[PATCH] [SCSI] hptiop: Add inbound queue offset bounds check in iop_get_config_itl

[Guangshuo Li <lgs201920130244@gmail.com>]

The function iop_get_config_itl() reads a 32‑bit offset (req32) from the
inbound queue register (hba->u.itl.iop->inbound_queue) and then uses it
without validation to compute:
    req = (base + req32)
followed by memcpy_fromio(config, req, sizeof(*config)).

Without verifying that req32 is within the valid I/O region and that
req32 + sizeof(*config) does not overflow the mapped I/O region, a
malicious or faulty device/firmware could cause the driver to read memory
outside the intended request structure — leading to an out‑of‑bounds I/O read.

According to kernel documentation:
  "The value returned from the inbound queue port is an offset relative
  to the IOP BAR0." ([docs.kernel.org](https://docs.kernel.org/scsi/hptiop.html))
However, the documentation does *not* specify a maximum offset, nor a bound
such as “offset + size ≤ IOP memory region size”.

In the driver code, hptiop_map_pci_bar_itl() does:
    hba->u.itl.iop = hptiop_map_pci_bar(hba, 0);
and uses pci_resource_len(hba->pcidev, 0) to obtain the mapped region size
for BAR0. Therefore we can use that size at runtime to bound req32 safely.

To implement the fix in iop_get_config_itl():
  - Retrieve the BAR0 region size via:
        struct pci_dev *pcidev = hba->pcidev;
        u32 length = pci_resource_len(pcidev, 0);
  - Then check:
        if (req32 == IOPMU_QUEUE_EMPTY || req32 + sizeof(*config) > length)
            return -EINVAL;
  - This ensures we do not rely on a hard‑coded maximum, but use the actual
    mapped region size for the bound.

Fixes: ede1e6f8b4324 ("[SCSI] hptiop: HighPoint RocketRAID 3xxx controller driver")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/scsi/hptiop.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/hptiop.c b/drivers/scsi/hptiop.c
index f18b770626e6..c01370893a81 100644
--- a/drivers/scsi/hptiop.c
+++ b/drivers/scsi/hptiop.c
@@ -404,7 +404,10 @@ static int iop_get_config_itl(struct hptiop_hba *hba,
 	struct hpt_iop_request_get_config __iomem *req;
 
 	req32 = readl(&hba->u.itl.iop->inbound_queue);
-	if (req32 == IOPMU_QUEUE_EMPTY)
+
+	struct pci_dev *pcidev = hba->pcidev;
+	u32 length = pci_resource_len(pcidev, 0);
+	if (req32 == IOPMU_QUEUE_EMPTY || req32 + sizeof(*config) > length)
 		return -1;
 
 	req = (struct hpt_iop_request_get_config __iomem *)
-- 
2.43.0