Re: CVE-2014-9900 fix is not upstream

[Johannes Berg]

> If we want to go down this route, probably the only option is to add
> __attribute__((pack)) those structs to just have no padding at all,
> thus breaking uapi.
> 

We could also spell out the padding bytes as reserved, i.e. instead of

struct ethtool_wolinfo {
ÂÂÂÂÂÂÂÂ__u32ÂÂÂcmd;
ÂÂÂÂÂÂÂÂ__u32ÂÂÂsupported;
ÂÂÂÂÂÂÂÂ__u32ÂÂÂwolopts;
ÂÂÂÂÂÂÂÂ__u8ÂÂÂÂsopass[SOPASS_MAX];ÂÂÂÂÂ// 6, actually
};

we could do

struct ethtool_wolinfo {
ÂÂÂÂÂÂÂÂ__u32ÂÂÂcmd;
ÂÂÂÂÂÂÂÂ__u32ÂÂÂsupported;
ÂÂÂÂÂÂÂÂ__u32ÂÂÂwolopts;
ÂÂÂÂÂÂÂÂ__u8ÂÂÂÂsopass[SOPASS_MAX];ÂÂÂÂÂ// 6, actually
	__u8	reserved[2];
};

and then the compiler has to properly treat it, since it's no longer
unnamed padding.

Maybe somebody can come up with a smart BUILD_BUG_ON() to ensure such
structs have no padding.

That would allow us to keep the C99 initializers (which is nice) and
not have to worry about this.

johannes