CVE-2023-53141: Vulnerability in Linux Linux

Severity: mediumType: vulnerabilityCVE-2023-53141

In the Linux kernel, the following vulnerability has been resolved: ila: do not generate empty messages in ila_xlat_nl_cmd_get_mapping() ila_xlat_nl_cmd_get_mapping() generates an empty skb, triggerring a recent sanity check [1]. Instead, return an error code, so that user space can get it. [1] skb_assert_len WARNING: CPU: 0 PID: 5923 at include/linux/skbuff.h:2527 skb_assert_len include/linux/skbuff.h:2527 [inline] WARNING: CPU: 0 PID: 5923 at include/linux/skbuff.h:2527 __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156 Modules linked in: CPU: 0 PID: 5923 Comm: syz-executor269 Not tainted 6.2.0-syzkaller-18300-g2ebd1fbb946d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : skb_assert_len include/linux/skbuff.h:2527 [inline] pc : __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156 lr : skb_assert_len include/linux/skbuff.h:2527 [inline] lr : __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156 sp : ffff80001e0d6c40 x29: ffff80001e0d6e60 x28: dfff800000000000 x27: ffff0000c86328c0 x26: dfff800000000000 x25: ffff0000c8632990 x24: ffff0000c8632a00 x23: 0000000000000000 x22: 1fffe000190c6542 x21: ffff0000c8632a10 x20: ffff0000c8632a00 x19: ffff80001856e000 x18: ffff80001e0d5fc0 x17: 0000000000000000 x16: ffff80001235d16c x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000001 x11: ff80800008353a30 x10: 0000000000000000 x9 : 21567eaf25bfb600 x8 : 21567eaf25bfb600 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff80001e0d6558 x4 : ffff800015c74760 x3 : ffff800008596744 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000000e Call trace: skb_assert_len include/linux/skbuff.h:2527 [inline] __dev_queue_xmit+0x1bc0/0x3488 net/core/dev.c:4156 dev_queue_xmit include/linux/netdevice.h:3033 [inline] __netlink_deliver_tap_skb net/netlink/af_netlink.c:307 [inline] __netlink_deliver_tap+0x45c/0x6f8 net/netlink/af_netlink.c:325 netlink_deliver_tap+0xf4/0x174 net/netlink/af_netlink.c:338 __netlink_sendskb net/netlink/af_netlink.c:1283 [inline] netlink_sendskb+0x6c/0x154 net/netlink/af_netlink.c:1292 netlink_unicast+0x334/0x8d4 net/netlink/af_netlink.c:1380 nlmsg_unicast include/net/netlink.h:1099 [inline] genlmsg_unicast include/net/genetlink.h:433 [inline] genlmsg_reply include/net/genetlink.h:443 [inline] ila_xlat_nl_cmd_get_mapping+0x620/0x7d0 net/ipv6/ila/ila_xlat.c:493 genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline] genl_rcv_msg+0x938/0xc1c net/netlink/genetlink.c:1065 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2574 genl_rcv+0x38/0x50 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x800/0xae0 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] ____sys_sendmsg+0x558/0x844 net/socket.c:2479 ___sys_sendmsg net/socket.c:2533 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2562 __do_sys_sendmsg net/socket.c:2571 [inline] __se_sys_sendmsg net/socket.c:2569 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2569 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 irq event stamp: 136484 hardirqs last enabled at (136483): [<ffff800008350244>] __up_console_sem+0x60/0xb4 kernel/printk/printk.c:345 hardirqs last disabled at (136484): [<ffff800012358d60>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (136418): [<ffff800008020ea8>] softirq_ha ---truncated---

AI Analysis

Technical Summary

CVE-2023-53141 is a vulnerability identified in the Linux kernel, specifically within the ILA (Identifier-Locator Addressing) subsystem's function ila_xlat_nl_cmd_get_mapping(). The vulnerability arises because this function can generate an empty socket buffer (skb), which violates a recent kernel sanity check (skb_assert_len). This assertion failure occurs when the skb length is zero, which is unexpected and triggers a kernel warning and potential crash. The root cause is that the function does not properly handle cases where no valid data is available to populate the skb, leading to the creation of an empty message. The patch for this issue modifies the function to return an error code instead of generating an empty skb, allowing user space applications to handle the error gracefully without causing kernel instability. The vulnerability is located in the netlink communication path, which is used for kernel-user space messaging, and the stack trace indicates that the issue can lead to kernel warnings and potentially a denial of service due to kernel panic or crash. The vulnerability affects Linux kernel versions that include the vulnerable ila_xlat_nl_cmd_get_mapping() implementation, with the affected versions identified by specific commit hashes. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

Potential Impact

For European organizations, this vulnerability primarily poses a risk of denial of service (DoS) on Linux-based systems that utilize the ILA subsystem and netlink communication. Since Linux is widely deployed across servers, cloud infrastructure, and embedded devices in Europe, exploitation could lead to system instability or crashes, disrupting critical services. The impact on confidentiality and integrity is minimal as the vulnerability does not directly allow privilege escalation or data leakage. However, availability could be significantly affected, especially for organizations relying on Linux servers for networking, cloud services, or telecommunications infrastructure. The vulnerability could be exploited by a local or potentially remote attacker with the ability to send crafted netlink messages, causing kernel crashes. This could affect service continuity in sectors such as finance, healthcare, government, and critical infrastructure, where Linux systems are prevalent. Given the lack of known exploits, the immediate threat level is moderate, but the potential for DoS in critical environments warrants prompt attention.

Mitigation Recommendations

European organizations should prioritize updating their Linux kernels to versions where this vulnerability has been patched, ensuring that the ila_xlat_nl_cmd_get_mapping() function no longer generates empty skb messages. System administrators should monitor kernel updates from their Linux distribution vendors and apply security patches promptly. Additionally, organizations should audit and restrict access to netlink sockets, limiting which users and processes can send netlink messages to reduce the attack surface. Employing kernel hardening techniques such as seccomp filters to restrict system calls related to netlink communication can further mitigate risk. Monitoring system logs for skb_assert_len warnings or kernel warnings related to netlink can help detect attempted exploitation. For critical systems, implementing redundancy and failover mechanisms can minimize service disruption in case of a kernel crash. Finally, organizations should engage with their Linux distribution security advisories and subscribe to vulnerability feeds to stay informed about any emerging exploits or patches related to this issue.