Search Linux Wireless

Re: [RFC - is this a bug?] wifi: ath10k: Asking for some light on this, please :)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 10/24/2023 7:37 PM, Gustavo A. R. Silva wrote:


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.

I'm seeing clarification from the development team.

/jeff




[Index of Archives]     [Linux Host AP]     [ATH6KL]     [Linux Wireless Personal Area Network]     [Linux Bluetooth]     [Wireless Regulations]     [Linux Netdev]     [Kernel Newbies]     [Linux Kernel]     [IDE]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite Hiking]     [MIPS Linux]     [ARM Linux]     [Linux RAID]

  Powered by Linux