vulnerability

Ubuntu: (Multiple Advisories) (CVE-2025-21866): Linux kernel vulnerabilities

Severity
5
CVSS
(AV:L/AC:L/Au:S/C:N/I:N/A:C)
Published
Mar 12, 2025
Added
May 20, 2025
Modified
Jun 3, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

powerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC

Erhard reported the following KASAN hit while booting his PowerMac G4
with a KASAN-enabled kernel 6.13-rc6:

BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8
Write of size 8 at addr f1000000 by task chronyd/1293

CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G W 6.13.0-rc6-PMacG4 #2
Tainted: [W]=WARN
Hardware name: PowerMac3,6 7455 0x80010303 PowerMac
Call Trace:
[c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)
[c24375b0] [c0504998] print_report+0xdc/0x504
[c2437610] [c050475c] kasan_report+0xf8/0x108
[c2437690] [c0505a3c] kasan_check_range+0x24/0x18c
[c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8
[c24376c0] [c004c014] patch_instructions+0x15c/0x16c
[c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c
[c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac
[c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec
[c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478
[c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14
[c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4
[c24379d0] [c027111c] do_seccomp+0x3dc/0x1890
[c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420
[c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c
--- interrupt: c00 at 0x5a1274
NIP: 005a1274 LR: 006a3b3c CTR: 005296c8
REGS: c2437f40 TRAP: 0c00 Tainted: G W (6.13.0-rc6-PMacG4)
MSR: 0200f932 CR: 24004422 XER: 00000000

GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932
GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57
GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002
GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001
NIP [005a1274] 0x5a1274
LR [006a3b3c] 0x6a3b3c
--- interrupt: c00

The buggy address belongs to the virtual mapping at
[f1000000, f1002000) created by:
text_area_cpu_up+0x20/0x190

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30
flags: 0x80000000(zone=2)
raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001
raw: 00000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>f1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
^
f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

f8 corresponds to KASAN_VMALLOC_INVALID which means the area is not
initialised hence not supposed to be used yet.

Powerpc text patching infrastructure allocates a virtual memory area
using get_vm_area() and flags it as VM_ALLOC. But that flag is meant
to be used for vmalloc() and vmalloc() allocated memory is not
supposed to be used before a call to __vmalloc_node_range() which is
never called for that area.

That went undetected until commit e4137f08816b ("mm, kasan, kmsan:
instrument copy_from/to_kernel_nofault")

The area allocated by text_area_cpu_up() is not vmalloc memory, it is
mapped directly on demand when needed by map_kernel_page(). There is
no VM flag corresponding to such usage, so just pass no flag. That way
the area will be unpoisonned and usable immediately.

Solution(s)

