wifi: mac80211: add strict mode disabling workarounds

Add a strict mode where we disable certain workarounds and have
additional checks such as, for now, that VHT capabilities from
association response match those from beacon/probe response. We
can extend the checks in the future.

Make it an opt-in setting by the driver so it can be set there
in some driver-specific way, for example. Also allow setting
this one hw flag through the hwflags debugfs, by writing a new
strict=0 or strict=1 value.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250205110958.5cecb0469479.I4a69617dc60ba0d6308416ffbc3102cfd08ba068@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 42 insertions, 2 deletions

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index bf0a2902d93c..69e03630f64c 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -492,6 +492,7 @@ static const char *hw_flag_names[] = {
 	FLAG(DISALLOW_PUNCTURING),
 	FLAG(DISALLOW_PUNCTURING_5GHZ),
 	FLAG(HANDLES_QUIET_CSA),
+	FLAG(STRICT),
 #undef FLAG
 };
 
@@ -524,6 +525,46 @@ static ssize_t hwflags_read(struct file *file, char __user *user_buf,
 	return rv;
 }
 
+static ssize_t hwflags_write(struct file *file, const char __user *user_buf,
+			     size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[100];
+	int val;
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, user_buf, count))
+		return -EFAULT;
+
+	if (count && buf[count - 1] == '\n')
+		buf[count - 1] = '\0';
+	else
+		buf[count] = '\0';
+
+	if (sscanf(buf, "strict=%d", &val) == 1) {
+		switch (val) {
+		case 0:
+			ieee80211_hw_set(&local->hw, STRICT);
+			return count;
+		case 1:
+			__clear_bit(IEEE80211_HW_STRICT, local->hw.flags);
+			return count;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static const struct file_operations hwflags_ops = {
+	.open = simple_open,
+	.read = hwflags_read,
+	.write = hwflags_write,
+};
+
 static ssize_t misc_read(struct file *file, char __user *user_buf,
 			 size_t count, loff_t *ppos)
 {
@@ -574,7 +615,6 @@ static ssize_t queues_read(struct file *file, char __user *user_buf,
 	return simple_read_from_buffer(user_buf, count, ppos, buf, res);
 }
 
-DEBUGFS_READONLY_FILE_OPS(hwflags);
 DEBUGFS_READONLY_FILE_OPS(queues);
 DEBUGFS_READONLY_FILE_OPS(misc);
 
@@ -651,7 +691,7 @@ void debugfs_hw_add(struct ieee80211_local *local)
 #ifdef CONFIG_PM
 	DEBUGFS_ADD_MODE(reset, 0200);
 #endif
-	DEBUGFS_ADD(hwflags);
+	DEBUGFS_ADD_MODE(hwflags, 0600);
 	DEBUGFS_ADD(user_power);
 	DEBUGFS_ADD(power);
 	DEBUGFS_ADD(hw_conf);