wifi: atmel: Avoid clashing function prototypes

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].

Of the 1549 warnings found, 188 come from the atmel driver. For example:

drivers/net/wireless/atmel/atmel.c:2518:2: warning: cast from 'int (*)(struct net_device *, struct iw_request_info *, void *, 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) atmel_config_commit,       /* SIOCSIWCOMMIT */
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The atmel 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.

This patch is a cleanup based on Brad Spengler/PaX Team's modifications
to the atmel driver in their last public patch of grsecurity/PaX based
on my understanding of the code. Changes or omissions from the original
code are mine and don't reflect the original grsecurity/PaX code.

[1] https://reviews.llvm.org/D134831

Cc: Simon Kelley <simon@thekelleys.org.uk>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221002032428.4091540-1-keescook@chromium.org

diff --git a/drivers/net/wireless/atmel/atmel.c b/drivers/net/wireless/atmel/atmel.c
index 45d079b..ed430b9 100644 (file)
--- a/drivers/net/wireless/atmel/atmel.c
+++ b/drivers/net/wireless/atmel/atmel.c
@@ -1643,9 +1643,10 @@ EXPORT_SYMBOL(stop_atmel_card);
 
 static int atmel_set_essid(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_point *dwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_point *dwrq = &wrqu->essid;
        struct atmel_private *priv = netdev_priv(dev);
 
        /* Check if we asked for `any' */
@@ -1671,9 +1672,10 @@ static int atmel_set_essid(struct net_device *dev,
 
 static int atmel_get_essid(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_point *dwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_point *dwrq = &wrqu->essid;
        struct atmel_private *priv = netdev_priv(dev);
 
        /* Get the current SSID */
@@ -1692,9 +1694,10 @@ static int atmel_get_essid(struct net_device *dev,
 
 static int atmel_get_wap(struct net_device *dev,
                         struct iw_request_info *info,
-                        struct sockaddr *awrq,
+                        union iwreq_data *wrqu,
                         char *extra)
 {
+       struct sockaddr *awrq = &wrqu->ap_addr;
        struct atmel_private *priv = netdev_priv(dev);
        memcpy(awrq->sa_data, priv->CurrentBSSID, ETH_ALEN);
        awrq->sa_family = ARPHRD_ETHER;
@@ -1704,9 +1707,10 @@ static int atmel_get_wap(struct net_device *dev,
 
 static int atmel_set_encode(struct net_device *dev,
                            struct iw_request_info *info,
-                           struct iw_point *dwrq,
+                           union iwreq_data *wrqu,
                            char *extra)
 {
+       struct iw_point *dwrq = &wrqu->encoding;
        struct atmel_private *priv = netdev_priv(dev);
 
        /* Basic checking: do we have a key to set ?
@@ -1793,9 +1797,10 @@ static int atmel_set_encode(struct net_device *dev,
 
 static int atmel_get_encode(struct net_device *dev,
                            struct iw_request_info *info,
-                           struct iw_point *dwrq,
+                           union iwreq_data *wrqu,
                            char *extra)
 {
+       struct iw_point *dwrq = &wrqu->encoding;
        struct atmel_private *priv = netdev_priv(dev);
        int index = (dwrq->flags & IW_ENCODE_INDEX) - 1;
 
@@ -2003,18 +2008,19 @@ static int atmel_get_auth(struct net_device *dev,
 
 static int atmel_get_name(struct net_device *dev,
                          struct iw_request_info *info,
-                         char *cwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
-       strcpy(cwrq, "IEEE 802.11-DS");
+       strcpy(wrqu->name, "IEEE 802.11-DS");
        return 0;
 }
 
 static int atmel_set_rate(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_param *vwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_param *vwrq = &wrqu->bitrate;
        struct atmel_private *priv = netdev_priv(dev);
 
        if (vwrq->fixed == 0) {
@@ -2053,9 +2059,10 @@ static int atmel_set_rate(struct net_device *dev,
 
 static int atmel_set_mode(struct net_device *dev,
                          struct iw_request_info *info,
-                         __u32 *uwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       __u32 *uwrq = &wrqu->mode;
        struct atmel_private *priv = netdev_priv(dev);
 
        if (*uwrq != IW_MODE_ADHOC && *uwrq != IW_MODE_INFRA)
@@ -2067,9 +2074,10 @@ static int atmel_set_mode(struct net_device *dev,
 
 static int atmel_get_mode(struct net_device *dev,
                          struct iw_request_info *info,
-                         __u32 *uwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       __u32 *uwrq = &wrqu->mode;
        struct atmel_private *priv = netdev_priv(dev);
 
