diff mbox series

[07/10] qcow2-refcount: check_refcounts_l2(): check reserved bits

Message ID 20210504152023.322862-8-vsementsov@virtuozzo.com
State New
Headers show
Series qcow2 check: check some reserved bits and subcluster bitmaps | expand

Commit Message

Vladimir Sementsov-Ogievskiy May 4, 2021, 3:20 p.m. UTC 
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.h          |  1 +
 block/qcow2-refcount.c | 12 +++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

Comments

Eric Blake May 4, 2021, 7:42 p.m. UTC | #1 
On 5/4/21 10:20 AM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/qcow2.h          |  1 +
>  block/qcow2-refcount.c | 12 +++++++++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>
diff mbox series

Patch

diff --git a/block/qcow2.h b/block/qcow2.h
index c0e1e83796..b8b1093b61 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -587,6 +587,7 @@  typedef enum QCow2MetadataOverlap {
 
 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
+#define L2E_STD_RESERVED_MASK 0x3f000000000001feULL
 
 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
 
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index dc940f3003..44fc0dd5dc 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1682,8 +1682,18 @@  static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
         int csize;
         l2_entry = get_l2_entry(s, l2_table, i);
         uint64_t l2_bitmap = get_l2_bitmap(s, l2_table, i);
+        QCow2ClusterType type = qcow2_get_cluster_type(bs, l2_entry);
 
-        switch (qcow2_get_cluster_type(bs, l2_entry)) {
+        if (type != QCOW2_CLUSTER_COMPRESSED) {
+            /* Check reserved bits of Standard Cluster Descriptor */
+            if (l2_entry & L2E_STD_RESERVED_MASK) {
+                fprintf(stderr, "ERROR found l2 entry with reserved bits set: "
+                        "%" PRIx64, l2_entry);
+                res->corruptions++;
+            }
+        }
+
+        switch (type) {
         case QCOW2_CLUSTER_COMPRESSED:
             /* Compressed clusters don't have QCOW_OFLAG_COPIED */
             if (l2_entry & QCOW_OFLAG_COPIED) {