Patch "wifi: iwlwifi: mvm: don't trust firmware n_channels" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wifi-iwlwifi-mvm-don-t-trust-firmware-n_channels.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7529b2dba76abd9757e354f57a3fac5ef549e1e4
Author: Johannes Berg <johannes.berg@xxxxxxxxx>
Date:   Sun May 14 12:15:53 2023 +0300

    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@xxxxxxxxx>
    Signed-off-by: Gregory Greenman <gregory.greenman@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20230514120631.d7b233139eb4.I51fd319df8e9d41881fc8450e83d78049518a79a@changeid
    Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
index 60296a754af26..34be3f75c2e96 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/nvm.c
@@ -502,6 +502,11 @@ 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);
@@ -513,6 +518,11 @@ 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);