From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bodo Stroesser <bostroesser@gmail.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>,
linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
jejb@linux.vnet.ibm.com, hare@suse.de, bvanassche@acm.org
Subject: Re: [PATCH 1/5] sgl_alloc_order: remove 4 GiB limit
Date: Mon, 24 Oct 2022 14:32:25 -0300 [thread overview]
Message-ID: <Y1bMKU5nq5DXYdbw@ziepe.ca> (raw)
In-Reply-To: <665f8dee-6688-60d1-5097-49f9726c38ec@gmail.com>
On Mon, Oct 24, 2022 at 04:32:30PM +0200, Bodo Stroesser wrote:
> > +struct scatterlist *sgl_alloc_order(size_t length, unsigned int order,
> > + bool chainable, gfp_t gfp, size_t *nent_p)
> > {
> > struct scatterlist *sgl, *sg;
> > struct page *page;
> > - unsigned int nent, nalloc;
> > + size_t nent, nalloc;
> > u32 elem_len;
> > - nent = round_up(length, PAGE_SIZE << order) >> (PAGE_SHIFT + order);
> > - /* Check for integer overflow */
> > - if (length > (nent << (PAGE_SHIFT + order)))
> > - return NULL;
> > + nent = length >> (PAGE_SHIFT + order);
> > + if (length % (1 << (PAGE_SHIFT + order)))
>
> This might end up doing a modulo operation for divisor 0, if caller
> specifies a too high order parameter, right?
If that happens then the first >> will be busted too and this is all
broken..
We assume the caller will pass a valid order paramter it seems, it is
not userspace controlled.
Jason
next prev parent reply other threads:[~2022-10-24 19:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-24 1:02 [PATCH 0/5] scatterlist: add operations for scsi_debug Douglas Gilbert
2022-10-24 1:02 ` [PATCH 1/5] sgl_alloc_order: remove 4 GiB limit Douglas Gilbert
2022-10-24 12:21 ` Jason Gunthorpe
2022-10-24 14:32 ` Bodo Stroesser
2022-10-24 17:32 ` Jason Gunthorpe [this message]
2022-10-24 19:58 ` Douglas Gilbert
2022-10-25 12:19 ` Jason Gunthorpe
2022-10-25 10:46 ` Bodo Stroesser
2022-10-25 12:18 ` Jason Gunthorpe
2022-10-24 1:02 ` [PATCH 2/5] scatterlist: add sgl_copy_sgl() function Douglas Gilbert
2022-10-24 1:02 ` [PATCH 3/5] scatterlist: add sgl_equal_sgl() function Douglas Gilbert
2022-10-24 1:02 ` [PATCH 4/5] scatterlist: add sgl_memset() Douglas Gilbert
2022-10-24 1:02 ` [PATCH 5/5] scsi_debug: change store from vmalloc to sgl Douglas Gilbert
2022-10-24 15:08 ` Bodo Stroesser
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