Re: [PATCH] net/xfrm/xfrm_replay: avoid division by zero

From: Steffen Klassert
Date: Fri Jan 18 2013 - 03:57:12 EST


On Thu, Jan 17, 2013 at 01:58:28PM -0500, Nickolai Zeldovich wrote:
> All of the xfrm_replay->advance functions in xfrm_replay.c check if
> x->replay_esn->replay_window is zero (and return if so). However,
> one of them, xfrm_replay_advance_bmp(), divides by that value (in the
> '%' operator) before doing the check, which can potentially trigger
> a divide-by-zero exception. Some compilers will also assume that the
> earlier division means the value cannot be zero later, and thus will
> eliminate the subsequent zero check as dead code.
>
> This patch moves the division to after the check.
>
> Signed-off-by: Nickolai Zeldovich <nickolai@xxxxxxxxxxxxx>

Applied, thanks!
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