On Mon, 25 Sept 2023 at 20:42, Vladimir Sementsov-Ogievskiy
<vsement...@yandex-team.ru> wrote:
>
> Coverity mark this size, got from the buffer as untrasted value, it's
> not good to use it as length when writing to file. Make the assertion
> more strict to also check upper bound.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
> ---
> softmmu/device_tree.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
> index 30aa3aea9f..adc4236e21 100644
> --- a/softmmu/device_tree.c
> +++ b/softmmu/device_tree.c
> @@ -660,7 +660,7 @@ void qmp_dumpdtb(const char *filename, Error **errp)
>
> size = fdt_totalsize(current_machine->fdt);
>
> - g_assert(size > 0);
> + g_assert(size > 0 && size <= FDT_MAX_SIZE);
FDT_MAX_SIZE is not "this is as big as an FDT can ever be". It's
only the internal sizing of device trees that we create ourselves
in the machine models (and which we will bump up if for some
reason we ever find ourselves needing to create bigger device
trees). So it's not really a suitable upper bound.
> if (!g_file_set_contents(filename, current_machine->fdt, size, &err)) {
> error_setg(errp, "Error saving FDT to file %s: %s",
Nothing bad happens if we pass g_file_set_contents() a very
large size -- we'll just create a large file. The user already
has lots of ways to fill up their disk if they want to, and
we don't have any idea how much disk space they might or might
not have.
I would just mark this as a false positive.
thanks
-- PMM
