qemu-img: Require -F with -b backing image
Back in commit d9f059aa6c (qemu-img: Deprecate use of -b without -F),
we deprecated the ability to create a file with a backing image that
requires qemu to perform format probing. Qemu can still probe older
files for backwards compatibility, but it is time to finish off the
ability to create such images, due to the potential security risk they
present. Update a couple of iotests affected by the change.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210503213600.569128-3-eblake@redhat.com>
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index acd35cb..ce96585 100644
--- a/block.c
+++ b/block.c
@@ -5074,7 +5074,7 @@
* -ENOTSUP - format driver doesn't support changing the backing file
*/
int bdrv_change_backing_file(BlockDriverState *bs, const char *backing_file,
- const char *backing_fmt, bool warn)
+ const char *backing_fmt, bool require)
{
BlockDriver *drv = bs->drv;
int ret;
@@ -5088,10 +5088,8 @@
return -EINVAL;
}
- if (warn && backing_file && !backing_fmt) {
- warn_report("Deprecated use of backing file without explicit "
- "backing format, use of this image requires "
- "potentially unsafe format probing");
+ if (require && backing_file && !backing_fmt) {
+ return -EINVAL;
}
if (drv->bdrv_change_backing_file != NULL) {
@@ -6601,24 +6599,11 @@
goto out;
} else {
if (!backing_fmt) {
- warn_report("Deprecated use of backing file without explicit "
- "backing format (detected format of %s)",
- bs->drv->format_name);
- if (bs->drv != &bdrv_raw) {
- /*
- * A probe of raw deserves the most attention:
- * leaving the backing format out of the image
- * will ensure bs->probed is set (ensuring we
- * don't accidentally commit into the backing
- * file), and allow more spots to warn the users
- * to fix their toolchain when opening this image
- * later. For other images, we can safely record
- * the format that we probed.
- */
- backing_fmt = bs->drv->format_name;
- qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, backing_fmt,
- NULL);
- }
+ error_setg(&local_err,
+ "Backing file specified without backing format");
+ error_append_hint(&local_err, "Detected format of %s.",
+ bs->drv->format_name);
+ goto out;
}
if (size == -1) {
/* Opened BS, have no size */
@@ -6635,9 +6620,9 @@
}
/* (backing_file && !(flags & BDRV_O_NO_BACKING)) */
} else if (backing_file && !backing_fmt) {
- warn_report("Deprecated use of unopened backing file without "
- "explicit backing format, use of this image requires "
- "potentially unsafe format probing");
+ error_setg(&local_err,
+ "Backing file specified without backing format");
+ goto out;
}
if (size == -1) {
