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]>
dreddy · Sep 15, 2021 · 8fba395 · 8fba395
1 parent 98bc07d
commit 8fba395
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diff --git a/block/qcow2-refcount.c b/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 "

diff --git a/block/qcow2.h b/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)