[PATCH v2 3/6] zd1201: Avoid clashing function prototypes

From: Gustavo A. R. Silva
Date: Thu Oct 27 2022 - 16:19:47 EST

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 30 warnings like these:

../drivers/net/wireless/zydas/zd1201.c:1560:2: warning: cast from 'int (*)(struct net_device *, struct iw_request_info *, struct iw_freq *, 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) zd1201_set_freq, /* SIOCSIWFREQ */
^~~~~~~~~~~~~~~~~~~~~~~~~~~~

The zd1201 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.

Link: https://github.com/KSPP/linux/issues/233
Link: https://reviews.llvm.org/D134831 [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
Changes in v2:
- Revert changes in zd1201_private_handler[].

v1:
- Link: https://lore.kernel.org/linux-hardening/b16526a7a35638224990d265db21c8b450b67545.1666038048.git.gustavoars@xxxxxxxxxx/

drivers/net/wireless/zydas/zd1201.c | 162 ++++++++++++++--------------
1 file changed, 83 insertions(+), 79 deletions(-)

diff --git a/drivers/net/wireless/zydas/zd1201.c b/drivers/net/wireless/zydas/zd1201.c
index 82bc0d44212e..f761ebe7acfc 100644
--- a/drivers/net/wireless/zydas/zd1201.c
+++ b/drivers/net/wireless/zydas/zd1201.c
@@ -886,7 +886,7 @@ static void zd1201_set_multicast(struct net_device *dev)
}

static int zd1201_config_commit(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *data, char *essid)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *essid)
{
struct zd1201 *zd = netdev_priv(dev);

@@ -894,15 +894,16 @@ static int zd1201_config_commit(struct net_device *dev,
}

static int zd1201_get_name(struct net_device *dev,
- struct iw_request_info *info, char *name, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
- strcpy(name, "IEEE 802.11b");
+ strcpy(wrqu->name, "IEEE 802.11b");
return 0;
}

static int zd1201_set_freq(struct net_device *dev,
- struct iw_request_info *info, struct iw_freq *freq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_freq *freq = &wrqu->freq;
struct zd1201 *zd = netdev_priv(dev);
short channel = 0;
int err;
@@ -922,8 +923,9 @@ static int zd1201_set_freq(struct net_device *dev,
}

static int zd1201_get_freq(struct net_device *dev,
- struct iw_request_info *info, struct iw_freq *freq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_freq *freq = &wrqu->freq;
struct zd1201 *zd = netdev_priv(dev);
short channel;
int err;
@@ -938,8 +940,9 @@ static int zd1201_get_freq(struct net_device *dev,
}

static int zd1201_set_mode(struct net_device *dev,
- struct iw_request_info *info, __u32 *mode, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ __u32 *mode = &wrqu->mode;
struct zd1201 *zd = netdev_priv(dev);
short porttype, monitor = 0;
unsigned char buffer[IW_ESSID_MAX_SIZE+2];
@@ -1001,8 +1004,9 @@ static int zd1201_set_mode(struct net_device *dev,
}

static int zd1201_get_mode(struct net_device *dev,
- struct iw_request_info *info, __u32 *mode, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ __u32 *mode = &wrqu->mode;
struct zd1201 *zd = netdev_priv(dev);
short porttype;
int err;
@@ -1038,8 +1042,9 @@ static int zd1201_get_mode(struct net_device *dev,
}

static int zd1201_get_range(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *wrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_point *wrq = &wrqu->data;
struct iw_range *range = (struct iw_range *)extra;

wrq->length = sizeof(struct iw_range);
@@ -1077,8 +1082,9 @@ static int zd1201_get_range(struct net_device *dev,
* the stats after asking the bssid.
*/
static int zd1201_get_wap(struct net_device *dev,
- struct iw_request_info *info, struct sockaddr *ap_addr, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct sockaddr *ap_addr = &wrqu->ap_addr;
struct zd1201 *zd = netdev_priv(dev);
unsigned char buffer[6];

