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authorEric Blake <eblake@redhat.com>2019-11-13 20:46:33 -0600
committerEric Blake <eblake@redhat.com>2019-11-18 16:01:34 -0600
commitcf7c49cf6aedb0486ca7ba7c32aa819fe51dadfb (patch)
treed22968feb61ad3cd6060605293ed8f1a9976d6b4 /block
parent9d7ab222da5a9de61b34f26ec442d37ccdd18cf0 (diff)
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bitmap: Enforce maximum bitmap name length
We document that for qcow2 persistent bitmaps, the name cannot exceed 1023 bytes. It is inconsistent if transient bitmaps do not have to abide by the same limit, and it is unlikely that any existing client even cares about using bitmap names this long. It's time to codify that ALL bitmaps managed by qemu (whether persistent in qcow2 or not) have a documented maximum length. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <20191114024635.11363-3-eblake@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Diffstat (limited to 'block')
-rw-r--r--block/dirty-bitmap.c12
-rw-r--r--block/qcow2-bitmap.c2
2 files changed, 11 insertions, 3 deletions
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 4bbb251..7039e82 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -104,9 +104,15 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
assert(is_power_of_2(granularity) && granularity >= BDRV_SECTOR_SIZE);
- if (name && bdrv_find_dirty_bitmap(bs, name)) {
- error_setg(errp, "Bitmap already exists: %s", name);
- return NULL;
+ if (name) {
+ if (bdrv_find_dirty_bitmap(bs, name)) {
+ error_setg(errp, "Bitmap already exists: %s", name);
+ return NULL;
+ }
+ if (strlen(name) > BDRV_BITMAP_MAX_NAME_SIZE) {
+ error_setg(errp, "Bitmap name too long: %s", name);
+ return NULL;
+ }
}
bitmap_size = bdrv_getlength(bs);
if (bitmap_size < 0) {
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index ef9ef62..809bbc5 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -42,6 +42,8 @@
#define BME_MIN_GRANULARITY_BITS 9
#define BME_MAX_NAME_SIZE 1023
+QEMU_BUILD_BUG_ON(BME_MAX_NAME_SIZE != BDRV_BITMAP_MAX_NAME_SIZE);
+
#if BME_MAX_TABLE_SIZE * 8ULL > INT_MAX
#error In the code bitmap table physical size assumed to fit into int
#endif