kernel.git/net/sched/sch_api.c, branch linux-3.16.y

net_sched: fix error recovery at qdisc creation

2017-11-11T13:33:34Z

commit 87b60cfacf9f17cf71933c6e33b66e68160af71d upstream. 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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

net_sched: update hierarchical backlog too

2016-08-22T21:38:15Z

commit 2ccccf5fb43ff62b2b96cc58d95fc0b3596516e4 upstream. 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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings

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

2015-06-03T13:30:07Z

commit 86e363dc3b50bfd50a1f315934583fbda673ab8d upstream. 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 Signed-off-by: Luis Henriques

net_sched: drr: warn when qdisc is not work conserving

2014-06-11T22:50:59Z

The DRR scheduler requires that items on the active list are work conserving, i.e. do not hold on to skbs for throttling purposes, etc. Attaching e.g. tbf renders DRR useless because all other classes on the active list are delayed as well. So, warn users that this configuration won't work as expected; we already do this in couple of other qdiscs, see e.g. commit b00355db3f88d96810a60011a30cfb2c3469409d ('pkt_sched: sch_hfsc: sch_htb: Add non-work-conserving warning handler') The 'const' change is needed to avoid compiler warning ("discards 'const' qualifier from pointer target type"). tested with: drr_hier() { parent=$1 classes=$2 for i in $(seq 1 $classes); do classid=$parent$(printf %x $i) tc class add dev eth0 parent $parent classid $classid drr tc qdisc add dev eth0 parent $classid tbf rate 64kbit burst 256kbit limit 64kbit done } tc qdisc add dev eth0 root handle 1: drr drr_hier 1: 32 tc filter add dev eth0 protocol all pref 1 parent 1: handle 1 flow hash keys dst perturb 1 divisor 32 Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-05-12T17:19:14Z

Conflicts: drivers/net/ethernet/altera/altera_sgdma.c net/netlink/af_netlink.c net/sched/cls_api.c net/sched/sch_api.c The netlink conflict dealt with moving to netlink_capable() and netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations in non-init namespaces. These were simple transformations from netlink_capable to netlink_ns_capable. The Altera driver conflict was simply code removal overlapping some void pointer cast cleanups in net-next. Signed-off-by: David S. Miller

net: Allow tc changes in user namespaces

2014-05-02T21:43:25Z

This switches a few remaining capable(CAP_NET_ADMIN) to ns_capable so that root in a user namespace may set tc rules inside that namespace. Signed-off-by: Stéphane Graber Acked-by: Serge E. Hallyn Cc: "Eric W. Biederman" Cc: Jamal Hadi Salim Cc: "David S. Miller" Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net: Use netlink_ns_capable to verify the permisions of netlink messages

2014-04-24T17:44:54Z

It is possible by passing a netlink socket to a more privileged executable and then to fool that executable into writing to the socket data that happens to be valid netlink message to do something that privileged executable did not intend to do. To keep this from happening replace bare capable and ns_capable calls with netlink_capable, netlink_net_calls and netlink_ns_capable calls. Which act the same as the previous calls except they verify that the opener of the socket had the desired permissions as well. Reported-by: Andy Lutomirski Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-03-15T02:31:55Z

Conflicts: drivers/net/usb/r8152.c drivers/net/xen-netback/netback.c Both the r8152 and netback conflicts were simple overlapping changes. Signed-off-by: David S. Miller

pkt_sched: add cond_resched() to class and qdisc dump

2014-03-12T03:54:23Z

We have seen delays of more than 50ms in class or qdisc dumps, in case device is under high TX stress, even with the prior 4KB per skb limit. Add cond_resched() to give a chance to higher prio tasks to get cpu. Signed-off-by; Eric Dumazet Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

pkt_sched: do not use rcu in tc_dump_qdisc()

2014-03-12T03:54:23Z

Like all rtnetlink dump operations, we hold RTNL in tc_dump_qdisc(), so we do not need to use rcu protection to protect list of netdevices. This will allow preemption to occur, thus reducing latencies. Following patch adds explicit cond_resched() calls. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller