The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e4bedf48aaa5552bc1f49703abd17606e7e6e82a Mon Sep 17 00:00:00 2001

From: Eric Dumazet edumazet@google.com Date: Thu, 14 Jan 2021 08:06:37 -0800 Subject: [PATCH] net_sched: reject silly cell_log in qdisc_get_rtab()

iproute2 probably never goes beyond 8 for the cell exponent, but stick to the max shift exponent for signed 32bit.

UBSAN reported: UBSAN: shift-out-of-bounds in net/sched/sch_api.c:389:22 shift exponent 130 is too large for 32-bit type 'int' CPU: 1 PID: 8450 Comm: syz-executor586 Not tainted 5.11.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x183/0x22e lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:148 [inline] __ubsan_handle_shift_out_of_bounds+0x432/0x4d0 lib/ubsan.c:395 __detect_linklayer+0x2a9/0x330 net/sched/sch_api.c:389 qdisc_get_rtab+0x2b5/0x410 net/sched/sch_api.c:435 cbq_init+0x28f/0x12c0 net/sched/sch_cbq.c:1180 qdisc_create+0x801/0x1470 net/sched/sch_api.c:1246 tc_modify_qdisc+0x9e3/0x1fc0 net/sched/sch_api.c:1662 rtnetlink_rcv_msg+0xb1d/0xe60 net/core/rtnetlink.c:5564 netlink_rcv_skb+0x1f0/0x460 net/netlink/af_netlink.c:2494 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] netlink_unicast+0x7de/0x9b0 net/netlink/af_netlink.c:1330 netlink_sendmsg+0xaa6/0xe90 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x5a2/0x900 net/socket.c:2345 ___sys_sendmsg net/socket.c:2399 [inline] __sys_sendmsg+0x319/0x400 net/socket.c:2432 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Acked-by: Cong Wang cong.wang@bytedance.com Link: https://lore.kernel.org/r/20210114160637.1660597-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 51cb553e4317..6fe4e5cc807c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -412,7 +412,8 @@ struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r, { struct qdisc_rate_table *rtab;

- if (tab == NULL || r->rate == 0 || r->cell_log == 0 || + if (tab == NULL || r->rate == 0 || + r->cell_log == 0 || r->cell_log >= 32 || nla_len(tab) != TC_RTAB_SIZE) { NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching"); return NULL;