From 2e076f199097d670ce5e5492cea57f552b93bba9 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Mon, 28 May 2018 15:47:40 +0200
Subject: [PATCH] nl80211: add scan features for improved scan privacy
Git-commit: 2e076f199097d670ce5e5492cea57f552b93bba9
Patch-mainline: v4.19-rc1
References: FATE#326294
Add the scan flags for randomized SN and minimized probe request
content for improved scan privacy.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
include/uapi/linux/nl80211.h | 15 +++++++++++++++
net/wireless/nl80211.c | 8 +++++++-
2 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index 28b36545de24..49f718e821a3 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -5133,6 +5133,11 @@ enum nl80211_feature_flags {
* support to nl80211.
* @NL80211_EXT_FEATURE_TXQS: Driver supports FQ-CoDel-enabled intermediate
* TXQs.
+ * @NL80211_EXT_FEATURE_SCAN_RANDOM_SN: Driver/device supports randomizing the
+ * SN in probe request frames if requested by %NL80211_SCAN_FLAG_RANDOM_SN.
+ * @NL80211_EXT_FEATURE_SCAN_MIN_PREQ_CONTENT: Driver/device can omit all data
+ * except for supported rates from the probe request content if requested
+ * by the %NL80211_SCAN_FLAG_MIN_PREQ_CONTENT flag.
*
* @NUM_NL80211_EXT_FEATURES: number of extended features.
* @MAX_NL80211_EXT_FEATURES: highest extended feature index.
@@ -5167,6 +5172,8 @@ enum nl80211_ext_feature_index {
NL80211_EXT_FEATURE_CONTROL_PORT_OVER_NL80211,
NL80211_EXT_FEATURE_DATA_ACK_SIGNAL_SUPPORT,
NL80211_EXT_FEATURE_TXQS,
+ NL80211_EXT_FEATURE_SCAN_RANDOM_SN,
+ NL80211_EXT_FEATURE_SCAN_MIN_PREQ_CONTENT,
/* add new features before the definition below */
NUM_NL80211_EXT_FEATURES,
@@ -5272,6 +5279,12 @@ enum nl80211_timeout_reason {
* possible scan results. This flag hints the driver to use the best
* possible scan configuration to improve the accuracy in scanning.
* Latency and power use may get impacted with this flag.
+ * @NL80211_SCAN_FLAG_RANDOM_SN: randomize the sequence number in probe
+ * request frames from this scan to avoid correlation/tracking being
+ * possible.
+ * @NL80211_SCAN_FLAG_MIN_PREQ_CONTENT: minimize probe request content to
+ * only have supported rates and no additional capabilities (unless
+ * added by userspace explicitly.)
*/
enum nl80211_scan_flags {
NL80211_SCAN_FLAG_LOW_PRIORITY = 1<<0,
@@ -5285,6 +5298,8 @@ enum nl80211_scan_flags {
NL80211_SCAN_FLAG_LOW_SPAN = 1<<8,
NL80211_SCAN_FLAG_LOW_POWER = 1<<9,
NL80211_SCAN_FLAG_HIGH_ACCURACY = 1<<10,
+ NL80211_SCAN_FLAG_RANDOM_SN = 1<<11,
+ NL80211_SCAN_FLAG_MIN_PREQ_CONTENT = 1<<12,
};
/**
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 6c3ded1223fb..d2677259e13e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6925,7 +6925,13 @@ nl80211_check_scan_flags(struct wiphy *wiphy, struct wireless_dev *wdev,
NL80211_EXT_FEATURE_OCE_PROBE_REQ_DEFERRAL_SUPPRESSION) ||
!nl80211_check_scan_feat(wiphy, *flags,
NL80211_SCAN_FLAG_OCE_PROBE_REQ_HIGH_TX_RATE,
- NL80211_EXT_FEATURE_OCE_PROBE_REQ_HIGH_TX_RATE))
+ NL80211_EXT_FEATURE_OCE_PROBE_REQ_HIGH_TX_RATE) ||
+ !nl80211_check_scan_feat(wiphy, *flags,
+ NL80211_SCAN_FLAG_RANDOM_SN,
+ NL80211_EXT_FEATURE_SCAN_RANDOM_SN) ||
+ !nl80211_check_scan_feat(wiphy, *flags,
+ NL80211_SCAN_FLAG_MIN_PREQ_CONTENT,
+ NL80211_EXT_FEATURE_SCAN_MIN_PREQ_CONTENT))
return -EOPNOTSUPP;
if (*flags & NL80211_SCAN_FLAG_RANDOM_ADDR) {
--
2.19.2