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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id a9-20020a170902710900b00183c6784704sm12680746pll.291.2022.11.16.14.43.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Nov 2022 14:43:14 -0800 (PST) Date: Wed, 16 Nov 2022 14:43:13 -0800 From: Kees Cook To: "Jason A. Donenfeld" Subject: Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible Message-ID: <202211161436.A45AD719A@keescook> References: <20221114164558.1180362-1-Jason@zx2c4.com> <20221114164558.1180362-4-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221114164558.1180362-4-Jason@zx2c4.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Darrick J . Wong" , patches@lists.linux.dev, netdev@vger.kernel.org, Andreas Dilger , Herbert Xu , Richard Weinberger , Helge Deller , Russell King , Jason Gunthorpe , Catalin Marinas , Jakub Kicinski , linux-mips@vger.kernel.org, linux-media@vger.kernel.org, Heiko Carstens , Jani Nikula , linux-block@vger.kernel.org, SeongJae Park , loongarch@lists.linux.dev, Jaegeuk Kim , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Thomas Bogendoerfer , Theodore Ts'o , linux-parisc@vger.kernel.org, "Martin K . Petersen" , Greg Kroah-Hartman , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Chr istoph =?iso-8859-1?Q?B=F6hmwalder?= , linux-crypto@vger.kernel.org, Sakari Ailus , linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, Nov 14, 2022 at 05:45:58PM +0100, Jason A. Donenfeld wrote: > - (get_random_u32_below(1024) + 1) * PAGE_SIZE; > + get_random_u32_between(1, 1024 + 1) * PAGE_SIZE; I really don't like "between". Can't this be named "inclusive" (and avoid adding 1 everywhere, which seems ugly), or at least named something less ambiguous? > - n = get_random_u32_below(100) + 1; > + n = get_random_u32_between(1, 101); Because I find this much less readable. "Below 100" is clear: 0-99 inclusive, plus 1, so 1-100 inclusive. "Between 1 and 101" is not obvious to me to mean: 1-100 inclusive. These seem so much nicer: get_random_u32_inclusive(1, 1024) get_random_u32_inclusive(1, 100) -- Kees Cook