From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Date: Wed, 4 Jan 2017 12:09:41 +0100 Subject: [PATCH] brcmfmac: avoid writing channel out of allocated array MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Our code was assigning number of channels to the index variable by default. If firmware reported channel we didn't predict this would result in using that initial index value and writing out of array. This never happened so far (we got a complete list of supported channels) but it means possible memory corruption so we should handle it anyway. This patch simply detects unexpected channel and ignores it. As we don't try to create new entry now, it's also safe to drop hw_value and center_freq assignment. For known channels we have these set anyway. I decided to fix this issue by assigning NULL or a target channel to the channel variable. This was one of possible ways, I prefefred this one as it also avoids using channel[index] over and over. Fixes: 58de92d2f95e ("brcmfmac: use static superset of channels for wiphy bands") Signed-off-by: Rafał Miłecki Acked-by: Arend van Spriel Signed-off-by: Kalle Valo --- --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c @@ -5915,7 +5915,6 @@ static int brcmf_construct_chaninfo(stru u32 i, j; u32 total; u32 chaninfo; - u32 index; pbuf = kzalloc(BRCMF_DCMD_MEDLEN, GFP_KERNEL); @@ -5963,33 +5962,36 @@ static int brcmf_construct_chaninfo(stru ch.bw == BRCMU_CHAN_BW_80) continue; - channel = band->channels; - index = band->n_channels; + channel = NULL; for (j = 0; j < band->n_channels; j++) { - if (channel[j].hw_value == ch.control_ch_num) { - index = j; + if (band->channels[j].hw_value == ch.control_ch_num) { + channel = &band->channels[j]; break; } } - channel[index].center_freq = - ieee80211_channel_to_frequency(ch.control_ch_num, - band->band); - channel[index].hw_value = ch.control_ch_num; + if (!channel) { + /* It seems firmware supports some channel we never + * considered. Something new in IEEE standard? + */ + brcmf_err("Ignoring unexpected firmware channel %d\n", + ch.control_ch_num); + continue; + } /* assuming the chanspecs order is HT20, * HT40 upper, HT40 lower, and VHT80. */ if (ch.bw == BRCMU_CHAN_BW_80) { - channel[index].flags &= ~IEEE80211_CHAN_NO_80MHZ; + channel->flags &= ~IEEE80211_CHAN_NO_80MHZ; } else if (ch.bw == BRCMU_CHAN_BW_40) { - brcmf_update_bw40_channel_flag(&channel[index], &ch); + brcmf_update_bw40_channel_flag(channel, &ch); } else { /* enable the channel and disable other bandwidths * for now as mentioned order assure they are enabled * for subsequent chanspecs. */ - channel[index].flags = IEEE80211_CHAN_NO_HT40 | - IEEE80211_CHAN_NO_80MHZ; + channel->flags = IEEE80211_CHAN_NO_HT40 | + IEEE80211_CHAN_NO_80MHZ; ch.bw = BRCMU_CHAN_BW_20; cfg->d11inf.encchspec(&ch); chaninfo = ch.chspec; @@ -5997,11 +5999,11 @@ static int brcmf_construct_chaninfo(stru &chaninfo); if (!err) { if (chaninfo & WL_CHAN_RADAR) - channel[index].flags |= + channel->flags |= (IEEE80211_CHAN_RADAR | IEEE80211_CHAN_NO_IR); if (chaninfo & WL_CHAN_PASSIVE) - channel[index].flags |= + channel->flags |= IEEE80211_CHAN_NO_IR; } }