[PATCH v6 09/14] efi_loader: net: add support to send http requests and parse http headers

[Heinrich Schuchardt]

On 28.11.24 15:44, Adriano Cordova wrote:
> Add network-stack agnostic way to send an http request and
> parse http headers from efi drivers. This uses wget as a
> backend and communicates with it via efi_wget_info.
>
> The function efi_net_do_request allocates a buffer on behalf of an
> efi application using efi_alloc and passes it to wget to receive
> the data. If the method is GET and the buffer is too small, it
> re-allocates the buffer based on the last received Content-Length
> header and tries again. If the method is HEAD it just issues one
> request. So issuing a HEAD request (to update Content-Length) and
> then a GET request is preferred but not required.
>
> The function efi_net_parse_headers parses a raw buffer containing
> an http header into an array of EFI specific 'http_header' structs.
>
> Signed-off-by: Adriano Cordova <adrianox at gmail.com>

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> ---
>
> (no changes since v4)
>
> Changes in v4:
> - Remove void* casts
> - Add documentation
>
> Changes in v3:
> - Add a struct wget_http_info efi_wget_info for efi_net to pass to wget
>    when issuing wget requests, instead of using the old wget_info (see v2
>    of the series 'wget: Expose wget to applications').
> - Let a pointer to the http status code be passed to efi_net_do_request
>    for it to fill it for the client after a request.
>   include/efi_loader.h     |  13 ++++
>   lib/efi_loader/efi_net.c | 155 +++++++++++++++++++++++++++++++++++++++
>   2 files changed, 168 insertions(+)
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 0da0248db4..b6f865ca76 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -16,6 +16,7 @@
>   #include <image.h>
>   #include <pe.h>
>   #include <linux/list.h>
> +#include <linux/sizes.h>
>   #include <linux/oid_registry.h>
>
>   struct blk_desc;
> @@ -136,6 +137,18 @@ void efi_net_get_addr(struct efi_ipv4_address *ip,
>   void efi_net_set_addr(struct efi_ipv4_address *ip,
>   		      struct efi_ipv4_address *mask,
>   		      struct efi_ipv4_address *gw);
> +efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method, void **buffer,
> +				u32 *status_code, ulong *file_size, char *headers_buffer);
> +#define MAX_HTTP_HEADERS_SIZE SZ_64K
> +#define MAX_HTTP_HEADERS 100
> +#define MAX_HTTP_HEADER_NAME 128
> +#define MAX_HTTP_HEADER_VALUE 512
> +struct http_header {
> +	uchar name[MAX_HTTP_HEADER_NAME];
> +	uchar value[MAX_HTTP_HEADER_VALUE];
> +};
> +
> +void efi_net_parse_headers(ulong *num_headers, struct http_header *headers);
>   #else
>   static inline void efi_net_get_dp(struct efi_device_path **dp) { }
>   static inline void efi_net_get_addr(struct efi_ipv4_address *ip,
> diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
> index e8af2e3d95..368f62c5b2 100644
> --- a/lib/efi_loader/efi_net.c
> +++ b/lib/efi_loader/efi_net.c
> @@ -17,6 +17,7 @@
>
>   #include <efi_loader.h>
>   #include <dm.h>
> +#include <linux/sizes.h>
>   #include <malloc.h>
>   #include <vsprintf.h>
>   #include <net.h>
> @@ -40,6 +41,12 @@ static struct efi_net_obj *netobj;
>    */
>   static struct efi_device_path *net_dp;
>
> +static struct wget_http_info efi_wget_info = {
> +	.set_bootdev = false,
> +	.check_buffer_size = true,
> +
> +};
> +
>   /*
>    * The notification function of this event is called in every timer cycle
>    * to check if a new network packet has been received.
> @@ -1175,3 +1182,151 @@ void efi_net_set_addr(struct efi_ipv4_address *ip,
>   		memcpy(&net_netmask, mask, sizeof(*mask));
>   #endif
>   }
> +
> +/**
> + * efi_net_set_buffer() - allocate a buffer of min 64K
> + *
> + * @buffer:	allocated buffer
> + * @size:	desired buffer size
> + * Return:	status code
> + */
> +static efi_status_t efi_net_set_buffer(void **buffer, size_t size)
> +{
> +	efi_status_t ret = EFI_SUCCESS;
> +
> +	if (size < SZ_64K)
