From e9789c7cc182484fc031fd88097eb14cb26c4596 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 26 Sep 2019 18:24:43 -0700 Subject: sch_cbq: validate TCA_CBQ_WRROPT to avoid crash syzbot reported a crash in cbq_normalize_quanta() caused by an out of range cl->priority. iproute2 enforces this check, but malicious users do not. kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN PTI Modules linked in: CPU: 1 PID: 26447 Comm: syz-executor.1 Not tainted 5.3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:cbq_normalize_quanta.part.0+0x1fd/0x430 net/sched/sch_cbq.c:902 RSP: 0018:ffff8801a5c333b0 EFLAGS: 00010206 RAX: 0000000020000003 RBX: 00000000fffffff8 RCX: ffffc9000712f000 RDX: 00000000000043bf RSI: ffffffff83be8962 RDI: 0000000100000018 RBP: ffff8801a5c33420 R08: 000000000000003a R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000002ef R13: ffff88018da95188 R14: dffffc0000000000 R15: 0000000000000015 FS: 00007f37d26b1700(0000) GS:ffff8801dad00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004c7cec CR3: 00000001bcd0a006 CR4: 00000000001626f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: [] cbq_normalize_quanta include/net/pkt_sched.h:27 [inline] [] cbq_addprio net/sched/sch_cbq.c:1097 [inline] [] cbq_set_wrr+0x2d7/0x450 net/sched/sch_cbq.c:1115 [] cbq_change_class+0x987/0x225b net/sched/sch_cbq.c:1537 [] tc_ctl_tclass+0x555/0xcd0 net/sched/sch_api.c:2329 [] rtnetlink_rcv_msg+0x485/0xc10 net/core/rtnetlink.c:5248 [] netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2510 [] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5266 [] netlink_unicast_kernel net/netlink/af_netlink.c:1324 [inline] [] netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1350 [] netlink_sendmsg+0x89a/0xd50 net/netlink/af_netlink.c:1939 [] sock_sendmsg_nosec net/socket.c:673 [inline] [] sock_sendmsg+0x12e/0x170 net/socket.c:684 [] ___sys_sendmsg+0x81d/0x960 net/socket.c:2359 [] __sys_sendmsg+0x105/0x1d0 net/socket.c:2397 [] SYSC_sendmsg net/socket.c:2406 [inline] [] SyS_sendmsg+0x29/0x30 net/socket.c:2404 [] do_syscall_64+0x528/0x770 arch/x86/entry/common.c:305 [] entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/sched/sch_cbq.c | 43 +++++++++++++++++++++++++++++-------------- 1 file changed, 29 insertions(+), 14 deletions(-) (limited to 'net') diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c index 06c7a2da21bc..39b427dc7512 100644 --- a/net/sched/sch_cbq.c +++ b/net/sched/sch_cbq.c @@ -1127,6 +1127,33 @@ static const struct nla_policy cbq_policy[TCA_CBQ_MAX + 1] = { [TCA_CBQ_POLICE] = { .len = sizeof(struct tc_cbq_police) }, }; +static int cbq_opt_parse(struct nlattr *tb[TCA_CBQ_MAX + 1], + struct nlattr *opt, + struct netlink_ext_ack *extack) +{ + int err; + + if (!opt) { + NL_SET_ERR_MSG(extack, "CBQ options are required for this operation"); + return -EINVAL; + } + + err = nla_parse_nested_deprecated(tb, TCA_CBQ_MAX, opt, + cbq_policy, extack); + if (err < 0) + return err; + + if (tb[TCA_CBQ_WRROPT]) { + const struct tc_cbq_wrropt *wrr = nla_data(tb[TCA_CBQ_WRROPT]); + + if (wrr->priority > TC_CBQ_MAXPRIO) { + NL_SET_ERR_MSG(extack, "priority is bigger than TC_CBQ_MAXPRIO"); + err = -EINVAL; + } + } + return err; +} + static int cbq_init(struct Qdisc *sch, struct nlattr *opt, struct netlink_ext_ack *extack) { @@ -1139,13 +1166,7 @@ static int cbq_init(struct Qdisc *sch, struct nlattr *opt, hrtimer_init(&q->delay_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); q->delay_timer.function = cbq_undelay; - if (!opt) { - NL_SET_ERR_MSG(extack, "CBQ options are required for this operation"); - return -EINVAL; - } - - err = nla_parse_nested_deprecated(tb, TCA_CBQ_MAX, opt, cbq_policy, - extack); + err = cbq_opt_parse(tb, opt, extack); if (err < 0) return err; @@ -1464,13 +1485,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t struct cbq_class *parent; struct qdisc_rate_table *rtab = NULL; - if (!opt) { - NL_SET_ERR_MSG(extack, "Mandatory qdisc options missing"); - return -EINVAL; - } - - err = nla_parse_nested_deprecated(tb, TCA_CBQ_MAX, opt, cbq_policy, - extack); + err = cbq_opt_parse(tb, opt, extack); if (err < 0) return err; -- cgit v1.2.3-59-g8ed1b