Re: [PATCH 2/5] usb/redir: avoid dynamic stack allocation (CVE-2021-3527)

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/3/21 11:14 AM, Gerd Hoffmann wrote:
> Use autofree heap allocation instead.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Fixes: 4f4321c11ff ("usb: use iovecs in USBPacket")
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  hw/usb/redirect.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
> index 17f06f34179a..db1a89a7cc92 100644
> --- a/hw/usb/redirect.c
> +++ b/hw/usb/redirect.c
> @@ -818,7 +818,7 @@ static void usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
>          usbredirparser_send_bulk_packet(dev->parser, p->id,
>                                          &bulk_packet, NULL, 0);
>      } else {
> -        uint8_t buf[size];
> +        g_autofree uint8_t *buf = g_malloc(size);
>          usb_packet_copy(p, buf, size);
>          usbredir_log_data(dev, "bulk data out:", buf, size);
>          usbredirparser_send_bulk_packet(dev->parser, p->id,
> @@ -923,7 +923,7 @@ static void usbredir_handle_interrupt_out_data(USBRedirDevice *dev,
>                                                 USBPacket *p, uint8_t ep)
>  {
>      struct usb_redir_interrupt_packet_header interrupt_packet;
> -    uint8_t buf[p->iov.size];
> +    g_autofree uint8_t *buf = g_malloc(p->iov.size);
>  
>      DPRINTF("interrupt-out ep %02X len %zd id %"PRIu64"\n", ep,
>              p->iov.size, p->id);
>