• Brian Norris's avatar
    mwifiex: correct channel stat buffer overflows · f7fb7898
    Brian Norris authored
    commit 4b5dde2d 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: bf354433 ("mwifiex: channel statistics support for mwifiex")
    Cc: Avinash Patil <patila@marvell.com>
    Cc: Xinming Hu <huxm@marvell.com>
    Signed-off-by: default avatarBrian Norris <briannorris@chromium.org>
    Reviewed-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
    Reviewed-by: default avatarGanapathi Bhat <gbhat@marvell.com>
    Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    f7fb7898
scan.c 85.7 KB