Re: [PATCH v3 2/3] treewide: use get_random_u32_{above,below}() instead of manual loop

From: Kees Cook
Date: Thu Nov 17 2022 - 17:00:11 EST


On Thu, Nov 17, 2022 at 09:29:05PM +0100, Jason A. Donenfeld wrote:
> These cases were done with this Coccinelle:
>
> @@
> expression E;
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (I > E);
> + I = get_random_u32_below(E + 1);
>
> @@
> expression E;
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (I >= E);
> + I = get_random_u32_below(E);
>
> @@
> expression E;
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (I < E);
> + I = get_random_u32_above(E - 1);
>
> @@
> expression E;
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (I <= E);
> + I = get_random_u32_above(E);
>
> @@
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (!I);
> + I = get_random_u32_above(0);
>
> @@
> identifier I;
> @@
> - do {
> ... when != I
> - I = get_random_u32();
> ... when != I
> - } while (I == 0);
> + I = get_random_u32_above(0);
>
> @@
> expression E;
> @@
> - E + 1 + get_random_u32_below(U32_MAX - E)
> + get_random_u32_above(E)
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook