From: Markus Armbruster <armbru@redhat.com>
References: <20181130122844.29103-1-ehabkost@redhat.com>
Date: Fri, 30 Nov 2018 14:22:21 +0100
In-Reply-To: <20181130122844.29103-1-ehabkost@redhat.com> (Eduardo Habkost's
	message of "Fri, 30 Nov 2018 10:28:44 -0200")
Message-ID: <87in0ek8du.fsf@dusky.pond.sub.org>
MIME-Version: 1.0
Content-Type: text/plain
Subject: Re: [Qemu-devel] [PATCH v2] hostmem: Validate host-nodes before
 setting bitmap
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: qemu-devel@nongnu.org, Igor Mammedov <imammedo@redhat.com>, Stefano Garzarella <sgarzare@redhat.com>, David Hildenbrand <david@redhat.com>

Eduardo Habkost <ehabkost@redhat.com> writes:

> host_memory_backend_set_host_nodes() was not validating
> host-nodes before writing to backend->host_nodes, making QEMU
> write beyond the end of the bitmap.
>
> Fix the crash and add a simple regression test for the fix.
>
> While at it, fix memory leak of the list returned by
> visit_type_uint16List().
>
> Reported-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v1 -> v2:
> * Remove extra `l = l->next` statement
>   (reported by Stefano Garzarella)
> * Fix (existing) leak of `host_nodes`
>   (reported by Markus Armbruster)
> ---
>  backends/hostmem.c                   | 17 +++++++++----
>  tests/acceptance/host-nodes-limit.py | 36 ++++++++++++++++++++++++++++
>  2 files changed, 49 insertions(+), 4 deletions(-)
>  create mode 100644 tests/acceptance/host-nodes-limit.py
>
> diff --git a/backends/hostmem.c b/backends/hostmem.c
> index 1a89342039..af800284e0 100644
> --- a/backends/hostmem.c
> +++ b/backends/hostmem.c
> @@ -103,14 +103,23 @@ host_memory_backend_set_host_nodes(Object *obj, Visitor *v, const char *name,
>  {
>  #ifdef CONFIG_NUMA
>      HostMemoryBackend *backend = MEMORY_BACKEND(obj);
> -    uint16List *l = NULL;
> +    uint16List *l, *host_nodes = NULL;
>  
> -    visit_type_uint16List(v, name, &l, errp);
> +    visit_type_uint16List(v, name, &host_nodes, errp);
>  
> -    while (l) {
> +    for (l = host_nodes; l; l = l->next) {
> +        if (l->value >= MAX_NODES) {
> +            error_setg(errp, "Invalid host-nodes value: %d", l->value);
> +            goto out;
> +        }
> +    }
> +
> +    for (l = host_nodes; l; l = l->next) {
>          bitmap_set(backend->host_nodes, l->value, 1);
> -        l = l->next;
>      }
> +
> +out:
> +    qapi_free_uint16List(host_nodes);
>  #else
>      error_setg(errp, "NUMA node binding are not supported by this QEMU");
>  #endif

Care to fix the leak in host_memory_backend_get_host_nodes(), too?

[...]

Reviewed-by: Markus Armbruster <armbru@redhat.com>