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    Subject[PATCH AUTOSEL 5.4 63/74] wireless: wext-spy: Fix out-of-bounds warning
    Date
    From: "Gustavo A. R. Silva" <gustavoars@kernel.org>

    [ 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@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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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);
    --
    2.30.2
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