githubmirror/efivar

src/efivar.c
492 строки12 KB
Peter Jones
efivar: prepare_data(): check for invalid filename.
26 сен 2017, 20:43
26 сен 2017, 20:43c8c7df1
/*
 * libefivar - library for the manipulation of EFI variables
 * Copyright 2012 Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of the
 * License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see
 * <http://www.gnu.org/licenses/>.
 *
 */

#include <ctype.h>
#include <err.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <limits.h>

extern char *optarg;
extern int optind, opterr, optopt;

#include <efivar/efivar.h>
#include "guid.h"

#define ACTION_LIST		0x1
#define ACTION_PRINT		0x2
#define ACTION_APPEND		0x4
#define ACTION_LIST_GUIDS	0x8
#define ACTION_WRITE		0x10
#define ACTION_PRINT_DEC	0x20

#define EDIT_APPEND	0
#define EDIT_WRITE	1

#define SHOW_VERBOSE	0
#define SHOW_DECIMAL	1

static const char *attribute_names[] = {
	"Non-Volatile",
	"Boot Service Access",
	"Runtime Service Access",
	"Hardware Error Record",
	"Authenticated Write Access",
	"Time-Based Authenticated Write Access",
	"Append Write",
	""
};

static int verbose_errors = 0;

static void
show_errors(void)
{
	int rc = 1;

	if (!verbose_errors)
		return;

	printf("Error trace:\n");
	for (int i = 0; rc > 0; i++) {
		char *filename = NULL;
		char *function = NULL;
		int line = 0;
		char *message = NULL;
		int error = 0;

		rc = efi_error_get(i, &filename, &function, &line, &message,
				   &error);
		if (rc < 0)
			err(1, "error fetching trace value");
		if (rc == 0)
			break;
		printf(" %s:%d %s(): %s: %s", filename, line, function,
		       strerror(error), message);
	}
}

static void
list_all_variables(void)
{
	efi_guid_t *guid = NULL;
	char *name = NULL;
	int rc;
	while ((rc = efi_get_next_variable_name(&guid, &name)) > 0)
		 printf(GUID_FORMAT "-%s\n",
			guid->a, guid->b, guid->c, bswap_16(guid->d),
			guid->e[0], guid->e[1], guid->e[2], guid->e[3],
			guid->e[4], guid->e[5], name);

	if (rc < 0) {
		fprintf(stderr, "efivar: error listing variables: %m\n");
		show_errors();
		exit(1);
	}
}

static void
parse_name(const char *guid_name, char **name, efi_guid_t *guid)
{
	unsigned int guid_len = sizeof("84be9c3e-8a32-42c0-891c-4cd3b072becc");
	char guid_buf[guid_len + 2];
	int rc;
	off_t name_pos = 0;

	const char *left, *right;

	left = strchr(guid_name, '{');
	right = strchr(guid_name, '}');
	if (left && right) {
		if (right[1] != '-' || right[2] == '\0') {
bad_name:
			errno = -EINVAL;
			fprintf(stderr, "efivar: invalid name \"%s\"\n",
				guid_name);
			show_errors();
			exit(1);
		}
		name_pos = right + 1 - guid_name;

		strncpy(guid_buf, guid_name, name_pos);
		guid_buf[name_pos++] = '\0';

		rc = efi_id_guid_to_guid(guid_buf, guid);
		if (rc < 0)
			goto bad_name;
	} else {
		/* it has to be at least the length of the guid, a dash, and
		 * one more character */
		if (strlen(guid_name) < guid_len + 2)
			goto bad_name;
		name_pos = guid_len - 1;

		if (guid_name[name_pos] != '-' || guid_name[name_pos+1] == '\0')
			goto bad_name;
		name_pos++;

		memset(guid_buf, 0, sizeof(guid_buf));
		strncpy(guid_buf, guid_name, guid_len - 1);

		rc = text_to_guid(guid_buf, guid);
		if (rc < 0)
			goto bad_name;
	}

	char *name_buf = NULL;
	int name_len;
	name_len = strlen(guid_name + name_pos) + 1;
	name_buf = calloc(1, name_len);
	if (!name_buf) {
		fprintf(stderr, "efivar: %m\n");
		exit(1);
	}
	strncpy(name_buf, guid_name + name_pos, name_len);
	*name = name_buf;
}

static void
show_variable(char *guid_name, int display_type)
{
	efi_guid_t guid;
	char *name = NULL;
	int rc;

	uint8_t *data = NULL;
	size_t data_size = 0;
	uint32_t attributes;

	parse_name(guid_name, &name, &guid);

