crypt.c

vxworks的tcpip协议栈源码

/* crypt.c - crytographic routines */

/* Copyright 1995 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Tom Truscott.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

/*
modification history
--------------------
01d,21jun95,dzb  added cryptRtnInit() to install crypt().
01c,13jun95,dzb  cleaned up i960 compiler warning.
01b,16jan95,dab  new version.
01a,21dec94,dab  VxWorks port - first WRS version.
	   +dzb  added: path for ppp header files, WRS copyright.
*/

#include "vxWorks.h"

/*
 * UNIX password, and DES, encryption.
 * By Tom Truscott, [e-mail],
 * from algorithms by Robert W. Baldwin and James Gillogly.
 *
 * References:
 * "Mathematical Cryptology for Computer Scientists and Mathematicians,"
 * by Wayne Patterson, 1987, ISBN 0-8476-7438-X.
 *
 * "Password Security: A Case History," R. Morris and Ken Thompson,
 * Communications of the ACM, vol. 22, pp. 594-597, Nov. 1979.
 *
 * "DES will be Totally Insecure within Ten Years," M.E. Hellman,
 * IEEE Spectrum, vol. 16, pp. 32-39, July 1979.
 */

/* =====  Configuration ==================== */

/*
 * define "MUST_ALIGN" if your compiler cannot load/store
 * long integers at arbitrary (e.g. odd) memory locations.
 * (Either that or never pass unaligned addresses to des_cipher!)
 */
#if !defined(vax)
#define	MUST_ALIGN
#endif

#ifdef CHAR_BITS
#if CHAR_BITS != 8
	#error C_block structure assumes 8 bit characters
#endif
#endif

/*
 * define "B64" to be the declaration for a 64 bit integer.
 * XXX this feature is currently unused, see "endian" comment below.
 */
#if defined(cray)
#define	B64	long
#endif
#if defined(convex)
#define	B64	long long
#endif

/*
 * define "LARGEDATA" to get faster permutations, by using about 72 kilobytes
 * of lookup tables.  This speeds up des_setkey() and des_cipher(), but has
 * little effect on crypt().
 */
#if defined(notdef)
#define	LARGEDATA
#endif

/* compile with "-DSTATIC= " when profiling */
#ifndef STATIC
#define	STATIC	static
#endif
STATIC void init_des();
STATIC void init_perm();
STATIC void permute();
STATIC int des_setkey();
STATIC int des_cipher();
#ifdef DEBUG
STATIC void prtab();
#endif

