On: An Ancient Kernel Hole Is Not Closed

[lmm]

Only if it's accessed at least once in each page (4K), AIUI.

[radarsat1 → lmm]

Right. If I simply zero the memory with `memset` then I guess it should be ok.

[clarry → radarsat1]

Unless the compiler decides that zeroing the memory doesn't do anything useful and optimizes it out.

[astrange → clarry]

Initializing your stack buffer probably does count as something useful, but in case it doesn't, try memset_s(3).

[mnarayan01 → radarsat1]

No: See http://en.cppreference.com/w/c/string/byte/memset#Notes -- if you don't read from it, the call may be optimized away.

[dom0 → radarsat1]

Like my brethren say it's probably a good idea to use a "secure" memset that won't have an accident ^W ^W ^W be optimized out.

[loeg → dom0]

Or keep >4kB objects off stack.

[radarsat1 → loeg]

I mean, that's probably a good practice. In my case I sort of had this idea that largish objects should be placed on the heap but I couldn't really figure out a good reason why, or what the limit should be, so I guess this vuln proposes both a reason and that the page limit is a good threshold.