memory tagging should be a game changer for C and C++; get with the program, @intel and @apple!!pic.twitter.com/z2vXAtTb7z
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Then UAF becomes exploitable again. This shows the weakness of 4-bit tag: doesn’t take many allocations to get a collision.
How about rv128 with 80 bit tags? 
Clearly the answer is to store pointers in the x87 floating point registers and put the tag in the top 16 bits
Or just get lucky. A drive-by exploit that "only" takes over 1 in 16 devices is pretty bad.
Well, presumably the allocator makes sure that new allocations don’t have the same tag as the old one, so you’d need at least two free->realloc->realloc cycles, but yeah.
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