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wireless: wext-spy: Fix out-of-bounds warning

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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@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422200032.GA168995@embeddedor
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Gustavo A. R. Silva 2021-04-22 15:00:32 -05:00 committed by Johannes Berg
parent 38f75922a6
commit e93bdd7840
1 changed files with 7 additions and 7 deletions
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14
net/wireless/wext-spy.c
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@ -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);