CVE-2024-49934
NoneCVSS
—
EPSS
0.3%
Published
Oct 21, 2024
CISA due date
—
Cloudanix analysis
A bug in the core operating system can make computers crash when removing memory hardware while certain large memory pages and network file systems are in use.
- Exploitation
- Local Privilege
- Attacker needs
- Local User
- Complexity
- Moderate
- Impact
- Denial Of Service
- Component
- OS kernel
- Class
- Memory Corruption
- Remediation
- Upgrade
- Effort
- Medium
- Patch risk
- Low
What it actually does
A flaw in the Linux kernel's dump_mapping function can dereference an invalid dentry.d_name.name pointer during memory hot-remove operations involving hugetlb pages and NFS inodes, resulting in a kernel page fault and crash.
Why it matters to the business
Unexpected system crashes and operational downtime can occur on systems performing memory device offline operations with huge pages and network file systems, disrupting high-memory workloads and requiring manual intervention.
How an attack unfolds
An attacker or automated process initiates memory device hot-remove (for example via daxctl) while hugetlb pages backed by NFS inodes are active; dump_mapping attempts to format an invalid dentry name, triggering a supervisor page fault. Threat actors in 2024 zero-day campaigns targeting Linux kernel resource and bounds issues could adapt similar local triggers for denial of service.
How to fix it
Apply kernel updates containing commit 1a4159138e718db6199f0abf376ad52f726dcc5c. For Rocky Linux 8 systems using Judy, upgrade to package version 1.0.5-18.module+el8.4.0+427+adf35707. Reboot into the fixed kernel and retest memory hot-remove scenarios.
How to confirm the fix worked
Confirm the running kernel contains the listed commit hash or package version, then execute controlled memory offline operations with hugetlb and NFS workloads while monitoring for absence of dump_mapping-related faults.
Typical attack path
- Initiate memory device offline or migration
- Access hugetlb pages associated with NFS inodes
- Trigger dump_mapping during page migration or offline handling
- Dereference invalid dentry.d_name.name causing page fault
- Kernel oops and system instability
How to detect it
Search kernel logs and dmesg for oops messages referencing dump_mapping, dentry_name, do_user_addr_fault, or page faults at address 0x1000 during memory_subsys_offline or device_offline events.
What your security team should do
- Prioritize kernel updates on systems using NFS and hugetlb with dynamic memory
- Review and restrict local access to memory hotplug interfaces
- Enable kernel panic-on-oops where appropriate for critical systems
- Monitor changelogs for related NFS and memory management fixes
The record
In the Linux kernel, the following vulnerability has been resolved: fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name It's observed that a crash occurs during hot-remove a memory device, in which user is accessing the hugetlb. See calltrace as following: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 14045 at arch/x86/mm/fault.c:1278 do_user_addr_fault+0x2a0/0x790 Modules linked in: kmem device_dax cxl_mem cxl_pmem cxl_port cxl_pci dax_hmem dax_pmem nd_pmem cxl_acpi nd_btt cxl_core crc32c_intel nvme virtiofs fuse nvme_core nfit libnvdimm dm_multipath scsi_dh_rdac scsi_dh_emc s mirror dm_region_hash dm_log dm_mod CPU: 1 PID: 14045 Comm: daxctl Not tainted 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:do_user_addr_fault+0x2a0/0x790 Code: 48 8b 00 a8 04 0f 84 b5 fe ff ff e9 1c ff ff ff 4c 89 e9 4c 89 e2 be 01 00 00 00 bf 02 00 00 00 e8 b5 ef 24 00 e9 42 fe ff ff <0f> 0b 48 83 c4 08 4c 89 ea 48 89 ee 4c 89 e7 5b 5d 41 5c 41 5d 41 RSP: 0000:ffffc90000a575f0 EFLAGS: 00010046 RAX: ffff88800c303600 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000001000 RSI: ffffffff82504162 RDI: ffffffff824b2c36 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000a57658 R13: 0000000000001000 R14: ffff88800bc2e040 R15: 0000000000000000 FS: 00007f51cb57d880(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001000 CR3: 00000000072e2004 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? __warn+0x8d/0x190 ? do_user_addr_fault+0x2a0/0x790 ? report_bug+0x1c3/0x1d0 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? do_user_addr_fault+0x2a0/0x790 ? exc_page_fault+0x31/0x200 exc_page_fault+0x68/0x200 <...snip...> BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI ---[ end trace 0000000000000000 ]--- BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 14045 Comm: daxctl Kdump: loaded Tainted: G W 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:dentry_name+0x1f4/0x440 <...snip...> ? dentry_name+0x2fa/0x440 vsnprintf+0x1f3/0x4f0 vprintk_store+0x23a/0x540 vprintk_emit+0x6d/0x330 _printk+0x58/0x80 dump_mapping+0x10b/0x1a0 ? __pfx_free_object_rcu+0x10/0x10 __dump_page+0x26b/0x3e0 ? vprintk_emit+0xe0/0x330 ? _printk+0x58/0x80 ? dump_page+0x17/0x50 dump_page+0x17/0x50 do_migrate_range+0x2f7/0x7f0 ? do_migrate_range+0x42/0x7f0 ? offline_pages+0x2f4/0x8c0 offline_pages+0x60a/0x8c0 memory_subsys_offline+0x9f/0x1c0 ? lockdep_hardirqs_on+0x77/0x100 ? _raw_spin_unlock_irqrestore+0x38/0x60 device_offline+0xe3/0x110 state_store+0x6e/0xc0 kernfs_fop_write_iter+0x143/0x200 vfs_write+0x39f/0x560 ksys_write+0x65/0xf0 do_syscall_64+0x62/0x130 Previously, some sanity check have been done in dump_mapping() before the print facility parsing '%pd' though, it's still possible to run into an invalid dentry.d_name.name. Since dump_mapping() only needs to dump the filename only, retrieve it by itself in a safer way to prevent an unnecessary crash. Note that either retrieving the filename with '%pd' or strncpy_from_kernel_nofault(), the filename could be unreliable.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Debian:11 | linux | 0 | No fix |