	errno = 0;
	rc = efi_get_variable(guid, name, &data, &data_size, &attributes);
	if (rc < 0) {
		fprintf(stderr, "efivar: show variable: %m\n");
		show_errors();
		exit(1);
	}

	if (display_type == SHOW_VERBOSE) {
		printf("GUID: "GUID_FORMAT "\n",
		       guid.a, guid.b, guid.c, bswap_16(guid.d),
		       guid.e[0], guid.e[1], guid.e[2], guid.e[3],
		       guid.e[4], guid.e[5]);
		printf("Name: \"%s\"\n", name);
		printf("Attributes:\n");
		for (int i = 0; attribute_names[i][0] != '\0'; i++) {
			if(attributes & (1 << i))
				printf("\t%s\n", attribute_names[i]);
		}
		printf("Value:\n");

		uint32_t index = 0;
		while (index < data_size) {
			char charbuf[] = "................";
			printf("%08x  ", index);
			/* print the hex values, and render the ascii bits into
			 * charbuf */
			while (index < data_size) {
				printf("%02x ", data[index]);
				if (index % 8 == 7)
					printf(" ");
				if (isprint(data[index]))
					charbuf[index % 16] = data[index];
				index++;
				if (index % 16 == 0)
					break;
			}

			/* If we're above data_size, finish out the line with
			 * space, and also finish out charbuf with space */
			while (index >= data_size && index % 16 != 0) {
				if (index % 8 == 7)
					printf(" ");
				printf("   ");
				charbuf[index % 16] = ' ';

				index++;
				if (index % 16 == 0)
					break;
			}
			printf("|%s|\n", charbuf);
		}
	} else if (display_type == SHOW_DECIMAL) {
		uint32_t index = 0;
		while (index < data_size) {
			// print the dec values
			while (index < data_size) {
				printf("%d ", data[index]);
				if (index % 8 == 7)
					printf(" ");
				index++;
				if (index % 16 == 0)
					break;
			}
		}
		printf("\n");
	}
}

static void
edit_variable(const char *guid_name, void *data, size_t data_size,
	      uint32_t attrib, int edit_type)
{
	efi_guid_t guid;
	char *name = NULL;
	int rc;
	uint8_t *old_data = NULL;
	size_t old_data_size = 0;
	uint32_t old_attributes = 0;

	parse_name(guid_name, &name, &guid);

	rc = efi_get_variable(guid, name, &old_data, &old_data_size,
				&old_attributes);
	if (rc < 0 && edit_type != EDIT_WRITE) {
		fprintf(stderr, "efivar: %m\n");
		show_errors();
		exit(1);
	}

	if (attrib != 0)
		old_attributes = attrib;

	switch (edit_type){
		case EDIT_APPEND:
			rc = efi_append_variable(guid, name, data, data_size,
					old_attributes);
			break;
		case EDIT_WRITE:
			rc = efi_set_variable(guid, name, data, data_size,
					old_attributes, 0644);
			break;
	}

	if (rc < 0) {
		fprintf(stderr, "efivar: %m\n");
		show_errors();
		exit(1);
	}
}

static void
validate_name(const char *name)
{
	if (name == NULL) {
		fprintf(stderr, "Invalid variable name\n");
		show_errors();
		exit(1);
	}
}

static void
prepare_data(const char *filename, void **data, size_t *data_size)
{
	int fd = -1;
	void *buf;
	size_t buflen = 0;
	struct stat statbuf;
	int rc;

	if (filename == NULL) {
		fprintf(stderr, "Input filename must be provided.\n");
		exit(1);
	}

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		goto err;

	memset(&statbuf, '\0', sizeof (statbuf));
	rc = fstat(fd, &statbuf);
	if (rc < 0)
		goto err;

	buflen = statbuf.st_size;
	buf = mmap(NULL, buflen, PROT_READ, MAP_PRIVATE|MAP_POPULATE, fd, 0);
	if (!buf)
		goto err;

	*data = buf;
	*data_size = buflen;

	close(fd);
	return;
err:
	if (fd >= 0)
		close(fd);
	fprintf(stderr, "Could not use \"%s\": %m\n", filename);
	exit(1);
}

static void
usage(const char *progname)
{
	printf("Usage: %s [OPTION...]\n", basename(progname));
	printf("  -l, --list                        list current variables\n");
	printf("  -p, --print                       print variable specified by --name\n");
	printf("  -d, --print-decimal               print variable in decimal values specified\n");
	printf("                                    by --name\n");
	printf("  -n, --name=<guid-name>            variable to manipulate, in the form\n");
	printf("                                    8be4df61-93ca-11d2-aa0d-00e098032b8c-Boot0000\n");
	printf("  -a, --append                      append to variable specified by --name\n");
	printf("  -f, --fromfile=<file>             use data from <file>\n");
	printf("  -t, --attributes=<attributes>     attributes to use on append\n");
	printf("  -L, --list-guids                  show internal guid list\n");
	printf("  -w, --write                       write to variable specified by --name\n\n");
	printf("Help options:\n");
	printf("  -?, --help                        Show this help message\n");
	printf("      --usage                       Display brief usage message\n");
	return;
}