        *uwrq = priv->operating_mode;
@@ -2078,9 +2086,10 @@ static int atmel_get_mode(struct net_device *dev,
 
 static int atmel_get_rate(struct net_device *dev,
                         struct iw_request_info *info,
-                        struct iw_param *vwrq,
+                        union iwreq_data *wrqu,
                         char *extra)
 {
+       struct iw_param *vwrq = &wrqu->bitrate;
        struct atmel_private *priv = netdev_priv(dev);
 
        if (priv->auto_tx_rate) {
@@ -2108,9 +2117,10 @@ static int atmel_get_rate(struct net_device *dev,
 
 static int atmel_set_power(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_param *vwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_param *vwrq = &wrqu->power;
        struct atmel_private *priv = netdev_priv(dev);
        priv->power_mode = vwrq->disabled ? 0 : 1;
        return -EINPROGRESS;
@@ -2118,9 +2128,10 @@ static int atmel_set_power(struct net_device *dev,
 
 static int atmel_get_power(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_param *vwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_param *vwrq = &wrqu->power;
        struct atmel_private *priv = netdev_priv(dev);
        vwrq->disabled = priv->power_mode ? 0 : 1;
        vwrq->flags = IW_POWER_ON;
@@ -2129,9 +2140,10 @@ static int atmel_get_power(struct net_device *dev,
 
 static int atmel_set_retry(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_param *vwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_param *vwrq = &wrqu->retry;
        struct atmel_private *priv = netdev_priv(dev);
 
        if (!vwrq->disabled && (vwrq->flags & IW_RETRY_LIMIT)) {
@@ -2152,9 +2164,10 @@ static int atmel_set_retry(struct net_device *dev,
 
 static int atmel_get_retry(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_param *vwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_param *vwrq = &wrqu->retry;
        struct atmel_private *priv = netdev_priv(dev);
 
        vwrq->disabled = 0;      /* Can't be disabled */
@@ -2175,9 +2188,10 @@ static int atmel_get_retry(struct net_device *dev,
 
 static int atmel_set_rts(struct net_device *dev,
                         struct iw_request_info *info,
-                        struct iw_param *vwrq,
+                        union iwreq_data *wrqu,
                         char *extra)
 {
+       struct iw_param *vwrq = &wrqu->rts;
        struct atmel_private *priv = netdev_priv(dev);
        int rthr = vwrq->value;
 
@@ -2193,9 +2207,10 @@ static int atmel_set_rts(struct net_device *dev,
 
 static int atmel_get_rts(struct net_device *dev,
                         struct iw_request_info *info,
-                        struct iw_param *vwrq,
+                        union iwreq_data *wrqu,
                         char *extra)
 {
+       struct iw_param *vwrq = &wrqu->rts;
        struct atmel_private *priv = netdev_priv(dev);
 
        vwrq->value = priv->rts_threshold;
@@ -2207,9 +2222,10 @@ static int atmel_get_rts(struct net_device *dev,
 
 static int atmel_set_frag(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_param *vwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_param *vwrq = &wrqu->frag;
        struct atmel_private *priv = netdev_priv(dev);
        int fthr = vwrq->value;
 
@@ -2226,9 +2242,10 @@ static int atmel_set_frag(struct net_device *dev,
 
 static int atmel_get_frag(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_param *vwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_param *vwrq = &wrqu->frag;
        struct atmel_private *priv = netdev_priv(dev);
 
        vwrq->value = priv->frag_threshold;
@@ -2240,9 +2257,10 @@ static int atmel_get_frag(struct net_device *dev,
 
 static int atmel_set_freq(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_freq *fwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_freq *fwrq = &wrqu->freq;
        struct atmel_private *priv = netdev_priv(dev);
        int rc = -EINPROGRESS;          /* Call commit handler */
 