> +		size = SZ_64K;
> +
> +	efi_free_pool(*buffer);
> +
> +	*buffer = efi_alloc(size);
> +	if (!*buffer)
> +		ret = EFI_OUT_OF_RESOURCES;
> +
> +	efi_wget_info.buffer_size = (ulong)size;
> +
> +	return ret;
> +}
> +
> +/**
> + * efi_net_parse_headers() - parse HTTP headers
> + *
> + * Parses the raw buffer efi_wget_info.headers into an array headers
> + * of efi structs http_headers. The array should be at least
> + * MAX_HTTP_HEADERS long.
> + *
> + * @num_headers:	number of headers
> + * @headers:		caller provided array of struct http_headers
> + */
> +void efi_net_parse_headers(ulong *num_headers, struct http_header *headers)
> +{
> +	if (!num_headers || !headers)
> +		return;
> +
> +	// Populate info with http headers.
> +	*num_headers = 0;
> +	const uchar *line_start = efi_wget_info.headers;
> +	const uchar *line_end;
> +	ulong count;
> +	struct http_header *current_header;
> +	const uchar *separator;
> +	size_t name_length, value_length;
> +
> +	// Skip the first line (request or status line)
> +	line_end = strstr(line_start, "\r\n");
> +
> +	if (line_end)
> +		line_start = line_end + 2;
> +
> +	while ((line_end = strstr(line_start, "\r\n")) != NULL) {
> +		count = *num_headers;
> +		if (line_start == line_end || count >= MAX_HTTP_HEADERS)
> +			break;
> +		current_header = headers + count;
> +		separator = strchr(line_start, ':');
> +		if (separator) {
> +			name_length = separator - line_start;
> +			++separator;
> +			while (*separator == ' ')
> +				++separator;
> +			value_length = line_end - separator;
> +			if (name_length < MAX_HTTP_HEADER_NAME &&
> +			    value_length < MAX_HTTP_HEADER_VALUE) {
> +				strncpy(current_header->name, line_start, name_length);
> +				current_header->name[name_length] = '\0';
> +				strncpy(current_header->value, separator, value_length);
> +				current_header->value[value_length] = '\0';
> +				(*num_headers)++;
> +			}
> +		}
> +		line_start = line_end + 2;
> +	}
> +}
> +
> +/**
> + * efi_net_do_request() - issue an HTTP request using wget
> + *
> + * @url:		url
> + * @method:		HTTP method
> + * @buffer:		data buffer
> + * @status_code:	HTTP status code
> + * @file_size:		file size in bytes
> + * @headers_buffer:	headers buffer
> + * Return:		status code
> + */
> +efi_status_t efi_net_do_request(u8 *url, enum efi_http_method method, void **buffer,
> +				u32 *status_code, ulong *file_size, char *headers_buffer)
> +{
> +	efi_status_t ret = EFI_SUCCESS;
> +	int wget_ret;
> +	static bool last_head;
> +
> +	if (!buffer || !file_size)
> +		return EFI_ABORTED;
> +
> +	efi_wget_info.method = (enum wget_http_method)method;
> +	efi_wget_info.headers = headers_buffer;
> +
> +	switch (method) {
> +	case HTTP_METHOD_GET:
> +		ret = efi_net_set_buffer(buffer, last_head ? (size_t)efi_wget_info.hdr_cont_len : 0);
> +		if (ret != EFI_SUCCESS)
> +			goto out;
> +		wget_ret = wget_request((ulong)*buffer, url, &efi_wget_info);
> +		if ((ulong)efi_wget_info.hdr_cont_len > efi_wget_info.buffer_size) {
> +			// Try again with updated buffer size
> +			ret = efi_net_set_buffer(buffer, (size_t)efi_wget_info.hdr_cont_len);
> +			if (ret != EFI_SUCCESS)
> +				goto out;
> +			if (wget_request((ulong)*buffer, url, &efi_wget_info)) {
> +				efi_free_pool(*buffer);
> +				ret = EFI_DEVICE_ERROR;
> +				goto out;
> +			}
> +		} else if (wget_ret) {
> +			efi_free_pool(*buffer);
> +			ret = EFI_DEVICE_ERROR;
> +			goto out;
> +		}
> +		// Pass the actual number of received bytes to the application
> +		*file_size = efi_wget_info.file_size;
> +		*status_code = efi_wget_info.status_code;
> +		last_head = false;
> +		break;
> +	case HTTP_METHOD_HEAD:
> +		ret = efi_net_set_buffer(buffer, 0);
> +		if (ret != EFI_SUCCESS)
> +			goto out;
> +		wget_request((ulong)*buffer, url, &efi_wget_info);
> +		*file_size = 0;
> +		*status_code = efi_wget_info.status_code;
> +		last_head = true;
> +		break;
> +	default:
> +		ret = EFI_UNSUPPORTED;
> +		break;
> +	}
> +
> +out:
> +	return ret;
> +}