[PATCH] HID: amd_sfh: Validate BAR 2 as memory-mapped I/O in probe

[Preetam Sundar Das <daspreetam4@gmail.com>]

Syzbot reported a page fault in amd_mp2_pci_probe(). The fuzzer creates
a malicious PCI device where BAR 2 is defined as an I/O port rather
than a memory-mapped I/O (MMIO) region.

The driver previously assumed BAR 2 would always be MMIO and blindly
passed the I/O port address to readl(), causing a fatal page fault
when the CPU attempted to read from restricted memory.

Fix this by explicitly checking the PCI resource flags after waking
the device. If BAR 2 is not an IORESOURCE_MEM region, safely reject
the device with -EINVAL to prevent the panic.

Fixes: 4f567b9f8141 ("SFH: PCIe driver to add support of AMD sensor fusion hub")
Reported-by: syzbot+4eadd4dfe9e66522bae8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=227a9acbe565367eb7a1277b47115df8706d9a12

Signed-off-by: Preetam Sundar Das <daspreetam4@gmail.com>
---
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
index 4b81cebdc335..aef105a81570 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
@@ -451,6 +451,9 @@ static int amd_mp2_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
 	if (rc)
 		return rc;
 
+	if (!(pci_resource_flags(pdev, 2) & IORESOURCE_MEM))
+		return -EINVAL;
+
 	rc = pcim_iomap_regions(pdev, BIT(2), DRIVER_NAME);
 	if (rc)
 		return rc;
-- 
2.43.0