| From 055a9ac4340a40d50ea69844ab50fc8dd94a1023 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 29 Nov 2021 09:53:27 -0800 |
| Subject: net: netlink: af_netlink: Prevent empty skb by adding a check on len. |
| |
| From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> |
| |
| [ Upstream commit f123cffdd8fe8ea6c7fded4b88516a42798797d0 ] |
| |
| Adding a check on len parameter to avoid empty skb. This prevents a |
| division error in netem_enqueue function which is caused when skb->len=0 |
| and skb->data_len=0 in the randomized corruption step as shown below. |
| |
| skb->data[prandom_u32() % skb_headlen(skb)] ^= 1<<(prandom_u32() % 8); |
| |
| Crash Report: |
| [ 343.170349] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family |
| 0 port 6081 - 0 |
| [ 343.216110] netem: version 1.3 |
| [ 343.235841] divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI |
| [ 343.236680] CPU: 3 PID: 4288 Comm: reproducer Not tainted 5.16.0-rc1+ |
| [ 343.237569] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), |
| BIOS 1.11.0-2.el7 04/01/2014 |
| [ 343.238707] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem] |
| [ 343.239499] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff |
| ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f |
| 74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03 |
| [ 343.241883] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246 |
| [ 343.242589] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX: |
| 0000000000000000 |
| [ 343.243542] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI: |
| ffff88800f8eda40 |
| [ 343.244474] RBP: ffff88800bcd7458 R08: 0000000000000000 R09: |
| ffffffff94fb8445 |
| [ 343.245403] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12: |
| 0000000000000000 |
| [ 343.246355] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15: |
| 0000000000000020 |
| [ 343.247291] FS: 00007fdde2bd7700(0000) GS:ffff888109780000(0000) |
| knlGS:0000000000000000 |
| [ 343.248350] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| [ 343.249120] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4: |
| 00000000000006e0 |
| [ 343.250076] Call Trace: |
| [ 343.250423] <TASK> |
| [ 343.250713] ? memcpy+0x4d/0x60 |
| [ 343.251162] ? netem_init+0xa0/0xa0 [sch_netem] |
| [ 343.251795] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.252443] netem_enqueue+0xe28/0x33c0 [sch_netem] |
| [ 343.253102] ? stack_trace_save+0x87/0xb0 |
| [ 343.253655] ? filter_irq_stacks+0xb0/0xb0 |
| [ 343.254220] ? netem_init+0xa0/0xa0 [sch_netem] |
| [ 343.254837] ? __kasan_check_write+0x14/0x20 |
| [ 343.255418] ? _raw_spin_lock+0x88/0xd6 |
| [ 343.255953] dev_qdisc_enqueue+0x50/0x180 |
| [ 343.256508] __dev_queue_xmit+0x1a7e/0x3090 |
| [ 343.257083] ? netdev_core_pick_tx+0x300/0x300 |
| [ 343.257690] ? check_kcov_mode+0x10/0x40 |
| [ 343.258219] ? _raw_spin_unlock_irqrestore+0x29/0x40 |
| [ 343.258899] ? __kasan_init_slab_obj+0x24/0x30 |
| [ 343.259529] ? setup_object.isra.71+0x23/0x90 |
| [ 343.260121] ? new_slab+0x26e/0x4b0 |
| [ 343.260609] ? kasan_poison+0x3a/0x50 |
| [ 343.261118] ? kasan_unpoison+0x28/0x50 |
| [ 343.261637] ? __kasan_slab_alloc+0x71/0x90 |
| [ 343.262214] ? memcpy+0x4d/0x60 |
| [ 343.262674] ? write_comp_data+0x2f/0x90 |
| [ 343.263209] ? __kasan_check_write+0x14/0x20 |
| [ 343.263802] ? __skb_clone+0x5d6/0x840 |
| [ 343.264329] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.264958] dev_queue_xmit+0x1c/0x20 |
| [ 343.265470] netlink_deliver_tap+0x652/0x9c0 |
| [ 343.266067] netlink_unicast+0x5a0/0x7f0 |
| [ 343.266608] ? netlink_attachskb+0x860/0x860 |
| [ 343.267183] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.267820] ? write_comp_data+0x2f/0x90 |
| [ 343.268367] netlink_sendmsg+0x922/0xe80 |
| [ 343.268899] ? netlink_unicast+0x7f0/0x7f0 |
| [ 343.269472] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.270099] ? write_comp_data+0x2f/0x90 |
| [ 343.270644] ? netlink_unicast+0x7f0/0x7f0 |
| [ 343.271210] sock_sendmsg+0x155/0x190 |
| [ 343.271721] ____sys_sendmsg+0x75f/0x8f0 |
| [ 343.272262] ? kernel_sendmsg+0x60/0x60 |
| [ 343.272788] ? write_comp_data+0x2f/0x90 |
| [ 343.273332] ? write_comp_data+0x2f/0x90 |
| [ 343.273869] ___sys_sendmsg+0x10f/0x190 |
| [ 343.274405] ? sendmsg_copy_msghdr+0x80/0x80 |
| [ 343.274984] ? slab_post_alloc_hook+0x70/0x230 |
| [ 343.275597] ? futex_wait_setup+0x240/0x240 |
| [ 343.276175] ? security_file_alloc+0x3e/0x170 |
| [ 343.276779] ? write_comp_data+0x2f/0x90 |
| [ 343.277313] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.277969] ? write_comp_data+0x2f/0x90 |
| [ 343.278515] ? __fget_files+0x1ad/0x260 |
| [ 343.279048] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.279685] ? write_comp_data+0x2f/0x90 |
| [ 343.280234] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.280874] ? sockfd_lookup_light+0xd1/0x190 |
| [ 343.281481] __sys_sendmsg+0x118/0x200 |
| [ 343.281998] ? __sys_sendmsg_sock+0x40/0x40 |
| [ 343.282578] ? alloc_fd+0x229/0x5e0 |
| [ 343.283070] ? write_comp_data+0x2f/0x90 |
| [ 343.283610] ? write_comp_data+0x2f/0x90 |
| [ 343.284135] ? __sanitizer_cov_trace_pc+0x21/0x60 |
| [ 343.284776] ? ktime_get_coarse_real_ts64+0xb8/0xf0 |
| [ 343.285450] __x64_sys_sendmsg+0x7d/0xc0 |
| [ 343.285981] ? syscall_enter_from_user_mode+0x4d/0x70 |
| [ 343.286664] do_syscall_64+0x3a/0x80 |
| [ 343.287158] entry_SYSCALL_64_after_hwframe+0x44/0xae |
| [ 343.287850] RIP: 0033:0x7fdde24cf289 |
| [ 343.288344] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 |
| 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f |
| 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b7 db 2c 00 f7 d8 64 89 01 48 |
| [ 343.290729] RSP: 002b:00007fdde2bd6d98 EFLAGS: 00000246 ORIG_RAX: |
| 000000000000002e |
| [ 343.291730] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: |
| 00007fdde24cf289 |
| [ 343.292673] RDX: 0000000000000000 RSI: 00000000200000c0 RDI: |
| 0000000000000004 |
| [ 343.293618] RBP: 00007fdde2bd6e20 R08: 0000000100000001 R09: |
| 0000000000000000 |
| [ 343.294557] R10: 0000000100000001 R11: 0000000000000246 R12: |
| 0000000000000000 |
| [ 343.295493] R13: 0000000000021000 R14: 0000000000000000 R15: |
| 00007fdde2bd7700 |
| [ 343.296432] </TASK> |
| [ 343.296735] Modules linked in: sch_netem ip6_vti ip_vti ip_gre ipip |
| sit ip_tunnel geneve macsec macvtap tap ipvlan macvlan 8021q garp mrp |
| hsr wireguard libchacha20poly1305 chacha_x86_64 poly1305_x86_64 |
| ip6_udp_tunnel udp_tunnel libblake2s blake2s_x86_64 libblake2s_generic |
| curve25519_x86_64 libcurve25519_generic libchacha xfrm_interface |
| xfrm6_tunnel tunnel4 veth netdevsim psample batman_adv nlmon dummy team |
