Re: [PATCH v3 05/15] efi_loader: add IPv4() to device path to text protocol

Ilias Apalodimas
2024-11-13T10:38:40Z

Hi Heinrich,

On Mon, 11 Nov 2024 at 23:10, Adriano Cordova <adrianox@gmail.com> wrote:
>
> From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
>
> Implement Ipv4() node support in the device path to text protocol.
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> Signed-off-by: Adriano Cordova <adrianox@gmail.com>
> ---
>
> (no changes since v2)
>
> lib/efi_loader/efi_device_path_to_text.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/lib/efi_loader/efi_device_path_to_text.c b/lib/efi_loader/efi_device_path_to_text.c
> index 0c7b30a26e..481a9712d9 100644
> --- a/lib/efi_loader/efi_device_path_to_text.c
> +++ b/lib/efi_loader/efi_device_path_to_text.c
> @@ -8,6 +8,7 @@
> #include <blk.h>
> #include <efi_loader.h>
> #include <malloc.h>
> +#include <net.h>
>
> #define MAC_OUTPUT_LEN 22
> #define UNKNOWN_OUTPUT_LEN 23
> @@ -170,6 +171,28 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
>
> break;
> }
> + case DEVICE_PATH_SUB_TYPE_MSG_IPV4: {
> + struct efi_device_path_ipv4 *idp =
> + (struct efi_device_path_ipv4 *)dp;
> +
> + s += sprintf(s, "IPv4(%pI4,", &idp->remote_ip_address);
> + switch (idp->protocol) {
> + case IPPROTO_TCP:
> + s += sprintf(s, "TCP,");
> + case IPPROTO_UDP:
> + s += sprintf(s, "UDP,");
> + default:
> + s += sprintf(s, "0x%x,", idp->protocol);
> + }
> + s += sprintf(s, idp->static_ip_address ? "Static" : "DHCP");
> + s += sprintf(s, ",%pI4", &idp->local_ip_address);
> + if (idp->dp.length == sizeof(struct efi_device_path_ipv4))
> + s += sprintf(s, ",%pI4,%pI4", &idp->gateway_ip_address,
> + &idp->subnet_mask);
> + s += sprintf(s, ")");

How confident are we that the produced device path won't overflow?
IIRC we only have 512 of space there and sprintf isn't the best tool
to catch overflows.

Thanks
/Ilias
> +
> + break;
> + }
> case DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS: {
> struct efi_device_path_usb_class *ucdp =
> (struct efi_device_path_usb_class *)dp;
> --
> 2.43.0
>