/* ==================================== */

/*
 * Cipher-block representation (Bob Baldwin):
 *
 * DES operates on groups of 64 bits, numbered 1..64 (sigh).  One
 * representation is to store one bit per byte in an array of bytes.  Bit N of
 * the NBS spec is stored as the LSB of the Nth byte (index N-1) in the array.
 * Another representation stores the 64 bits in 8 bytes, with bits 1..8 in the
 * first byte, 9..16 in the second, and so on.  The DES spec apparently has
 * bit 1 in the MSB of the first byte, but that is particularly noxious so we
 * bit-reverse each byte so that bit 1 is the LSB of the first byte, bit 8 is
 * the MSB of the first byte.  Specifically, the 64-bit input data and key are
 * converted to LSB format, and the output 64-bit block is converted back into
 * MSB format.
 *
 * DES operates internally on groups of 32 bits which are expanded to 48 bits
 * by permutation E and shrunk back to 32 bits by the S boxes.  To speed up
 * the computation, the expansion is applied only once, the expanded
 * representation is maintained during the encryption, and a compression
 * permutation is applied only at the end.  To speed up the S-box lookups,
 * the 48 bits are maintained as eight 6 bit groups, one per byte, which
 * directly feed the eight S-boxes.  Within each byte, the 6 bits are the
 * most significant ones.  The low two bits of each byte are zero.  (Thus,
 * bit 1 of the 48 bit E expansion is stored as the "4"-valued bit of the
 * first byte in the eight byte representation, bit 2 of the 48 bit value is
 * the "8"-valued bit, and so on.)  In fact, a combined "SPE"-box lookup is
 * used, in which the output is the 64 bit result of an S-box lookup which
 * has been permuted by P and expanded by E, and is ready for use in the next
 * iteration.  Two 32-bit wide tables, SPE[0] and SPE[1], are used for this
 * lookup.  Since each byte in the 48 bit path is a multiple of four, indexed
 * lookup of SPE[0] and SPE[1] is simple and fast.  The key schedule and
 * "salt" are also converted to this 8*(6+2) format.  The SPE table size is
 * 8*64*8 = 4K bytes.
 *
 * To speed up bit-parallel operations (such as XOR), the 8 byte
 * representation is "union"ed with 32 bit values "i0" and "i1", and, on
 * machines which support it, a 64 bit value "b64".  This data structure,
 * "C_block", has two problems.  First, alignment restrictions must be
 * honored.  Second, the byte-order (e.g. little-endian or big-endian) of
 * the architecture becomes visible.
 *
 * The byte-order problem is unfortunate, since on the one hand it is good
 * to have a machine-independent C_block representation (bits 1..8 in the
 * first byte, etc.), and on the other hand it is good for the LSB of the
 * first byte to be the LSB of i0.  We cannot have both these things, so we
 * currently use the "little-endian" representation and avoid any multi-byte
 * operations that depend on byte order.  This largely precludes use of the
 * 64-bit datatype since the relative order of i0 and i1 are unknown.  It
 * also inhibits grouping the SPE table to look up 12 bits at a time.  (The
 * 12 bits can be stored in a 16-bit field with 3 low-order zeroes and 1
 * high-order zero, providing fast indexing into a 64-bit wide SPE.)  On the
 * other hand, 64-bit datatypes are currently rare, and a 12-bit SPE lookup
 * requires a 128 kilobyte table, so perhaps this is not a big loss.
 *
 * Permutation representation (Jim Gillogly):
 *
 * A transformation is defined by its effect on each of the 8 bytes of the
 * 64-bit input.  For each byte we give a 64-bit output that has the bits in
 * the input distributed appropriately.  The transformation is then the OR
 * of the 8 sets of 64-bits.  This uses 8*256*8 = 16K bytes of storage for
 * each transformation.  Unless LARGEDATA is defined, however, a more compact
 * table is used which looks up 16 4-bit "chunks" rather than 8 8-bit chunks.
 * The smaller table uses 16*16*8 = 2K bytes for each transformation.  This
 * is slower but tolerable, particularly for password encryption in which
 * the SPE transformation is iterated many times.  The small tables total 9K
 * bytes, the large tables total 72K bytes.
 *
 * The transformations used are:
 * IE3264: MSB->LSB conversion, initial permutation, and expansion.
 *	This is done by collecting the 32 even-numbered bits and applying
 *	a 32->64 bit transformation, and then collecting the 32 odd-numbered
 *	bits and applying the same transformation.  Since there are only
 *	32 input bits, the IE3264 transformation table is half the size of
 *	the usual table.
 * CF6464: Compression, final permutation, and LSB->MSB conversion.
 *	This is done by two trivial 48->32 bit compressions to obtain
 *	a 64-bit block (the bit numbering is given in the "CIFP" table)
 *	followed by a 64->64 bit "cleanup" transformation.  (It would
 *	be possible to group the bits in the 64-bit block so that 2
 *	identical 32->32 bit transformations could be used instead,
 *	saving a factor of 4 in space and possibly 2 in time, but
 *	byte-ordering and other complications rear their ugly head.
 *	Similar opportunities/problems arise in the key schedule
 *	transforms.)
 * PC1ROT: MSB->LSB, PC1 permutation, rotate, and PC2 permutation.
 *	This admittedly baroque 64->64 bit transformation is used to
 *	produce the first code (in 8*(6+2) format) of the key schedule.
 * PC2ROT[0]: Inverse PC2 permutation, rotate, and PC2 permutation.
 *	It would be possible to define 15 more transformations, each
 *	with a different rotation, to generate the entire key schedule.
 *	To save space, however, we instead permute each code into the
 *	next by using a transformation that "undoes" the PC2 permutation,
 *	rotates the code, and then applies PC2.  Unfortunately, PC2
 *	transforms 56 bits into 48 bits, dropping 8 bits, so PC2 is not
 *	invertible.  We get around that problem by using a modified PC2
 *	which retains the 8 otherwise-lost bits in the unused low-order
 *	bits of each byte.  The low-order bits are cleared when the
 *	codes are stored into the key schedule.
 * PC2ROT[1]: Same as PC2ROT[0], but with two rotations.
 *	This is faster than applying PC2ROT[0] twice,
 *
 * The Bell Labs "salt" (Bob Baldwin):
 *
 * The salting is a simple permutation applied to the 48-bit result of E.
 * Specifically, if bit i (1 <= i <= 24) of the salt is set then bits i and
 * i+24 of the result are swapped.  The salt is thus a 24 bit number, with
 * 16777216 possible values.  (The original salt was 12 bits and could not
 * swap bits 13..24 with 36..48.)
 *
 * It is possible, but ugly, to warp the SPE table to account for the salt
 * permutation.  Fortunately, the conditional bit swapping requires only
 * about four machine instructions and can be done on-the-fly with about an
 * 8% performance penalty.
 */

typedef union {
	unsigned char b[8];
	struct {
		int	i0;
		int	i1;
	} b32;
#if defined(B64)
	B64	b64;
#endif
} C_block;