@@ -1098,15 +1104,16 @@ static int zd1201_get_wap(struct net_device *dev,
}

static int zd1201_set_scan(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *srq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
/* We do everything in get_scan */
return 0;
}

static int zd1201_get_scan(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *srq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_point *srq = &wrqu->data;
struct zd1201 *zd = netdev_priv(dev);
int err, i, j, enabled_save;
struct iw_event iwe;
@@ -1197,8 +1204,9 @@ static int zd1201_get_scan(struct net_device *dev,
}

static int zd1201_set_essid(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *data, char *essid)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *essid)
{
+ struct iw_point *data = &wrqu->data;
struct zd1201 *zd = netdev_priv(dev);

if (data->length > IW_ESSID_MAX_SIZE)
@@ -1212,8 +1220,9 @@ static int zd1201_set_essid(struct net_device *dev,
}

static int zd1201_get_essid(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *data, char *essid)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *essid)
{
+ struct iw_point *data = &wrqu->data;
struct zd1201 *zd = netdev_priv(dev);

memcpy(essid, zd->essid, zd->essidlen);
@@ -1224,8 +1233,9 @@ static int zd1201_get_essid(struct net_device *dev,
}

static int zd1201_get_nick(struct net_device *dev, struct iw_request_info *info,
- struct iw_point *data, char *nick)
+ union iwreq_data *wrqu, char *nick)
{
+ struct iw_point *data = &wrqu->data;
strcpy(nick, "zd1201");
data->flags = 1;
data->length = strlen(nick);
@@ -1233,8 +1243,9 @@ static int zd1201_get_nick(struct net_device *dev, struct iw_request_info *info,
}

static int zd1201_set_rate(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->bitrate;
struct zd1201 *zd = netdev_priv(dev);
short rate;
int err;
@@ -1266,8 +1277,9 @@ static int zd1201_set_rate(struct net_device *dev,
}

static int zd1201_get_rate(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->bitrate;
struct zd1201 *zd = netdev_priv(dev);
short rate;
int err;
@@ -1299,8 +1311,9 @@ static int zd1201_get_rate(struct net_device *dev,
}

static int zd1201_set_rts(struct net_device *dev, struct iw_request_info *info,
- struct iw_param *rts, char *extra)
+ union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rts = &wrqu->rts;
struct zd1201 *zd = netdev_priv(dev);
int err;
short val = rts->value;
@@ -1319,8 +1332,9 @@ static int zd1201_set_rts(struct net_device *dev, struct iw_request_info *info,
}

static int zd1201_get_rts(struct net_device *dev, struct iw_request_info *info,
- struct iw_param *rts, char *extra)
+ union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rts = &wrqu->rts;
struct zd1201 *zd = netdev_priv(dev);
short rtst;
int err;
@@ -1336,8 +1350,9 @@ static int zd1201_get_rts(struct net_device *dev, struct iw_request_info *info,
}

static int zd1201_set_frag(struct net_device *dev, struct iw_request_info *info,
- struct iw_param *frag, char *extra)
+ union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *frag = &wrqu->frag;
struct zd1201 *zd = netdev_priv(dev);
int err;
short val = frag->value;
@@ -1357,8 +1372,9 @@ static int zd1201_set_frag(struct net_device *dev, struct iw_request_info *info,
}

static int zd1201_get_frag(struct net_device *dev, struct iw_request_info *info,
- struct iw_param *frag, char *extra)
+ union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *frag = &wrqu->frag;
struct zd1201 *zd = netdev_priv(dev);
short fragt;
int err;
@@ -1374,20 +1390,21 @@ static int zd1201_get_frag(struct net_device *dev, struct iw_request_info *info,
}

static int zd1201_set_retry(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
return 0;
}

static int zd1201_get_retry(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
return 0;
}

static int zd1201_set_encode(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *erq, char *key)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *key)
{
+ struct iw_point *erq = &wrqu->encoding;
struct zd1201 *zd = netdev_priv(dev);
short i;
int err, rid;
@@ -1443,8 +1460,9 @@ static int zd1201_set_encode(struct net_device *dev,
}

static int zd1201_get_encode(struct net_device *dev,
- struct iw_request_info *info, struct iw_point *erq, char *key)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *key)
{
+ struct iw_point *erq = &wrqu->encoding;
struct zd1201 *zd = netdev_priv(dev);
short i;
int err;
@@ -1476,8 +1494,9 @@ static int zd1201_get_encode(struct net_device *dev,
}

