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Commit b8fa0b03 authored by Pi-Hsun Shih's avatar Pi-Hsun Shih Committed by Greg Kroah-Hartman
Browse files

wireless: Use offsetof instead of custom macro. 



commit 6989310f5d4327e8595664954edd40a7f99ddd0d upstream.

Use offsetof to calculate offset of a field to take advantage of
compiler built-in version when possible, and avoid UBSAN warning when
compiling with Clang:

==================================================================
UBSAN: Undefined behaviour in net/wireless/wext-core.c:525:14
member access within null pointer of type 'struct iw_point'
CPU: 3 PID: 165 Comm: kworker/u16:3 Tainted: G S      W         4.19.23 #43
Workqueue: cfg80211 __cfg80211_scan_done [cfg80211]
Call trace:
 dump_backtrace+0x0/0x194
 show_stack+0x20/0x2c
 __dump_stack+0x20/0x28
 dump_stack+0x70/0x94
 ubsan_epilogue+0x14/0x44
 ubsan_type_mismatch_common+0xf4/0xfc
 __ubsan_handle_type_mismatch_v1+0x34/0x54
 wireless_send_event+0x3cc/0x470
 ___cfg80211_scan_done+0x13c/0x220 [cfg80211]
 __cfg80211_scan_done+0x28/0x34 [cfg80211]
 process_one_work+0x170/0x35c
 worker_thread+0x254/0x380
 kthread+0x13c/0x158
 ret_from_fork+0x10/0x18
===================================================================

Signed-off-by: default avatarPi-Hsun Shih <pihsun@chromium.org>
Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20191204081307.138765-1-pihsun@chromium.org


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d3472f74

include/uapi/linux/wireless.h

+3 −2
Original line number Diff line number Diff line
@@ -74,6 +74,8 @@ 
#include <linux/socket.h>		/* for "struct sockaddr" et al	*/

#include <linux/if.h>			/* for IFNAMSIZ and co... */



#include <stddef.h>                     /* for offsetof */



/***************************** VERSION *****************************/

/*

 * This constant is used to know the availability of the wireless
@@ -1090,8 +1092,7 @@ struct iw_event { 
/* iw_point events are special. First, the payload (extra data) come at

 * the end of the event, so they are bigger than IW_EV_POINT_LEN. Second,

 * we omit the pointer, so start at an offset. */

#define IW_EV_POINT_OFF (((char *) &(((struct iw_point *) NULL)->length)) - \

			  (char *) NULL)

#define IW_EV_POINT_OFF offsetof(struct iw_point, length)

#define IW_EV_POINT_LEN	(IW_EV_LCP_LEN + sizeof(struct iw_point) - \

			 IW_EV_POINT_OFF)