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Message-ID: <lsq.1510009387.24476904@decadent.org.uk>
Date: Mon, 06 Nov 2017 23:03:07 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC: akpm@...ux-foundation.org, "Dmitry Vyukov" <dvyukov@...gle.com>,
"David S. Miller" <davem@...emloft.net>,
"Eric Dumazet" <edumazet@...gle.com>
Subject: [PATCH 3.2 069/147] net_sched: fix error recovery at qdisc creation
3.2.95-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@...gle.com>
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:
[<ffffffff81bbbed4>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81bbbed4>] dump_stack+0x6c/0x98 lib/dump_stack.c:51
[<ffffffff816682b1>] kasan_object_err+0x21/0x70 mm/kasan/report.c:158
[<ffffffff81668524>] print_address_description mm/kasan/report.c:196 [inline]
[<ffffffff81668524>] kasan_report_error+0x1b4/0x4b0 mm/kasan/report.c:285
[<ffffffff81668953>] kasan_report mm/kasan/report.c:305 [inline]
[<ffffffff81668953>] __asan_report_load8_noabort+0x43/0x50 mm/kasan/report.c:326
[<ffffffff82527b02>] mq_destroy+0x242/0x290 net/sched/sch_mq.c:33
[<ffffffff82524bdd>] qdisc_destroy+0x12d/0x290 net/sched/sch_generic.c:953
[<ffffffff82524e30>] qdisc_create_dflt+0xf0/0x120 net/sched/sch_generic.c:848
[<ffffffff8252550d>] attach_default_qdiscs net/sched/sch_generic.c:1029 [inline]
[<ffffffff8252550d>] dev_activate+0x6ad/0x880 net/sched/sch_generic.c:1064
[<ffffffff824b1db1>] __dev_open+0x221/0x320 net/core/dev.c:1403
[<ffffffff824b24ce>] __dev_change_flags+0x15e/0x3e0 net/core/dev.c:6858
[<ffffffff824b27de>] dev_change_flags+0x8e/0x140 net/core/dev.c:6926
[<ffffffff824f5bf6>] dev_ifsioc+0x446/0x890 net/core/dev_ioctl.c:260
[<ffffffff824f61fa>] dev_ioctl+0x1ba/0xb80 net/core/dev_ioctl.c:546
[<ffffffff82430509>] sock_do_ioctl+0x99/0xb0 net/socket.c:879
[<ffffffff82430d30>] sock_ioctl+0x2a0/0x390 net/socket.c:958
[<ffffffff816f3b68>] vfs_ioctl fs/ioctl.c:44 [inline]
[<ffffffff816f3b68>] do_vfs_ioctl+0x8a8/0xe50 fs/ioctl.c:611
[<ffffffff816f41a4>] SYSC_ioctl fs/ioctl.c:626 [inline]
[<ffffffff816f41a4>] SyS_ioctl+0x94/0xc0 fs/ioctl.c:617
[<ffffffff8123e357>] entry_SYSCALL_64_fastpath+0x12/0x17
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
[bwh: Backported to 3.2:
- Drop changes to sch_hhf (doesn't exist) and sch_sfq (doesn't have this bug)
- Adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -866,6 +866,8 @@ qdisc_create(struct net_device *dev, str
return sch;
}
+ /* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
+ ops->destroy(sch);
err_out3:
dev_put(dev);
kfree((char *) sch - sch->padded);
--- a/net/sched/sch_mq.c
+++ b/net/sched/sch_mq.c
@@ -52,7 +52,7 @@ static int mq_init(struct Qdisc *sch, st
/* pre-allocate qdiscs, attachment can't fail */
priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
GFP_KERNEL);
- if (priv->qdiscs == NULL)
+ if (!priv->qdiscs)
return -ENOMEM;
for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
@@ -60,17 +60,13 @@ static int mq_init(struct Qdisc *sch, st
qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops,
TC_H_MAKE(TC_H_MAJ(sch->handle),
TC_H_MIN(ntx + 1)));
- if (qdisc == NULL)
- goto err;
+ if (!qdisc)
+ return -ENOMEM;
priv->qdiscs[ntx] = qdisc;
}
sch->flags |= TCQ_F_MQROOT;
return 0;
-
-err:
- mq_destroy(sch);
- return -ENOMEM;
}
static void mq_attach(struct Qdisc *sch)
--- a/net/sched/sch_mqprio.c
+++ b/net/sched/sch_mqprio.c
@@ -117,20 +117,17 @@ static int mqprio_init(struct Qdisc *sch
/* pre-allocate qdisc, attachment can't fail */
priv->qdiscs = kcalloc(dev->num_tx_queues, sizeof(priv->qdiscs[0]),
GFP_KERNEL);
- if (priv->qdiscs == NULL) {
- err = -ENOMEM;
- goto err;
- }
+ if (!priv->qdiscs)
+ return -ENOMEM;
for (i = 0; i < dev->num_tx_queues; i++) {
dev_queue = netdev_get_tx_queue(dev, i);
qdisc = qdisc_create_dflt(dev_queue, &pfifo_fast_ops,
TC_H_MAKE(TC_H_MAJ(sch->handle),
TC_H_MIN(i + 1)));
- if (qdisc == NULL) {
- err = -ENOMEM;
- goto err;
- }
+ if (!qdisc)
+ return -ENOMEM;
+
priv->qdiscs[i] = qdisc;
}
@@ -142,7 +139,7 @@ static int mqprio_init(struct Qdisc *sch
priv->hw_owned = 1;
err = dev->netdev_ops->ndo_setup_tc(dev, qopt->num_tc);
if (err)
- goto err;
+ return err;
} else {
netdev_set_num_tc(dev, qopt->num_tc);
for (i = 0; i < qopt->num_tc; i++)
@@ -156,10 +153,6 @@ static int mqprio_init(struct Qdisc *sch
sch->flags |= TCQ_F_MQROOT;
return 0;
-
-err:
- mqprio_destroy(sch);
- return err;
}
static void mqprio_attach(struct Qdisc *sch)
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