243 [] tc_get_qdisc+0x1a6/0x1d4 [] ? mark_lock+0x2e/0x226 [] rtnetlink_rcv_msg+0x181/0x194 [] ? rtnl_lock+0x17/0x19 [] ? rtnl_lock+0x17/0x19 [] ? __rtnl_unlock+0x17/0x17 [] netlink_rcv_skb+0x4d/0x93 [] rtnetlink_rcv+0x26/0x2d [] netlink_unicast+0xcb/0x150 [] ? might_fault+0x59/0xa9 [] netlink_sendmsg+0x4fa/0x51c [] sock_sendmsg_nosec+0x12/0x1d [] sock_sendmsg+0x29/0x2e [] ___sys_sendmsg+0x1b4/0x23a [] ? native_sched_clock+0x35/0x37 [] ? sched_clock_local+0x12/0x72 [] ? sched_clock_cpu+0x9e/0xb7 [] ? current_kernel_time+0xe/0x32 [] ? lock_release_holdtime.part.29+0x71/0x7f [] ? read_seqcount_begin.constprop.27+0x5f/0x76 [] ? trace_hardirqs_on_caller+0x17d/0x199 [] ? __fget_light+0x50/0x78 [] __sys_sendmsg+0x42/0x60 [] SyS_sendmsg+0x12/0x1c [] system_call_fastpath+0x12/0x6f ---[ end trace ef29d3fb28e97ae7 ]--- For long term, we probably need to clean up the qdisc_graft() code in case it hides other bugs like this. Fixes: 95dc19299f74 ("pkt_sched: give visibility to mq slave qdiscs") Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net_sched: destroy proto tp when all filters are gone

2015-03-09T19:35:55Z

Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: fix skb->protocol use in case of accelerated vlan path

2015-01-13T22:51:08Z

tc code implicitly considers skb->protocol even in case of accelerated vlan paths and expects vlan protocol type here. However, on rx path, if the vlan header was already stripped, skb->protocol contains value of next header. Similar situation is on tx path. So for skbs that use skb->vlan_tci for tagging, use skb->vlan_proto instead. Reported-by: Jamal Hadi Salim Signed-off-by: Jiri Pirko Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: initialize bstats syncp

2014-10-22T01:45:21Z

Use netdev_alloc_pcpu_stats to allocate percpu stats and initialize syncp. Fixes: 22e0f8b9322c "net: sched: make bstats per cpu and estimator RCU safe" Signed-off-by: Sabrina Dubroca Acked-by: Cong Wang Signed-off-by: David S. Miller

net: sched: avoid costly atomic operation in fq_dequeue()

2014-10-06T04:55:10Z

Standard qdisc API to setup a timer implies an atomic operation on every packet dequeue : qdisc_unthrottled() It turns out this is not really needed for FQ, as FQ has no concept of global qdisc throttling, being a qdisc handling many different flows, some of them can be throttled, while others are not. Fix is straightforward : add a 'bool throttle' to qdisc_watchdog_schedule_ns(), and remove calls to qdisc_unthrottled() in sch_fq. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller