CVE-2021-47606

CVE Details

Release Date:

2024-06-19

Description

In the Linux kernel, the following vulnerability has been resolved:\nnet: netlink: af_netlink: Prevent empty skb by adding a check on len.\nAdding a check on len parameter to avoid empty skb. This prevents a\ndivision error in netem_enqueue function which is caused when skb->len=0\nand skb->data_len=0 in the randomized corruption step as shown below.\nskb->data[prandom_u32() % skb_headlen(skb)] ^= 1<<(prandom_u32() % 8);\nCrash Report:\n[ 343.170349] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family\n0 port 6081 - 0\n[ 343.216110] netem: version 1.3\n[ 343.235841] divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI\n[ 343.236680] CPU: 3 PID: 4288 Comm: reproducer Not tainted 5.16.0-rc1+\n[ 343.237569] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),\nBIOS 1.11.0-2.el7 04/01/2014\n[ 343.238707] RIP: 0010:netem_enqueue+0x1590/0x33c0 [sch_netem]\n[ 343.239499] Code: 89 85 58 ff ff ff e8 5f 5d e9 d3 48 8b b5 48 ff ff\nff 8b 8d 50 ff ff ff 8b 85 58 ff ff ff 48 8b bd 70 ff ff ff 31 d2 2b 4f\n74 f1 48 b8 00 00 00 00 00 fc ff df 49 01 d5 4c 89 e9 48 c1 e9 03\n[ 343.241883] RSP: 0018:ffff88800bcd7368 EFLAGS: 00010246\n[ 343.242589] RAX: 00000000ba7c0a9c RBX: 0000000000000001 RCX:\n0000000000000000\n[ 343.243542] RDX: 0000000000000000 RSI: ffff88800f8edb10 RDI:\nffff88800f8eda40\n[ 343.244474] RBP: ffff88800bcd7458 R08: 0000000000000000 R09:\nffffffff94fb8445\n[ 343.245403] R10: ffffffff94fb8336 R11: ffffffff94fb8445 R12:\n0000000000000000\n[ 343.246355] R13: ffff88800a5a7000 R14: ffff88800a5b5800 R15:\n0000000000000020\n[ 343.247291] FS: 00007fdde2bd7700(0000) GS:ffff888109780000(0000)\nknlGS:0000000000000000\n[ 343.248350] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 343.249120] CR2: 00000000200000c0 CR3: 000000000ef4c000 CR4:\n00000000000006e0\n[ 343.250076] Call Trace:\n[ 343.250423] \n[ 343.250713] ? memcpy+0x4d/0x60\n[ 343.251162] ? netem_init+0xa0/0xa0 [sch_netem]\n[ 343.251795] ? __sanitizer_cov_trace_pc+0x21/0x60\n[ 343.252443] netem_enqueue+0xe28/0x33c0 [sch_netem]\n[ 343.253102] ? stack_trace_save+0x87/0xb0\n[ 343.253655] ? filter_irq_stacks+0xb0/0xb0\n[ 343.254220] ? netem_init+0xa0/0xa0 [sch_netem]\n[ 343.254837] ? __kasan_check_write+0x14/0x20\n[ 343.255418] ? _raw_spin_lock+0x88/0xd6\n[ 343.255953] dev_qdisc_enqueue+0x50/0x180\n[ 343.256508] __dev_queue_xmit+0x1a7e/0x3090\n[ 343.257083] ? netdev_core_pick_tx+0x300/0x300\n[ 343.257690] ? check_kcov_mode+0x10/0x40\n[ 343.258219] ? _raw_spin_unlock_irqrestore+0x29/0x40\n[ 343.258899] ? __kasan_init_slab_obj+0x24/0x30\n[ 343.259529] ? setup_object.isra.71+0x23/0x90\n[ 343.260121] ? new_slab+0x26e/0x4b0\n[ 343.260609] ? kasan_poison+0x3a/0x50\n[ 343.261118] ? kasan_unpoison+0x28/0x50\n[ 343.261637] ? __kasan_slab_alloc+0x71/0x90\n[ 343.262214] ? memcpy+0x4d/0x60\n[ 343.262674] ? write_comp_data+0x2f/0x90\n[ 343.263209] ? __kasan_check_write+0x14/0x20\n[ 343.263802] ? __skb_clone+0x5d6/0x840\n[ 343.264329] ? __sanitizer_cov_trace_pc+0x21/0x60\n[ 343.264958] dev_queue_xmit+0x1c/0x20\n[ 343.265470] netlink_deliver_tap+0x652/0x9c0\n[ 343.266067] netlink_unicast+0x5a0/0x7f0\n[ 343.266608] ? netlink_attachskb+0x860/0x860\n[ 343.267183] ? __sanitizer_cov_trace_pc+0x21/0x60\n[ 343.267820] ? write_comp_data+0x2f/0x90\n[ 343.268367] netlink_sendmsg+0x922/0xe80\n[ 343.268899] ? netlink_unicast+0x7f0/0x7f0\n[ 343.269472] ? __sanitizer_cov_trace_pc+0x21/0x60\n[ 343.270099] ? write_comp_data+0x2f/0x90\n[ 343.270644] ? netlink_unicast+0x7f0/0x7f0\n[ 343.271210] sock_sendmsg+0x155/0x190\n[ 343.271721] ____sys_sendmsg+0x75f/0x8f0\n[ 343.272262] ? kernel_sendmsg+0x60/0x60\n[ 343.272788] ? write_comp_data+0x2f/0x90\n[ 343.273332] ? write_comp_data+0x2f/0x90\n[ 343.273869] ___sys_sendmsg+0x10f/0x190\n[ 343.274405] ? sendmsg_copy_msghdr+0x80/0x80\n[ 343.274984] ? slab_post_alloc_hook+0x70/0x230\n[ 343.275597] ? futex_wait_setup+0x240/0x240\n[ 343.276175] ? security_file_alloc+0x3e/0x170\n[ 343.276779] ? write_comp_d\n---truncated---

See more information about CVE-2021-47606 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (kernel)	ELSA-2024-5363	2024-08-14