Bug Summary

File:src/lib/libcrypto/bn/bn_lib.c
Warning:line 725, column 16
Array access (via field 'd') results in a null pointer dereference

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name bn_lib.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/lib/libcrypto/obj -resource-dir /usr/local/lib/clang/13.0.0 -D LIBRESSL_INTERNAL -D LIBRESSL_CRYPTO_INTERNAL -D DSO_DLFCN -D HAVE_DLFCN_H -D HAVE_FUNOPEN -D OPENSSL_NO_HW_PADLOCK -I /usr/src/lib/libcrypto -I /usr/src/lib/libcrypto/asn1 -I /usr/src/lib/libcrypto/bio -I /usr/src/lib/libcrypto/bn -I /usr/src/lib/libcrypto/bytestring -I /usr/src/lib/libcrypto/dh -I /usr/src/lib/libcrypto/dsa -I /usr/src/lib/libcrypto/ec -I /usr/src/lib/libcrypto/ecdh -I /usr/src/lib/libcrypto/ecdsa -I /usr/src/lib/libcrypto/evp -I /usr/src/lib/libcrypto/hmac -I /usr/src/lib/libcrypto/modes -I /usr/src/lib/libcrypto/ocsp -I /usr/src/lib/libcrypto/rsa -I /usr/src/lib/libcrypto/x509 -I /usr/src/lib/libcrypto/obj -D AES_ASM -D BSAES_ASM -D VPAES_ASM -D OPENSSL_IA32_SSE2 -D RSA_ASM -D OPENSSL_BN_ASM_MONT -D OPENSSL_BN_ASM_MONT5 -D OPENSSL_BN_ASM_GF2m -D MD5_ASM -D GHASH_ASM -D RC4_MD5_ASM -D SHA1_ASM -D SHA256_ASM -D SHA512_ASM -D WHIRLPOOL_ASM -D OPENSSL_CPUID_OBJ -D PIC -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/lib/libcrypto/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/lib/libcrypto/bn/bn_lib.c
1/* $OpenBSD: bn_lib.c,v 1.53 2021/12/27 15:12:22 jsing Exp $ */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
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.
8 *
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).
15 *
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.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
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)"
40 *
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
51 * SUCH DAMAGE.
52 *
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.]
57 */
58
59#ifndef BN_DEBUG
60# undef NDEBUG /* avoid conflicting definitions */
61# define NDEBUG
62#endif
63
64#include <assert.h>
65#include <limits.h>
66#include <stdio.h>
67#include <string.h>
68
69#include <openssl/opensslconf.h>
70
71#include <openssl/err.h>
72
73#include "bn_lcl.h"
74
75/* This stuff appears to be completely unused, so is deprecated */
76#ifndef OPENSSL_NO_DEPRECATED
77/* For a 32 bit machine
78 * 2 - 4 == 128
79 * 3 - 8 == 256
80 * 4 - 16 == 512
81 * 5 - 32 == 1024
82 * 6 - 64 == 2048
83 * 7 - 128 == 4096
84 * 8 - 256 == 8192
85 */
86static int bn_limit_bits = 0;
87static int bn_limit_num = 8; /* (1<<bn_limit_bits) */
88static int bn_limit_bits_low = 0;
89static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
90static int bn_limit_bits_high = 0;
91static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
92static int bn_limit_bits_mont = 0;
93static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
94
95BIGNUM *
96BN_new(void)
97{
98 BIGNUM *ret;
99
100 if ((ret = malloc(sizeof(BIGNUM))) == NULL((void *)0)) {
4
←
Assuming the condition is false
→
5
←
Taking false branch
→
101 BNerror(ERR_R_MALLOC_FAILURE)ERR_put_error(3,(0xfff),((1|64)),"/usr/src/lib/libcrypto/bn/bn_lib.c"
,101);
102 return (NULL((void *)0));
103 }
104 ret->flags = BN_FLG_MALLOCED0x01;
105 ret->top = 0;
106 ret->neg = 0;
107 ret->dmax = 0;
