[PULL,31/32] qcow2-refcount: check_refblocks(): add separate message for reserved

Commit Message

Hanna Czenczek Sept. 15, 2021, 5:53 p.m. UTC

From: Vladimir Sementsov-Ogievskiy <[e-mail]>

Split checking for reserved bits out of aligned offset check.

Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
Reviewed-by: Eric Blake <[e-mail]>
Tested-by: Kirill Tkhai <[e-mail]>
Reviewed-by: Hanna Reitz <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Hanna Reitz <[e-mail]>
---
 block/qcow2.h          |  1 +
 block/qcow2-refcount.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

Patch

diff --git a/block/qcow2.h b/block/qcow2.h
index 58fd7f1678..fd48a89d45 100644
--- 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)
 
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 1c246b9227..4614572252 100644
--- 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 "