1 /* crypto/bn/bn_lib.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
60 # undef NDEBUG /* avoid conflicting definitions */
70 const char BN_version[]="Big Number" OPENSSL_VERSION_PTEXT;
72 /* This stuff appears to be completely unused, so is deprecated */
73 #ifndef OPENSSL_NO_DEPRECATED
74 /* For a 32 bit machine
83 static int bn_limit_bits=0;
84 static int bn_limit_num=8; /* (1<<bn_limit_bits) */
85 static int bn_limit_bits_low=0;
86 static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
87 static int bn_limit_bits_high=0;
88 static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
89 static int bn_limit_bits_mont=0;
90 static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
92 void BN_set_params(int mult, int high, int low, int mont)
96 if (mult > (int)(sizeof(int)*8)-1)
103 if (high > (int)(sizeof(int)*8)-1)
104 high=sizeof(int)*8-1;
105 bn_limit_bits_high=high;
106 bn_limit_num_high=1<<high;
110 if (low > (int)(sizeof(int)*8)-1)
112 bn_limit_bits_low=low;
113 bn_limit_num_low=1<<low;
117 if (mont > (int)(sizeof(int)*8)-1)
118 mont=sizeof(int)*8-1;
119 bn_limit_bits_mont=mont;
120 bn_limit_num_mont=1<<mont;
124 int BN_get_params(int which)
126 if (which == 0) return(bn_limit_bits);
127 else if (which == 1) return(bn_limit_bits_high);
128 else if (which == 2) return(bn_limit_bits_low);
129 else if (which == 3) return(bn_limit_bits_mont);
134 const BIGNUM *BN_value_one(void)
136 static BN_ULONG data_one=1L;
137 static BIGNUM const_one={&data_one,1,1,0,BN_FLG_STATIC_DATA};
142 int BN_num_bits_word(BN_ULONG l)
144 static const char bits[256]={
145 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
146 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
147 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
148 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
149 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
150 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
151 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
152 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
153 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
154 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
155 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
156 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
157 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
158 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
159 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
160 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
163 #if defined(SIXTY_FOUR_BIT_LONG)
164 if (l & 0xffffffff00000000L)
166 if (l & 0xffff000000000000L)
168 if (l & 0xff00000000000000L)
170 return(bits[(int)(l>>56)]+56);
172 else return(bits[(int)(l>>48)]+48);
176 if (l & 0x0000ff0000000000L)
178 return(bits[(int)(l>>40)]+40);
180 else return(bits[(int)(l>>32)]+32);
185 #ifdef SIXTY_FOUR_BIT
186 if (l & 0xffffffff00000000LL)
188 if (l & 0xffff000000000000LL)
190 if (l & 0xff00000000000000LL)
192 return(bits[(int)(l>>56)]+56);
194 else return(bits[(int)(l>>48)]+48);
198 if (l & 0x0000ff0000000000LL)
200 return(bits[(int)(l>>40)]+40);
202 else return(bits[(int)(l>>32)]+32);
209 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
213 return(bits[(int)(l>>24L)]+24);
214 else return(bits[(int)(l>>16L)]+16);
219 #if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
221 return(bits[(int)(l>>8)]+8);
224 return(bits[(int)(l )] );
229 int BN_num_bits(const BIGNUM *a)
234 if (BN_is_zero(a)) return 0;
235 return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
238 void BN_clear_free(BIGNUM *a)
242 if (a == NULL) return;
246 OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
247 if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
250 i=BN_get_flags(a,BN_FLG_MALLOCED);
251 OPENSSL_cleanse(a,sizeof(BIGNUM));
256 void BN_free(BIGNUM *a)
258 if (a == NULL) return;
260 if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
262 if (a->flags & BN_FLG_MALLOCED)
266 #ifndef OPENSSL_NO_DEPRECATED
267 a->flags|=BN_FLG_FREE;
273 void BN_init(BIGNUM *a)
275 memset(a,0,sizeof(BIGNUM));
283 if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
285 BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
288 ret->flags=BN_FLG_MALLOCED;
297 /* This is used both by bn_expand2() and bn_dup_expand() */
298 /* The caller MUST check that words > b->dmax before calling this */
299 static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
301 BN_ULONG *A,*a = NULL;
307 if (words > (INT_MAX/(4*BN_BITS2)))
309 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
312 if (BN_get_flags(b,BN_FLG_STATIC_DATA))
314 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
317 a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words);
320 BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
324 /* Valgrind complains in BN_consttime_swap because we process the whole
325 * array even if it's not initialised yet. This doesn't matter in that
326 * function - what's important is constant time operation (we're not
327 * actually going to use the data)
329 memset(a, 0, sizeof(BN_ULONG)*words);
334 /* Check if the previous number needs to be copied */
337 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
340 * The fact that the loop is unrolled
341 * 4-wise is a tribute to Intel. It's
342 * the one that doesn't have enough
343 * registers to accomodate more data.
344 * I'd unroll it 8-wise otherwise:-)
346 * <appro@fy.chalmers.se>
348 BN_ULONG a0,a1,a2,a3;
349 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
350 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
357 case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
358 * the switch table by doing a=top&3; a--; goto jump_table[a];
359 * which fails for top== 0 */
365 memset(A,0,sizeof(BN_ULONG)*words);
366 memcpy(A,b->d,sizeof(b->d[0])*b->top);
372 /* This is an internal function that can be used instead of bn_expand2()
373 * when there is a need to copy BIGNUMs instead of only expanding the
374 * data part, while still expanding them.