| Debian:11 | linux-6.1 | 0 | 6.1.128-1~deb11u1 |
| Debian:11 | linux-6.1 | 0 | 6.1.6.1.128-1~deb11u1 |
| Debian:12 | linux | 0 | No fix |
| Debian:12 | linux | 0 | 6.1.123-1 |
| Debian:13 | linux | 0 | No fix |
| Debian:13 | linux | 0 | 6.11.4-1 |
| Linux | Kernel | 0 | 6.1.120 |
| Linux | Kernel | 5.0.0 | 6.1.120 |
| SUSE:Linux Enterprise High Availability Extension 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise High Availability Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5-RT_Update_23 | 0 | 1-150500.11.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_21 | 0 | 1-150500.11.5.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6-RT_Update_6 | 0 | 1-150600.1.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_6 | 0 | 1-150600.13.3.5 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-default-base | 0 | 5.14.21-150500.55.88.1.150500.6.39.4 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Linux Enterprise Micro 5.5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-64kb | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-default-base | 0 | 5.14.21-150500.55.88.1.150500.6.39.4 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-source | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP5 | kernel-zfcpdump | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-64kb | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-default-base | 0 | 6.4.0-150600.23.30.1.150600.12.12.6 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-coco_debug | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-source-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Confidential Computing Technical Preview 15 SP6 | kernel-syms-coco | 0 | 6.4.0-15061.9.coco15sp6.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-docs | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-obs-build | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-source | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP5 | kernel-syms | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-docs | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-obs-build | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP6 | kernel-syms | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Legacy 15 SP5 | kernel-default | 0 | 5.14.21-150500.55.88.1 |
| SUSE:Linux Enterprise Module for Legacy 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-source-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP5 | kernel-syms-azure | 0 | 5.14.21-150500.33.75.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-azure | 0 | 6.4.0-150600.8.20.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-source-azure | 0 | 6.4.0-150600.8.20.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP6 | kernel-syms-azure | 0 | 6.4.0-150600.8.20.1 |
| SUSE:Linux Enterprise Workstation Extension 15 SP6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| SUSE:Real Time Module 15 SP5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-rt_debug | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP5 | kernel-syms-rt | 0 | 5.14.21-150500.13.79.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt | 0 | 6.4.0-150600.10.20.1 |
| SUSE:Real Time Module 15 SP6 | kernel-rt_debug | 0 | 6.4.0-150600.10.20.1 |
| SUSE:Real Time Module 15 SP6 | kernel-source-rt | 0 | 6.4.0-150600.10.20.1 |
| SUSE:Real Time Module 15 SP6 | kernel-syms-rt | 0 | 6.4.0-150600.10.20.1 |
| Ubuntu:24.10 | linux | 0 | 6.11.0-18.18 |
| Ubuntu:24.10 | linux-aws | 0 | 6.11.0-1009.10 |
| Ubuntu:24.10 | linux-azure | 0 | 6.11.0-1009.9 |
| Ubuntu:24.10 | linux-gcp | 0 | 6.11.0-1009.9 |
| Ubuntu:24.10 | linux-lowlatency | 0 | 6.11.0-1010.11 |
| Ubuntu:24.10 | linux-oracle | 0 | 6.11.0-1011.12 |
| Ubuntu:24.10 | linux-raspi | 0 | 6.11.0-1008.8 |
| Ubuntu:24.10 | linux-realtime | 0 | 6.11.0-1005.5 |
| openSUSE:Leap 15.5 | kernel-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-rt_debug | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-source-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-source-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.5 | kernel-syms-azure | 0 | 5.14.21-150500.33.75.1 |
| openSUSE:Leap 15.5 | kernel-syms-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Leap 15.6 | dtb-aarch64 | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-64kb | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-azure | 0 | 6.4.0-150600.8.20.1 |
| openSUSE:Leap 15.6 | kernel-debug | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-default | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-default-base | 0 | 6.4.0-150600.23.30.1.150600.12.12.6 |
| openSUSE:Leap 15.6 | kernel-docs | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-kvmsmall | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-obs-build | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-obs-qa | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-rt | 0 | 6.4.0-150600.10.20.1 |
| openSUSE:Leap 15.6 | kernel-rt_debug | 0 | 6.4.0-150600.10.20.1 |
| openSUSE:Leap 15.6 | kernel-source | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-source-azure | 0 | 6.4.0-150600.8.20.1 |
| openSUSE:Leap 15.6 | kernel-source-rt | 0 | 6.4.0-150600.10.20.1 |
| openSUSE:Leap 15.6 | kernel-syms | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap 15.6 | kernel-syms-azure | 0 | 6.4.0-150600.8.20.1 |
| openSUSE:Leap 15.6 | kernel-syms-rt | 0 | 6.4.0-150600.10.20.1 |
| openSUSE:Leap 15.6 | kernel-zfcpdump | 0 | 6.4.0-150600.23.30.1 |
| openSUSE:Leap Micro 5.5 | kernel-rt | 0 | 5.14.21-150500.13.79.1 |
| openSUSE:Tumbleweed | kernel-source | 0 | 6.11.8-1.1 |
| openSUSE:Tumbleweed | kernel-source-longterm | 0 | 6.12.11-1.1 |
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