published October 18, 2026
In the Linux kernel, the following vulnerability has been resolved:
HID: amd_sfh: Validate PCI BAR size before mapping
The amd_sfh driver maps PCI BAR 2 using pcim_iomap_regions() and
subsequently accesses MMIO registers at offsets up to 0x10958 (e.g.,
AMD_P2C_MSG3 at 0x1068C). However, the driver never validates that the BAR
size is large enough to cover these accesses. If the driver is bound to a
device with a smaller BAR 2, this leads to an out-of-bounds memory access
and a page fault during the probe function.
For example, a page fault can occur when reading from privdata->mmio +
AMD_P2C_MSG3 in mp2_select_ops():
BUG: unable to handle page fault for address: ffffc9000390368c
PGD 100000067 P4D 100000067 PUD 1012c1067 PMD 105b64067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:readl arch/x86/include/asm/io.h:59 [inline]
RIP: 0010:mp2_select_ops drivers/hid/amd-sfh-hid/amd_sfh_pcie.c:282
[inline]
RIP: 0010:amd_mp2_pci_probe+0x337/0x5f0
drivers/hid/amd-sfh-hid/amd_sfh_pcie.c:487
Call Trace:
<TASK>
local_pci_probe drivers/pci/pci-driver.c:332 [inline]
pci_call_probe drivers/pci/pci-driver.c:394 [inline]
__pci_device_probe drivers/pci/pci-driver.c:455 [inline]
pci_device_probe+0x431/0xc90 drivers/pci/pci-driver.c:489
Fix this by verifying that the length of BAR 2 is at least 128KB before
attempting to map it. Since the maximum accessed offset is 0x10958, and PCI
BAR sizes are powers of 2, any legitimate hardware will have a BAR size of
at least 128KB.