qcow2-refcount: check_refblocks(): add separate message for reserved

Split checking for reserved bits out of aligned offset check.

Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Tested-by: Kirill Tkhai <[email protected]>
Reviewed-by: Hanna Reitz <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Hanna Reitz <[email protected]>

Author: Vladimir Sementsov-Ogievskiy

block/qcow2-refcount.c

@@ -2089,9 +2089,17 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,
 
     for(i = 0; i < s->refcount_table_size; i++) {
         uint64_t offset, cluster;
-        offset = s->refcount_table[i];
+        offset = s->refcount_table[i] & REFT_OFFSET_MASK;
         cluster = offset >> s->cluster_bits;
 
+        if (s->refcount_table[i] & REFT_RESERVED_MASK) {
+            fprintf(stderr, "ERROR refcount table entry %" PRId64 " has "
+                    "reserved bits set\n", i);
+            res->corruptions++;
+            *rebuild = true;
+            continue;
+        }
+
         /* Refcount blocks are cluster aligned */
         if (offset_into_cluster(s, offset)) {
             fprintf(stderr, "ERROR refcount block %" PRId64 " is not "

block/qcow2.h

@@ -591,6 +591,7 @@ typedef enum QCow2MetadataOverlap {
 #define L2E_STD_RESERVED_MASK 0x3f000000000001feULL
 
 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
+#define REFT_RESERVED_MASK 0x1ffULL
 
 #define INV_OFFSET (-1ULL)