On 30 Sep 2015 at 9:10, James Cameron wrote:
> On Tue, Sep 29, 2015 at 05:21:28PM +0200, PaX Team wrote:
> > hi all,
> >
> > in drivers/net/wireless/mwifiex/sta_ioctl.c the following functions
> >
> > mwifiex_set_wpa_ie_helper
> > mwifiex_set_wapi_ie
> > mwifiex_set_wps_ie
> >
> > can truncate the incoming ie_len argument from u16 to u8 when it gets
> > stored in mwifiex_private.wpa_ie_len, mwifiex_private.wapi_ie_len and
> > mwifiex_private.wps_ie_len, respectively. based on some light code
> > reading it seems a length value of 256 is valid (IEEE_MAX_IE_SIZE and
> > MWIFIEX_MAX_VSIE_LEN seem to limit it) and thus would get truncated
> > to 0 when stored in those u8 fields. the question is whether this is
> > intentional or a bug somewhere.
>
> i agree, while there is a test to ensure ie_len is not greater than
> 256, there is a possibility that it will be exactly 256, which means
> 256 bytes will be given to memcpy but
> mwifiex_private.{wpa,wapi,wps}_ie_len will be zero.
>
> i suggest changing the lengths to u16. not tested.
while this is probably a necessary first step you'll also have to verify
all loads from these fields for integer truncation that can occur now
(the stores were checked by the plugin i mentioned above). based on a
naive grep the code seems to be fine but someone with actual knowledge
of the code had better verify it ;).
> diff --git a/drivers/net/wireless/mwifiex/main.h b/drivers/net/wireless/mwifiex/main.h
> index fe12560..b66e9a7 100644
> --- a/drivers/net/wireless/mwifiex/main.h
> +++ b/drivers/net/wireless/mwifiex/main.h
> @@ -512,14 +512,14 @@ struct mwifiex_private {
> struct mwifiex_wep_key wep_key[NUM_WEP_KEYS];
> u16 wep_key_curr_index;
> u8 wpa_ie[256];
> - u8 wpa_ie_len;
> + u16 wpa_ie_len;
> u8 wpa_is_gtk_set;
> struct host_cmd_ds_802_11_key_material aes_key;
> struct host_cmd_ds_802_11_key_material_v2 aes_key_v2;
> u8 wapi_ie[256];
> - u8 wapi_ie_len;
> + u16 wapi_ie_len;
> u8 *wps_ie;
> - u8 wps_ie_len;
> + u16 wps_ie_len;
> u8 wmm_required;
> u8 wmm_enabled;
> u8 wmm_qosinfo;
>
> --
> James Cameron
> http://quozl.linux.org.au/
>
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
