[PATCH v4 6/6] bus: mhi: core: Add range checks for BHI and BHIe

[Bhaumik Bhatt]

When obtaining the BHI or BHIe offsets during the power up
preparation phase, range checks are missing. These can help
controller drivers avoid accessing any address outside of the
MMIO region. Ensure that mhi_cntrl->reg_len is set before MHI
registration as it is a required field and range checks will
fail without it.

Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Reviewed-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>
---
 drivers/bus/mhi/core/init.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 1cc2f22..aeb1e3c 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -885,7 +885,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	if (!mhi_cntrl || !mhi_cntrl->cntrl_dev || !mhi_cntrl->regs ||
 	    !mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put ||
 	    !mhi_cntrl->status_cb || !mhi_cntrl->read_reg ||
-	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs || !mhi_cntrl->irq)
+	    !mhi_cntrl->write_reg || !mhi_cntrl->nr_irqs ||
+	    !mhi_cntrl->irq || !mhi_cntrl->reg_len)
 		return -EINVAL;
 
 	ret = parse_config(mhi_cntrl, config);
@@ -1077,6 +1078,13 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 		dev_err(dev, "Error getting BHI offset\n");
 		goto error_reg_offset;
 	}
+
+	if (bhi_off >= mhi_cntrl->reg_len) {
+		dev_err(dev, "BHI offset: 0x%x is out of range: 0x%zx\n",
+			bhi_off, mhi_cntrl->reg_len);
+		ret = -EINVAL;
+		goto error_reg_offset;
+	}
 	mhi_cntrl->bhi = mhi_cntrl->regs + bhi_off;
 
 	if (mhi_cntrl->fbc_download || mhi_cntrl->rddm_size) {
@@ -1086,6 +1094,14 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 			dev_err(dev, "Error getting BHIE offset\n");
 			goto error_reg_offset;
 		}
+
+		if (bhie_off >= mhi_cntrl->reg_len) {
+			dev_err(dev,
+				"BHIe offset: 0x%x is out of range: 0x%zx\n",
+				bhie_off, mhi_cntrl->reg_len);
+			ret = -EINVAL;
+			goto error_reg_offset;
+		}
 		mhi_cntrl->bhie = mhi_cntrl->regs + bhie_off;
 	}
 
-- 
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