Re: [PATCH v2] lib: gcd: prevent possible div by 0

From: Davidlohr Bueso
Date: Wed Sep 12 2012 - 15:05:07 EST


ping? Cc'ing Greg for stable.

On Mon, 2012-09-10 at 16:35 +0200, Davidlohr Bueso wrote:
> Account for all properties when a and/or b are 0:
> gcd(0, 0) = 0
> gcd(a, 0) = a
> gcd(0, b) = b
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Davidlohr Bueso <dave@xxxxxxx>
> ---
> V2: simplified checking with b = 0 (Eric)
>
> lib/gcd.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/lib/gcd.c b/lib/gcd.c
> index cce4f3c..3657f12 100644
> --- a/lib/gcd.c
> +++ b/lib/gcd.c
> @@ -9,6 +9,9 @@ unsigned long gcd(unsigned long a, unsigned long b)
>
> if (a < b)
> swap(a, b);
> +
> + if (!b)
> + return a;
> while ((r = a % b) != 0) {
> a = b;
> b = r;


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