[PATCH 1/2] images: write checksum into barebox header

["Ulrich Ölmann" <u.oelmann@pengutronix.de>]

From: Jan Luebbe <jlu@pengutronix.de>

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>
Signed-off-by: Ulrich Ölmann <u.oelmann@pengutronix.de>
---
 images/Makefile      |   3 +-
 include/filetype.h   |   2 +
 scripts/.gitignore   |   1 +
 scripts/Makefile     |   1 +
 scripts/bareboxcrc.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 225 insertions(+), 1 deletion(-)
 create mode 100644 scripts/bareboxcrc.c

diff --git a/images/Makefile b/images/Makefile
index da9cc8d396ee..812074e624b0 100644
--- a/images/Makefile
+++ b/images/Makefile
@@ -71,7 +71,8 @@ quiet_cmd_pblx ?= PBLX    $@
       cmd_pblx ?= cat $(obj)/$(patsubst %.pblx,%.pblb,$(2)) > $@; \
 		  $(call size_append, $(obj)/barebox.z) >> $@; \
 		  cat $(obj)/barebox.z >> $@; \
-		  $(objtree)/scripts/fix_size -f $@
+		  $(objtree)/scripts/fix_size -f $@; \
+		  $(objtree)/scripts/bareboxcrc $@
 
 $(obj)/%.pblx: $(obj)/%.pblb $(obj)/barebox.z FORCE
 	$(call if_changed,pblx,$(@F))
diff --git a/include/filetype.h b/include/filetype.h
index e87ca174a89d..ec0e01f64f9f 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -51,6 +51,8 @@ enum filetype is_fat_or_mbr(const unsigned char *sector, unsigned long *bootsec)
 int is_fat_boot_sector(const void *_buf);
 bool filetype_is_barebox_image(enum filetype ft);
 