static int zd1201_set_power(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *vwrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *vwrq = &wrqu->power;
struct zd1201 *zd = netdev_priv(dev);
short enabled, duration, level;
int err;
@@ -1515,8 +1534,9 @@ static int zd1201_set_power(struct net_device *dev,
}

static int zd1201_get_power(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *vwrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *vwrq = &wrqu->power;
struct zd1201 *zd = netdev_priv(dev);
short enabled, level, duration;
int err;
@@ -1553,57 +1573,37 @@ static int zd1201_get_power(struct net_device *dev,

static const iw_handler zd1201_iw_handler[] =
{
- (iw_handler) zd1201_config_commit, /* SIOCSIWCOMMIT */
- (iw_handler) zd1201_get_name, /* SIOCGIWNAME */
- (iw_handler) NULL, /* SIOCSIWNWID */
- (iw_handler) NULL, /* SIOCGIWNWID */
- (iw_handler) zd1201_set_freq, /* SIOCSIWFREQ */
- (iw_handler) zd1201_get_freq, /* SIOCGIWFREQ */
- (iw_handler) zd1201_set_mode, /* SIOCSIWMODE */
- (iw_handler) zd1201_get_mode, /* SIOCGIWMODE */
- (iw_handler) NULL, /* SIOCSIWSENS */
- (iw_handler) NULL, /* SIOCGIWSENS */
- (iw_handler) NULL, /* SIOCSIWRANGE */
- (iw_handler) zd1201_get_range, /* SIOCGIWRANGE */
- (iw_handler) NULL, /* SIOCSIWPRIV */
- (iw_handler) NULL, /* SIOCGIWPRIV */
- (iw_handler) NULL, /* SIOCSIWSTATS */
- (iw_handler) NULL, /* SIOCGIWSTATS */
- (iw_handler) NULL, /* SIOCSIWSPY */
- (iw_handler) NULL, /* SIOCGIWSPY */
- (iw_handler) NULL, /* -- hole -- */
- (iw_handler) NULL, /* -- hole -- */
- (iw_handler) NULL/*zd1201_set_wap*/, /* SIOCSIWAP */
- (iw_handler) zd1201_get_wap, /* SIOCGIWAP */
- (iw_handler) NULL, /* -- hole -- */
- (iw_handler) NULL, /* SIOCGIWAPLIST */
- (iw_handler) zd1201_set_scan, /* SIOCSIWSCAN */
- (iw_handler) zd1201_get_scan, /* SIOCGIWSCAN */
- (iw_handler) zd1201_set_essid, /* SIOCSIWESSID */
- (iw_handler) zd1201_get_essid, /* SIOCGIWESSID */
- (iw_handler) NULL, /* SIOCSIWNICKN */
- (iw_handler) zd1201_get_nick, /* SIOCGIWNICKN */
- (iw_handler) NULL, /* -- hole -- */
- (iw_handler) NULL, /* -- hole -- */
- (iw_handler) zd1201_set_rate, /* SIOCSIWRATE */
- (iw_handler) zd1201_get_rate, /* SIOCGIWRATE */
- (iw_handler) zd1201_set_rts, /* SIOCSIWRTS */
- (iw_handler) zd1201_get_rts, /* SIOCGIWRTS */
- (iw_handler) zd1201_set_frag, /* SIOCSIWFRAG */
- (iw_handler) zd1201_get_frag, /* SIOCGIWFRAG */
- (iw_handler) NULL, /* SIOCSIWTXPOW */
- (iw_handler) NULL, /* SIOCGIWTXPOW */
- (iw_handler) zd1201_set_retry, /* SIOCSIWRETRY */
- (iw_handler) zd1201_get_retry, /* SIOCGIWRETRY */
- (iw_handler) zd1201_set_encode, /* SIOCSIWENCODE */
- (iw_handler) zd1201_get_encode, /* SIOCGIWENCODE */
- (iw_handler) zd1201_set_power, /* SIOCSIWPOWER */
- (iw_handler) zd1201_get_power, /* SIOCGIWPOWER */
+ IW_HANDLER(SIOCSIWCOMMIT, zd1201_config_commit),
+ IW_HANDLER(SIOCGIWNAME, zd1201_get_name),
+ IW_HANDLER(SIOCSIWFREQ, zd1201_set_freq),
+ IW_HANDLER(SIOCGIWFREQ, zd1201_get_freq),
+ IW_HANDLER(SIOCSIWMODE, zd1201_set_mode),
+ IW_HANDLER(SIOCGIWMODE, zd1201_get_mode),
+ IW_HANDLER(SIOCGIWRANGE, zd1201_get_range),
+ IW_HANDLER(SIOCGIWAP, zd1201_get_wap),
+ IW_HANDLER(SIOCSIWSCAN, zd1201_set_scan),
+ IW_HANDLER(SIOCGIWSCAN, zd1201_get_scan),
+ IW_HANDLER(SIOCSIWESSID, zd1201_set_essid),
+ IW_HANDLER(SIOCGIWESSID, zd1201_get_essid),
+ IW_HANDLER(SIOCGIWNICKN, zd1201_get_nick),
+ IW_HANDLER(SIOCSIWRATE, zd1201_set_rate),
+ IW_HANDLER(SIOCGIWRATE, zd1201_get_rate),
+ IW_HANDLER(SIOCSIWRTS, zd1201_set_rts),
+ IW_HANDLER(SIOCGIWRTS, zd1201_get_rts),
+ IW_HANDLER(SIOCSIWFRAG, zd1201_set_frag),
+ IW_HANDLER(SIOCGIWFRAG, zd1201_get_frag),
+ IW_HANDLER(SIOCSIWRETRY, zd1201_set_retry),
+ IW_HANDLER(SIOCGIWRETRY, zd1201_get_retry),
+ IW_HANDLER(SIOCSIWENCODE, zd1201_set_encode),
+ IW_HANDLER(SIOCGIWENCODE, zd1201_get_encode),
+ IW_HANDLER(SIOCSIWPOWER, zd1201_set_power),
+ IW_HANDLER(SIOCGIWPOWER, zd1201_get_power),
};