108 ret->d = NULL((void *)0);
6
←
Null pointer value stored to field 'd'
→
109 bn_check_top(ret);
110 return (ret);
111}
112
113void
114BN_init(BIGNUM *a)
115{
116 memset(a, 0, sizeof(BIGNUM));
117 bn_check_top(a);
118}
119
120void
121BN_clear(BIGNUM *a)
122{
123 bn_check_top(a);
124 if (a->d != NULL((void *)0))
125 explicit_bzero(a->d, a->dmax * sizeof(a->d[0]));
126 a->top = 0;
127 a->neg = 0;
128}
129
130void
131BN_clear_free(BIGNUM *a)
132{
133 int i;
134
135 if (a == NULL((void *)0))
136 return;
137 bn_check_top(a);
138 if (a->d != NULL((void *)0) && !(BN_get_flags(a, BN_FLG_STATIC_DATA0x02)))
139 freezero(a->d, a->dmax * sizeof(a->d[0]));
140 i = BN_get_flags(a, BN_FLG_MALLOCED0x01);
141 explicit_bzero(a, sizeof(BIGNUM));
142 if (i)
143 free(a);
144}
145
146void
147BN_free(BIGNUM *a)
148{
149 BN_clear_free(a);
150}
151
152void
153BN_set_params(int mult, int high, int low, int mont)
154{
155 if (mult >= 0) {
156 if (mult > (int)(sizeof(int) * 8) - 1)
157 mult = sizeof(int) * 8 - 1;
158 bn_limit_bits = mult;
159 bn_limit_num = 1 << mult;
160 }
161 if (high >= 0) {
162 if (high > (int)(sizeof(int) * 8) - 1)
163 high = sizeof(int) * 8 - 1;
164 bn_limit_bits_high = high;
165 bn_limit_num_high = 1 << high;
166 }
167 if (low >= 0) {
168 if (low > (int)(sizeof(int) * 8) - 1)
169 low = sizeof(int) * 8 - 1;
170 bn_limit_bits_low = low;
171 bn_limit_num_low = 1 << low;
172 }
173 if (mont >= 0) {
174 if (mont > (int)(sizeof(int) * 8) - 1)
175 mont = sizeof(int) * 8 - 1;
176 bn_limit_bits_mont = mont;
177 bn_limit_num_mont = 1 << mont;
178 }
179}
180
181int
182BN_get_params(int which)
183{
184 if (which == 0)
185 return (bn_limit_bits);
186 else if (which == 1)
187 return (bn_limit_bits_high);
188 else if (which == 2)
189 return (bn_limit_bits_low);
190 else if (which == 3)
191 return (bn_limit_bits_mont);
192 else
193 return (0);
194}
195#endif
196
197void
198BN_set_flags(BIGNUM *b, int n)
199{
200 b->flags |= n;
201}
202
203int
204BN_get_flags(const BIGNUM *b, int n)
205{
206 return b->flags & n;
207}
208
209void
210BN_with_flags(BIGNUM *dest, const BIGNUM *b, int flags)
211{
212 int dest_flags;
213
214 dest_flags = (dest->flags & BN_FLG_MALLOCED0x01) |
215 (b->flags & ~BN_FLG_MALLOCED0x01) | BN_FLG_STATIC_DATA0x02 | flags;
216
217 *dest = *b;
218 dest->flags = dest_flags;
219}
220
221const BIGNUM *
222BN_value_one(void)
223{
224 static const BN_ULONGunsigned long data_one = 1L;
225 static const BIGNUM const_one = {
226 (BN_ULONGunsigned long *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA0x02
227 };
228
229 return (&const_one);
230}
231
232int
233BN_num_bits_word(BN_ULONGunsigned long l)
234{
235 BN_ULONGunsigned long x, mask;
236 int bits;
237 unsigned int shift;
238
239 /* Constant time calculation of floor(log2(l)) + 1. */
240 bits = (l != 0);
241 shift = BN_BITS432; /* On _LP64 this is 32, otherwise 16. */
242 do {
243 x = l >> shift;
244 /* If x is 0, set mask to 0, otherwise set it to all 1s. */
245 mask = ((~x & (x - 1)) >> (BN_BITS264 - 1)) - 1;
246 bits += shift & mask;
247 /* If x is 0, leave l alone, otherwise set l = x. */
248 l ^= (x ^ l) & mask;
249 } while ((shift /= 2) != 0);
250
251 return bits;
252}
253
254int
255BN_num_bits(const BIGNUM *a)
256{
257 int i = a->top - 1;
258
259 bn_check_top(a);
260
261 if (BN_is_zero(a))
