Fix the following out-of-bounds warning: net/wireless/wext-spy.c:178:2: warning: 'memcpy' offset [25, 28] from the object at 'threshold' is out of the bounds of referenced subobject 'low' with type 'struct iw_quality' at offset 20 [-Warray-bounds] The problem is that the original code is trying to copy data into a couple of struct members adjacent to each other in a single call to memcpy(). This causes a legitimate compiler warning because memcpy() overruns the length of &threshold.low and &spydata->spy_thr_low. As these are just a couple of struct members, fix this by using direct assignments, instead of memcpy(). This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot <lkp@xxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> --- Changes in v2: - Use direct struct assignments instead of memcpy(). - Fix one more instance of this same issue in function iw_handler_get_thrspy(). - Update changelog text. - Add Kees' RB tag. net/wireless/wext-spy.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/net/wireless/wext-spy.c b/net/wireless/wext-spy.c index 33bef22e44e9..b379a0371653 100644 --- a/net/wireless/wext-spy.c +++ b/net/wireless/wext-spy.c @@ -120,8 +120,8 @@ int iw_handler_set_thrspy(struct net_device * dev, return -EOPNOTSUPP; /* Just do it */ - memcpy(&(spydata->spy_thr_low), &(threshold->low), - 2 * sizeof(struct iw_quality)); + spydata->spy_thr_low = threshold->low; + spydata->spy_thr_high = threshold->high; /* Clear flag */ memset(spydata->spy_thr_under, '\0', sizeof(spydata->spy_thr_under)); @@ -147,8 +147,8 @@ int iw_handler_get_thrspy(struct net_device * dev, return -EOPNOTSUPP; /* Just do it */ - memcpy(&(threshold->low), &(spydata->spy_thr_low), - 2 * sizeof(struct iw_quality)); + threshold->low = spydata->spy_thr_low; + threshold->high = spydata->spy_thr_high; return 0; } @@ -173,10 +173,10 @@ static void iw_send_thrspy_event(struct net_device * dev, memcpy(threshold.addr.sa_data, address, ETH_ALEN); threshold.addr.sa_family = ARPHRD_ETHER; /* Copy stats */ - memcpy(&(threshold.qual), wstats, sizeof(struct iw_quality)); + threshold.qual = *wstats; /* Copy also thresholds */ - memcpy(&(threshold.low), &(spydata->spy_thr_low), - 2 * sizeof(struct iw_quality)); + threshold.low = spydata->spy_thr_low; + threshold.high = spydata->spy_thr_high; /* Send event to user space */ wireless_send_event(dev, SIOCGIWTHRSPY, &wrqu, (char *) &threshold); -- 2.27.0
