UBUNTU-CVE-2026-98640: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: HID: amdsfh: Validate PCI BAR size before mapping The amdsfh driver maps PCI BAR 2 using pcimiomapregions() and subsequently accesses MMIO registers at offsets up to 0x10958 (e.g., AMDP2CMSG3 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 + AMDP2CMSG3 in mp2selectops(): 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:mp2selectops drivers/hid/amd-sfh-hid/amdsfhpcie.c:282 [inline] RIP: 0010:amdmp2pciprobe+0x337/0x5f0 drivers/hid/amd-sfh-hid/amdsfhpcie.c:487 Call Trace: <TASK> localpciprobe drivers/pci/pci-driver.c:332 [inline] pcicallprobe drivers/pci/pci-driver.c:394 [inline] pcideviceprobe drivers/pci/pci-driver.c:455 [inline] pcideviceprobe+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.