Re: [Qemu-devel] [PATCH] hw/i386: fix unbounded stack for load_multiboot

[Fam Zheng <famz@redhat.com>]

On Wed, 03/09 14:14, Peter Xu wrote:
> Use heap rather than stack for kcmdline.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/i386/multiboot.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
> index 9e164e6..bc45394 100644
> --- a/hw/i386/multiboot.c
> +++ b/hw/i386/multiboot.c
> @@ -324,10 +324,9 @@ int load_multiboot(FWCfgState *fw_cfg,
>      }
>  
>      /* Commandline support */
> -    char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
> -    snprintf(kcmdline, sizeof(kcmdline), "%s %s",
> -             kernel_filename, kernel_cmdline);
> +    char *kcmdline = g_strdup_printf("%s %s", kernel_filename, kernel_cmdline);
>      stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
> +    g_free(kcmdline);
>  
>      stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));

While at it, it's better to move the variable declaration to the beginning of
function.

Fam