Re: drivers: random: Shift out-of-bounds in _mix_pool_bytes

[Theodore Ts'o]

On Mon, Oct 20, 2014 at 05:58:25PM +0400, Andrey Ryabinin wrote:
> It's triggering when input_rotate == 0, so UBSan complains about right shift in rol32()
> 
> static inline __u32 rol32(__u32 word, unsigned int shift)
> {
> 	return (word << shift) | (word >> (32 - shift));
> }

Ah, thanks; I don't know why I didn't see that.

So the only real question is whether we fix it in the call to rol32,
or in the rol32 function itself (i.e):

static inline __u32 rol32(__u32 word, unsigned int shift)
{
	return shift ? ((word << shift) | (word >> (32 - shift))) : word;
}

Dos that make sense to everyone?

						- Ted
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