[U-Boot] [PATCH] Revert "part: Allocate only one legacy_mbr buffer"

[Faiz Abbas]

Hi Alexey,

On 04/09/19 3:42 PM, Alexey Brodkin wrote:
> Hi Faiz,
> 
>> -----Original Message-----
>> From: Faiz Abbas <faiz_abbas at ti.com>
>> Sent: Wednesday, September 4, 2019 12:22 PM
>> To: u-boot at lists.denx.de
>> Cc: paulemge at forallsecure.com; faiz_abbas at ti.com; Alexey Brodkin <abrodkin at synopsys.com>;
>> trini at konsulko.com
>> Subject: [PATCH] Revert "part: Allocate only one legacy_mbr buffer"
>>
>> This reverts commit 8639e34d2c5e12cc2e45c95b1a2e97c22bf6a711.
>>
>> The blk_dread() call following the allocation will read one block from
>> the device. This will lead to overflow if the blocksize is greater than
>> the size of legacy_mbr. Fix this by allocating one block size.
> 
> Did you read justification of my change that you're reverting now?
> With your change in place we'll allocate a buffer
> of size = (sizeof(legacy_mbr) * dev_desc->blksz).
> 
> Is that something you really want?

Oops. You're right. I thought your patch was changing buffer size from
blksz to legacy_mbr.

> 
> I guess what you really want to do is to allocate buffer for "mbr"
> dynamically of size which is max(sizeof(legacy_mbr), dev_desc->blksz).
>

With the assumption that blksz is always greater than
sizeof(legacy_mbr), this should work:

ALLOC_CACHE_ALIGN_BUFFER(legacy_mbr, mbr, DIV_ROUND_UP(dev_desc->blksz,
sizeof(legacy_mbr)));

Will send a proper fix.

Thanks,
Faiz