| bonding tls vcan ip6_gre ip6_tunnel tunnel6 gre tun ip6t_rpfilter |
| ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set |
| ebtable_nat ebtable_broute ip6table_nat ip6table_mangle |
| ip6table_security ip6table_raw iptable_nat nf_nat nf_conntrack |
| nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_security |
| iptable_raw ebtable_filter ebtables rfkill ip6table_filter ip6_tables |
| iptable_filter ppdev bochs drm_vram_helper drm_ttm_helper ttm |
| drm_kms_helper cec parport_pc drm joydev floppy parport sg syscopyarea |
| sysfillrect sysimgblt i2c_piix4 qemu_fw_cfg fb_sys_fops pcspkr |
| [ 343.297459] ip_tables xfs virtio_net net_failover failover sd_mod |
| sr_mod cdrom t10_pi ata_generic pata_acpi ata_piix libata virtio_pci |
| virtio_pci_legacy_dev serio_raw virtio_pci_modern_dev dm_mirror |
| dm_region_hash dm_log dm_mod |
| [ 343.311074] Dumping ftrace buffer: |
| [ 343.311532] (ftrace buffer empty) |
| [ 343.312040] ---[ end trace a2e3db5a6ae05099 ]--- |
| [ 343.312691] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem] |
| [ 343.313481] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff |
| ff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f |
| 74 <f7> f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03 |
| [ 343.315893] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246 |
| [ 343.316622] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX: |
| 0000000000000000 |
| [ 343.317585] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI: |
| ffff88800f8eda40 |
| [ 343.318549] RBP: ffff88800bcd7458 R08: 0000000000000000 R09: |
| ffffffff94fb8445 |
| [ 343.319503] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12: |
| 0000000000000000 |
| [ 343.320455] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15: |
| 0000000000000020 |
| [ 343.321414] FS: 00007fdde2bd7700(0000) GS:ffff888109780000(0000) |
| knlGS:0000000000000000 |
| [ 343.322489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| [ 343.323283] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4: |
| 00000000000006e0 |
| [ 343.324264] Kernel panic - not syncing: Fatal exception in interrupt |
| [ 343.333717] Dumping ftrace buffer: |
| [ 343.334175] (ftrace buffer empty) |
| [ 343.334653] Kernel Offset: 0x13600000 from 0xffffffff81000000 |
| (relocation range: 0xffffffff80000000-0xffffffffbfffffff) |
| [ 343.336027] Rebooting in 86400 seconds.. |
| |
| Reported-by: syzkaller <syzkaller@googlegroups.com> |
| Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> |
| Link: https://lore.kernel.org/r/20211129175328.55339-1-harshit.m.mogalapalli@oracle.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/netlink/af_netlink.c | 5 +++++ |
| 1 file changed, 5 insertions(+) |
| |
| diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c |
| index ada47e59647a0..81ba8e51e01ff 100644 |
| --- a/net/netlink/af_netlink.c |
| +++ b/net/netlink/af_netlink.c |
| @@ -1871,6 +1871,11 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) |
| if (msg->msg_flags & MSG_OOB) |
| return -EOPNOTSUPP; |
| |
| + if (len == 0) { |
| + pr_warn_once("Zero length message leads to an empty skb\n"); |
| + return -ENODATA; |
| + } |
| + |
| err = scm_send(sock, msg, &scm, true); |
| if (err < 0) |
| return err; |
| -- |
| 2.33.0 |
| |