From 77c0d0cd10e793989d1e8b835a9a09694182cb39 Mon Sep 17 00:00:00 2001 From: =?utf8?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=utf8 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 --- .../broadcom/brcm80211/brcmfmac/cfg80211.c | 32 ++++++++++++---------- 1 file changed, 17 insertions(+), 15 deletions(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c index 15eaf72..895404c 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c @@ -5825,7 +5825,6 @@ static int brcmf_construct_chaninfo(struct brcmf_cfg80211_info *cfg, u32 i, j; u32 total; u32 chaninfo; - u32 index; pbuf = kzalloc(BRCMF_DCMD_MEDLEN, GFP_KERNEL); @@ -5873,33 +5872,36 @@ static int brcmf_construct_chaninfo(struct brcmf_cfg80211_info *cfg, 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; @@ -5907,11 +5909,11 @@ static int brcmf_construct_chaninfo(struct brcmf_cfg80211_info *cfg, &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; } } -- 2.7.4