In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Add struct_group() to mark region of struct cm4000_dev that should be initialized to zero. Cc: Harald Welte <lafo...@gnumonks.org> Cc: Arnd Bergmann <a...@arndb.de> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> Signed-off-by: Kees Cook <keesc...@chromium.org> Acked-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> Link: https://lore.kernel.org/lkml/yqdvxaofjli1j...@kroah.com --- drivers/char/pcmcia/cm4000_cs.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c index 8f1bce0b4fe5..2f43e7088e16 100644 --- a/drivers/char/pcmcia/cm4000_cs.c +++ b/drivers/char/pcmcia/cm4000_cs.c @@ -116,8 +116,9 @@ struct cm4000_dev { wait_queue_head_t atrq; /* wait for ATR valid */ wait_queue_head_t readq; /* used by write to wake blk.read */ - /* warning: do not move this fields. + /* warning: do not move this struct group. * initialising to zero depends on it - see ZERO_DEV below. */ + struct_group(init, unsigned char atr_csum; unsigned char atr_len_retry; unsigned short atr_len; @@ -140,12 +141,10 @@ struct cm4000_dev { struct timer_list timer; /* used to keep monitor running */ int monitor_running; + ); }; -#define ZERO_DEV(dev) \ - memset(&dev->atr_csum,0, \ - sizeof(struct cm4000_dev) - \ - offsetof(struct cm4000_dev, atr_csum)) +#define ZERO_DEV(dev) memset(&dev->init, 0, sizeof(dev->init)) static struct pcmcia_device *dev_table[CM4000_MAX_DEV]; static struct class *cmm_class; -- 2.30.2
