Re: [Intel-wired-lan] [PATCH iwl-net] ice: fix integer overflow in ice_get_pfa_module_tlv

[Paul Menzel]

Dear Paul, dear Jacob,

Am 16.05.24 um 23:18 schrieb Jacob Keller:
From: Paul Greenwalt <paul.greenw...@intel.com>

It's possible that an NVM with an invalid tlv_len could cause an integer
overflow of next_tlv which can result an infinite loop.

Fix this issue by changing next_tlv from u16 to u32 to prevent overflow.

Why is 32-bit enough?

Also check that tlv_len is valid and less than pfa_len.

Signed-off-by: Paul Greenwalt <paul.greenw...@intel.com>
Signed-off-by: Jacob Keller <jacob.e.kel...@intel.com>
---
  drivers/net/ethernet/intel/ice/ice_nvm.c | 8 ++++++--
  1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_nvm.c 
b/drivers/net/ethernet/intel/ice/ice_nvm.c
index 84eab92dc03c..9e58d319355f 100644
--- a/drivers/net/ethernet/intel/ice/ice_nvm.c
+++ b/drivers/net/ethernet/intel/ice/ice_nvm.c
@@ -441,7 +441,7 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, 
u16 *module_tlv_len,
                       u16 module_type)
  {
        u16 pfa_len, pfa_ptr;

By the way, is pfa_ptr an actual pointer address?

-       u16 next_tlv;
+       u32 next_tlv;
        int status;
  
  	status = ice_read_sr_word(hw, ICE_SR_PFA_PTR, &pfa_ptr);
@@ -458,7 +458,7 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, 
u16 *module_tlv_len,
         * of TLVs to find the requested one.
         */
        next_tlv = pfa_ptr + 1;
-       while (next_tlv < pfa_ptr + pfa_len) {
+       while (next_tlv < ((u32)pfa_ptr + pfa_len)) {
                u16 tlv_sub_module_type;
                u16 tlv_len;
  
@@ -474,6 +474,10 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
                        ice_debug(hw, ICE_DBG_INIT, "Failed to read TLV 
length.\n");
                        break;
                }
+               if (tlv_len > pfa_len) {
+                       ice_debug(hw, ICE_DBG_INIT, "Invalid TLV length.\n");

Please print both values. Should this be at least a warning, if it’s not 
an expected situation?

+                       return -EINVAL;
+               }
                if (tlv_sub_module_type == module_type) {
                        if (tlv_len) {
                                *module_tlv = next_tlv;


Kind regards,

Paul