Re: [PATCH] rbd: fix integer overflow in rbd_header_from_disk()

[Alex Elder <elder@dreamhost.com>]

On 04/18/2012 01:09 PM, Xi Wang wrote:
> On Apr 18, 2012, at 10:21 AM, Alex Elder wrote:
>>
>> This looks good, however I have changed it to use UINT_MAX
>> rather than ULONG_MAX, because on some architectures size_t
>> (__kernel_size_t) is defined as type (unsigned int).  It
>> is the more conservative value, and even on architectures
>> where __BITS_PER_LONG is 64, it still offers a sane upper
>> bound on the number of snapshots for a rbd device.
>
> Looks good to me.
>
> BTW, on which arch is size_t 32-bit while long is 64?
> Several commits still use ULONG_MAX, such as

In my tree, these at least *can* be:  arm, m68k, mips,
powerpc, sparc, x86, and others (including generic).

It may not matter in practice, but I prefer to be very
careful.  As long as you're going out of your way to
avoid overflow might as well make sure it works on all
architectures in the process.

					-Alex

> http://git.kernel.org/linus/64486697
>
> - xi
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