On 25/10/24 14:48, Johannes Berg wrote:
On Fri, 2024-10-25 at 14:36 -0600, Gustavo A. R. Silva wrote:
Yeah, I was actually going to mention this commit, as it's the one that introduced
that `bool radar_detected` to the flex struct. However, it wasn't obvious to me
how `struct ieee80211_chanctx_conf conf` could overwrite `radar_detected` as I didn't
see `conf->drv_priv` being accessed through `struct struct ieee80211_chanctx_conf`.
You have to look at the drivers, see hwsim_clear_chanctx_magic() for
example; I wonder why hwsim_check_chanctx_magic() never caught this.
Sorry, I actually meant through `struct ieee80211_chanctx`. Something like:
struct ieee80211_chanctx *foo;
...
foo->conf.drv_priv[i] = something;
or
struct bar *ptr = (void *)foo->conf->drv_priv;
then write something into *ptr...
In the above cases the code will indeed overwrite `radar_detected`.
Right, that's what it does though, no? Except it doesn't have, in the
driver, "foo->conf." because mac80211 only gives it a pointer to conf,
so it's only "conf->drv_priv" (and it's the "struct bar" example.)
OK, so do you mean that pointer to `conf` is actually coming from
`foo->conf`?
This is probably a dumb question but, where is that pointer to `conf`
coming from exactly?
I'd really like to understand this better so I can determine whether
I'm dealing with a bug when analyzing similar instances in the future. :)
So yeah, pretty sure it will overwrite that, and I do wonder why it
wasn't caught. I guess no radar detection tests with MLO yet.
--
Gustavo
