Re: [PATCH] Fix problem with size of allocation in libsas

From: James Bottomley
Date: Sun Nov 11 2007 - 19:00:26 EST


On Mon, 2007-11-12 at 00:24 +0100, Jesper Juhl wrote:
> From: Jesper Juhl <jesper.juhl@xxxxxxxxx>
>
> in sas_get_phy_change_count(), the line
> disc_resp = alloc_smp_resp(DISCOVER_RESP_SIZE);
> will allocate 56 bytes due to this define:
> #define DISCOVER_RESP_SIZE 56
> But, the struct is actually 60 bytes in size.
>
> So change the define to be
> #define DISCOVER_RESP_SIZE sizeof(struct smp_resp)
> so we always get the correct size even when people
> fiddle with the structure.
>
> This change also fixes the same problem in
> sas_get_phy_attached_sas_addr()
>
> (Found by the Coverity checker. Compile tested only)

Well, your fix is definitely wrong.

Could you explain the problem a little more? The discover response SMP
frame is 56 bytes as mandated by the standard. I don't see anywhere in
the code where we're actually using a value beyond the 56th byte ...
where is the problem use?

James


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