@@ -2270,9 +2288,10 @@ static int atmel_set_freq(struct net_device *dev,
 
 static int atmel_get_freq(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_freq *fwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_freq *fwrq = &wrqu->freq;
        struct atmel_private *priv = netdev_priv(dev);
 
        fwrq->m = priv->channel;
@@ -2282,7 +2301,7 @@ static int atmel_get_freq(struct net_device *dev,
 
 static int atmel_set_scan(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_point *dwrq,
+                         union iwreq_data *dwrq,
                          char *extra)
 {
        struct atmel_private *priv = netdev_priv(dev);
@@ -2320,9 +2339,10 @@ static int atmel_set_scan(struct net_device *dev,
 
 static int atmel_get_scan(struct net_device *dev,
                          struct iw_request_info *info,
-                         struct iw_point *dwrq,
+                         union iwreq_data *wrqu,
                          char *extra)
 {
+       struct iw_point *dwrq = &wrqu->data;
        struct atmel_private *priv = netdev_priv(dev);
        int i;
        char *current_ev = extra;
@@ -2391,9 +2411,10 @@ static int atmel_get_scan(struct net_device *dev,
 
 static int atmel_get_range(struct net_device *dev,
                           struct iw_request_info *info,
-                          struct iw_point *dwrq,
+                          union iwreq_data *wrqu,
                           char *extra)
 {
+       struct iw_point *dwrq = &wrqu->data;
        struct atmel_private *priv = netdev_priv(dev);
        struct iw_range *range = (struct iw_range *) extra;
        int k, i, j;
@@ -2465,9 +2486,10 @@ static int atmel_get_range(struct net_device *dev,
 
 static int atmel_set_wap(struct net_device *dev,
                         struct iw_request_info *info,
-                        struct sockaddr *awrq,
+                        union iwreq_data *wrqu,
                         char *extra)
 {
+       struct sockaddr *awrq = &wrqu->ap_addr;
        struct atmel_private *priv = netdev_priv(dev);
        int i;
        static const u8 any[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
@@ -2507,7 +2529,7 @@ static int atmel_set_wap(struct net_device *dev,
 
 static int atmel_config_commit(struct net_device *dev,
                               struct iw_request_info *info,    /* NULL */
-                              void *zwrq,                      /* NULL */
+                              union iwreq_data *zwrq,          /* NULL */
                               char *extra)                     /* NULL */
 {
        return atmel_open(dev);
@@ -2515,66 +2537,40 @@ static int atmel_config_commit(struct net_device *dev,
 