/*
 * Convert twenty-four-bit long in host-order
 * to six bits (and 2 low-order zeroes) per char little-endian format.
 */
#define	TO_SIX_BIT(rslt, src) {				\
		C_block cvt;				\
		cvt.b[0] = src; src >>= 6;		\
		cvt.b[1] = src; src >>= 6;		\
		cvt.b[2] = src; src >>= 6;		\
		cvt.b[3] = src;				\
		rslt = (cvt.b32.i0 & 0x3f3f3f3fL) << 2;	\
	}

/*
 * These macros may someday permit efficient use of 64-bit integers.
 */
#define	ZERO(d,d0,d1)			d0 = 0, d1 = 0
#define	LOAD(d,d0,d1,bl)		d0 = (bl).b32.i0, d1 = (bl).b32.i1
#define	LOADREG(d,d0,d1,s,s0,s1)	d0 = s0, d1 = s1
#define	OR(d,d0,d1,bl)			d0 |= (bl).b32.i0, d1 |= (bl).b32.i1
#define	STORE(s,s0,s1,bl)		(bl).b32.i0 = s0, (bl).b32.i1 = s1
#define	DCL_BLOCK(d,d0,d1)		int d0, d1

#if defined(LARGEDATA)
	/* Waste memory like crazy.  Also, do permutations in line */
#define	LGCHUNKBITS	3
#define	CHUNKBITS	(1<<LGCHUNKBITS)
#define	PERM6464(d,d0,d1,cpp,p)				\
	LOAD(d,d0,d1,(p)[(0<<CHUNKBITS)+(cpp)[0]]);		\
	OR (d,d0,d1,(p)[(1<<CHUNKBITS)+(cpp)[1]]);		\
	OR (d,d0,d1,(p)[(2<<CHUNKBITS)+(cpp)[2]]);		\
	OR (d,d0,d1,(p)[(3<<CHUNKBITS)+(cpp)[3]]);		\
	OR (d,d0,d1,(p)[(4<<CHUNKBITS)+(cpp)[4]]);		\
	OR (d,d0,d1,(p)[(5<<CHUNKBITS)+(cpp)[5]]);		\
	OR (d,d0,d1,(p)[(6<<CHUNKBITS)+(cpp)[6]]);		\
	OR (d,d0,d1,(p)[(7<<CHUNKBITS)+(cpp)[7]]);
#define	PERM3264(d,d0,d1,cpp,p)				\
	LOAD(d,d0,d1,(p)[(0<<CHUNKBITS)+(cpp)[0]]);		\
	OR (d,d0,d1,(p)[(1<<CHUNKBITS)+(cpp)[1]]);		\
	OR (d,d0,d1,(p)[(2<<CHUNKBITS)+(cpp)[2]]);		\
	OR (d,d0,d1,(p)[(3<<CHUNKBITS)+(cpp)[3]]);
#else
	/* "small data" */
#define	LGCHUNKBITS	2
#define	CHUNKBITS	(1<<LGCHUNKBITS)
#define	PERM6464(d,d0,d1,cpp,p)				\
	{ C_block tblk; permute(cpp,&tblk,p,8); LOAD (d,d0,d1,tblk); }
#define	PERM3264(d,d0,d1,cpp,p)				\
	{ C_block tblk; permute(cpp,&tblk,p,4); LOAD (d,d0,d1,tblk); }

STATIC
void
permute(cp, out, p, chars_in)
	unsigned char *cp;
	C_block *out;
	register C_block *p;
	int chars_in;
{
	register DCL_BLOCK(D,D0,D1);
	register C_block *tp;
	register int t;

	ZERO(D,D0,D1);
	do {
		t = *cp++;
		tp = &p[t&0xf]; OR(D,D0,D1,*tp); p += (1<<CHUNKBITS);
		tp = &p[t>>4];  OR(D,D0,D1,*tp); p += (1<<CHUNKBITS);
	} while (--chars_in > 0);
	STORE(D,D0,D1,*out);
}
#endif /* LARGEDATA */


/* =====  (mostly) Standard DES Tables ==================== */

static unsigned char IP[] = {		/* initial permutation */
	58, 50, 42, 34, 26, 18, 10,  2,
	60, 52, 44, 36, 28, 20, 12,  4,
	62, 54, 46, 38, 30, 22, 14,  6,
	64, 56, 48, 40, 32, 24, 16,  8,
	57, 49, 41, 33, 25, 17,  9,  1,
	59, 51, 43, 35, 27, 19, 11,  3,
	61, 53, 45, 37, 29, 21, 13,  5,
	63, 55, 47, 39, 31, 23, 15,  7,
};

