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-rw-r--r--netboot.c346
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+/*
+ * netboot - trivial UEFI first-stage bootloader netboot support
+ *
+ * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Significant portions of this code are derived from Tianocore
+ * (http://tianocore.sf.net) and are Copyright 2009-2012 Intel
+ * Corporation.
+ */
+
+#include <efi.h>
+#include <efilib.h>
+#include <string.h>
+#include "shim.h"
+#include "netboot.h"
+#include "str.h"
+
+#define ntohs(x) __builtin_bswap16(x) /* supported both by GCC and clang */
+#define htons(x) ntohs(x)
+
+static EFI_PXE_BASE_CODE *pxe;
+static EFI_IP_ADDRESS tftp_addr;
+static CHAR8 *full_path;
+
+
+typedef struct {
+ UINT16 OpCode;
+ UINT16 Length;
+ UINT8 Data[1];
+} EFI_DHCP6_PACKET_OPTION;
+
+/*
+ * usingNetboot
+ * Returns TRUE if we identify a protocol that is enabled and Providing us with
+ * the needed information to fetch a grubx64.efi image
+ */
+BOOLEAN findNetboot(EFI_HANDLE device)
+{
+ EFI_STATUS status;
+
+ status = uefi_call_wrapper(BS->HandleProtocol, 3, device,
+ &PxeBaseCodeProtocol, (VOID **)&pxe);
+ if (status != EFI_SUCCESS) {
+ pxe = NULL;
+ return FALSE;
+ }
+
+ if (!pxe || !pxe->Mode) {
+ pxe = NULL;
+ return FALSE;
+ }
+
+ if (!pxe->Mode->Started || !pxe->Mode->DhcpAckReceived) {
+ pxe = NULL;
+ return FALSE;
+ }
+
+ /*
+ * We've located a pxe protocol handle thats been started and has
+ * received an ACK, meaning its something we'll be able to get
+ * tftp server info out of
+ */
+ return TRUE;
+}
+
+static CHAR8 *get_v6_bootfile_url(EFI_PXE_BASE_CODE_DHCPV6_PACKET *pkt)
+{
+ void *optr = NULL, *end = NULL;
+ EFI_DHCP6_PACKET_OPTION *option = NULL;
+ CHAR8 *url = NULL;
+ UINT32 urllen = 0;
+
+ optr = pkt->DhcpOptions;
+ end = optr + sizeof(pkt->DhcpOptions);
+
+ for (;;) {
+ option = (EFI_DHCP6_PACKET_OPTION *)optr;
+
+ if (ntohs(option->OpCode) == 0)
+ break;
+
+ if (ntohs(option->OpCode) == 59) {
+ /* This is the bootfile url option */
+ urllen = ntohs(option->Length);
+ if ((void *)(option->Data + urllen) > end)
+ break;
+ url = AllocateZeroPool(urllen + 1);
+ if (!url)
+ break;
+ memcpy(url, option->Data, urllen);
+ return url;
+ }
+ optr += 4 + ntohs(option->Length);
+ if (optr + sizeof(EFI_DHCP6_PACKET_OPTION) > end)
+ break;
+ }
+
+ return NULL;
+}
+
+static CHAR16 str2ns(CHAR8 *str)
+{
+ CHAR16 ret = 0;
+ CHAR8 v;
+ for(;*str;str++) {
+ if ('0' <= *str && *str <= '9')
+ v = *str - '0';
+ else if ('A' <= *str && *str <= 'F')
+ v = *str - 'A' + 10;
+ else if ('a' <= *str && *str <= 'f')
+ v = *str - 'a' + 10;
+ else
+ v = 0;
+ ret = (ret << 4) + v;
+ }
+ return htons(ret);
+}
+
+static CHAR8 *str2ip6(CHAR8 *str)
+{
+ UINT8 i = 0, j = 0, p = 0;
+ size_t len = 0, dotcount = 0;
+ enum { MAX_IP6_DOTS = 7 };
+ CHAR8 *a = NULL, *b = NULL, t = 0;
+ static UINT16 ip[8];
+
+ memset(ip, 0, sizeof(ip));
+
+ /* Count amount of ':' to prevent overflows.
