On Sun, 2007-11-11 at 19:33 -0500, Douglas Gilbert wrote: > James Bottomley wrote: > > 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? > > The response size of SMP DISCOVER keeps growing with > each rev. Currently in SAS-2 revision 12 it is 112 bytes long! > The original SAS standard and SAS 1.1 have implicit response > sizes and for DISCOVER that is 56 bytes. > > To be compliant with SAS-2 the code should read byte 3 of > a DISCOVER response. If it is zero then the response length > is 56 bytes, otherwise the response length is that many > dwords (i.e. 4 byte units) plus 4 bytes for the CRC. > [Similar logic applies to many other SMP responses.] > > I have tables for all SMP requests and response (up until > SAS-2 rev 12) in my smp_utils package, see the smp_lib.c > file. Right at the moment, we're requiring the 1.1 56 byte response because the request has byte three zeroed (sas 2 requires responders to return the 1.1 response frame in this case). I suppose if we ever need to do zoning, there might be a case to move to larger sizes, but at the moment it would just tell us about features we're not using anyway (plus we're bound to confuse some older expanders). James - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
