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wifi: cfg80211: Avoid clashing function prototypes
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When built with Control Flow Integrity, function prototypes between
caller and function declaration must match. These mismatches are visible
at compile time with the new -Wcast-function-type-strict in Clang[1].

Fix a total of 73 warnings like these:

drivers/net/wireless/intersil/orinoco/wext.c:1379:27: warning: cast from 'int (*)(struct net_device *, struct iw_request_info *, struct iw_param *, char *)' to 'iw_handler' (aka 'int (*)(struct net_device *, struct iw_request_info *, union iwreq_data *, char *)') converts to incompatible function type [-Wcast-function-type-strict]
        IW_HANDLER(SIOCGIWPOWER,        (iw_handler)orinoco_ioctl_getpower),
                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../net/wireless/wext-compat.c:1607:33: warning: cast from 'int (*)(struct net_device *, struct iw_request_info *, struct iw_point *, char *)' to 'iw_handler' (aka 'int (*)(struct net_device *, struct iw_request_info *, union iwreq_data *, char *)') converts to incompatible function type [-Wcast-function-type-strict]
        [IW_IOCTL_IDX(SIOCSIWGENIE)]    = (iw_handler) cfg80211_wext_siwgenie,
                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../drivers/net/wireless/intersil/orinoco/wext.c:1390:27: error: incompatible function pointer types initializing 'const iw_handler' (aka 'int (*const)(struct net_device *, struct iw_request_info *, union iwreq_data *, char *)') with an expression of type 'int (struct net_device *, struct iw_request_info *, struct iw_param *, char *)' [-Wincompatible-function-pointer-types]
        IW_HANDLER(SIOCGIWRETRY,        cfg80211_wext_giwretry),
                                        ^~~~~~~~~~~~~~~~~~~~~~

The cfg80211 Wireless Extension handler callbacks (iw_handler) use a
union for the data argument. Actually use the union and perform explicit
member selection in the function body instead of having a function
prototype mismatch. There are no resulting binary differences
before/after changes.

These changes were made partly manually and partly with the help of
Coccinelle.

Link: https://github.com/KSPP/linux/issues/234
Link: https://reviews.llvm.org/D134831 [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/a68822bf8dd587988131bb6a295280cb4293f05d.1667934775.git.gustavoars@kernel.org
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Gustavo A. R. Silva authored and Kalle Valo committed Nov 16, 2022
1 parent 2c0e077 commit 02ae6a7
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Showing 7 changed files with 113 additions and 127 deletions.
2 changes: 1 addition & 1 deletion drivers/net/wireless/intel/ipw2x00/ipw2200.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9856,7 +9856,7 @@ static int ipw_wx_sw_reset(struct net_device *dev,

/* Rebase the WE IOCTLs to zero for the handler array */
static iw_handler ipw_wx_handlers[] = {
IW_HANDLER(SIOCGIWNAME, (iw_handler)cfg80211_wext_giwname),
IW_HANDLER(SIOCGIWNAME, cfg80211_wext_giwname),
IW_HANDLER(SIOCSIWFREQ, ipw_wx_set_freq),
IW_HANDLER(SIOCGIWFREQ, ipw_wx_get_freq),
IW_HANDLER(SIOCSIWMODE, ipw_wx_set_mode),
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22 changes: 11 additions & 11 deletions drivers/net/wireless/intersil/orinoco/wext.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1363,31 +1363,31 @@ static const struct iw_priv_args orinoco_privtab[] = {

