> -----Original Message-----
> From: Kees Cook <kees@xxxxxxxxxx>
> Sent: Monday, 16 December 2024 6:29
> To: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> Cc: Kees Cook <kees@xxxxxxxxxx>; Gustavo A . R . Silva <gustavoars@xxxxxxxxxx>;
> Korenblit, Miriam Rachel <miriam.rachel.korenblit@xxxxxxxxx>; Kalle Valo
> <kvalo@xxxxxxxxxx>; Berg, Johannes <johannes.berg@xxxxxxxxx>; Triebitz, Shaul
> <shaul.triebitz@xxxxxxxxx>; Grumbach, Emmanuel
> <emmanuel.grumbach@xxxxxxxxx>; Ben Shimol, Yedidya
> <yedidya.ben.shimol@xxxxxxxxx>; Berg, Benjamin <benjamin.berg@xxxxxxxxx>;
> Dmitry Antipov <dmantipov@xxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-
> wireless@xxxxxxxxxxxxxxx; linux-hardening@xxxxxxxxxxxxxxx
> Subject: [PATCH RESEND] wifi: iwlwifi: mvm: Fix __counted_by usage in
> cfg80211_wowlan_nd_*
>
> Both struct cfg80211_wowlan_nd_match and struct cfg80211_wowlan_nd_info
> pre-allocate space for channels and matches, but then may end up using fewer
> that the full allocation. Shrink the associated counter (n_channels and n_matches)
> after counting the results. This avoids compile-time (and run-time) warnings from
> __counted_by. (The counter member needs to be updated _before_ accessing the
> array index.)
>
> Seen with coming GCC 15:
>
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c: In function
> 'iwl_mvm_query_set_freqs':
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c:2877:66: warning: operation on
> 'match->n_channels' may be undefined [-Wsequence-point]
> 2877 | match->channels[match->n_channels++] =
> | ~~~~~~~~~~~~~~~~~^~
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c:2885:66: warning: operation on
> 'match->n_channels' may be undefined [-Wsequence-point]
> 2885 | match->channels[match->n_channels++] =
> | ~~~~~~~~~~~~~~~~~^~
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c: In function
> 'iwl_mvm_query_netdetect_reasons':
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c:2982:58: warning: operation on
> 'net_detect->n_matches' may be undefined [-Wsequence-point]
> 2982 | net_detect->matches[net_detect->n_matches++] = match;
> | ~~~~~~~~~~~~~~~~~~~~~^~
>
> Fixes: aa4ec06c455d ("wifi: cfg80211: use __counted_by where appropriate")
> Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/20240619211233.work.355-kees@xxxxxxxxxx
> Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
> ---
> Pinging this patch again, see
> https://lore.kernel.org/lkml/20240619211233.work.355-kees@xxxxxxxxxx/
> ---
> drivers/net/wireless/intel/iwlwifi/mvm/d3.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
> b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
> index f85c01e04ebf..7d973546c9fb 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/d3.c
> @@ -2954,6 +2954,7 @@ static void iwl_mvm_query_set_freqs(struct iwl_mvm
> *mvm,
> int idx)
> {
> int i;
> + int n_channels = 0;
>
> if (fw_has_api(&mvm->fw->ucode_capa,
> IWL_UCODE_TLV_API_SCAN_OFFLOAD_CHANS)) { @@ -
> 2962,7 +2963,7 @@ static void iwl_mvm_query_set_freqs(struct iwl_mvm
> *mvm,
>
> for (i = 0; i < SCAN_OFFLOAD_MATCHING_CHANNELS_LEN * 8;
> i++)
> if (matches[idx].matching_channels[i / 8] & (BIT(i % 8)))
> - match->channels[match->n_channels++] =
> + match->channels[n_channels++] =
> mvm->nd_channels[i]->center_freq;
> } else {
> struct iwl_scan_offload_profile_match_v1 *matches = @@ -
> 2970,9 +2971,11 @@ static void iwl_mvm_query_set_freqs(struct iwl_mvm
> *mvm,
>
> for (i = 0; i < SCAN_OFFLOAD_MATCHING_CHANNELS_LEN_V1 *
> 8; i++)
> if (matches[idx].matching_channels[i / 8] & (BIT(i % 8)))
> - match->channels[match->n_channels++] =
> + match->channels[n_channels++] =
> mvm->nd_channels[i]->center_freq;
> }
> + /* We may have ended up with fewer channels than we allocated. */
> + match->n_channels = n_channels;
> }
>
> /**
> @@ -3053,6 +3056,8 @@ static void iwl_mvm_query_netdetect_reasons(struct
> iwl_mvm *mvm,
> GFP_KERNEL);
> if (!net_detect || !n_matches)
> goto out_report_nd;
> + net_detect->n_matches = n_matches;
> + n_matches = 0;
>
> for_each_set_bit(i, &matched_profiles, mvm->n_nd_match_sets) {
> struct cfg80211_wowlan_nd_match *match; @@ -3066,8
> +3071,9 @@ static void iwl_mvm_query_netdetect_reasons(struct iwl_mvm
> *mvm,
> GFP_KERNEL);
> if (!match)
> goto out_report_nd;
> + match->n_channels = n_channels;
>
> - net_detect->matches[net_detect->n_matches++] = match;
> + net_detect->matches[n_matches++] = match;
>
> /* We inverted the order of the SSIDs in the scan
> * request, so invert the index here.
> @@ -3082,6 +3088,8 @@ static void iwl_mvm_query_netdetect_reasons(struct
> iwl_mvm *mvm,
>
> iwl_mvm_query_set_freqs(mvm, d3_data->nd_results, match, i);
> }
> + /* We may have fewer matches than we allocated. */
> + net_detect->n_matches = n_matches;
>
> out_report_nd:
> wakeup.net_detect = net_detect;
> --
> 2.34.1
Hi ,
The patch was already applied and marked in Patchwork as such.
Miri