+#define BAREBOX_CRC_MAGIC_VALUE		"crc"
+
 #define ARM_HEAD_SIZE			0x30
 #define ARM_HEAD_MAGICWORD_OFFSET	0x20
 #define ARM_HEAD_SIZE_OFFSET		0x2C
diff --git a/scripts/.gitignore b/scripts/.gitignore
index 533bffd97d36..d11ac7f97f32 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -2,6 +2,7 @@ bin2c
 mkimage
 fix_size
 bareboxenv
+bareboxcrc
 bareboxcrc32
 kernel-install
 bareboximd
diff --git a/scripts/Makefile b/scripts/Makefile
index a5c16b2f3133..1683d38c222d 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -8,6 +8,7 @@ hostprogs-y                      += bin2c
 hostprogs-y                      += mkimage
 hostprogs-y                      += fix_size
 hostprogs-y                      += bareboxenv
+hostprogs-y                      += bareboxcrc
 hostprogs-y                      += bareboxcrc32
 hostprogs-y                      += kernel-install
 hostprogs-$(CONFIG_IMD)          += bareboximd
diff --git a/scripts/bareboxcrc.c b/scripts/bareboxcrc.c
new file mode 100644
index 000000000000..37cb9b0a6ce8
--- /dev/null
+++ b/scripts/bareboxcrc.c
@@ -0,0 +1,219 @@
+/*
+ * bareboxcrc.c
+ *
+ * Copyright (C) 2016 Jan Luebbe <j.luebbe@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define _DEFAULT_SOURCE
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <limits.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <endian.h>
+
+#include "compiler.h"
+
+#include "../include/filetype.h"
+#include "../crypto/crc32.c"
+
+#define EX_SUCCESS		0
+#define EX_NO_CHECKSUM		1
+#define EX_CHECKSUM_FAULTY	2
+#define EX_NO_BAREBOX_HEADER	3
+#define EX_IMAGE_TOO_SMALL	4
+#define EX_IMAGE_TOO_BIG	5
+#define EX_LOCATION_OCCUPIED	6
+#define EX_OUT_OF_MEMORY	7
+#define EX_IO_ERROR		8
+#define EX_WRONG_USAGE		9
+
+void usage(char *prgname)
+{
+	fprintf(stderr, "Usage : %s [OPTION] FILE\n"
+		"\n"
+		"options:\n"
+		"  -c        verify checksum\n"
+		"  -f        force\n",
+		prgname);
+}
+
+int get_barebox_head_size(const char *head)
+{
+	if (!strcmp(head + ARM_HEAD_MAGICWORD_OFFSET, "barebox"))
+		return ARM_HEAD_SIZE;
+	else if (!strcmp(head + MIPS_HEAD_MAGICWORD_OFFSET, "barebox"))
+		return MIPS_HEAD_SIZE;
+
+	return 0;
+}
+
+int checksum(FILE *image, bool check, bool force, off_t size)
+{
+	void *buf = malloc(size);
+	int ret = EX_SUCCESS;
+	size_t head_size;
+	uint32_t crc = 0;
+	uint32_t *p;
+
+	if (!buf) {
+		fprintf(stderr, "malloc: out of memory\n");
+		return EX_OUT_OF_MEMORY;
+	}
+
+	if (fseeko(image, 0, SEEK_SET) == -1) {
+		perror("fseeko");
+		ret = EX_IO_ERROR;
+		goto out;
+	}
+
+	if (fread(buf, 1, size, image) < size) {
+		perror("fread");
+		ret = EX_IO_ERROR;
+		goto out;
+	}
+
+	head_size = get_barebox_head_size(buf);
+	if (!head_size) {
+		fprintf(stderr, "image does not contain a barebox header\n");
+		ret = EX_NO_BAREBOX_HEADER;
+		goto out;
+	}
+
+	if (size < head_size + 2 * sizeof(uint32_t)) {
+		fprintf(stderr, "image is too small\n");
+		ret = EX_IMAGE_TOO_SMALL;
+		goto out;
+	}
+
+	p = buf + head_size;
+
+	if (check) {
+		if (strcmp((const char*) p, BAREBOX_CRC_MAGIC_VALUE)) {
+			fprintf(stderr, "image does not contain a checksum\n");
+			ret = EX_NO_CHECKSUM;
+			goto out;
+		}
+	} else {
+		if (!force && (*p != 0x55555555 || *(p+1) != 0x55555555)) {
+			fprintf(stderr, "location for magic value and CRC seems already "
+					"to be occupied by something else\n");
+			ret = EX_LOCATION_OCCUPIED;
+			goto out;
+		}
+
+		if (fseeko(image, head_size, SEEK_SET) == -1) {
+			perror("fseeko");
+			ret = EX_IO_ERROR;
+			goto out;
+		}
+
+		if (fwrite(BAREBOX_CRC_MAGIC_VALUE, sizeof(uint32_t), 1, image) != 1) {
+			perror("fwrite");
+			ret = EX_IO_ERROR;
+			goto out;
+		}
+
+		sprintf((char*) p, "%s", BAREBOX_CRC_MAGIC_VALUE);
+	}
+
+	crc = crc32(crc, buf, head_size + sizeof(uint32_t));
+	crc = crc32(crc, buf + head_size + 2 * sizeof(uint32_t),
+			size - (head_size + 2 * sizeof(uint32_t)));
+	crc = htobe32(crc);
+
+	if (check) {
+		if (crc != *(p + 1)) {
+			fprintf(stderr, "embedded checksum is faulty\n");
+			ret = EX_CHECKSUM_FAULTY;
+		}
+	} else {
+		if (fwrite(&crc, sizeof(uint32_t), 1, image) != 1) {
+			perror("fwrite");
+			ret = EX_IO_ERROR;
+		}
+	}
+
+out:
+	free(buf);
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	FILE *image;
+	bool check = false;
+	bool force = false;
+	int opt;
+	int ret;
+	off_t size;
+
+	while((opt = getopt(argc, argv, "cf")) != -1) {
+		switch (opt) {
+		case 'c':
+			check = true;
+			break;
+		case 'f':
+			force = true;
+			break;
+		}
+	}
+
+	if (optind >= argc) {
+		usage(argv[0]);
+		exit(EX_WRONG_USAGE);
+	}
+
+	image = fopen(argv[optind], check ? "r" : "r+");
+	if (image == NULL) {
+		perror("fopen");
+		exit(EX_IO_ERROR);
+	}
+
+	if (fseeko(image, 0, SEEK_END) == -1) {
+		perror("fseeko");
+		exit(EX_IO_ERROR);
+	}
+	size = ftello(image);
+	if (size == -1) {
+		perror("ftello");
+		exit(EX_IO_ERROR);
+	}
+	if (size > 0xa00000) {
+		fprintf(stderr, "error: image should be smaller than 10 MiB\n");
+		exit(EX_IMAGE_TOO_BIG);
+	}
+
+	ret = checksum(image, check, force, size);
+	if (ret)
+		exit(ret);
+
+	if (fclose(image) != 0) {
+		perror("fclose");
+		exit(EX_IO_ERROR);
+	}
+
+	exit(EX_SUCCESS);
+}
-- 
2.8.1


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