+ * max. count = 7. Returns an invalid ip6 that
+ * can be checked against
+ */
+ for (a = str; *a != 0; ++a) {
+ if (*a == ':')
+ ++dotcount;
+ }
+ if (dotcount > MAX_IP6_DOTS)
+ return (CHAR8 *)ip;
+
+ len = strlen(str);
+ a = b = str;
+ for (i = p = 0; i < len; i++, b++) {
+ if (*b != ':')
+ continue;
+ *b = '\0';
+ ip[p++] = str2ns(a);
+ *b = ':';
+ a = b + 1;
+ if (b[1] == ':' )
+ break;
+ }
+ a = b = (str + len);
+ for (j = len, p = 7; j > i; j--, a--) {
+ if (*a != ':')
+ continue;
+ t = *b;
+ *b = '\0';
+ ip[p--] = str2ns(a+1);
+ *b = t;
+ b = a;
+ }
+ return (CHAR8 *)ip;
+}
+
+static BOOLEAN extract_tftp_info(CHAR8 *url)
+{
+ CHAR8 *start, *end;
+ CHAR8 ip6str[40];
+ CHAR8 ip6inv[16];
+ CHAR8 *template = (CHAR8 *)translate_slashes(DEFAULT_LOADER_CHAR);
+
+ // to check against str2ip6() errors
+ memset(ip6inv, 0, sizeof(ip6inv));
+
+ if (strncmp((UINT8 *)url, (UINT8 *)"tftp://", 7)) {
+ Print(L"URLS MUST START WITH tftp://\n");
+ return FALSE;
+ }
+ start = url + 7;
+ if (*start != '[') {
+ Print(L"TFTP SERVER MUST BE ENCLOSED IN [..]\n");
+ return FALSE;
+ }
+
+ start++;
+ end = start;
+ while ((*end != '\0') && (*end != ']')) {
+ end++;
+ if (end - start >= (int)sizeof(ip6str)) {
+ Print(L"TFTP URL includes malformed IPv6 address\n");
+ return FALSE;
+ }
+ }
+ if (*end == '\0') {
+ Print(L"TFTP SERVER MUST BE ENCLOSED IN [..]\n");
+ return FALSE;
+ }
+ memset(ip6str, 0, sizeof(ip6str));
+ memcpy(ip6str, start, end - start);
+ end++;
+ memcpy(&tftp_addr.v6, str2ip6(ip6str), 16);
+ if (memcmp(&tftp_addr.v6, ip6inv, sizeof(ip6inv)) == 0)
+ return FALSE;
+ full_path = AllocateZeroPool(strlen(end)+strlen(template)+1);
+ if (!full_path)
+ return FALSE;
+ memcpy(full_path, end, strlen(end));
+ end = (CHAR8 *)strrchr((char *)full_path, '/');
+ if (!end)
+ end = (CHAR8 *)full_path;
+ memcpy(end, template, strlen(template));
+ end[strlen(template)] = '\0';
+
+ return TRUE;
+}
+
+static EFI_STATUS parseDhcp6()
+{
+ EFI_PXE_BASE_CODE_DHCPV6_PACKET *packet = (EFI_PXE_BASE_CODE_DHCPV6_PACKET *)&pxe->Mode->DhcpAck.Raw;
+ CHAR8 *bootfile_url;
+
+ bootfile_url = get_v6_bootfile_url(packet);
+ if (!bootfile_url)
+ return EFI_NOT_FOUND;
+ if (extract_tftp_info(bootfile_url) == FALSE) {
+ FreePool(bootfile_url);
+ return EFI_NOT_FOUND;
+ }
+ FreePool(bootfile_url);
+ return EFI_SUCCESS;
+}
+
+static EFI_STATUS parseDhcp4()
+{
+ CHAR8 *template = (CHAR8 *)translate_slashes(DEFAULT_LOADER_CHAR);
+ INTN template_len = strlen(template) + 1;
+
+ INTN dir_len = strnlena(pxe->Mode->DhcpAck.Dhcpv4.BootpBootFile, 127);
+ INTN i;
+ UINT8 *dir = pxe->Mode->DhcpAck.Dhcpv4.BootpBootFile;
+
+ for (i = dir_len; i >= 0; i--) {
+ if (dir[i] == '/')
+ break;
+ }
+ dir_len = (i >= 0) ? i + 1 : 0;
+
+ full_path = AllocateZeroPool(dir_len + template_len);
+
+ if (!full_path)
+ return EFI_OUT_OF_RESOURCES;
+
+ if (dir_len > 0) {
+ strncpya(full_path, dir, dir_len);
+ if (full_path[dir_len-1] == '/' && template[0] == '/')
+ full_path[dir_len-1] = '\0';
+ }
+ if (dir_len == 0 && dir[0] != '/' && template[0] == '/')
+ template++;
+ strcata(full_path, template);
+ memcpy(&tftp_addr.v4, pxe->Mode->DhcpAck.Dhcpv4.BootpSiAddr, 4);
+
+ return EFI_SUCCESS;
+}
+
+EFI_STATUS parseNetbootinfo(EFI_HANDLE image_handle)
+{
+
+ EFI_STATUS rc;
+
+ if (!pxe)
+ return EFI_NOT_READY;
+
+ memset((UINT8 *)&tftp_addr, 0, sizeof(tftp_addr));
+
+ /*
+ * If we've discovered an active pxe protocol figure out
+ * if its ipv4 or ipv6
+ */
+ if (pxe->Mode->UsingIpv6){
+ rc = parseDhcp6();
+ } else
+ rc = parseDhcp4();
+ return rc;
+}
+
+EFI_STATUS FetchNetbootimage(EFI_HANDLE image_handle, VOID **buffer, UINT64 *bufsiz)
+{
+ EFI_STATUS rc;
+ EFI_PXE_BASE_CODE_TFTP_OPCODE read = EFI_PXE_BASE_CODE_TFTP_READ_FILE;
+ BOOLEAN overwrite = FALSE;
+ BOOLEAN nobuffer = FALSE;
+ UINTN blksz = 512;
+
+ Print(L"Fetching Netboot Image\n");
+ if (*buffer == NULL) {
+ *buffer = AllocatePool(4096 * 1024);
+ if (!*buffer)
+ return EFI_OUT_OF_RESOURCES;
+ *bufsiz = 4096 * 1024;
+ }
+
+try_again:
+ rc = uefi_call_wrapper(pxe->Mtftp, 10, pxe, read, *buffer, overwrite,
+ bufsiz, &blksz, &tftp_addr, full_path, NULL, nobuffer);
+
+ if (rc == EFI_BUFFER_TOO_SMALL) {
+ /* try again, doubling buf size */
+ *bufsiz *= 2;
+ FreePool(*buffer);
+ *buffer = AllocatePool(*bufsiz);
+ if (!*buffer)
+ return EFI_OUT_OF_RESOURCES;
+ goto try_again;
+ }
+
+ if (rc != EFI_SUCCESS && *buffer) {
+ FreePool(*buffer);
+ }
+ return rc;
+}
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