| Message ID | 20170630012354.98931-1-briannorris@chromium.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4b5dde2d6234ff5bc68e97e6901d1f2a0a7f3749 |
| Delegated to: | Kalle Valo |
| Headers | show |
On Thu, Jun 29, 2017 at 06:23:54PM -0700, Brian Norris wrote: > 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: <stable@vger.kernel.org> > Cc: Avinash Patil <patila@marvell.com> > Cc: Xinming Hu <huxm@marvell.com> > Signed-off-by: Brian Norris <briannorris@chromium.org> > --- > I've got a ton of other patches still queued up locally, and I hope to send > them soon. But I realized this one is a nasty bug (with a trivial fix), so it's > probably best to get this out the door quickly. This does make sense to me. Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > > drivers/net/wireless/marvell/mwifiex/cfg80211.c | 2 +- > drivers/net/wireless/marvell/mwifiex/scan.c | 6 ++++++ > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c > index a850ec0054e2..82f4e796ed39 100644 > --- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c > +++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c > @@ -4219,7 +4219,7 @@ int mwifiex_init_channel_scan_gap(struct mwifiex_adapter *adapter) > 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); > > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c > index ae9630b49342..9900855746ac 100644 > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > @@ -2492,6 +2492,12 @@ mwifiex_update_chan_statistics(struct mwifiex_private *priv, > 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; > -- > 2.13.2.725.g09c95d1e9-goog >
Hi Brian, > ---------------------------------------------------------------------- > On Thu, Jun 29, 2017 at 06:23:54PM -0700, Brian Norris wrote: > > 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: <stable@vger.kernel.org> > > Cc: Avinash Patil <patila@marvell.com> > > Cc: Xinming Hu <huxm@marvell.com> > > Signed-off-by: Brian Norris <briannorris@chromium.org> > > --- > > I've got a ton of other patches still queued up locally, and I hope > to > > send them soon. But I realized this one is a nasty bug (with a > trivial > > fix), so it's probably best to get this out the door quickly. > > This does make sense to me. > > Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > Changes look good. Reviewed-by: Ganapathi Bhat <gbhat@marvell.com> > > > > drivers/net/wireless/marvell/mwifiex/cfg80211.c | 2 +- > > drivers/net/wireless/marvell/mwifiex/scan.c | 6 ++++++ > > 2 files changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c > > b/drivers/net/wireless/marvell/mwifiex/cfg80211.c > > index a850ec0054e2..82f4e796ed39 100644 > > --- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c > > +++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c > > @@ -4219,7 +4219,7 @@ int mwifiex_init_channel_scan_gap(struct > mwifiex_adapter *adapter) > > 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); > > > > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c > > b/drivers/net/wireless/marvell/mwifiex/scan.c > > index ae9630b49342..9900855746ac 100644 > > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > > @@ -2492,6 +2492,12 @@ mwifiex_update_chan_statistics(struct > mwifiex_private *priv, > > 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; > > -- > > 2.13.2.725.g09c95d1e9-goog > > > > -- > Dmitry Regards, Ganapathi
Brian Norris <briannorris@chromium.org> wrote: > 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: <stable@vger.kernel.org> > Cc: Avinash Patil <patila@marvell.com> > Cc: Xinming Hu <huxm@marvell.com> > Signed-off-by: Brian Norris <briannorris@chromium.org> > Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > Reviewed-by: Ganapathi Bhat <gbhat@marvell.com> Patch applied to wireless-drivers-next.git, thanks. 4b5dde2d6234 mwifiex: correct channel stat buffer overflows
diff --git a/drivers/net/wireless/marvell/mwifiex/cfg80211.c b/drivers/net/wireless/marvell/mwifiex/cfg80211.c index a850ec0054e2..82f4e796ed39 100644 --- a/drivers/net/wireless/marvell/mwifiex/cfg80211.c +++ b/drivers/net/wireless/marvell/mwifiex/cfg80211.c @@ -4219,7 +4219,7 @@ int mwifiex_init_channel_scan_gap(struct mwifiex_adapter *adapter) 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); diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c index ae9630b49342..9900855746ac 100644 --- a/drivers/net/wireless/marvell/mwifiex/scan.c +++ b/drivers/net/wireless/marvell/mwifiex/scan.c @@ -2492,6 +2492,12 @@ mwifiex_update_chan_statistics(struct mwifiex_private *priv, 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;
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: <stable@vger.kernel.org> Cc: Avinash Patil <patila@marvell.com> Cc: Xinming Hu <huxm@marvell.com> Signed-off-by: Brian Norris <briannorris@chromium.org> --- I've got a ton of other patches still queued up locally, and I hope to send them soon. But I realized this one is a nasty bug (with a trivial fix), so it's probably best to get this out the door quickly. drivers/net/wireless/marvell/mwifiex/cfg80211.c | 2 +- drivers/net/wireless/marvell/mwifiex/scan.c | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-)