static const iw_handler orinoco_handler[] = {
IW_HANDLER(SIOCSIWCOMMIT, orinoco_ioctl_commit),
IW_HANDLER(SIOCGIWNAME, (iw_handler)cfg80211_wext_giwname),
IW_HANDLER(SIOCGIWNAME, cfg80211_wext_giwname),
IW_HANDLER(SIOCSIWFREQ, orinoco_ioctl_setfreq),
IW_HANDLER(SIOCGIWFREQ, orinoco_ioctl_getfreq),
IW_HANDLER(SIOCSIWMODE, (iw_handler)cfg80211_wext_siwmode),
IW_HANDLER(SIOCGIWMODE, (iw_handler)cfg80211_wext_giwmode),
IW_HANDLER(SIOCSIWMODE, cfg80211_wext_siwmode),
IW_HANDLER(SIOCGIWMODE, cfg80211_wext_giwmode),
IW_HANDLER(SIOCSIWSENS, orinoco_ioctl_setsens),
IW_HANDLER(SIOCGIWSENS, orinoco_ioctl_getsens),
IW_HANDLER(SIOCGIWRANGE, (iw_handler)cfg80211_wext_giwrange),
IW_HANDLER(SIOCGIWRANGE, cfg80211_wext_giwrange),
IW_HANDLER(SIOCSIWSPY, iw_handler_set_spy),
IW_HANDLER(SIOCGIWSPY, iw_handler_get_spy),
IW_HANDLER(SIOCSIWTHRSPY, iw_handler_set_thrspy),
IW_HANDLER(SIOCGIWTHRSPY, iw_handler_get_thrspy),
IW_HANDLER(SIOCSIWAP, orinoco_ioctl_setwap),
IW_HANDLER(SIOCGIWAP, orinoco_ioctl_getwap),
IW_HANDLER(SIOCSIWSCAN, (iw_handler)cfg80211_wext_siwscan),
IW_HANDLER(SIOCGIWSCAN, (iw_handler)cfg80211_wext_giwscan),
IW_HANDLER(SIOCSIWSCAN, cfg80211_wext_siwscan),
IW_HANDLER(SIOCGIWSCAN, cfg80211_wext_giwscan),
IW_HANDLER(SIOCSIWESSID, orinoco_ioctl_setessid),
IW_HANDLER(SIOCGIWESSID, orinoco_ioctl_getessid),
IW_HANDLER(SIOCSIWRATE, orinoco_ioctl_setrate),
IW_HANDLER(SIOCGIWRATE, orinoco_ioctl_getrate),
IW_HANDLER(SIOCSIWRTS, (iw_handler)cfg80211_wext_siwrts),
IW_HANDLER(SIOCGIWRTS, (iw_handler)cfg80211_wext_giwrts),
IW_HANDLER(SIOCSIWFRAG, (iw_handler)cfg80211_wext_siwfrag),
IW_HANDLER(SIOCGIWFRAG, (iw_handler)cfg80211_wext_giwfrag),
IW_HANDLER(SIOCGIWRETRY, (iw_handler)cfg80211_wext_giwretry),
IW_HANDLER(SIOCSIWRTS, cfg80211_wext_siwrts),
IW_HANDLER(SIOCGIWRTS, cfg80211_wext_giwrts),
IW_HANDLER(SIOCSIWFRAG, cfg80211_wext_siwfrag),
IW_HANDLER(SIOCGIWFRAG, cfg80211_wext_giwfrag),
IW_HANDLER(SIOCGIWRETRY, cfg80211_wext_giwretry),
IW_HANDLER(SIOCSIWENCODE, orinoco_ioctl_setiwencode),
IW_HANDLER(SIOCGIWENCODE, orinoco_ioctl_getiwencode),
IW_HANDLER(SIOCSIWPOWER, orinoco_ioctl_setpower),
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20 changes: 10 additions & 10 deletions include/net/cfg80211-wext.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,34 +19,34 @@
*/
int cfg80211_wext_giwname(struct net_device *dev,
struct iw_request_info *info,
char *name, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_siwmode(struct net_device *dev, struct iw_request_info *info,
u32 *mode, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwmode(struct net_device *dev, struct iw_request_info *info,
u32 *mode, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_siwscan(struct net_device *dev,
struct iw_request_info *info,
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwscan(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwrange(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_siwrts(struct net_device *dev,
struct iw_request_info *info,
struct iw_param *rts, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwrts(struct net_device *dev,
struct iw_request_info *info,
struct iw_param *rts, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_siwfrag(struct net_device *dev,
struct iw_request_info *info,
struct iw_param *frag, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwfrag(struct net_device *dev,
struct iw_request_info *info,
struct iw_param *frag, char *extra);
union iwreq_data *wrqu, char *extra);
int cfg80211_wext_giwretry(struct net_device *dev,
struct iw_request_info *info,
struct iw_param *retry, char *extra);
union iwreq_data *wrqu, char *extra);

#endif /* __NET_CFG80211_WEXT_H */
3 changes: 2 additions & 1 deletion net/wireless/scan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3229,8 +3229,9 @@ static int ieee80211_scan_results(struct cfg80211_registered_device *rdev,

int cfg80211_wext_giwscan(struct net_device *dev,
struct iw_request_info *info,
struct iw_point *data, char *extra)
union iwreq_data *wrqu, char *extra)
{
struct iw_point *data = &wrqu->data;
struct cfg80211_registered_device *rdev;
int res;

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