Patch "wext: handle NULL extra data in iwe_stream_add_point better" has been added to the 4.4-stable tree

Patch "wext: handle NULL extra data in iwe_stream_add_point better" has been added to the 4.4-stable tree

[gregkh]

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

    wext: handle NULL extra data in iwe_stream_add_point better

to the 4.4-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:
     wext-handle-null-extra-data-in-iwe_stream_add_point-better.patch
and it can be found in the queue-4.4 subdirectory.

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


>From 93be2b74279c15c2844684b1a027fdc71dd5d9bf Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 11 Jan 2017 15:35:25 +0100
Subject: wext: handle NULL extra data in iwe_stream_add_point better

From: Arnd Bergmann <arnd@arndb.de>

commit 93be2b74279c15c2844684b1a027fdc71dd5d9bf upstream.

gcc-7 complains that wl3501_cs passes NULL into a function that
then uses the argument as the input for memcpy:

drivers/net/wireless/wl3501_cs.c: In function 'wl3501_get_scan':
include/net/iw_handler.h:559:3: error: argument 2 null where non-null expected [-Werror=nonnull]
   memcpy(stream + point_len, extra, iwe->u.data.length);

This works fine here because iwe->u.data.length is guaranteed to be 0
and the memcpy doesn't actually have an effect.

Making the length check explicit avoids the warning and should have
no other effect here.

Also check the pointer itself, since otherwise we get warnings
elsewhere in the code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/net/iw_handler.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/include/net/iw_handler.h
+++ b/include/net/iw_handler.h
@@ -556,7 +556,8 @@ iwe_stream_add_point(struct iw_request_i
 		memcpy(stream + lcp_len,
 		       ((char *) &iwe->u) + IW_EV_POINT_OFF,
 		       IW_EV_POINT_PK_LEN - IW_EV_LCP_PK_LEN);
-		memcpy(stream + point_len, extra, iwe->u.data.length);
+		if (iwe->u.data.length && extra)
+			memcpy(stream + point_len, extra, iwe->u.data.length);
 		stream += event_len;
 	}
 	return stream;


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/wext-handle-null-extra-data-in-iwe_stream_add_point-better.patch