Re: [Qemu-block] [PATCH 0/4] Misc qcow2 corruption checks

[Alberto Garcia]

On Thu 02 Nov 2017 06:24:40 PM CET, Max Reitz wrote:
> There are two more cases which might need a check that the return
> value of an allocation function isn't 0:
>
> The first is qcow2_alloc_bytes() which has an assert(offset) after
> potentially setting offset = new_cluster (with new_cluster being the
> return value of alloc_clusters_noref()).

Ok. I don't know how to reproduce it, though, but a check won't hurt.

> The second is qcow2_crypto_hdr_init_func() which is simply missing a
> pre-write overlap check.

But that is called when you create a new image, i.e., this is not QEMU
handling a corrupted image incorrectly, but QEMU itself trying to create
a corrupted image.

I'd rather use assert(qcow2_pre_write_overlap_check(...) == 0);

Berto