[Intel-wired-lan] [PATCH] i40e: fix MMIO write access to an invalid page in i40e_clear_hw

[Kyungwook Boo <bookyungwook@gmail.com>]

In i40e_clear_hw(), when the device sends a specific input(e.g., 0),
an integer underflow in the num_{pf,vf}_int variables can occur,
leading to MMIO write access to an invalid page.

To fix this, we change the type of the unsigned integer variables
num_{pf,vf}_int to signed integers. Additionally, in the for-loop where the
integer underflow occurs, we also change the type of the loop variable i to
a signed integer.

Signed-off-by: Kyungwook Boo <bookyungwook@gmail.com>
Signed-off-by: Loktionov, Aleksandr <aleksandr.loktionov@intel.com>
Signed-off-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Link: https://lore.kernel.org/lkml/ffc91764-1142-4ba2-91b6-8c773f6f7095@gmail.com/T/
---
 drivers/net/ethernet/intel/i40e/i40e_common.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_common.c b/drivers/net/ethernet/intel/i40e/i40e_common.c
index 370b4bddee44..9a73cb94dc5e 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_common.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_common.c
@@ -817,8 +817,8 @@ int i40e_pf_reset(struct i40e_hw *hw)
 void i40e_clear_hw(struct i40e_hw *hw)
 {
 	u32 num_queues, base_queue;
-	u32 num_pf_int;
-	u32 num_vf_int;
+	s32 num_pf_int;
+	s32 num_vf_int;
 	u32 num_vfs;
 	u32 i, j;
 	u32 val;
@@ -848,18 +848,18 @@ void i40e_clear_hw(struct i40e_hw *hw)
 	/* stop all the interrupts */
 	wr32(hw, I40E_PFINT_ICR0_ENA, 0);
 	val = 0x3 << I40E_PFINT_DYN_CTLN_ITR_INDX_SHIFT;
-	for (i = 0; i < num_pf_int - 2; i++)
+	for (s32 i = 0; i < num_pf_int - 2; i++)
 		wr32(hw, I40E_PFINT_DYN_CTLN(i), val);
 
 	/* Set the FIRSTQ_INDX field to 0x7FF in PFINT_LNKLSTx */
 	val = eol << I40E_PFINT_LNKLST0_FIRSTQ_INDX_SHIFT;
 	wr32(hw, I40E_PFINT_LNKLST0, val);
-	for (i = 0; i < num_pf_int - 2; i++)
+	for (s32 i = 0; i < num_pf_int - 2; i++)
 		wr32(hw, I40E_PFINT_LNKLSTN(i), val);
 	val = eol << I40E_VPINT_LNKLST0_FIRSTQ_INDX_SHIFT;
 	for (i = 0; i < num_vfs; i++)
 		wr32(hw, I40E_VPINT_LNKLST0(i), val);
-	for (i = 0; i < num_vf_int - 2; i++)
+	for (s32 i = 0; i < num_vf_int - 2; i++)
 		wr32(hw, I40E_VPINT_LNKLSTN(i), val);
 
 	/* warn the HW of the coming Tx disables */
-- 
2.25.1