ghsa-xr8h-4cmg-pxjm
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
powerpc: Don't try to copy PPR for task with NULL pt_regs
powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which from my (arguably very short) checking is not commonly done for other archs. This is fine, except when PF_IO_WORKER's have been created and the task does something that causes a coredump to be generated. Then we get this crash:
Kernel attempted to read user page (160) - exploit attempt? (uid: 1000) BUG: Kernel NULL pointer dereference on read at 0x00000160 Faulting instruction address: 0xc0000000000c3a60 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0 REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+) MSR: 800000000280b033 CR: 88082828 XER: 200400f8 ... NIP memcpy_power7+0x200/0x7d0 LR ppr_get+0x64/0xb0 Call Trace: ppr_get+0x40/0xb0 (unreliable) __regset_get+0x180/0x1f0 regset_get_alloc+0x64/0x90 elf_core_dump+0xb98/0x1b60 do_coredump+0x1c34/0x24a0 get_signal+0x71c/0x1410 do_notify_resume+0x140/0x6f0 interrupt_exit_user_prepare_main+0x29c/0x320 interrupt_exit_user_prepare+0x6c/0xa0 interrupt_return_srr_user+0x8/0x138
Because ppr_get() is trying to copy from a PF_IO_WORKER with a NULL pt_regs.
Check for a valid pt_regs in both ppc_get/ppr_set, and return an error if not set. The actual error value doesn't seem to be important here, so just pick -EINVAL.
[mpe: Trim oops in change log, add Fixes & Cc stable]
{
"affected": [],
"aliases": [
"CVE-2023-53326"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-09-16T17:15:38Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc: Don\u0027t try to copy PPR for task with NULL pt_regs\n\npowerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which\nfrom my (arguably very short) checking is not commonly done for other\narchs. This is fine, except when PF_IO_WORKER\u0027s have been created and\nthe task does something that causes a coredump to be generated. Then we\nget this crash:\n\n Kernel attempted to read user page (160) - exploit attempt? (uid: 1000)\n BUG: Kernel NULL pointer dereference on read at 0x00000160\n Faulting instruction address: 0xc0000000000c3a60\n Oops: Kernel access of bad area, sig: 11 [#1]\n LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries\n Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod\n CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88\n Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries\n NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0\n REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+)\n MSR: 800000000280b033 \u003cSF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE\u003e CR: 88082828 XER: 200400f8\n ...\n NIP memcpy_power7+0x200/0x7d0\n LR ppr_get+0x64/0xb0\n Call Trace:\n ppr_get+0x40/0xb0 (unreliable)\n __regset_get+0x180/0x1f0\n regset_get_alloc+0x64/0x90\n elf_core_dump+0xb98/0x1b60\n do_coredump+0x1c34/0x24a0\n get_signal+0x71c/0x1410\n do_notify_resume+0x140/0x6f0\n interrupt_exit_user_prepare_main+0x29c/0x320\n interrupt_exit_user_prepare+0x6c/0xa0\n interrupt_return_srr_user+0x8/0x138\n\nBecause ppr_get() is trying to copy from a PF_IO_WORKER with a NULL\npt_regs.\n\nCheck for a valid pt_regs in both ppc_get/ppr_set, and return an error\nif not set. The actual error value doesn\u0027t seem to be important here, so\njust pick -EINVAL.\n\n[mpe: Trim oops in change log, add Fixes \u0026 Cc stable]",
"id": "GHSA-xr8h-4cmg-pxjm",
"modified": "2025-09-16T18:31:27Z",
"published": "2025-09-16T18:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53326"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01849382373b867ddcbe7536b9dfa89f3bcea60e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/064a1c7b0f8403260d77627e62424a72ca26cee2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7624973bc15b76d000e8e6f9b8080fcb76d36595"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/80a4200d51e5a7e046f4a90f5faa5bafd5a60c58"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fd7276189450110ed835eb0a334e62d2f1c4e3be"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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