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From: Kees Cook <keescook@chromium.org>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Jason Gunthorpe" <jgg@nvidia.com>,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"Theodore Ts'o" <tytso@mit.edu>,
	"Andreas Dilger" <adilger.kernel@dilger.ca>,
	"Jaegeuk Kim" <jaegeuk@kernel.org>,
	"Richard Weinberger" <richard@nod.at>,
	"Darrick J . Wong" <djwong@kernel.org>,
	"SeongJae Park" <sj@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Helge Deller" <deller@gmx.de>,
	netdev@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-media@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
	linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-mmc@vger.kernel.org, linux-parisc@vger.kernel.org
Subject: Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible
Date: Wed, 16 Nov 2022 14:43:13 -0800	[thread overview]
Message-ID: <202211161436.A45AD719A@keescook> (raw)
In-Reply-To: <20221114164558.1180362-4-Jason@zx2c4.com>

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

WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: "Darrick J . Wong" <djwong@kernel.org>,
	patches@lists.linux.dev, netdev@vger.kernel.org,
	"Andreas Dilger" <adilger.kernel@dilger.ca>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Richard Weinberger" <richard@nod.at>,
	"Helge Deller" <deller@gmx.de>,
	"Russell King" <linux@armlinux.org.uk>,
	"Jason Gunthorpe" <jgg@nvidia.com>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	linux-mips@vger.kernel.org, linux-media@vger.kernel.org,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	linux-block@vger.kernel.org, "SeongJae Park" <sj@kernel.org>,
	loongarch@lists.linux.dev, "Jaegeuk Kim" <jaegeuk@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	linux-arm-kernel@lists.infradead.org,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	"Theodore Ts'o" <tytso@mit.edu>,
	linux-parisc@vger.kernel.org,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Chr istoph Böhmwalder" <christoph.boehmwalder@linbit.com>,
	linux-crypto@vger.kernel.org,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	linux-fsdevel@vger.kernel.org,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible
Date: Wed, 16 Nov 2022 14:43:13 -0800	[thread overview]
Message-ID: <202211161436.A45AD719A@keescook> (raw)
In-Reply-To: <20221114164558.1180362-4-Jason@zx2c4.com>

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

WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-kernel@vger.kernel.org, patches@lists.linux.dev,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Jason Gunthorpe" <jgg@nvidia.com>,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"Theodore Ts'o" <tytso@mit.edu>,
	"Andreas Dilger" <adilger.kernel@dilger.ca>,
	"Jaegeuk Kim" <jaegeuk@kernel.org>,
	"Richard Weinberger" <richard@nod.at>,
	"Darrick J . Wong" <djwong@kernel.org>,
	"SeongJae Park" <sj@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Helge Deller" <deller@gmx.de>,
	netdev@vger.kernel.org, linux-crypto@vger.kernel.org,
	linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-media@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
	linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-mmc@vger.kernel.org, linux-parisc@vger.kernel.org
Subject: Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible
Date: Wed, 16 Nov 2022 14:43:13 -0800	[thread overview]
Message-ID: <202211161436.A45AD719A@keescook> (raw)
In-Reply-To: <20221114164558.1180362-4-Jason@zx2c4.com>

