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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Kees Cook <keescook@chromium.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Leon Romanovsky <leon@kernel.org>,
	Bart Van Assche <Bart.VanAssche@wdc.com>,
	Doug Ledford <dledford@redhat.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] test_overflow: Add shift overflow tests
Date: Tue, 31 Jul 2018 20:13:53 -0600	[thread overview]
Message-ID: <20180801021353.GA31192@ziepe.ca> (raw)
In-Reply-To: <20180801000039.44314-3-keescook@chromium.org>

On Tue, Jul 31, 2018 at 05:00:38PM -0700, Kees Cook wrote:
> +	/* Overflow: high bit falls off. */
> +	/* 10010110 */
> +	err |= TEST_ONE_SHIFT(150, 1, u8, 0, true);
> +	/* 1000100010010110 */
> +	err |= TEST_ONE_SHIFT(34966, 1, u16, 0, true);
> +	/* 10000100000010001000100010010110 */
> +	err |= TEST_ONE_SHIFT(2215151766U, 1, u32, 0, true);
> +	err |= TEST_ONE_SHIFT(2215151766U, 1, unsigned int, 0, true);
> +	/* 1000001000010000010000000100000010000100000010001000100010010110 */
> +	err |= TEST_ONE_SHIFT(9372061470395238550ULL, 1, u64, 0, true);

This same idea should be repeated with signed outputs and check both
overflow past the end (<<2) and overflow into the signed bit (<<1)

        /* Overflow, high bit falls into the sign bit or off the end */
	/* 01001011 */
	err |= TEST_ONE_SHIFT(75, 1, s8, 0, true);
	err |= TEST_ONE_SHIFT(75, 2, s8, 0, true);

And also general type mismatch overflow:

	err |= TEST_ONE_SHIFT(0x100, 0, u8, 0, true);
	err |= TEST_ONE_SHIFT(0xFF, 0, s8, 0, true);

Thanks,
Jason

  reply	other threads:[~2018-08-01  2:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-01  0:00 [PATCH v2 0/3] overflow.h: Add arithmetic shift helper Kees Cook
2018-08-01  0:00 ` [PATCH v2 1/3] " Kees Cook
2018-08-01  1:59   ` Randy Dunlap
2018-08-01  2:15   ` Jason Gunthorpe
2018-08-01  4:22     ` Kees Cook
2018-08-01  7:57   ` Dan Carpenter
2018-08-01  8:07     ` Dan Carpenter
2018-08-01 15:38       ` Kees Cook
2018-08-01 15:48       ` Jason Gunthorpe
2018-08-01  0:00 ` [PATCH v2 2/3] test_overflow: Add shift overflow tests Kees Cook
2018-08-01  2:13   ` Jason Gunthorpe [this message]
2018-08-01  5:51     ` Kees Cook
2018-08-01  0:00 ` [PATCH v2 3/3] RDMA/mlx5: Fix shift overflow in mlx5_ib_create_wq Kees Cook

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