ghsa-p4mq-5hwr-hc6r
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2025-21866"
],
"database_specific": {
"cwe_ids": [
"CWE-770"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-03-12T10:15:19Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/code-patching: Fix KASAN hit by not flagging text patching area as VM_ALLOC\n\nErhard reported the following KASAN hit while booting his PowerMac G4\nwith a KASAN-enabled kernel 6.13-rc6:\n\n BUG: KASAN: vmalloc-out-of-bounds in copy_to_kernel_nofault+0xd8/0x1c8\n Write of size 8 at addr f1000000 by task chronyd/1293\n\n CPU: 0 UID: 123 PID: 1293 Comm: chronyd Tainted: G W 6.13.0-rc6-PMacG4 #2\n Tainted: [W]=WARN\n Hardware name: PowerMac3,6 7455 0x80010303 PowerMac\n Call Trace:\n [c2437590] [c1631a84] dump_stack_lvl+0x70/0x8c (unreliable)\n [c24375b0] [c0504998] print_report+0xdc/0x504\n [c2437610] [c050475c] kasan_report+0xf8/0x108\n [c2437690] [c0505a3c] kasan_check_range+0x24/0x18c\n [c24376a0] [c03fb5e4] copy_to_kernel_nofault+0xd8/0x1c8\n [c24376c0] [c004c014] patch_instructions+0x15c/0x16c\n [c2437710] [c00731a8] bpf_arch_text_copy+0x60/0x7c\n [c2437730] [c0281168] bpf_jit_binary_pack_finalize+0x50/0xac\n [c2437750] [c0073cf4] bpf_int_jit_compile+0xb30/0xdec\n [c2437880] [c0280394] bpf_prog_select_runtime+0x15c/0x478\n [c24378d0] [c1263428] bpf_prepare_filter+0xbf8/0xc14\n [c2437990] [c12677ec] bpf_prog_create_from_user+0x258/0x2b4\n [c24379d0] [c027111c] do_seccomp+0x3dc/0x1890\n [c2437ac0] [c001d8e0] system_call_exception+0x2dc/0x420\n [c2437f30] [c00281ac] ret_from_syscall+0x0/0x2c\n --- interrupt: c00 at 0x5a1274\n NIP: 005a1274 LR: 006a3b3c CTR: 005296c8\n REGS: c2437f40 TRAP: 0c00 Tainted: G W (6.13.0-rc6-PMacG4)\n MSR: 0200f932 \u003cVEC,EE,PR,FP,ME,IR,DR,RI\u003e CR: 24004422 XER: 00000000\n\n GPR00: 00000166 af8f3fa0 a7ee3540 00000001 00000000 013b6500 005a5858 0200f932\n GPR08: 00000000 00001fe9 013d5fc8 005296c8 2822244c 00b2fcd8 00000000 af8f4b57\n GPR16: 00000000 00000001 00000000 00000000 00000000 00000001 00000000 00000002\n GPR24: 00afdbb0 00000000 00000000 00000000 006e0004 013ce060 006e7c1c 00000001\n NIP [005a1274] 0x5a1274\n LR [006a3b3c] 0x6a3b3c\n --- interrupt: c00\n\n The buggy address belongs to the virtual mapping at\n [f1000000, f1002000) created by:\n text_area_cpu_up+0x20/0x190\n\n The buggy address belongs to the physical page:\n page: refcount:1 mapcount:0 mapping:00000000 index:0x0 pfn:0x76e30\n flags: 0x80000000(zone=2)\n raw: 80000000 00000000 00000122 00000000 00000000 00000000 ffffffff 00000001\n raw: 00000000\n page dumped because: kasan: bad access detected\n\n Memory state around the buggy address:\n f0ffff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n f0ffff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\n \u003ef1000000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ^\n f1000080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n f1000100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8\n ==================================================================\n\nf8 corresponds to KASAN_VMALLOC_INVALID which means the area is not\ninitialised hence not supposed to be used yet.\n\nPowerpc text patching infrastructure allocates a virtual memory area\nusing get_vm_area() and flags it as VM_ALLOC. But that flag is meant\nto be used for vmalloc() and vmalloc() allocated memory is not\nsupposed to be used before a call to __vmalloc_node_range() which is\nnever called for that area.\n\nThat went undetected until commit e4137f08816b (\"mm, kasan, kmsan:\ninstrument copy_from/to_kernel_nofault\")\n\nThe area allocated by text_area_cpu_up() is not vmalloc memory, it is\nmapped directly on demand when needed by map_kernel_page(). There is\nno VM flag corresponding to such usage, so just pass no flag. That way\nthe area will be unpoisonned and usable immediately.",
"id": "GHSA-p4mq-5hwr-hc6r",
"modified": "2025-03-13T21:31:19Z",
"published": "2025-03-12T12:30:59Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21866"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2d542f13d26344e3452eee77613026ce9b653065"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2e6c80423f201405fd65254e52decd21663896f3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6847b3e40bb963e57b61d1cc6fe84cb37b9d3d4c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8d06e9208184b2851fa79a3a39d6860320c8bdf8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/97de5852058a299ba447cd9782fe96488d30108b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c905a3053518212a1017e50bd2be3bee59305bb0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d262a192d38e527faa5984629aabda2e0d1c4f54"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f8d4c5b653c1bc0df56e15658bbf64fc359adc4e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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