wifi: iwlwifi: mvm: don't trust firmware n_channels

[ Upstream commit 682b6dc29d98e857e6ca4bbc077c7dc2899b7473 ]

If the firmware sends us a corrupted MCC response with
n_channels much larger than the command response can be,
we might copy far too much (uninitialized) memory and
even crash if the n_channels is large enough to make it
run out of the one page allocated for the FW response.

Fix that by checking the lengths. Doing a < comparison
would be sufficient, but the firmware should be doing
it correctly, so check more strictly.

Fixes: dcaf9f5ecb6f ("iwlwifi: mvm: add MCC update FW API")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230514120631.d7b233139eb4.I51fd319df8e9d41881fc8450e83d78049518a79a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
index f49887379c43f399ec60624115383102a6f99390..f485c0dd75d609f21d8aeb72ce4a5ee04367608b 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
@@ -508,6 +508,11 @@ iwl_mvm_update_mcc(struct iwl_mvm *mvm, const char *alpha2,
                struct iwl_mcc_update_resp *mcc_resp = (void *)pkt->data;
 
                n_channels =  __le32_to_cpu(mcc_resp->n_channels);
+               if (iwl_rx_packet_payload_len(pkt) !=
+                   struct_size(mcc_resp, channels, n_channels)) {
+                       resp_cp = ERR_PTR(-EINVAL);
+                       goto exit;
+               }
                resp_len = sizeof(struct iwl_mcc_update_resp) +
                           n_channels * sizeof(__le32);
                resp_cp = kmemdup(mcc_resp, resp_len, GFP_KERNEL);
@@ -519,6 +524,11 @@ iwl_mvm_update_mcc(struct iwl_mvm *mvm, const char *alpha2,
                struct iwl_mcc_update_resp_v3 *mcc_resp_v3 = (void *)pkt->data;
 
                n_channels =  __le32_to_cpu(mcc_resp_v3->n_channels);
+               if (iwl_rx_packet_payload_len(pkt) !=
+                   struct_size(mcc_resp_v3, channels, n_channels)) {
+                       resp_cp = ERR_PTR(-EINVAL);
+                       goto exit;
+               }
                resp_len = sizeof(struct iwl_mcc_update_resp) +
                           n_channels * sizeof(__le32);
                resp_cp = kzalloc(resp_len, GFP_KERNEL);