firmware-utils: add a file {en,de}cryption tool, based on the PC1 encryption algrithm

SVN-Revision: 16550

2 files changed, 362 insertions, 0 deletions

diff --git a/tools/firmware-utils/Makefile b/tools/firmware-utils/Makefile
index 96b4b59..6917bd8 100644
--- a/tools/firmware-utils/Makefile
+++ b/tools/firmware-utils/Makefile
@@ -49,6 +49,7 @@ define Host/Compile
 	$(call cc,nand_ecc)
 	$(call cc2,mkplanexfw sha1)
 	$(call cc2,mktplinkfw md5)
+	$(call cc,pc1crypt)
 endef
 
 define Host/Install
diff --git a/tools/firmware-utils/src/pc1crypt.c b/tools/firmware-utils/src/pc1crypt.c
new file mode 100644
index 0000000..9c2eb83
--- /dev/null
+++ b/tools/firmware-utils/src/pc1crypt.c
@@ -0,0 +1,361 @@
+/*
+ *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  This code was based on:
+ *	PC1 Cipher Algorithm ( Pukall Cipher 1 )
+ *	By Alexander PUKALL 1991
+ *	free code no restriction to use
+ *	please include the name of the Author in the final software
+ *	the Key is 128 bits
+ *	http://membres.lycos.fr/pc1/
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>     /* for unlink() */
+#include <libgen.h>
+#include <getopt.h>     /* for getopt() */
+#include <stdarg.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+struct pc1_ctx {
+	unsigned short	ax;
+	unsigned short	bx;
+	unsigned short	cx;
+	unsigned short	dx;
+	unsigned short	si;
+	unsigned short	tmp;
+	unsigned short	x1a2;
+	unsigned short	x1a0[8];
+	unsigned short	res;
+	unsigned short	i;
+	unsigned short	inter;
+	unsigned short	cfc;
+	unsigned short	cfd;
+	unsigned short	compte;
+	unsigned char	cle[17];
+	short		c;
+};
+
+static void pc1_finish(struct pc1_ctx *pc1)
+{
+	/* erase all variables */
+	memset(pc1, 0, sizeof(struct pc1_ctx));
+}
+
+static void pc1_code(struct pc1_ctx *pc1)
+{
+	pc1->dx = pc1->x1a2 + pc1->i;
+	pc1->ax = pc1->x1a0[pc1->i];
+	pc1->cx = 0x015a;
+	pc1->bx = 0x4e35;
+
+	pc1->tmp = pc1->ax;
+	pc1->ax = pc1->si;
+	pc1->si = pc1->tmp;
+
+	pc1->tmp = pc1->ax;
+	pc1->ax = pc1->dx;
+	pc1->dx = pc1->tmp;
+
+	if (pc1->ax != 0) {
+		pc1->ax = pc1->ax * pc1->bx;
+	}
+
+	pc1->tmp = pc1->ax;
+	pc1->ax = pc1->cx;
+	pc1->cx = pc1->tmp;
+
+	if (pc1->ax != 0) {
+		pc1->ax = pc1->ax * pc1->si;
+		pc1->cx = pc1->ax + pc1->cx;
+	}
+
+	pc1->tmp = pc1->ax;
+	pc1->ax = pc1->si;
+	pc1->si = pc1->tmp;
+	pc1->ax = pc1->ax * pc1->bx;
+	pc1->dx = pc1->cx + pc1->dx;
+
+	pc1->ax = pc1->ax + 1;
+
+	pc1->x1a2 = pc1->dx;
+	pc1->x1a0[pc1->i] = pc1->ax;
+
+	pc1->res = pc1->ax ^ pc1->dx;
+	pc1->i = pc1->i + 1;
+}
+
+static void pc1_assemble(struct pc1_ctx *pc1)
+{
+	pc1->x1a0[0] = (pc1->cle[0] * 256) + pc1->cle[1];
+
+	pc1_code(pc1);
+	pc1->inter = pc1->res;
+
+	pc1->x1a0[1] = pc1->x1a0[0] ^ ((pc1->cle[2]*256) + pc1->cle[3]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[2] = pc1->x1a0[1] ^ ((pc1->cle[4]*256) + pc1->cle[5]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[3] = pc1->x1a0[2] ^ ((pc1->cle[6]*256) + pc1->cle[7]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[4] = pc1->x1a0[3] ^ ((pc1->cle[8]*256) + pc1->cle[9]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[5] = pc1->x1a0[4] ^ ((pc1->cle[10]*256) + pc1->cle[11]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[6] = pc1->x1a0[5] ^ ((pc1->cle[12]*256) + pc1->cle[13]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->x1a0[7] = pc1->x1a0[6] ^ ((pc1->cle[14]*256) + pc1->cle[15]);
+	pc1_code(pc1);
+	pc1->inter = pc1->inter ^ pc1->res;
+
+	pc1->i = 0;
+}
+
+static unsigned char pc1_decrypt(struct pc1_ctx *pc1, short c)
+{
+	pc1_assemble(pc1);
+	pc1->cfc = pc1->inter >> 8;
+	pc1->cfd = pc1->inter & 255; /* cfc^cfd = random byte */
+
+	c = c ^ (pc1->cfc ^ pc1->cfd);
+	for (pc1->compte = 0; pc1->compte <= 15; pc1->compte++) {
+		/* we mix the plaintext byte with the key */
+		pc1->cle[pc1->compte] = pc1->cle[pc1->compte] ^ c;
+	}
+
+	return c;
+}
+
+static unsigned char pc1_encrypt(struct pc1_ctx *pc1, short c)
