From f1a3b283f852c613fae004f87bbbacc8cef5a061 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 7 Nov 2023 16:04:40 +0000 Subject: net_sched: sch_fq: better validate TCA_FQ_WEIGHTS and TCA_FQ_PRIOMAP syzbot was able to trigger the following report while providing too small TCA_FQ_WEIGHTS attribute [1] Fix is to use NLA_POLICY_EXACT_LEN() to ensure user space provided correct sizes. Apply the same fix to TCA_FQ_PRIOMAP. [1] BUG: KMSAN: uninit-value in fq_load_weights net/sched/sch_fq.c:960 [inline] BUG: KMSAN: uninit-value in fq_change+0x1348/0x2fe0 net/sched/sch_fq.c:1071 fq_load_weights net/sched/sch_fq.c:960 [inline] fq_change+0x1348/0x2fe0 net/sched/sch_fq.c:1071 fq_init+0x68e/0x780 net/sched/sch_fq.c:1159 qdisc_create+0x12f3/0x1be0 net/sched/sch_api.c:1326 tc_modify_qdisc+0x11ef/0x2c20 rtnetlink_rcv_msg+0x16a6/0x1840 net/core/rtnetlink.c:6558 netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x34/0x40 net/core/rtnetlink.c:6576 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2588 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2642 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2680 [inline] __se_sys_sendmsg net/socket.c:2678 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560 __alloc_skb+0x318/0x740 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1286 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline] netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2588 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2642 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2680 [inline] __se_sys_sendmsg net/socket.c:2678 [inline] __x64_sys_sendmsg+0x307/0x490 net/socket.c:2678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b CPU: 1 PID: 5001 Comm: syz-executor300 Not tainted 6.6.0-syzkaller-12401-g8f6f76a6a29f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 Fixes: 29f834aa326e ("net_sched: sch_fq: add 3 bands and WRR scheduling") Fixes: 49e7265fd098 ("net_sched: sch_fq: add TCA_FQ_WEIGHTS attribute") Reported-by: syzbot Signed-off-by: Eric Dumazet Acked-by: Jamal Hadi Salim Link: https://lore.kernel.org/r/20231107160440.1992526-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/sched/sch_fq.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'net/sched/sch_fq.c') diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 0fd18c344ab5..3a31c47fea9b 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -919,14 +919,8 @@ static const struct nla_policy fq_policy[TCA_FQ_MAX + 1] = { [TCA_FQ_TIMER_SLACK] = { .type = NLA_U32 }, [TCA_FQ_HORIZON] = { .type = NLA_U32 }, [TCA_FQ_HORIZON_DROP] = { .type = NLA_U8 }, - [TCA_FQ_PRIOMAP] = { - .type = NLA_BINARY, - .len = sizeof(struct tc_prio_qopt), - }, - [TCA_FQ_WEIGHTS] = { - .type = NLA_BINARY, - .len = FQ_BANDS * sizeof(s32), - }, + [TCA_FQ_PRIOMAP] = NLA_POLICY_EXACT_LEN(sizeof(struct tc_prio_qopt)), + [TCA_FQ_WEIGHTS] = NLA_POLICY_EXACT_LEN(FQ_BANDS * sizeof(s32)), }; /* compress a u8 array with all elems <= 3 to an array of 2-bit fields */ -- cgit