block/vdi: Fix image opening and creation for odd disk sizes

The fix is based on a patch from Kevin Wolf. Here his comment:

"The number of blocks needs to be rounded up to cover all of the virtual hard
disk. Without this fix, we can't even open our own images if their size is not
a multiple of the block size."

While Kevin's patch addressed vdi_create, my modification also fixes
vdi_open which now accepts images with odd disk sizes.

v3:
Don't allow reading of disk images with too large disk sizes.
Neither VBoxManage nor old versions of qemu-img read such images.
This change requires rounding of odd disk sizes before we do the checks.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: François Revol <revol@free.fr>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit f21dc3a4652eeb82117d7d55d975278fe1444b26)

Conflicts:

	block/vdi.c

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/block/vdi.c b/block/vdi.c
index 45aa81c70..64bf66f0b 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -399,6 +399,15 @@ static int vdi_open(BlockDriverState *bs, const char *filename, int flags)
     vdi_header_print(&header);
 #endif
 
+    if (header.disk_size % SECTOR_SIZE != 0) {
+        /* 'VBoxManage convertfromraw' can create images with odd disk sizes.
+           We accept them but round the disk size to the next multiple of
+           SECTOR_SIZE. */
+        logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size);
+        header.disk_size += SECTOR_SIZE - 1;
+        header.disk_size &= ~(SECTOR_SIZE - 1);
+    }
+
     if (header.version != VDI_VERSION_1_1) {
         logout("unsupported version %u.%u\n",
                header.version >> 16, header.version & 0xffff);
@@ -417,9 +426,9 @@ static int vdi_open(BlockDriverState *bs, const char *filename, int flags)
     } else if (header.block_size != 1 * MiB) {
         logout("unsupported block size %u B\n", header.block_size);
         goto fail;
-    } else if (header.disk_size !=
+    } else if (header.disk_size >
                (uint64_t)header.blocks_in_image * header.block_size) {
-        logout("unexpected block number %u B\n", header.blocks_in_image);
+        logout("unsupported disk size %" PRIu64 " B\n", header.disk_size);
         goto fail;
     } else if (!uuid_is_null(header.uuid_link)) {
         logout("link uuid != 0, unsupported\n");
@@ -831,7 +840,10 @@ static int vdi_create(const char *filename, QEMUOptionParameter *options)
         return -errno;
     }
 
-    blocks = bytes / block_size;
+    /* We need enough blocks to store the given disk size,
+       so always round up. */
+    blocks = (bytes + block_size - 1) / block_size;
+
     bmap_size = blocks * sizeof(uint32_t);
     bmap_size = ((bmap_size + SECTOR_SIZE - 1) & ~(SECTOR_SIZE -1));