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iwd
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band: validate channel/freq conversions with E-4 

IWD's channel/frequency conversions use simple math to convert and
have very minimal checks to ensure the input is valid. This can
lead to some channels/frequencies being calculated which are not
in IWD's E-4 table, specifically in the 5GHz band.

This is especially noticable using mac80211_hwsim which includes
some obscure high 5ghz frequencies which are not part of the 802.11
spec.

To fix this calculate the frequency or channel then iterate E-4
operating classes to check that the value actually matches a class.
This commit is contained in:
James Prestwood 2022-12-29 16:24:27 -08:00 committed by Denis Kenzior
parent cfdfe9c54c
commit 553052a337
1 changed files with 54 additions and 25 deletions
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79
src/band.c
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@ -1283,6 +1283,8 @@ int band_freq_to_ht_chandef(uint32_t freq, const struct band_freq_attrs *attr,
uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
{
unsigned int i;
enum band_freq band = 0;
uint32_t channel = 0;
if (freq >= 2412 && freq <= 2484) {
@ -1297,10 +1299,8 @@ uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
channel /= 5;
}
if (out_band)
*out_band = BAND_FREQ_2_4_GHZ;
return channel;
band = BAND_FREQ_2_4_GHZ;
goto check_e4;
}
if (freq >= 5005 && freq < 5900) {
@ -1309,10 +1309,9 @@ uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
channel = (freq - 5000) / 5;
if (out_band)
*out_band = BAND_FREQ_5_GHZ;
band = BAND_FREQ_5_GHZ;
return channel;
goto check_e4;
}
if (freq >= 4905 && freq < 5000) {
@ -1321,10 +1320,9 @@ uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
channel = (freq - 4000) / 5;
if (out_band)
*out_band = BAND_FREQ_5_GHZ;
band = BAND_FREQ_5_GHZ;
return channel;
goto check_e4;
}
if (freq > 5950 && freq <= 7115) {
@ -1333,17 +1331,31 @@ uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
channel = (freq - 5950) / 5;
if (out_band)
*out_band = BAND_FREQ_6_GHZ;
band = BAND_FREQ_6_GHZ;
return channel;
goto check_e4;
}
if (freq == 5935) {
if (out_band)
*out_band = BAND_FREQ_6_GHZ;
band = BAND_FREQ_6_GHZ;
channel = 2;
}
return 2;
if (!band || !channel)
return 0;
check_e4:
for (i = 0; i < L_ARRAY_SIZE(e4_operating_classes); i++) {
const struct operating_class_info *info =
&e4_operating_classes[i];
if (e4_has_frequency(info, freq) == 0 ||
e4_has_ccfi(info, freq) == 0) {
if (out_band)
*out_band = band;
return channel;
}
}
return 0;
@ -1351,26 +1363,33 @@ uint8_t band_freq_to_channel(uint32_t freq, enum band_freq *out_band)
uint32_t band_channel_to_freq(uint8_t channel, enum band_freq band)
{
unsigned int i;
uint32_t freq = 0;
if (band == BAND_FREQ_2_4_GHZ) {
if (channel >= 1 && channel <= 13)
return 2407 + 5 * channel;
freq = 2407 + 5 * channel;
else if (channel == 14)
freq = 2484;
if (channel == 14)
return 2484;
goto check_e4;
}
if (band == BAND_FREQ_5_GHZ) {
if (channel >= 1 && channel <= 179)
return 5000 + 5 * channel;
freq = 5000 + 5 * channel;
else if (channel >= 181 && channel <= 199)
freq = 4000 + 5 * channel;
if (channel >= 181 && channel <= 199)
return 4000 + 5 * channel;
goto check_e4;
}
if (band == BAND_FREQ_6_GHZ) {
/* operating class 136 */
if (channel == 2)
return 5935;
if (channel == 2) {
freq = 5935;
goto check_e4;
}
/* Channels increment by 4, starting with 1 */
if (channel % 4 != 1)
@ -1380,7 +1399,17 @@ uint32_t band_channel_to_freq(uint8_t channel, enum band_freq band)
return 0;
/* operating classes 131, 132, 133, 134, 135 */
return 5950 + 5 * channel;
freq = 5950 + 5 * channel;
}
check_e4:
for (i = 0; i < L_ARRAY_SIZE(e4_operating_classes); i++) {
const struct operating_class_info *info =
&e4_operating_classes[i];
if (e4_has_frequency(info, freq) == 0 ||
e4_has_ccfi(info, freq) == 0)
return freq;
}
return 0;