| Message ID | 20241203152049.348806-1-lihaoyu499@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | net: wireless: sme: Initialize n_channels before accessing channels in cfg80211_conn_scan | expand |
On Tue, 2024-12-03 at 23:20 +0800, Haoyu Li wrote: > With the new __counted_by annocation in cfg80211_scan_request struct, > the "n_channels" struct member must be set before accessing the > "channels" array. Failing to do so will trigger a runtime warning > when enabling CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. > > Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by") > > Signed-off-by: Haoyu Li <lihaoyu499@gmail.com> nit: there should be no newline between these My tolerance for this is going WAY down, it seems it's all just busy- work, and then everyone complains and I need to handle "urgent fixes" because of it etc. I'm having severe second thoughts about ever having accepted the __counted_by annotations, I think we should just revert it. Experiment failed, we found ... that the code is fine but constantly needs changes to make the checkers happy. johannes
On Tue, 2024-12-03 at 10:20 -0600, Gustavo A. R. Silva wrote: > > "Right now, any addition of a counted_by annotation must also > include an open-coded assignment of the counter variable after > the allocation: > > p = alloc(p, array, how_many); > p->counter = how_many; Not sure where you copied that from, but quite obviously Kees didn't follow that guidance in e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by"), otherwise we wouldn't have this patch. > -- Built-in Function: TYPE __builtin_counted_by_ref (PTR) Even with that though, we still have to actually implement it, and make sure we use struct_size everywhere when we allocate these things... In fact we probably need a new allocation function, not just struct_size, but rather kzalloc_struct_size(...) or so. Which e3eac9f32ec0 didn't do, and which anyway we still don't do e.g. in nl80211_trigger_scan() because we have multiple variable things in the allocation, so we *can't*. That therefore doesn't even help here. So that's not a very convincing argument. In a way moving again to "you need the newest unreleased compiler" makes it *worse*, not *better*? But of course if you do that now it'll basically mean again nobody is running it and you get to kick the can further down the road ... I still think it's a failed experiment. It didn't do any good here as far as I can tell, and we've spent a ton of time on it. johannes
diff --git a/net/wireless/sme.c b/net/wireless/sme.c index 431da30817a6..268171600087 100644 --- a/net/wireless/sme.c +++ b/net/wireless/sme.c @@ -83,6 +83,7 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev) if (!request) return -ENOMEM; + request->n_channels = n_channels; if (wdev->conn->params.channel) { enum nl80211_band band = wdev->conn->params.channel->band; struct ieee80211_supported_band *sband =
With the new __counted_by annocation in cfg80211_scan_request struct, the "n_channels" struct member must be set before accessing the "channels" array. Failing to do so will trigger a runtime warning when enabling CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by") Signed-off-by: Haoyu Li <lihaoyu499@gmail.com> --- net/wireless/sme.c | 1 + 1 file changed, 1 insertion(+)