2024-06-02 07:22:13

by Miri Korenblit

[permalink] [raw]
Subject: [PATCH] wifi: cfg80211: reject non-conformant 6 GHz center frequencies

From: Benjamin Berg <[email protected]>

On 6 GHz (and also 5 GHz to some degree), only a specific set of center
frequencies should be used depending on the channel bandwidth. Verify
this is the case on 6 GHz. For 5 GHz, we are more accepting as there are
APs that got it wrong historically.

Signed-off-by: Benjamin Berg <[email protected]>
Signed-off-by: Miri Korenblit <[email protected]>
---
net/wireless/chan.c | 38 ++++++++++++++++++++++++++++++++++++++
net/wireless/tests/chan.c | 22 +++++++++++-----------
2 files changed, 49 insertions(+), 11 deletions(-)

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 3414b2c3abcc..bc98573f36be 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -263,6 +263,37 @@ static int cfg80211_chandef_get_width(const struct cfg80211_chan_def *c)
return nl80211_chan_width_to_mhz(c->width);
}

+static bool cfg80211_valid_center_freq(u32 center,
+ enum nl80211_chan_width width)
+{
+ int bw;
+ int step;
+
+ /* We only do strict verification on 6 GHz */
+ if (center < 5955 || center > 7115)
+ return true;
+
+ bw = nl80211_chan_width_to_mhz(width);
+ if (bw < 0)
+ return false;
+
+ /* Validate that the channels bw is entirely within the 6 GHz band */
+ if (center - bw / 2 < 5945 || center + bw / 2 > 7125)
+ return false;
+
+ /* With 320 MHz the permitted channels overlap */
+ if (bw == 320)
+ step = 160;
+ else
+ step = bw;
+
+ /*
+ * Valid channels are packed from lowest frequency towards higher ones.
+ * So test that the lower frequency alignes with one of these steps.
+ */
+ return (center - bw / 2 - 5945) % step == 0;
+}
+
bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
{
u32 control_freq, oper_freq;
@@ -374,6 +405,13 @@ bool cfg80211_chandef_valid(const struct cfg80211_chan_def *chandef)
return false;
}

+ if (!cfg80211_valid_center_freq(chandef->center_freq1, chandef->width))
+ return false;
+
+ if (chandef->width == NL80211_CHAN_WIDTH_80P80 &&
+ !cfg80211_valid_center_freq(chandef->center_freq2, chandef->width))
+ return false;
+
/* channel 14 is only for IEEE 802.11b */
if (chandef->center_freq1 == 2484 &&
chandef->width != NL80211_CHAN_WIDTH_20_NOHT)
diff --git a/net/wireless/tests/chan.c b/net/wireless/tests/chan.c
index d02258ac2dab..74bbee25085f 100644
--- a/net/wireless/tests/chan.c
+++ b/net/wireless/tests/chan.c
@@ -113,16 +113,16 @@ static const struct chandef_compat_case {
},
},
{
- .desc = "different primary 160 MHz",
+ .desc = "different primary 320 MHz",
.c1 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 + 150,
+ .center_freq1 = 6475 + 110,
},
.c2 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 - 10,
+ .center_freq1 = 6475 - 50,
},
},
{
@@ -131,12 +131,12 @@ static const struct chandef_compat_case {
.c1 = {
.width = NL80211_CHAN_WIDTH_160,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 + 70,
+ .center_freq1 = 6475 + 30,
},
.c2 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 - 10,
+ .center_freq1 = 6475 - 50,
},
.compat = true,
},
@@ -145,12 +145,12 @@ static const struct chandef_compat_case {
.c1 = {
.width = NL80211_CHAN_WIDTH_160,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 + 70,
+ .center_freq1 = 6475 + 30,
},
.c2 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 - 10,
+ .center_freq1 = 6475 - 50,
.punctured = 0xf,
},
.compat = true,
@@ -160,13 +160,13 @@ static const struct chandef_compat_case {
.c1 = {
.width = NL80211_CHAN_WIDTH_160,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 + 70,
+ .center_freq1 = 6475 + 30,
.punctured = 0xc0,
},
.c2 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 - 10,
+ .center_freq1 = 6475 - 50,
.punctured = 0xc000,
},
.compat = true,
@@ -176,13 +176,13 @@ static const struct chandef_compat_case {
.c1 = {
.width = NL80211_CHAN_WIDTH_160,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 + 70,
+ .center_freq1 = 6475 + 30,
.punctured = 0x80,
},
.c2 = {
.width = NL80211_CHAN_WIDTH_320,
.chan = &chan_6ghz_105,
- .center_freq1 = 6475 - 10,
+ .center_freq1 = 6475 - 50,
.punctured = 0xc000,
},
},
--
2.34.1