[PATCH v2 08/15] efi_loader: device_path: add support for HTTP device path

[Ilias Apalodimas]

On Fri, 8 Nov 2024 at 15:40, Adriano Cordova <adrianox at gmail.com> wrote:
>
> Add efi_dp_from_http to form a device path from HTTP. The
> device path is the concatenation of the device path returned
> by efi_dp_from_ipv4 together with an URI node and an END node.
>
> Signed-off-by: Adriano Cordova <adrianox at gmail.com>
> ---
>  include/efi_loader.h             |  1 +
>  lib/efi_loader/efi_device_path.c | 51 ++++++++++++++++++++++++++++++++
>  2 files changed, 52 insertions(+)
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 44d29e7967..ab79364857 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -872,6 +872,7 @@ struct efi_device_path *efi_dp_part_node(struct blk_desc *desc, int part);
>  struct efi_device_path *efi_dp_from_file(const struct efi_device_path *dp,
>                                          const char *path);
>  struct efi_device_path *efi_dp_from_eth(void);
> +struct efi_device_path *efi_dp_from_http(const char *server);
>  struct efi_device_path *efi_dp_from_mem(uint32_t mem_type,
>                                         uint64_t start_address,
>                                         uint64_t end_address);
> diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> index 3e02341224..dc79a61196 100644
> --- a/lib/efi_loader/efi_device_path.c
> +++ b/lib/efi_loader/efi_device_path.c
> @@ -1012,6 +1012,57 @@ struct efi_device_path *efi_dp_from_ipv4(struct efi_ipv4_address *ip,
>         return dp2;
>  }
>
> +struct efi_device_path *efi_dp_from_http(const char *server)
> +{
> +       struct efi_device_path *dp1, *dp2;
> +       struct efi_device_path_uri *uridp;
> +       efi_uintn_t uridp_len;
> +       char *pos;
> +       char tmp[128];
> +       struct efi_ipv4_address ip;
> +       struct efi_ipv4_address mask;
> +
> +       efi_net_get_addr(&ip, &mask, NULL);
> +
> +       dp1 = efi_dp_from_ipv4(&ip, &mask, NULL);
> +
> +       strcpy(tmp, "http://");
> +
> +       if (server) {
> +               memcpy(tmp + strlen("http://"), server, strlen(server) + 1);

We need some sanity checking here, since the server name is a user
input and might overflow tmp

> +       } else {
> +#ifdef CONFIG_NET_LWIP

#iif IS_ENABLED is preferred here
> +               // The lwip stack does not set env variables for server
> +               efi_free_pool(dp1);
> +               return NULL;

Can you move this checking on top? You can avoid alloc/free buffers is
LWIP is enabled and we domnt have a server

> +#else
> +               ip_to_string(net_server_ip, tmp + strlen("http://"));
> +#endif
> +       }
> +
> +       uridp_len = sizeof(struct efi_device_path) + strlen(tmp) + 1;
> +       uridp = efi_alloc(uridp_len + sizeof(END));
> +       if (!uridp) {
> +               log_err("Out of memory\n");
> +               return NULL;
> +       }
> +       uridp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
> +       uridp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_URI;
> +       uridp->dp.length = uridp_len;
> +       debug("device path: setting uri device path to %s\n", tmp);
> +       memcpy(uridp->uri, tmp, strlen(tmp) + 1);
> +
> +       pos = (char *)uridp + uridp_len;
> +       memcpy(pos, &END, sizeof(END));
> +
> +       dp2 = efi_dp_concat(dp1, (const struct efi_device_path *)uridp, 0);
> +
> +       efi_free_pool(uridp);
> +       efi_free_pool(dp1);
> +
> +       return dp2;
> +}
> +
>  /* Construct a device-path for memory-mapped image */
>  struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
>                                         uint64_t start_address,
> --
> 2.43.0
>

Thanks
/Ilias