On Mon, Oct 17, 2022 at 03:33:01PM -0500, Gustavo A. R. Silva wrote:
> 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 53 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,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thank you for working on these! Was this conversion done manually, via
coccinelle, or something else?
> The orinoco 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. No significant binary differences were seen
> before/after changes.
What does "significant" mean here? :P Anything related to line counts
can just be ignored. But I'd expect the .text output of
drivers/net/wireless/intersil/orinoco/wext.o before/after to be
identical.
> [...]
> IW_HANDLER(SIOCSIWRTS, (iw_handler)cfg80211_wext_siwrts),
^^^ I think these are fixed explicitly later, but maybe better to just
collapse them into this patch?
> [...]
> @@ -1391,15 +1406,15 @@ static const iw_handler orinoco_handler[] = {
> Added typecasting since we no longer use iwreq_data -- Moustafa
> */
> static const iw_handler orinoco_private_handler[] = {
> - [0] = (iw_handler)orinoco_ioctl_reset,
> - [1] = (iw_handler)orinoco_ioctl_reset,
> - [2] = (iw_handler)orinoco_ioctl_setport3,
> - [3] = (iw_handler)orinoco_ioctl_getport3,
> - [4] = (iw_handler)orinoco_ioctl_setpreamble,
> - [5] = (iw_handler)orinoco_ioctl_getpreamble,
> - [6] = (iw_handler)orinoco_ioctl_setibssport,
> - [7] = (iw_handler)orinoco_ioctl_getibssport,
> - [9] = (iw_handler)orinoco_ioctl_getrid,
> + [0] = orinoco_ioctl_reset,
> + [1] = orinoco_ioctl_reset,
> + [2] = orinoco_ioctl_setport3,
> + [3] = orinoco_ioctl_getport3,
> + [4] = orinoco_ioctl_setpreamble,
> + [5] = orinoco_ioctl_getpreamble,
> + [6] = orinoco_ioctl_setibssport,
> + [7] = orinoco_ioctl_getibssport,
> + [9] = orinoco_ioctl_getrid,
Oops, I broke atmel. These really are 0-indexed...
static const iw_handler atmel_private_handler[] =
{
- NULL, /* SIOCIWFIRSTPRIV */
+ IW_HANDLER(SIOCIWFIRSTPRIV, NULL),
};
I'll send a fix!
--
Kees Cook
