[SCSI] libosd: Fix NULL dereference BUG when target is not OSD conformant

Very old OSC's Target had a BUG in the Get/Set attributes where
it was looking in the wrong places for attribute lists length.
If used with the open-osd initiator, the initiator would dereference
a NULL pointer when retrieving system_information attributes.

Checks are added that retrieval of each attribute is successful
before accessing its value.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/osd/osd_initiator.c

@@ -131,7 +131,7 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
 
 	pFirst = get_attrs[a++].val_ptr;
 	OSD_INFO("OSD_ATTR_RI_PRODUCT_REVISION_LEVEL [%u]\n",
-		get_unaligned_be32(pFirst));
+		pFirst ? get_unaligned_be32(pFirst) : ~0U);
 
 	pFirst = get_attrs[a++].val_ptr;
 	OSD_INFO("OSD_ATTR_RI_PRODUCT_SERIAL_NUMBER [%s]\n",
@@ -143,15 +143,18 @@ static int _osd_print_system_info(struct osd_dev *od, void *caps)
 
 	pFirst = get_attrs[a++].val_ptr;
 	OSD_INFO("OSD_ATTR_RI_TOTAL_CAPACITY [0x%llx]\n",
-		_LLU(get_unaligned_be64(pFirst)));
+		pFirst ? _LLU(get_unaligned_be64(pFirst)) : ~0ULL);
 
 	pFirst = get_attrs[a++].val_ptr;
 	OSD_INFO("OSD_ATTR_RI_USED_CAPACITY [0x%llx]\n",
-		_LLU(get_unaligned_be64(pFirst)));
+		pFirst ? _LLU(get_unaligned_be64(pFirst)) : ~0ULL);
 
 	pFirst = get_attrs[a++].val_ptr;
 	OSD_INFO("OSD_ATTR_RI_NUMBER_OF_PARTITIONS [%llu]\n",
-		_LLU(get_unaligned_be64(pFirst)));
+		pFirst ? _LLU(get_unaligned_be64(pFirst)) : ~0ULL);
+
+	if (a >= nelem)
+		goto out;
 
 	/* FIXME: Where are the time utilities */
 	pFirst = get_attrs[a++].val_ptr;