* [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning
@ 2021-04-21 23:43 Gustavo A. R. Silva
2021-04-22 0:22 ` Kees Cook
2021-04-22 7:04 ` Johannes Berg
0 siblings, 2 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2021-04-21 23:43 UTC (permalink / raw)
To: Johannes Berg, David S. Miller, Jakub Kicinski
Cc: linux-wireless, netdev, linux-kernel, Gustavo A. R. Silva,
linux-hardening, Kees Cook
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 members, fix this by copying each one of
them in separate calls to memcpy().
Also, while there, use sizeof(threshold.qual) instead of
sizeof(struct iw_quality)) in another call to memcpy()
above.
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>
---
net/wireless/wext-spy.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/net/wireless/wext-spy.c b/net/wireless/wext-spy.c
index 33bef22e44e9..bb2de7c6bee4 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));
+ memcpy(&spydata->spy_thr_low, &threshold->low, sizeof(threshold->low));
+ memcpy(&spydata->spy_thr_high, &threshold->high, sizeof(threshold->high));
/* Clear flag */
memset(spydata->spy_thr_under, '\0', sizeof(spydata->spy_thr_under));
@@ -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));
+ memcpy(&threshold.qual, wstats, sizeof(threshold.qual));
/* Copy also thresholds */
- memcpy(&(threshold.low), &(spydata->spy_thr_low),
- 2 * sizeof(struct iw_quality));
+ memcpy(&threshold.low, &spydata->spy_thr_low, sizeof(threshold.low));
+ memcpy(&threshold.high, &spydata->spy_thr_high, sizeof(threshold.high));
/* Send event to user space */
wireless_send_event(dev, SIOCGIWTHRSPY, &wrqu, (char *) &threshold);
--
2.27.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning
2021-04-21 23:43 [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning Gustavo A. R. Silva
@ 2021-04-22 0:22 ` Kees Cook
2021-04-22 7:04 ` Johannes Berg
1 sibling, 0 replies; 4+ messages in thread
From: Kees Cook @ 2021-04-22 0:22 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Johannes Berg, David S. Miller, Jakub Kicinski, linux-wireless,
netdev, linux-kernel, linux-hardening
On Wed, Apr 21, 2021 at 06:43:37PM -0500, Gustavo A. R. Silva wrote:
> 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 members, fix this by copying each one of
> them in separate calls to memcpy().
>
> Also, while there, use sizeof(threshold.qual) instead of
> sizeof(struct iw_quality)) in another call to memcpy()
> above.
>
> 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>
Thanks!
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> net/wireless/wext-spy.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/net/wireless/wext-spy.c b/net/wireless/wext-spy.c
> index 33bef22e44e9..bb2de7c6bee4 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));
> + memcpy(&spydata->spy_thr_low, &threshold->low, sizeof(threshold->low));
> + memcpy(&spydata->spy_thr_high, &threshold->high, sizeof(threshold->high));
>
> /* Clear flag */
> memset(spydata->spy_thr_under, '\0', sizeof(spydata->spy_thr_under));
> @@ -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));
> + memcpy(&threshold.qual, wstats, sizeof(threshold.qual));
> /* Copy also thresholds */
> - memcpy(&(threshold.low), &(spydata->spy_thr_low),
> - 2 * sizeof(struct iw_quality));
> + memcpy(&threshold.low, &spydata->spy_thr_low, sizeof(threshold.low));
> + memcpy(&threshold.high, &spydata->spy_thr_high, sizeof(threshold.high));
>
> /* Send event to user space */
> wireless_send_event(dev, SIOCGIWTHRSPY, &wrqu, (char *) &threshold);
> --
> 2.27.0
>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning
2021-04-21 23:43 [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning Gustavo A. R. Silva
2021-04-22 0:22 ` Kees Cook
@ 2021-04-22 7:04 ` Johannes Berg
2021-04-22 20:03 ` Gustavo A. R. Silva
1 sibling, 1 reply; 4+ messages in thread
From: Johannes Berg @ 2021-04-22 7:04 UTC (permalink / raw)
To: Gustavo A. R. Silva, David S. Miller, Jakub Kicinski
Cc: linux-wireless, netdev, linux-kernel, linux-hardening, Kees Cook
On Wed, 2021-04-21 at 18:43 -0500, Gustavo A. R. Silva wrote:
>
> /* Just do it */
> - memcpy(&(spydata->spy_thr_low), &(threshold->low),
> - 2 * sizeof(struct iw_quality));
> + memcpy(&spydata->spy_thr_low, &threshold->low, sizeof(threshold->low));
> + memcpy(&spydata->spy_thr_high, &threshold->high, sizeof(threshold->high));
>
It would've been really simple to stick to 80 columns here (and
everywhere in the patch), please do that.
Also, why not just use struct assigments?
spydata->spy_thr_low = threshold->low;
etc.
Seems far simpler (and shorter lines).
johannes
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning
2021-04-22 7:04 ` Johannes Berg
@ 2021-04-22 20:03 ` Gustavo A. R. Silva
0 siblings, 0 replies; 4+ messages in thread
From: Gustavo A. R. Silva @ 2021-04-22 20:03 UTC (permalink / raw)
To: Johannes Berg, Gustavo A. R. Silva, David S. Miller, Jakub Kicinski
Cc: linux-wireless, netdev, linux-kernel, linux-hardening, Kees Cook
On 4/22/21 02:04, Johannes Berg wrote:
> On Wed, 2021-04-21 at 18:43 -0500, Gustavo A. R. Silva wrote:
>>
>> /* Just do it */
>> - memcpy(&(spydata->spy_thr_low), &(threshold->low),
>> - 2 * sizeof(struct iw_quality));
>> + memcpy(&spydata->spy_thr_low, &threshold->low, sizeof(threshold->low));
>> + memcpy(&spydata->spy_thr_high, &threshold->high, sizeof(threshold->high));
>>
>
> It would've been really simple to stick to 80 columns here (and
> everywhere in the patch), please do that.
>
> Also, why not just use struct assigments?
>
> spydata->spy_thr_low = threshold->low;
>
> etc.
> Done: https://lore.kernel.org/lkml/20210422200032.GA168995@embeddedor/
> Seems far simpler (and shorter lines).
Done:
https://lore.kernel.org/lkml/20210422200032.GA168995@embeddedor/
Thanks for the feedback.
--
Gustavo
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-04-22 20:03 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-21 23:43 [PATCH][next] wireless: wext-spy: Fix out-of-bounds warning Gustavo A. R. Silva
2021-04-22 0:22 ` Kees Cook
2021-04-22 7:04 ` Johannes Berg
2021-04-22 20:03 ` Gustavo A. R. Silva
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).