+{
+	pc1_assemble(pc1);
+	pc1->cfc = pc1->inter >> 8;
+	pc1->cfd = pc1->inter & 255; /* cfc^cfd = random byte */
+
+	for (pc1->compte = 0; pc1->compte <= 15; pc1->compte++) {
+		/* we mix the plaintext byte with the key */
+		pc1->cle[pc1->compte] = pc1->cle[pc1->compte] ^ c;
+	}
+	c = c ^ (pc1->cfc ^ pc1->cfd);
+
+	return c;
+}
+
+static void pc1_init(struct pc1_ctx *pc1)
+{
+	memset(pc1, 0, sizeof(struct pc1_ctx));
+
+	/* ('Remsaalps!123456') is the key used, you can change it */
+	strcpy(pc1->cle, "Remsaalps!123456");
+}
+
+static void pc1_decrypt_buf(struct pc1_ctx *pc1, unsigned char *buf,
+			    unsigned len)
+{
+	unsigned i;
+
+	for (i = 0; i < len; i++)
+		buf[i] = pc1_decrypt(pc1, buf[i]);
+}
+
+static void pc1_encrypt_buf(struct pc1_ctx *pc1, unsigned char *buf,
+			    unsigned len)
+{
+	unsigned i;
+
+	for (i = 0; i < len; i++)
+		buf[i] = pc1_encrypt(pc1, buf[i]);
+}
+
+/*
+ * Globals
+ */
+static char *ifname;
+static char *progname;
+static char *ofname;
+static int decrypt;
+
+/*
+ * Message macros
+ */
+#define ERR(fmt, ...) do { \
+	fflush(0); \
+	fprintf(stderr, "[%s] *** error: " fmt "\n", \
+			progname, ## __VA_ARGS__ ); \
+} while (0)
+
+#define ERRS(fmt, ...) do { \
+	int save = errno; \
+	fflush(0); \
+	fprintf(stderr, "[%s] *** error: " fmt "\n", \
+			progname, ## __VA_ARGS__, strerror(save)); \
+} while (0)
+
+void usage(int status)
+{
+	FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
+	struct board_info *board;
+
+	fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
+	fprintf(stream,
+"\n"
+"Options:\n"
+"  -d              decrypt instead of encrypt"
+"  -i <file>       read input from the file <file>\n"
+"  -o <file>       write output to the file <file>\n"
+"  -h              show this screen\n"
+	);
+
+	exit(status);
+}
+
+#define BUFSIZE		(64 * 1024)
+
+int main(int argc, char *argv[])
+{
+	struct pc1_ctx pc1;
+	int res = EXIT_FAILURE;
+	int err;
+	struct stat st;
+	char *buf;
+	unsigned total;
+
+	FILE *outfile, *infile;
+
+	progname = basename(argv[0]);
+
+	while ( 1 ) {
+		int c;
+
+		c = getopt(argc, argv, "di:o:h");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'd':
+			decrypt = 1;
+			break;
+		case 'i':
+			ifname = optarg;
+			break;
+		case 'o':
+			ofname = optarg;
+			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
+			break;
+		default:
+			usage(EXIT_FAILURE);
+			break;
+		}
+	}
+
+	if (ifname == NULL) {
+		ERR("no input file specified");
+		goto err;
+	}
+
+	if (ofname == NULL) {
+		ERR("no output file specified");
+		goto err;
+	}
+
+	err = stat(ifname, &st);
+	if (err){
+		ERRS("stat failed on %s", ifname);
+		goto err;
+	}
+
+	total = st.st_size;
+	buf = malloc(BUFSIZE);
+	if (!buf) {
+		ERR("no memory for buffer\n");
+		goto err;
+	}
+
+	infile = fopen(ifname, "r");
+	if (infile == NULL) {
+		ERRS("could not open \"%s\" for reading", ifname);
+		goto err_free;
+	}
+
+	outfile = fopen(ofname, "w");
+	if (outfile == NULL) {
+		ERRS("could not open \"%s\" for writing", ofname);
+		goto err_close_in;
+	}
+
+	pc1_init(&pc1);
+	while (total > 0) {
+		unsigned datalen;
+
+		if (total > BUFSIZE)
+			datalen = BUFSIZE;
+		else
+			datalen = total;
+
+		errno = 0;
+		fread(buf, datalen, 1, infile);
+		if (errno != 0) {
+			ERRS("unable to read from file %s", ifname);
+			goto err_close_out;
+		}
+
+		if (decrypt)
+			pc1_decrypt_buf(&pc1, buf, datalen);
+		else
+			pc1_encrypt_buf(&pc1, buf, datalen);
+
+		errno = 0;
+		fwrite(buf, datalen, 1, outfile);
+		if (errno) {
+			ERRS("unable to write to file %s", ofname);
+			goto err_close_out;
+		}
+
+		total -= datalen;
+	}
+	pc1_finish(&pc1);
+
+	res = EXIT_SUCCESS;
+
+ out_flush:
+	fflush(outfile);
+
+ err_close_out:
+	fclose(outfile);
+	if (res != EXIT_SUCCESS) {
+		unlink(ofname);
+	}
+
+ err_close_in:
+	fclose(infile);
+
+ err_free:
+	free(buf);
+
+ err:
+	return res;
+}
+