Patch "wireless: wext-spy: Fix out-of-bounds warning" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wireless-wext-spy-fix-out-of-bounds-warning.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d2562debf9c1e0bb3231f8becd429218cfb192ed
Author: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Date:   Thu Apr 22 15:00:32 2021 -0500

    wireless: wext-spy: Fix out-of-bounds warning
    
    [ Upstream commit e93bdd78406da9ed01554c51e38b2a02c8ef8025 ]
    
    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>
    Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
    Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20210422200032.GA168995@embeddedor
    Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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);