high CVSS 7.8

CVE-2024-27022·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: fork: defer linking file vma until vma is fully initialized Thorvald reported a WARNING [1]. And the root cause is below race: CPU 1 CPU 2 fork hugetlbfs_fallocate dup_mmap hugetlbfs_punch_hole i_mmap_lock_write(mapping); vma_interval_tree_insert_after -- Child vma is visible through i_mmap tree. i_mmap_unlock_write(mapping); hugetlb_dup_vma_private -- Clear vma_lock outside i_mmap_rwsem! i_mmap_lock_write(mapping); hugetlb_vmdelete_list vma_interval_tree_foreach hugetlb_vma_trylock_write -- Vma_lock is cleared. tmp->vm_ops->open -- Alloc new vma_lock outside i_mmap_rwsem! hugetlb_vma_unlock_write -- Vma_lock is assigned!!! i_mmap_unlock_write(mapping); hugetlb_dup_vma_private() and hugetlb_vm_op_open() are called outside i_mmap_rwsem lock while vma lock can be used in the same time. Fix this by deferring linking file vma until vma is fully initialized. Those vmas should be initialized first before they can be used.

Severity
high
Software
Kernel
Fixed in
6.8.8
Published
2024-05-01

Affected versions

From: 6.7

Until: 6.8.8

Fixed in: 6.8.8

How to fix this CVE

Update your Linux kernel to version 6.8.8 or later to resolve a race condition in the fork() system call that affects hugetlbfs virtual memory area initialization. The vulnerability stems from improper synchronization when file-backed VMAs are linked before their internal locks are fully initialized, creating a window where concurrent operations can access incomplete structures. Ensure your system is running a patched kernel version to eliminate the risk of memory corruption or denial of service.

sudo dnf update kernel kernel-devel kernel-headers

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed kernel version: uname -r — if version is between 6.7 and 6.8.7, your system is vulnerable
  2. Verify hugetlbfs support is enabled: grep -i hugetlbfs /boot/config-$(uname -r) — if output shows CONFIG_HUGETLBFS=y, the vulnerable code path is active
  3. Monitor kernel logs for VMA-related warnings: dmesg | grep -i 'vma_lock\|hugetlb' — exploitation may generate synchronization warnings
  4. After patching, confirm kernel update: uname -r — should show 6.8.8 or higher

FAQ

What is CVE-2024-27022?

CVE-2024-27022 is a race condition in Linux kernel fork operations involving hugetlbfs where virtual memory area (VMA) locks are cleared and reallocated outside proper synchronization boundaries, allowing concurrent file operations to access partially initialized VMA structures and potentially trigger memory corruption.

Is CVE-2024-27022 being actively exploited?

No, CVE-2024-27022 is not listed in the CISA Known Exploited Vulnerabilities catalog and no public exploits are currently available, though the vulnerability does carry a high CVSS score of 7.8.

What versions of Kernel are affected by CVE-2024-27022?

Linux kernel versions 6.7.0 through 6.8.7 are vulnerable; version 6.8.8 and all subsequent releases contain the fix.

How do I check if my server is vulnerable to CVE-2024-27022?

Run 'uname -r' to check your kernel version; if it displays a version between 6.7 and 6.8.7 inclusive, your system is affected. Additionally verify hugetlbfs is in use with 'grep CONFIG_HUGETLBFS /boot/config-$(uname -r)'.

Does Defensia detect CVE-2024-27022?

Yes — Defensia's CVE advisory scanner compares installed kernel versions against the NVD database. If Linux kernel is installed on a monitored server running versions 6.7–6.8.7, CVE-2024-27022 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2024-42256CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: cifs: Fix server re-repick on subrequest retry When a subrequest is marked for needing retry, netfs will call cifs_prepare_write() which will make cifs repick the server for the op before renegotiating credits; it then calls cifs_issue_write() which invokes smb2_async_writev() - which re-repicks the server. If a different server is then selected, this causes the increment of server->in_flight to happen against one record and the decrement to happen against another, leading to misaccounting. Fix this by just removing the repick code in smb2_async_writev(). As this is only called from netfslib-driven code, cifs_prepare_write() should always have been called first, and so server should never be NULL and the preparatory step is repeated in the event that we do a retry. The problem manifests as a warning looking something like: WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Which may be triggered by a number of different xfstests running against an Azure server in multichannel mode. generic/249 seems the most repeatable, but generic/215, generic/249 and generic/308 may also show it.
CVE-2024-36031CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: keys: Fix overwrite of key expiration on instantiation The expiry time of a key is unconditionally overwritten during instantiation, defaulting to turn it permanent. This causes a problem for DNS resolution as the expiration set by user-space is overwritten to TIME64_MAX, disabling further DNS updates. Fix this by restoring the condition that key_set_expiry is only called when the pre-parser sets a specific expiry.
CVE-2024-38612CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.
CVE-2024-38623CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Use variable length array instead of fixed size Should fix smatch warning: ntfs_set_label() error: __builtin_memcpy() 'uni->name' too small (20 vs 256)
CVE-2021-47548CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port() The if statement: if (port >= DSAF_GE_NUM) return; limits the value of port less than DSAF_GE_NUM (i.e., 8). However, if the value of port is 6 or 7, an array overflow could occur: port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off; because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6). To fix this possible array overflow, we first check port and if it is greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

References

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