static int zd1201_set_hostauth(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->param;
struct zd1201 *zd = netdev_priv(dev);

if (!zd->ap)
@@ -1613,8 +1613,9 @@ static int zd1201_set_hostauth(struct net_device *dev,
}

static int zd1201_get_hostauth(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->param;
struct zd1201 *zd = netdev_priv(dev);
short hostauth;
int err;
@@ -1632,8 +1633,9 @@ static int zd1201_get_hostauth(struct net_device *dev,
}

static int zd1201_auth_sta(struct net_device *dev,
- struct iw_request_info *info, struct sockaddr *sta, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct sockaddr *sta = &wrqu->ap_addr;
struct zd1201 *zd = netdev_priv(dev);
unsigned char buffer[10];

@@ -1648,8 +1650,9 @@ static int zd1201_auth_sta(struct net_device *dev,
}

static int zd1201_set_maxassoc(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->param;
struct zd1201 *zd = netdev_priv(dev);

if (!zd->ap)
@@ -1659,8 +1662,9 @@ static int zd1201_set_maxassoc(struct net_device *dev,
}

static int zd1201_get_maxassoc(struct net_device *dev,
- struct iw_request_info *info, struct iw_param *rrq, char *extra)
+ struct iw_request_info *info, union iwreq_data *wrqu, char *extra)
{
+ struct iw_param *rrq = &wrqu->param;
struct zd1201 *zd = netdev_priv(dev);
short maxassoc;
int err;
@@ -1703,8 +1707,8 @@ static const struct iw_handler_def zd1201_iw_handlers = {
.num_standard = ARRAY_SIZE(zd1201_iw_handler),
.num_private = ARRAY_SIZE(zd1201_private_handler),
.num_private_args = ARRAY_SIZE(zd1201_private_args),
- .standard = (iw_handler *)zd1201_iw_handler,
- .private = (iw_handler *)zd1201_private_handler,
+ .standard = zd1201_iw_handler,
+ .private = zd1201_private_handler,
.private_args = (struct iw_priv_args *) zd1201_private_args,
.get_wireless_stats = zd1201_get_wireless_stats,
};
--
2.34.1