wifi: wil6210: cfg80211: Use __counted_by() in struct wmi_start_scan_cmd and avoid...

Prepare for the coming implementation by GCC and Clang of the
__counted_by attribute. Flexible array members annotated with
__counted_by can have their accesses bounds-checked at run-time
via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE
(for strcpy/memcpy-family functions).

Also, -Wflex-array-member-not-at-end is coming in GCC-14, and we are
getting ready to enable it globally.

So, use the `DEFINE_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix the following warning:
drivers/net/wireless/ath/wil6210/cfg80211.c:896:43: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/ZgSP/CMSVfr68R2u@neat

diff --git a/drivers/net/wireless/ath/wil6210/cfg80211.c b/drivers/net/wireless/ath/wil6210/cfg80211.c
index 8993028709ecfb427d074dc5fd1f0fa7d53bf2b9..e8f1d30a8d73c50a815345d576eaef687cb9a920 100644 (file)
--- a/drivers/net/wireless/ath/wil6210/cfg80211.c
+++ b/drivers/net/wireless/ath/wil6210/cfg80211.c
@@ -892,10 +892,8 @@ static int wil_cfg80211_scan(struct wiphy *wiphy,
        struct wil6210_priv *wil = wiphy_to_wil(wiphy);
        struct wireless_dev *wdev = request->wdev;
        struct wil6210_vif *vif = wdev_to_vif(wil, wdev);
-       struct {
-               struct wmi_start_scan_cmd cmd;
-               u16 chnl[4];
-       } __packed cmd;
+       DEFINE_FLEX(struct wmi_start_scan_cmd, cmd,
+                   channel_list, num_channels, 4);
        uint i, n;
        int rc;
 
@@ -977,9 +975,8 @@ static int wil_cfg80211_scan(struct wiphy *wiphy,
        vif->scan_request = request;
        mod_timer(&vif->scan_timer, jiffies + WIL6210_SCAN_TO);
 
-       memset(&cmd, 0, sizeof(cmd));
-       cmd.cmd.scan_type = WMI_ACTIVE_SCAN;
-       cmd.cmd.num_channels = 0;
+       cmd->scan_type = WMI_ACTIVE_SCAN;
+       cmd->num_channels = 0;
        n = min(request->n_channels, 4U);
        for (i = 0; i < n; i++) {
                int ch = request->channels[i]->hw_value;
@@ -991,7 +988,8 @@ static int wil_cfg80211_scan(struct wiphy *wiphy,
                        continue;
                }
                /* 0-based channel indexes */
-               cmd.cmd.channel_list[cmd.cmd.num_channels++].channel = ch - 1;
+               cmd->num_channels++;
+               cmd->channel_list[cmd->num_channels - 1].channel = ch - 1;
                wil_dbg_misc(wil, "Scan for ch %d  : %d MHz\n", ch,
                             request->channels[i]->center_freq);
        }
@@ -1007,16 +1005,15 @@ static int wil_cfg80211_scan(struct wiphy *wiphy,
        if (rc)
                goto out_restore;
 
-       if (wil->discovery_mode && cmd.cmd.scan_type == WMI_ACTIVE_SCAN) {
-               cmd.cmd.discovery_mode = 1;
+       if (wil->discovery_mode && cmd->scan_type == WMI_ACTIVE_SCAN) {
+               cmd->discovery_mode = 1;
                wil_dbg_misc(wil, "active scan with discovery_mode=1\n");
        }
 
        if (vif->mid == 0)
                wil->radio_wdev = wdev;
        rc = wmi_send(wil, WMI_START_SCAN_CMDID, vif->mid,
-                     &cmd, sizeof(cmd.cmd) +
-                     cmd.cmd.num_channels * sizeof(cmd.cmd.channel_list[0]));
+                     cmd, struct_size(cmd, channel_list, cmd->num_channels));
 
 out_restore:
        if (rc) {

diff --git a/drivers/net/wireless/ath/wil6210/wmi.h b/drivers/net/wireless/ath/wil6210/wmi.h
index 71bf2ae27a984f146117a712b4a460befaa3dfb2..b47606d9068c8bdde9e68cdbc7b3795198a97736 100644 (file)
--- a/drivers/net/wireless/ath/wil6210/wmi.h
+++ b/drivers/net/wireless/ath/wil6210/wmi.h
@@ -474,7 +474,7 @@ struct wmi_start_scan_cmd {
        struct {
                u8 channel;
                u8 reserved;
-       } channel_list[];
+       } channel_list[] __counted_by(num_channels);
 } __packed;
 
 #define WMI_MAX_PNO_SSID_NUM   (16)