bus: mhi: host: Range check CHDBOFF and ERDBOFF

If the value read from the CHDBOFF and ERDBOFF registers is outside the
range of the MHI register space then an invalid address might be computed
which later causes a kernel panic.  Range check the read value to prevent
a crash due to bad data from the device.

Fixes: 6cd330ae76ff ("bus: mhi: core: Add support for ringing channel/event ring doorbells")
Cc: stable@vger.kernel.org
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Link: https://lore.kernel.org/r/1679674384-27209-1-git-send-email-quic_jhugo@quicinc.com
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index 3d779ee..b46a082 100644 (file)
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -516,6 +516,12 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
                return -EIO;
        }
 
+       if (val >= mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)) {
+               dev_err(dev, "CHDB offset: 0x%x is out of range: 0x%zx\n",
+                       val, mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB));
+               return -ERANGE;
+       }
+
        /* Setup wake db */
        mhi_cntrl->wake_db = base + val + (8 * MHI_DEV_WAKE_DB);
        mhi_cntrl->wake_set = false;
@@ -532,6 +538,12 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl)
                return -EIO;
        }
 
+       if (val >= mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings)) {
+               dev_err(dev, "ERDB offset: 0x%x is out of range: 0x%zx\n",
+                       val, mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings));
+               return -ERANGE;
+       }
+
        /* Setup event db address for each ev_ring */
        mhi_event = mhi_cntrl->mhi_event;
        for (i = 0; i < mhi_cntrl->total_ev_rings; i++, val += 8, mhi_event++) {