int main(int argc, char *argv[])
{
	int c = 0;
	int i = 0;
	int action = 0;
	void *data = NULL;
	size_t data_size = 0;
	char *name = NULL;
	char *file = NULL;
	uint32_t attributes = 0;
	char *sopts = "lpdn:af:t:Lw?";
	struct option lopts[] =
		{ {"list", no_argument, 0, 'l'},
		  {"print", no_argument, 0, 'p'},
		  {"print-decimal", no_argument, 0, 'd'},
		  {"name", required_argument, 0, 'n'},
		  {"append", no_argument, 0, 'a'},
		  {"fromfile", required_argument, 0, 'f'},
		  {"attributes", required_argument, 0, 't'},
		  {"list-guids", no_argument, 0, 'L'},
		  {"write", no_argument, 0, 'w'},
		  {"help", no_argument, 0, '?'},
		  {"usage", no_argument, 0, 0},
		  {0, 0, 0, 0}
		};

	while ((c = getopt_long(argc, argv, sopts, lopts, &i)) != -1) {
		switch (c) {
			case 'l':
				action |= ACTION_LIST;
				break;
			case 'p':
				action |= ACTION_PRINT;
				break;
			case 'd':
				action |= ACTION_PRINT_DEC;
				break;
			case 'n':
				name = optarg;
				break;
			case 'a':
				action |= ACTION_APPEND;
				break;
			case 'f':
				file = optarg;
				break;
			case 't':
				attributes = strtoul(optarg, NULL, 10);
				if (errno == ERANGE || errno == EINVAL) {
					fprintf(stderr, "invalid argument for -t: %s: %s\n", optarg, strerror(errno));
					return EXIT_FAILURE;
				}
				break;
			case 'L':
				action |= ACTION_LIST_GUIDS;
				break;
			case 'w':
				action |= ACTION_WRITE;
				break;
			case '?':
				usage(argv[0]);
				return EXIT_SUCCESS;
			case 0:
				if (strcmp(lopts[i].name, "usage")) {
					usage(argv[0]);
					return EXIT_SUCCESS;
				}
				break;
		}
	}

	if (name)
		action |= ACTION_PRINT;

	switch (action) {
		case ACTION_LIST:
			list_all_variables();
			break;
		case ACTION_PRINT:
			validate_name(name);
			show_variable(name, SHOW_VERBOSE);
			break;
		case ACTION_PRINT_DEC | ACTION_PRINT:
			validate_name(name);
			show_variable(name, SHOW_DECIMAL);
			break;
		case ACTION_APPEND | ACTION_PRINT:
			validate_name(name);
			prepare_data(file, &data, &data_size);
			edit_variable(name, data, data_size, attributes,
				      EDIT_APPEND);
			break;
		case ACTION_WRITE | ACTION_PRINT:
			validate_name(name);
			prepare_data(file, &data, &data_size);
			edit_variable(name, data, data_size, attributes,
				      EDIT_WRITE);
			break;
		case ACTION_LIST_GUIDS: {
			efi_guid_t sentinal = {0xffffffff,0xffff,0xffff,0xffff,
					       {0xff,0xff,0xff,0xff,0xff,0xff}};
			extern struct guidname efi_well_known_guids[];
			extern struct guidname *efi_well_known_guids_end;
			intptr_t start = (intptr_t)&efi_well_known_guids;
			intptr_t end = (intptr_t)&efi_well_known_guids_end;
			unsigned int i;

			struct guidname *guid = &efi_well_known_guids[0];
			for (i = 0; i < (end-start) / sizeof(*guid); i++) {
				if (!efi_guid_cmp(&sentinal, &guid[i].guid))
					break;
				printf("{"GUID_FORMAT"} {%s} %s %s\n",
					guid[i].guid.a, guid[i].guid.b,
					guid[i].guid.c, bswap_16(guid[i].guid.d),
					guid[i].guid.e[0], guid[i].guid.e[1],
					guid[i].guid.e[2], guid[i].guid.e[3],
					guid[i].guid.e[4], guid[i].guid.e[5],
					guid[i].symbol + strlen("efi_guid_"),
					guid[i].symbol, guid[i].name);
			}
		}
	};

	return 0;
}