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

Ilias Apalodimas
2024-11-10T09:20:26Z

On Fri, 8 Nov 2024 at 15:40, Adriano Cordova <adrianox@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@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