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

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2022-11-16 22:43 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-14 16:45 [PATCH v2 0/3] convert tree to get_random_u32_{below,above,between}() Jason A. Donenfeld
2022-11-14 16:45 ` Jason A. Donenfeld
2022-11-14 16:45 ` Jason A. Donenfeld
2022-11-14 16:45 ` [PATCH v2 1/3] treewide: use get_random_u32_below() instead of deprecated function Jason A. Donenfeld
2022-11-14 16:45   ` Jason A. Donenfeld
2022-11-14 17:35   ` Russell King (Oracle)
2022-11-14 17:35     ` Russell King (Oracle)
2022-11-14 17:35     ` Russell King (Oracle)
2022-11-15  9:49   ` Ulf Hansson
2022-11-14 16:45 ` [PATCH v2 2/3] treewide: use get_random_u32_{above,below}() instead of manual loop Jason A. Donenfeld
2022-11-14 16:45   ` Jason A. Donenfeld
2022-11-14 16:45   ` Jason A. Donenfeld
2022-11-14 16:45 ` [PATCH v2 3/3] treewide: use get_random_u32_between() when possible Jason A. Donenfeld
2022-11-14 16:45   ` Jason A. Donenfeld
2022-11-14 16:45   ` Jason A. Donenfeld
2022-11-16 22:43   ` Kees Cook [this message]
2022-11-16 22:43     ` Kees Cook
2022-11-16 22:43     ` Kees Cook
2022-11-16 23:55     ` Jason A. Donenfeld
2022-11-16 23:55       ` Jason A. Donenfeld
2022-11-16 23:55       ` Jason A. Donenfeld
2022-11-17  0:03       ` Jason A. Donenfeld
2022-11-17  0:03         ` Jason A. Donenfeld
2022-11-17  0:03         ` Jason A. Donenfeld
2022-11-17  0:31         ` Kees Cook
2022-11-17  0:31           ` Kees Cook
2022-11-17  0:31           ` Kees Cook
2022-11-17  0:43           ` Jason A. Donenfeld
2022-11-17  0:43             ` Jason A. Donenfeld
2022-11-17  0:43             ` Jason A. Donenfeld
2022-11-17  0:47             ` Kees Cook
2022-11-17  0:47               ` Kees Cook
2022-11-17  0:47               ` Kees Cook
2022-11-17 15:42               ` Theodore Ts'o
2022-11-17 15:42                 ` Theodore Ts'o
2022-11-17 15:42                 ` Theodore Ts'o
2022-11-17 16:19                 ` Jason A. Donenfeld
2022-11-17 16:19                   ` Jason A. Donenfeld
2022-11-17 16:19                   ` Jason A. Donenfeld
2022-11-17 22:15                 ` David Laight
2022-11-17 22:15                   ` David Laight
2022-11-17 22:15                   ` David Laight
2022-11-17  2:05       ` Jason A. Donenfeld
2022-11-17  2:05         ` Jason A. Donenfeld
2022-11-17  2:05         ` Jason A. Donenfeld
2022-11-17 10:32         ` Russell King (Oracle)
2022-11-17 10:32           ` Russell King (Oracle)
2022-11-17 10:32           ` Russell King (Oracle)
2022-11-17 20:29 ` [PATCH v3 0/3] convert tree to get_random_u32_{below,above,inclusive}() Jason A. Donenfeld
2022-11-17 20:29   ` Jason A. Donenfeld
2022-11-17 20:29   ` Jason A. Donenfeld
2022-11-17 20:29   ` [PATCH v3 1/3] treewide: use get_random_u32_below() instead of deprecated function Jason A. Donenfeld
2022-11-17 20:29     ` Jason A. Donenfeld
2022-11-17 21:59     ` Kees Cook
2022-11-17 21:59       ` Kees Cook
2022-11-17 21:59       ` Kees Cook
2022-11-17 20:29   ` [PATCH v3 2/3] treewide: use get_random_u32_{above,below}() instead of manual loop Jason A. Donenfeld
2022-11-17 20:29     ` Jason A. Donenfeld
2022-11-17 20:29     ` Jason A. Donenfeld
2022-11-17 21:58     ` Kees Cook
2022-11-17 21:58       ` Kees Cook
2022-11-17 21:58       ` Kees Cook
2022-11-17 20:29   ` [PATCH v3 3/3] treewide: use get_random_u32_inclusive() when possible Jason A. Donenfeld
2022-11-17 20:29     ` Jason A. Donenfeld
2022-11-17 20:29     ` Jason A. Donenfeld
2022-11-17 21:57     ` Kees Cook
2022-11-17 21:57       ` Kees Cook
2022-11-17 21:57       ` Kees Cook
2022-11-17 22:10       ` Jason A. Donenfeld
2022-11-17 22:10         ` Jason A. Donenfeld
2022-11-17 22:10         ` Jason A. Donenfeld

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