This is a note to let you know that I've just added the patch titled mwifiex: correct channel stat buffer overflows to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mwifiex-correct-channel-stat-buffer-overflows.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 4b5dde2d6234ff5bc68e97e6901d1f2a0a7f3749 Mon Sep 17 00:00:00 2001 From: Brian Norris <briannorris@xxxxxxxxxxxx> Date: Thu, 29 Jun 2017 18:23:54 -0700 Subject: mwifiex: correct channel stat buffer overflows From: Brian Norris <briannorris@xxxxxxxxxxxx> commit 4b5dde2d6234ff5bc68e97e6901d1f2a0a7f3749 upstream. mwifiex records information about various channels as it receives scan information. It does this by appending to a buffer that was sized to the max number of supported channels on any band, but there are numerous problems: (a) scans can return info from more than one band (e.g., both 2.4 and 5 GHz), so the determined "max" is not large enough (b) some firmware appears to return multiple results for a given channel, so the max *really* isn't large enough (c) there is no bounds checking when stashing these stats, so problems (a) and (b) can easily lead to buffer overflows Let's patch this by setting a slightly-more-correct max (that accounts for a combination of both 2.4G and 5G bands) and adding a bounds check when writing to our statistics buffer. Due to problem (b), we still might not properly report all known survey information (e.g., with "iw <dev> survey dump"), since duplicate results (or otherwise "larger than expected" results) will cause some truncation. But that's a problem for a future bugfix. (And because of this known deficiency, only log the excess at the WARN level, since that isn't visible by default in this driver and would otherwise be a bit too noisy.) Fixes: bf35443314ac ("mwifiex: channel statistics support for mwifiex") Cc: Avinash Patil <patila@xxxxxxxxxxx> Cc: Xinming Hu <huxm@xxxxxxxxxxx> Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> Reviewed-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Reviewed-by: Ganapathi Bhat <gbhat@xxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/mwifiex/cfg80211.c | 2 +- drivers/net/wireless/mwifiex/scan.c | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) --- a/drivers/net/wireless/mwifiex/cfg80211.c +++ b/drivers/net/wireless/mwifiex/cfg80211.c @@ -3740,7 +3740,7 @@ int mwifiex_init_channel_scan_gap(struct if (adapter->config_bands & BAND_A) n_channels_a = mwifiex_band_5ghz.n_channels; - adapter->num_in_chan_stats = max_t(u32, n_channels_bg, n_channels_a); + adapter->num_in_chan_stats = n_channels_bg + n_channels_a; adapter->chan_stats = vmalloc(sizeof(*adapter->chan_stats) * adapter->num_in_chan_stats); --- a/drivers/net/wireless/mwifiex/scan.c +++ b/drivers/net/wireless/mwifiex/scan.c @@ -2170,6 +2170,12 @@ mwifiex_update_chan_statistics(struct mw sizeof(struct mwifiex_chan_stats); for (i = 0 ; i < num_chan; i++) { + if (adapter->survey_idx >= adapter->num_in_chan_stats) { + mwifiex_dbg(adapter, WARN, + "FW reported too many channel results (max %d)\n", + adapter->num_in_chan_stats); + return; + } chan_stats.chan_num = fw_chan_stats->chan_num; chan_stats.bandcfg = fw_chan_stats->bandcfg; chan_stats.flags = fw_chan_stats->flags; Patches currently in stable-queue which might be from briannorris@xxxxxxxxxxxx are queue-4.4/mwifiex-correct-channel-stat-buffer-overflows.patch