[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>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 0bbbf271fbb..552f58b655d 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/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;