| Message ID | 20211231100311.1964437-1-jiasheng@iscas.ac.cn |
|---|---|
| State | New |
| Headers | show |
| Series | mac80211: mlme: check for null after calling kmemdup | expand |
On Fri, 2021-12-31 at 18:03 +0800, Jiasheng Jiang wrote: > As the possible failure of the alloc, the ifmgd->assoc_req_ies might be > NULL pointer and will be used by cfg80211_rx_assoc_resp() with the wrong > length. > Therefore it might be better to set length to 0 if fails as same as > ieee80211_mgd_stop(). > That feels a bit vague, and indeed I cannot find any place that would actually dereference the pointer if it's NULL? Still maybe a good as a cleanup. > Fixes: 4d9ec73d2b78 ("cfg80211: Report Association Request frame IEs in association events") > Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn> > --- > net/mac80211/mlme.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c > index 9bed6464c5bd..258b492c699c 100644 > --- a/net/mac80211/mlme.c > +++ b/net/mac80211/mlme.c > @@ -1058,7 +1058,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata) > pos = skb_tail_pointer(skb); > kfree(ifmgd->assoc_req_ies); > ifmgd->assoc_req_ies = kmemdup(ie_start, pos - ie_start, GFP_ATOMIC); > - ifmgd->assoc_req_ies_len = pos - ie_start; > + if (!ifmgd->assoc_req_ies) > + ifmgd->assoc_req_ies_len = 0; > + else > + ifmgd->assoc_req_ies_len = pos - ie_start; > But it seems it would be better to actually fail the association in this case? There's a reason we're reporting this, so that we can see HT/VHT/..., and I'm sure that will be necessary in many cases. johannes
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 9bed6464c5bd..258b492c699c 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1058,7 +1058,10 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata) pos = skb_tail_pointer(skb); kfree(ifmgd->assoc_req_ies); ifmgd->assoc_req_ies = kmemdup(ie_start, pos - ie_start, GFP_ATOMIC); - ifmgd->assoc_req_ies_len = pos - ie_start; + if (!ifmgd->assoc_req_ies) + ifmgd->assoc_req_ies_len = 0; + else + ifmgd->assoc_req_ies_len = pos - ie_start; drv_mgd_prepare_tx(local, sdata, 0);
As the possible failure of the alloc, the ifmgd->assoc_req_ies might be NULL pointer and will be used by cfg80211_rx_assoc_resp() with the wrong length. Therefore it might be better to set length to 0 if fails as same as ieee80211_mgd_stop(). Fixes: 4d9ec73d2b78 ("cfg80211: Report Association Request frame IEs in association events") Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn> --- net/mac80211/mlme.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)