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Re: [Qemu-devel] [PATCH 8/8] hw/i386: fix unbounded stack for load_multi
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 8/8] hw/i386: fix unbounded stack for load_multiboot |
Date: |
Tue, 8 Mar 2016 13:29:21 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 08/03/2016 08:00, Peter Xu wrote:
> @@ -159,6 +159,12 @@ int load_multiboot(FWCfgState *fw_cfg,
> uint8_t *mb_bootinfo_data;
> uint32_t cmdline_len;
>
> +#define __KERN_FNAME_LEN (1024)
> +#define __KERN_CMDLINE_LEN (4096)
> +
> + assert(strlen(kernel_filename) + 1 >= __KERN_FNAME_LEN);
> + assert(strlen(kernel_cmdline) + 1 >= __KERN_CMDLINE_LEN);
> +
> /* Ok, let's see if it is a multiboot image.
> The header is 12x32bit long, so the latest entry may be 8192 - 48. */
> for (i = 0; i < (8192 - 48); i += 4) {
> @@ -324,7 +330,7 @@ int load_multiboot(FWCfgState *fw_cfg,
> }
>
> /* Commandline support */
> - char kcmdline[strlen(kernel_filename) + strlen(kernel_cmdline) + 2];
> + char kcmdline[__KERN_FNAME_LEN + __KERN_CMDLINE_LEN];
> snprintf(kcmdline, sizeof(kcmdline), "%s %s",
> kernel_filename, kernel_cmdline);
> stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
> @@ -370,4 +376,6 @@ int load_multiboot(FWCfgState *fw_cfg,
> nb_option_roms++;
>
> return 1; /* yes, we are multiboot */
> +#undef __KERN_FNAME_LEN
> +#undef __KERN_CMDLINE_LEN
Just put it in the heap using g_strdup_printf.
Paolo
- [Qemu-devel] [PATCH 6/8] usb: fix unbounded stack for usb_mtp_add_str, (continued)