linux-kernel - [PATCH 4.9 67/93] wext: handle NULL extra data in iwe_stream_add

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170809181338.385747935@linuxfoundation.org>
Date:   Wed,  9 Aug 2017 11:14:00 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH 4.9 67/93] wext: handle NULL extra data in iwe_stream_add_point better

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@...db.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@...db.de>
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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;