 static const iw_handler atmel_handler[] =
 {
-       (iw_handler) atmel_config_commit,       /* SIOCSIWCOMMIT */
-       (iw_handler) atmel_get_name,            /* SIOCGIWNAME */
-       (iw_handler) NULL,                      /* SIOCSIWNWID */
-       (iw_handler) NULL,                      /* SIOCGIWNWID */
-       (iw_handler) atmel_set_freq,            /* SIOCSIWFREQ */
-       (iw_handler) atmel_get_freq,            /* SIOCGIWFREQ */
-       (iw_handler) atmel_set_mode,            /* SIOCSIWMODE */
-       (iw_handler) atmel_get_mode,            /* SIOCGIWMODE */
-       (iw_handler) NULL,                      /* SIOCSIWSENS */
-       (iw_handler) NULL,                      /* SIOCGIWSENS */
-       (iw_handler) NULL,                      /* SIOCSIWRANGE */
-       (iw_handler) atmel_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) atmel_set_wap,             /* SIOCSIWAP */
-       (iw_handler) atmel_get_wap,             /* SIOCGIWAP */
-       (iw_handler) NULL,                      /* -- hole -- */
-       (iw_handler) NULL,                      /* SIOCGIWAPLIST */
-       (iw_handler) atmel_set_scan,            /* SIOCSIWSCAN */
-       (iw_handler) atmel_get_scan,            /* SIOCGIWSCAN */
-       (iw_handler) atmel_set_essid,           /* SIOCSIWESSID */
-       (iw_handler) atmel_get_essid,           /* SIOCGIWESSID */
-       (iw_handler) NULL,                      /* SIOCSIWNICKN */
-       (iw_handler) NULL,                      /* SIOCGIWNICKN */
-       (iw_handler) NULL,                      /* -- hole -- */
-       (iw_handler) NULL,                      /* -- hole -- */
-       (iw_handler) atmel_set_rate,            /* SIOCSIWRATE */
-       (iw_handler) atmel_get_rate,            /* SIOCGIWRATE */
-       (iw_handler) atmel_set_rts,             /* SIOCSIWRTS */
-       (iw_handler) atmel_get_rts,             /* SIOCGIWRTS */
-       (iw_handler) atmel_set_frag,            /* SIOCSIWFRAG */
-       (iw_handler) atmel_get_frag,            /* SIOCGIWFRAG */
-       (iw_handler) NULL,                      /* SIOCSIWTXPOW */
-       (iw_handler) NULL,                      /* SIOCGIWTXPOW */
-       (iw_handler) atmel_set_retry,           /* SIOCSIWRETRY */
-       (iw_handler) atmel_get_retry,           /* SIOCGIWRETRY */
-       (iw_handler) atmel_set_encode,          /* SIOCSIWENCODE */
-       (iw_handler) atmel_get_encode,          /* SIOCGIWENCODE */
-       (iw_handler) atmel_set_power,           /* SIOCSIWPOWER */
-       (iw_handler) atmel_get_power,           /* SIOCGIWPOWER */
-       (iw_handler) NULL,                      /* -- hole -- */
-       (iw_handler) NULL,                      /* -- hole -- */
-       (iw_handler) NULL,                      /* SIOCSIWGENIE */
-       (iw_handler) NULL,                      /* SIOCGIWGENIE */
-       (iw_handler) atmel_set_auth,            /* SIOCSIWAUTH */
-       (iw_handler) atmel_get_auth,            /* SIOCGIWAUTH */
-       (iw_handler) atmel_set_encodeext,       /* SIOCSIWENCODEEXT */
-       (iw_handler) atmel_get_encodeext,       /* SIOCGIWENCODEEXT */
-       (iw_handler) NULL,                      /* SIOCSIWPMKSA */
+       IW_HANDLER(SIOCSIWCOMMIT,       atmel_config_commit),
+       IW_HANDLER(SIOCGIWNAME,         atmel_get_name),
+       IW_HANDLER(SIOCSIWFREQ,         atmel_set_freq),
+       IW_HANDLER(SIOCGIWFREQ,         atmel_get_freq),
+       IW_HANDLER(SIOCSIWMODE,         atmel_set_mode),
+       IW_HANDLER(SIOCGIWMODE,         atmel_get_mode),
+       IW_HANDLER(SIOCGIWRANGE,        atmel_get_range),
+       IW_HANDLER(SIOCSIWAP,           atmel_set_wap),
+       IW_HANDLER(SIOCGIWAP,           atmel_get_wap),
+       IW_HANDLER(SIOCSIWSCAN,         atmel_set_scan),
+       IW_HANDLER(SIOCGIWSCAN,         atmel_get_scan),
+       IW_HANDLER(SIOCSIWESSID,        atmel_set_essid),
+       IW_HANDLER(SIOCGIWESSID,        atmel_get_essid),
+       IW_HANDLER(SIOCSIWRATE,         atmel_set_rate),
+       IW_HANDLER(SIOCGIWRATE,         atmel_get_rate),
+       IW_HANDLER(SIOCSIWRTS,          atmel_set_rts),
+       IW_HANDLER(SIOCGIWRTS,          atmel_get_rts),
+       IW_HANDLER(SIOCSIWFRAG,         atmel_set_frag),
+       IW_HANDLER(SIOCGIWFRAG,         atmel_get_frag),
+       IW_HANDLER(SIOCSIWRETRY,        atmel_set_retry),
+       IW_HANDLER(SIOCGIWRETRY,        atmel_get_retry),
+       IW_HANDLER(SIOCSIWENCODE,       atmel_set_encode),
+       IW_HANDLER(SIOCGIWENCODE,       atmel_get_encode),
+       IW_HANDLER(SIOCSIWPOWER,        atmel_set_power),
+       IW_HANDLER(SIOCGIWPOWER,        atmel_get_power),
+       IW_HANDLER(SIOCSIWAUTH,         atmel_set_auth),
+       IW_HANDLER(SIOCGIWAUTH,         atmel_get_auth),
+       IW_HANDLER(SIOCSIWENCODEEXT,    atmel_set_encodeext),
+       IW_HANDLER(SIOCGIWENCODEEXT,    atmel_get_encodeext),
 };
 
 static const iw_handler atmel_private_handler[] =
 {
-       NULL,                           /* SIOCIWFIRSTPRIV */
+       IW_HANDLER(SIOCIWFIRSTPRIV,     NULL),
 };
 
 struct atmel_priv_ioctl {
@@ -2614,8 +2610,8 @@ static const struct iw_handler_def atmel_handler_def = {
        .num_standard   = ARRAY_SIZE(atmel_handler),
        .num_private    = ARRAY_SIZE(atmel_private_handler),
        .num_private_args = ARRAY_SIZE(atmel_private_args),
-       .standard       = (iw_handler *) atmel_handler,
-       .private        = (iw_handler *) atmel_private_handler,
+       .standard       = atmel_handler,
+       .private        = atmel_private_handler,
        .private_args   = (struct iw_priv_args *) atmel_private_args,
        .get_wireless_stats = atmel_get_wireless_stats
 };