/* The final permutation is the inverse of IP - no table is necessary */

static unsigned char ExpandTr[] = {	/* expansion operation */
	32,  1,  2,  3,  4,  5,
	 4,  5,  6,  7,  8,  9,
	 8,  9, 10, 11, 12, 13,
	12, 13, 14, 15, 16, 17,
	16, 17, 18, 19, 20, 21,
	20, 21, 22, 23, 24, 25,
	24, 25, 26, 27, 28, 29,
	28, 29, 30, 31, 32,  1,
};

static unsigned char PC1[] = {		/* permuted choice table 1 */
	57, 49, 41, 33, 25, 17,  9,
	 1, 58, 50, 42, 34, 26, 18,
	10,  2, 59, 51, 43, 35, 27,
	19, 11,  3, 60, 52, 44, 36,

	63, 55, 47, 39, 31, 23, 15,
	 7, 62, 54, 46, 38, 30, 22,
	14,  6, 61, 53, 45, 37, 29,
	21, 13,  5, 28, 20, 12,  4,
};

static unsigned char Rotates[] = {	/* PC1 rotation schedule */
	1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1,
};

/* note: each "row" of PC2 is left-padded with bits that make it invertible */
static unsigned char PC2[] = {		/* permuted choice table 2 */
	 9, 18,    14, 17, 11, 24,  1,  5,
	22, 25,     3, 28, 15,  6, 21, 10,
	35, 38,    23, 19, 12,  4, 26,  8,
	43, 54,    16,  7, 27, 20, 13,  2,

	 0,  0,    41, 52, 31, 37, 47, 55,
	 0,  0,    30, 40, 51, 45, 33, 48,
	 0,  0,    44, 49, 39, 56, 34, 53,
	 0,  0,    46, 42, 50, 36, 29, 32,
};

static unsigned char S[8][64] = {	/* 48->32 bit substitution tables */
					/* S[1]			*/
	{14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7,
	 0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8,
	 4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0,
	15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13},
					/* S[2]			*/
	{15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10,
	 3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5,
	 0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15,
	13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9},
					/* S[3]			*/
	{10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8,
	13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1,
	13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7,
	 1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12},
					/* S[4]			*/
	 {7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15,
	13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9,
	10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4,
	 3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14},
					/* S[5]			*/
	 {2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9,
	14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6,
	 4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14,
	11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3},
					/* S[6]			*/
	{12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11,
	10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8,
	 9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6,
	 4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13},
					/* S[7]			*/
	 {4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1,
	13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6,
	 1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2,
	 6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12},
					/* S[8]			*/
	{13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7,
	 1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2,
	 7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8,
	 2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11}
};

static unsigned char P32Tr[] = {	/* 32-bit permutation function */
	16,  7, 20, 21,
	29, 12, 28, 17,
	 1, 15, 23, 26,
	 5, 18, 31, 10,
	 2,  8, 24, 14,
	32, 27,  3,  9,
	19, 13, 30,  6,
	22, 11,  4, 25,
};

static unsigned char CIFP[] = {		/* compressed/interleaved permutation */
	 1,  2,  3,  4,   17, 18, 19, 20,
	 5,  6,  7,  8,   21, 22, 23, 24,
	 9, 10, 11, 12,   25, 26, 27, 28,
	13, 14, 15, 16,   29, 30, 31, 32,

	33, 34, 35, 36,   49, 50, 51, 52,
	37, 38, 39, 40,   53, 54, 55, 56,
	41, 42, 43, 44,   57, 58, 59, 60,
	45, 46, 47, 48,   61, 62, 63, 64,
};

static unsigned char itoa64[] =		/* 0..63 => ascii-64 */
	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";


/* =====  Tables that are initialized at run time  ==================== */


static unsigned char a64toi[128];	/* ascii-64 => 0..63 */

/* Initial key schedule permutation */
static C_block	PC1ROT[64/CHUNKBITS][1<<CHUNKBITS];

/* Subsequent key schedule rotation permutations */
static C_block	PC2ROT[2][64/CHUNKBITS][1<<CHUNKBITS];

/* Initial permutation/expansion table */
static C_block	IE3264[32/CHUNKBITS][1<<CHUNKBITS];

/* Table that combines the S, P, and E operations.  */
static int SPE[2][8][64];

/* compressed/interleaved => final permutation table */
static C_block	CF6464[64/CHUNKBITS][1<<CHUNKBITS];


/* ==================================== */


static C_block	constdatablock;			/* encryption constant */
static char	cryptresult[1+4+4+11+1];	/* encrypted result */

/*
 * Return a pointer to static data consisting of the "setting"
 * followed by an encryption produced by the "key" and "setting".
 */
char *
crypt(key, setting)
	register const char *key;
	register const char *setting;
{