From: Eric Dumazet edumazet@google.com
[ Upstream commit e9789c7cc182484fc031fd88097eb14cb26c4596 ]
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: [<ffffffff83be9d57>] cbq_normalize_quanta include/net/pkt_sched.h:27 [inline] [<ffffffff83be9d57>] cbq_addprio net/sched/sch_cbq.c:1097 [inline] [<ffffffff83be9d57>] cbq_set_wrr+0x2d7/0x450 net/sched/sch_cbq.c:1115 [<ffffffff83bee8a7>] cbq_change_class+0x987/0x225b net/sched/sch_cbq.c:1537 [<ffffffff83b96985>] tc_ctl_tclass+0x555/0xcd0 net/sched/sch_api.c:2329 [<ffffffff83a84655>] rtnetlink_rcv_msg+0x485/0xc10 net/core/rtnetlink.c:5248 [<ffffffff83cadf0a>] netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2510 [<ffffffff83a7db6d>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5266 [<ffffffff83cac2c6>] netlink_unicast_kernel net/netlink/af_netlink.c:1324 [inline] [<ffffffff83cac2c6>] netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1350 [<ffffffff83cacd4a>] netlink_sendmsg+0x89a/0xd50 net/netlink/af_netlink.c:1939 [<ffffffff8399d46e>] sock_sendmsg_nosec net/socket.c:673 [inline] [<ffffffff8399d46e>] sock_sendmsg+0x12e/0x170 net/socket.c:684 [<ffffffff8399f1fd>] ___sys_sendmsg+0x81d/0x960 net/socket.c:2359 [<ffffffff839a2d05>] __sys_sendmsg+0x105/0x1d0 net/socket.c:2397 [<ffffffff839a2df9>] SYSC_sendmsg net/socket.c:2406 [inline] [<ffffffff839a2df9>] SyS_sendmsg+0x29/0x30 net/socket.c:2404 [<ffffffff8101ccc8>] do_syscall_64+0x528/0x770 arch/x86/entry/common.c:305 [<ffffffff84400091>] entry_SYSCALL_64_after_hwframe+0x42/0xb7
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_cbq.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-)
--- a/net/sched/sch_cbq.c +++ b/net/sched/sch_cbq.c @@ -1340,6 +1340,26 @@ static const struct nla_policy cbq_polic [TCA_CBQ_POLICE] = { .len = sizeof(struct tc_cbq_police) }, };
+static int cbq_opt_parse(struct nlattr *tb[TCA_CBQ_MAX + 1], struct nlattr *opt) +{ + int err; + + if (!opt) + return -EINVAL; + + err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy); + 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) + err = -EINVAL; + } + return err; +} + static int cbq_init(struct Qdisc *sch, struct nlattr *opt) { struct cbq_sched_data *q = qdisc_priv(sch); @@ -1347,7 +1367,7 @@ static int cbq_init(struct Qdisc *sch, s struct tc_ratespec *r; int err;
- err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy); + err = cbq_opt_parse(tb, opt); if (err < 0) return err;
@@ -1728,10 +1748,7 @@ cbq_change_class(struct Qdisc *sch, u32 struct cbq_class *parent; struct qdisc_rate_table *rtab = NULL;
- if (opt == NULL) - return -EINVAL; - - err = nla_parse_nested(tb, TCA_CBQ_MAX, opt, cbq_policy); + err = cbq_opt_parse(tb, opt); if (err < 0) return err;