375 * Especially useful when needing to expand BIGNUMs that are declared
376 * 'const' and should therefore not be changed.
377 * The reason to use this instead of a BN_dup() followed by a bn_expand2()
378 * is memory allocation overhead. A BN_dup() followed by a bn_expand2()
379 * will allocate new memory for the BIGNUM data twice, and free it once,
380 * while bn_dup_expand() makes sure allocation is made only once.
383 #ifndef OPENSSL_NO_DEPRECATED
384 BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
390 /* This function does not work if
391 * words <= b->dmax && top < words
392 * because BN_dup() does not preserve 'dmax'!
393 * (But bn_dup_expand() is not used anywhere yet.)
398 BN_ULONG *a = bn_expand_internal(b, words);
412 /* r == NULL, BN_new failure */
416 /* If a == NULL, there was an error in allocation in
417 bn_expand_internal(), and NULL should be returned */
429 /* This is an internal function that should not be used in applications.
430 * It ensures that 'b' has enough room for a 'words' word number
431 * and initialises any unused part of b->d with leading zeros.
432 * It is mostly used by the various BIGNUM routines. If there is an error,
433 * NULL is returned. If not, 'b' is returned. */
435 BIGNUM *bn_expand2(BIGNUM *b, int words)
441 BN_ULONG *a = bn_expand_internal(b, words);
443 if(b->d) OPENSSL_free(b->d);
448 /* None of this should be necessary because of what b->top means! */
450 /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
451 if (b->top < b->dmax)
454 BN_ULONG *A = &(b->d[b->top]);
455 for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
457 A[0]=0; A[1]=0; A[2]=0; A[3]=0;
458 A[4]=0; A[5]=0; A[6]=0; A[7]=0;
460 for (i=(b->dmax - b->top)&7; i>0; i--,A++)
462 assert(A == &(b->d[b->dmax]));
469 BIGNUM *BN_dup(const BIGNUM *a)
473 if (a == NULL) return NULL;
477 if (t == NULL) return NULL;
487 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
495 if (a == b) return(a);
496 if (bn_wexpand(a,b->top) == NULL) return(NULL);
501 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
503 BN_ULONG a0,a1,a2,a3;
504 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
505 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
512 case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
515 memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
524 void BN_swap(BIGNUM *a, BIGNUM *b)
526 int flags_old_a, flags_old_b;
528 int tmp_top, tmp_dmax, tmp_neg;
533 flags_old_a = a->flags;
534 flags_old_b = b->flags;
551 a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
552 b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
557 void BN_clear(BIGNUM *a)
561 memset(a->d,0,a->dmax*sizeof(a->d[0]));
566 BN_ULONG BN_get_word(const BIGNUM *a)
570 else if (a->top == 1)
576 int BN_set_word(BIGNUM *a, BN_ULONG w)
579 if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
582 a->top = (w ? 1 : 0);
587 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
596 if (ret == NULL) return(NULL);
605 i=((n-1)/BN_BYTES)+1;
606 m=((n-1)%(BN_BYTES));
607 if (bn_wexpand(ret, (int)i) == NULL)
624 /* need to call this due to clear byte at top if avoiding
625 * having the top bit set (-ve number) */
630 /* ignore negative */
631 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
641 *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
646 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
649 BN_ULONG t1,t2,*ap,*bp;
655 if (i != 0) return(i);
658 for (i=a->top-1; i>=0; i--)
663 return((t1 > t2) ? 1 : -1);
668 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
674 if ((a == NULL) || (b == NULL))
687 if (a->neg != b->neg)
695 else { gt= -1; lt=1; }
697 if (a->top > b->top) return(gt);
698 if (a->top < b->top) return(lt);
699 for (i=a->top-1; i>=0; i--)
703 if (t1 > t2) return(gt);
704 if (t1 < t2) return(lt);
709 int BN_set_bit(BIGNUM *a, int n)
720 if (bn_wexpand(a,i+1) == NULL) return(0);
721 for(k=a->top; k<i+1; k++)
726 a->d[i]|=(((BN_ULONG)1)<<j);
731 int BN_clear_bit(BIGNUM *a, int n)
740 if (a->top <= i) return(0);
742 a->d[i]&=(~(((BN_ULONG)1)<<j));
747 int BN_is_bit_set(const BIGNUM *a, int n)
755 if (a->top <= i) return 0;
756 return(((a->d[i])>>j)&((BN_ULONG)1));
759 int BN_mask_bits(BIGNUM *a, int n)
768 if (w >= a->top) return 0;
774 a->d[w]&= ~(BN_MASK2<<b);
780 void BN_set_negative(BIGNUM *a, int b)
782 if (b && !BN_is_zero(a))
788 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
795 if (aa != bb) return((aa > bb)?1:-1);
796 for (i=n-2; i>=0; i--)
800 if (aa != bb) return((aa > bb)?1:-1);
805 /* Here follows a specialised variants of bn_cmp_words(). It has the
806 property of performing the operation on arrays of different sizes.
807 The sizes of those arrays is expressed through cl, which is the
808 common length ( basicall, min(len(a),len(b)) ), and dl, which is the
809 delta between the two lengths, calculated as len(a)-len(b).
810 All lengths are the number of BN_ULONGs... */
812 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
823 return -1; /* a < b */
831 return 1; /* a > b */
834 return bn_cmp_words(a,b,cl);