ubuntu-upgrade-linux-image-5-15-0-1026-nvidia-tegra-igxubuntu-upgrade-linux-image-5-15-0-1026-nvidia-tegra-igx-rtubuntu-upgrade-linux-image-5-15-0-1037-nvidia-tegraubuntu-upgrade-linux-image-5-15-0-1037-nvidia-tegra-rtubuntu-upgrade-linux-image-5-15-0-1066-gkeopubuntu-upgrade-linux-image-5-15-0-1076-ibmubuntu-upgrade-linux-image-5-15-0-1077-intel-iot-realtimeubuntu-upgrade-linux-image-5-15-0-1078-nvidiaubuntu-upgrade-linux-image-5-15-0-1078-nvidia-lowlatencyubuntu-upgrade-linux-image-5-15-0-1078-raspiubuntu-upgrade-linux-image-5-15-0-1079-intel-iotgubuntu-upgrade-linux-image-5-15-0-1080-kvmubuntu-upgrade-linux-image-5-15-0-1081-gkeubuntu-upgrade-linux-image-5-15-0-1081-oracleubuntu-upgrade-linux-image-5-15-0-1083-gcpubuntu-upgrade-linux-image-5-15-0-1083-gcp-fipsubuntu-upgrade-linux-image-5-15-0-1084-awsubuntu-upgrade-linux-image-5-15-0-1084-aws-fipsubuntu-upgrade-linux-image-5-15-0-1084-realtimeubuntu-upgrade-linux-image-5-15-0-1089-azureubuntu-upgrade-linux-image-5-15-0-1089-azure-fipsubuntu-upgrade-linux-image-5-15-0-140-fipsubuntu-upgrade-linux-image-5-15-0-140-genericubuntu-upgrade-linux-image-5-15-0-140-generic-64kubuntu-upgrade-linux-image-5-15-0-140-generic-lpaeubuntu-upgrade-linux-image-5-15-0-140-lowlatencyubuntu-upgrade-linux-image-5-15-0-140-lowlatency-64kubuntu-upgrade-linux-image-5-4-0-1064-xilinx-zynqmpubuntu-upgrade-linux-image-5-4-0-1092-ibmubuntu-upgrade-linux-image-5-4-0-1105-bluefieldubuntu-upgrade-linux-image-5-4-0-1120-fipsubuntu-upgrade-linux-image-5-4-0-1129-raspiubuntu-upgrade-linux-image-5-4-0-1133-kvmubuntu-upgrade-linux-image-5-4-0-1144-oracleubuntu-upgrade-linux-image-5-4-0-1146-awsubuntu-upgrade-linux-image-5-4-0-1146-aws-fipsubuntu-upgrade-linux-image-5-4-0-1149-gcpubuntu-upgrade-linux-image-5-4-0-1149-gcp-fipsubuntu-upgrade-linux-image-5-4-0-1151-azureubuntu-upgrade-linux-image-5-4-0-1151-azure-fipsubuntu-upgrade-linux-image-5-4-0-216-genericubuntu-upgrade-linux-image-5-4-0-216-generic-lpaeubuntu-upgrade-linux-image-5-4-0-216-lowlatencyubuntu-upgrade-linux-image-6-11-0-1010-realtimeubuntu-upgrade-linux-image-6-11-0-1013-raspiubuntu-upgrade-linux-image-6-11-0-1014-awsubuntu-upgrade-linux-image-6-11-0-1014-lowlatencyubuntu-upgrade-linux-image-6-11-0-1014-lowlatency-64kubuntu-upgrade-linux-image-6-11-0-1015-azureubuntu-upgrade-linux-image-6-11-0-1015-azure-fdeubuntu-upgrade-linux-image-6-11-0-1015-gcpubuntu-upgrade-linux-image-6-11-0-1015-gcp-64kubuntu-upgrade-linux-image-6-11-0-1016-oracleubuntu-upgrade-linux-image-6-11-0-1016-oracle-64kubuntu-upgrade-linux-image-6-11-0-1022-oemubuntu-upgrade-linux-image-6-11-0-26-genericubuntu-upgrade-linux-image-6-11-0-26-generic-64kubuntu-upgrade-linux-image-awsubuntu-upgrade-linux-image-aws-fipsubuntu-upgrade-linux-image-aws-lts-20-04ubuntu-upgrade-linux-image-aws-lts-22-04ubuntu-upgrade-linux-image-azureubuntu-upgrade-linux-image-azure-cvmubuntu-upgrade-linux-image-azure-fdeubuntu-upgrade-linux-image-azure-fipsubuntu-upgrade-linux-image-azure-lts-20-04ubuntu-upgrade-linux-image-azure-lts-22-04ubuntu-upgrade-linux-image-bluefieldubuntu-upgrade-linux-image-fipsubuntu-upgrade-linux-image-gcpubuntu-upgrade-linux-image-gcp-64kubuntu-upgrade-linux-image-gcp-fipsubuntu-upgrade-linux-image-gcp-lts-20-04ubuntu-upgrade-linux-image-gcp-lts-22-04ubuntu-upgrade-linux-image-genericubuntu-upgrade-linux-image-generic-64kubuntu-upgrade-linux-image-generic-64k-hwe-24-04ubuntu-upgrade-linux-image-generic-hwe-18-04ubuntu-upgrade-linux-image-generic-hwe-24-04ubuntu-upgrade-linux-image-generic-lpaeubuntu-upgrade-linux-image-gkeubuntu-upgrade-linux-image-gke-5-15ubuntu-upgrade-linux-image-gkeopubuntu-upgrade-linux-image-gkeop-5-15ubuntu-upgrade-linux-image-ibmubuntu-upgrade-linux-image-ibm-lts-20-04ubuntu-upgrade-linux-image-intelubuntu-upgrade-linux-image-intel-iot-realtimeubuntu-upgrade-linux-image-intel-iotgubuntu-upgrade-linux-image-kvmubuntu-upgrade-linux-image-lowlatencyubuntu-upgrade-linux-image-lowlatency-64kubuntu-upgrade-linux-image-lowlatency-64k-hwe-20-04ubuntu-upgrade-linux-image-lowlatency-64k-hwe-24-04ubuntu-upgrade-linux-image-lowlatency-hwe-18-04ubuntu-upgrade-linux-image-lowlatency-hwe-20-04ubuntu-upgrade-linux-image-lowlatency-hwe-24-04ubuntu-upgrade-linux-image-nvidiaubuntu-upgrade-linux-image-nvidia-lowlatencyubuntu-upgrade-linux-image-nvidia-tegraubuntu-upgrade-linux-image-nvidia-tegra-igxubuntu-upgrade-linux-image-nvidia-tegra-igx-rtubuntu-upgrade-linux-image-nvidia-tegra-rtubuntu-upgrade-linux-image-oemubuntu-upgrade-linux-image-oem-24-04bubuntu-upgrade-linux-image-oem-osp1ubuntu-upgrade-linux-image-oracleubuntu-upgrade-linux-image-oracle-64kubuntu-upgrade-linux-image-oracle-lts-20-04ubuntu-upgrade-linux-image-oracle-lts-22-04ubuntu-upgrade-linux-image-raspiubuntu-upgrade-linux-image-raspi-hwe-18-04ubuntu-upgrade-linux-image-raspi-nolpaeubuntu-upgrade-linux-image-raspi2ubuntu-upgrade-linux-image-realtimeubuntu-upgrade-linux-image-snapdragon-hwe-18-04ubuntu-upgrade-linux-image-virtualubuntu-upgrade-linux-image-virtual-hwe-18-04ubuntu-upgrade-linux-image-virtual-hwe-24-04ubuntu-upgrade-linux-image-xilinx-zynqmp
Title
NEW

Explore Exposure Command

Confidently identify and prioritize exposures from endpoint to cloud with full attack surface visibility and threat-aware risk context.