wifi: iwlwifi: mvm: avoid NULL pointer dereference

iwl_mvm_tx_skb_sta() and iwl_mvm_tx_mpdu() verify that the mvmvsta
pointer is not NULL.
It retrieves this pointer using iwl_mvm_sta_from_mac80211, which is
dereferencing the ieee80211_sta pointer.
If sta is NULL, iwl_mvm_sta_from_mac80211 will dereference a NULL
pointer.
Fix this by checking the sta pointer before retrieving the mvmsta
from it. If sta is not NULL, then mvmsta isn't either.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20240825191257.880921ce23b7.I340052d70ab6d3410724ce955eb00da10e08188f@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
index 7ff5ea5e7aca579deafe72988a7411acd6994a45..db926b2f4d8d515b938043e8ee8a70cd5618eb67 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -1203,6 +1203,9 @@ static int iwl_mvm_tx_mpdu(struct iwl_mvm *mvm, struct sk_buff *skb,
        bool is_ampdu = false;
        int hdrlen;
 
+       if (WARN_ON_ONCE(!sta))
+               return -1;
+
        mvmsta = iwl_mvm_sta_from_mac80211(sta);
        fc = hdr->frame_control;
        hdrlen = ieee80211_hdrlen(fc);
@@ -1210,9 +1213,6 @@ static int iwl_mvm_tx_mpdu(struct iwl_mvm *mvm, struct sk_buff *skb,
        if (IWL_MVM_NON_TRANSMITTING_AP && ieee80211_is_probe_resp(fc))
                return -1;
 
-       if (WARN_ON_ONCE(!mvmsta))
-               return -1;
-
        if (WARN_ON_ONCE(mvmsta->deflink.sta_id == IWL_MVM_INVALID_STA))
                return -1;
 
@@ -1343,7 +1343,7 @@ drop:
 int iwl_mvm_tx_skb_sta(struct iwl_mvm *mvm, struct sk_buff *skb,
                       struct ieee80211_sta *sta)
 {
-       struct iwl_mvm_sta *mvmsta = iwl_mvm_sta_from_mac80211(sta);
+       struct iwl_mvm_sta *mvmsta;
        struct ieee80211_tx_info info;
        struct sk_buff_head mpdus_skbs;
        struct ieee80211_vif *vif;
@@ -1352,9 +1352,11 @@ int iwl_mvm_tx_skb_sta(struct iwl_mvm *mvm, struct sk_buff *skb,
        struct sk_buff *orig_skb = skb;
        const u8 *addr3;
 
-       if (WARN_ON_ONCE(!mvmsta))
+       if (WARN_ON_ONCE(!sta))
                return -1;
 
+       mvmsta = iwl_mvm_sta_from_mac80211(sta);
+
        if (WARN_ON_ONCE(mvmsta->deflink.sta_id == IWL_MVM_INVALID_STA))
                return -1;