On 10/24/23 14:49, Johannes Berg wrote:
On Tue, 2023-10-24 at 14:41 -0600, Gustavo A. R. Silva wrote:It seems we run into the same issue in the function below, even in the case this `memset()` is unnecessary (which it seems it's not): 8920 memset(skb->data, 0, sizeof(*cmd)); Notice that if `cap->peer_chan_len == 0` or `cap->peer_chan_len == 1`, in the original code, we have `len == sizeof(*cmd) == 128`:Right.- /* tdls peer update cmd has place holder for one channel*/ - chan_len = cap->peer_chan_len ? (cap->peer_chan_len - 1) : 0; - - len = sizeof(*cmd) + chan_len * sizeof(*chan); + len = struct_size(cmd, peer_capab.peer_chan_list, cap->peer_chan_len); skb = ath10k_wmi_alloc_skb(ar, len); if (!skb) which makes `round_len == roundup(len, 4) == struct_size(cmd,...,...) == 104` when `cap->peer_chan_len == 0`And yeah, that's really the issue, it only matters for ==0. For a moment there I thought that doesn't even make sense, but it looks like it never even becomes non-zero. No idea then, sorry. You'd hope firmware doesn't care about the actual message size if the inner data says "0 entries", but who knows? And how many firmware versions are there? :) So I guess you'd want to stay compatible, even if it means having a chan_len = min(cap->peer_chan_len, 1); for the struct_size()?
Yeah, that's an alternative. I'll wait for the maintainers to chime in and see if they have a different opinion. Thanks -- Gustavo
