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authorTaehee Yoo <ap420073@gmail.com>2021-05-23 17:38:53 +0300
committerDavid S. Miller <davem@davemloft.net>2021-05-24 23:11:44 +0300
commit9b76eade16423ef06829cccfe3e100cfce31afcd (patch)
tree4ef33b043118a07aef5f5a868aa9f50938f7c5d2 /net/sched
parent4dd649d130c634415c26df771e09e373f77fc688 (diff)
downloadlinux-9b76eade16423ef06829cccfe3e100cfce31afcd.tar.xz
sch_dsmark: fix a NULL deref in qdisc_reset()
If Qdisc_ops->init() is failed, Qdisc_ops->reset() would be called. When dsmark_init(Qdisc_ops->init()) is failed, it possibly doesn't initialize dsmark_qdisc_data->q. But dsmark_reset(Qdisc_ops->reset()) uses dsmark_qdisc_data->q pointer wihtout any null checking. So, panic would occur. Test commands: sysctl net.core.default_qdisc=dsmark -w ip link add dummy0 type dummy ip link add vw0 link dummy0 type virt_wifi ip link set vw0 up Splat looks like: KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] CPU: 3 PID: 684 Comm: ip Not tainted 5.12.0+ #910 RIP: 0010:qdisc_reset+0x2b/0x680 Code: 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 41 57 41 56 41 55 41 54 55 48 89 fd 48 83 c7 18 53 48 89 fa 48 c1 ea 03 48 83 ec 20 <80> 3c 02 00 0f 85 09 06 00 00 4c 8b 65 18 0f 1f 44 00 00 65 8b 1d RSP: 0018:ffff88800fda6bf8 EFLAGS: 00010282 RAX: dffffc0000000000 RBX: ffff8880050ed800 RCX: 0000000000000000 RDX: 0000000000000003 RSI: ffffffff99e34100 RDI: 0000000000000018 RBP: 0000000000000000 R08: fffffbfff346b553 R09: fffffbfff346b553 R10: 0000000000000001 R11: fffffbfff346b552 R12: ffffffffc0824940 R13: ffff888109e83800 R14: 00000000ffffffff R15: ffffffffc08249e0 FS: 00007f5042287680(0000) GS:ffff888119800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ae1f4dbd90 CR3: 0000000006760002 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? rcu_read_lock_bh_held+0xa0/0xa0 dsmark_reset+0x3d/0xf0 [sch_dsmark] qdisc_reset+0xa9/0x680 qdisc_destroy+0x84/0x370 qdisc_create_dflt+0x1fe/0x380 attach_one_default_qdisc.constprop.41+0xa4/0x180 dev_activate+0x4d5/0x8c0 ? __dev_open+0x268/0x390 __dev_open+0x270/0x390 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_dsmark.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index cd2748e2d4a2..d320bcfb2da2 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -407,7 +407,8 @@ static void dsmark_reset(struct Qdisc *sch)
struct dsmark_qdisc_data *p = qdisc_priv(sch);
pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
- qdisc_reset(p->q);
+ if (p->q)
+ qdisc_reset(p->q);
sch->qstats.backlog = 0;
sch->q.qlen = 0;
}