From 2e076f199097d670ce5e5492cea57f552b93bba9 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 28 May 2018 15:47:40 +0200 Subject: [PATCH] nl80211: add scan features for improved scan privacy Add the scan flags for randomized SN and minimized probe request content for improved scan privacy. Signed-off-by: Johannes Berg Signed-off-by: Johannes Berg --- 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) { -- 2.11.0