262 return 0;
263 return ((i * BN_BITS264) + BN_num_bits_word(a->d[i]));
264}
265
266/* This is used both by bn_expand2() and bn_dup_expand() */
267/* The caller MUST check that words > b->dmax before calling this */
268static BN_ULONGunsigned long *
269bn_expand_internal(const BIGNUM *b, int words)
270{
271 BN_ULONGunsigned long *A, *a = NULL((void *)0);
272 const BN_ULONGunsigned long *B;
273 int i;
274
275 bn_check_top(b);
276
277 if (words > (INT_MAX2147483647/(4*BN_BITS264))) {
278 BNerror(BN_R_BIGNUM_TOO_LONG)ERR_put_error(3,(0xfff),(114),"/usr/src/lib/libcrypto/bn/bn_lib.c"
,278);
279 return NULL((void *)0);
280 }
281 if (BN_get_flags(b, BN_FLG_STATIC_DATA0x02)) {
282 BNerror(BN_R_EXPAND_ON_STATIC_BIGNUM_DATA)ERR_put_error(3,(0xfff),(105),"/usr/src/lib/libcrypto/bn/bn_lib.c"
,282);
283 return (NULL((void *)0));
284 }
285 a = A = reallocarray(NULL((void *)0), words, sizeof(BN_ULONGunsigned long));
286 if (A == NULL((void *)0)) {
287 BNerror(ERR_R_MALLOC_FAILURE)ERR_put_error(3,(0xfff),((1|64)),"/usr/src/lib/libcrypto/bn/bn_lib.c"
,287);
288 return (NULL((void *)0));
289 }
290#if 1
291 B = b->d;
292 /* Check if the previous number needs to be copied */
293 if (B != NULL((void *)0)) {
294 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
295 /*
296 * The fact that the loop is unrolled
297 * 4-wise is a tribute to Intel. It's
298 * the one that doesn't have enough
299 * registers to accommodate more data.
300 * I'd unroll it 8-wise otherwise:-)
301 *
302 * <appro@fy.chalmers.se>
303 */
304 BN_ULONGunsigned long a0, a1, a2, a3;
305 a0 = B[0];
306 a1 = B[1];
307 a2 = B[2];
308 a3 = B[3];
309 A[0] = a0;
310 A[1] = a1;
311 A[2] = a2;
312 A[3] = a3;
313 }
314 switch (b->top & 3) {
315 case 3:
316 A[2] = B[2];
317 case 2:
318 A[1] = B[1];
319 case 1:
320 A[0] = B[0];
321 }
322 }
323
324#else
325 memset(A, 0, sizeof(BN_ULONGunsigned long) * words);
326 memcpy(A, b->d, sizeof(b->d[0]) * b->top);
327#endif
328
329 return (a);
330}
331
332/* This is an internal function that can be used instead of bn_expand2()
333 * when there is a need to copy BIGNUMs instead of only expanding the
334 * data part, while still expanding them.
335 * Especially useful when needing to expand BIGNUMs that are declared
336 * 'const' and should therefore not be changed.
337 * The reason to use this instead of a BN_dup() followed by a bn_expand2()
338 * is memory allocation overhead. A BN_dup() followed by a bn_expand2()
339 * will allocate new memory for the BIGNUM data twice, and free it once,
340 * while bn_dup_expand() makes sure allocation is made only once.
341 */
342
343#ifndef OPENSSL_NO_DEPRECATED
344BIGNUM *
345bn_dup_expand(const BIGNUM *b, int words)
346{
347 BIGNUM *r = NULL((void *)0);
348
349 bn_check_top(b);
350
351 /* This function does not work if
352 * words <= b->dmax && top < words
353 * because BN_dup() does not preserve 'dmax'!
354 * (But bn_dup_expand() is not used anywhere yet.)
355 */
356
357 if (words > b->dmax) {
358 BN_ULONGunsigned long *a = bn_expand_internal(b, words);
359
360 if (a) {
361 r = BN_new();
362 if (r) {
363 r->top = b->top;
364 r->dmax = words;
365 r->neg = b->neg;
366 r->d = a;
367 } else {
368 /* r == NULL, BN_new failure */
369 free(a);
370 }
371 }
372 /* If a == NULL, there was an error in allocation in
373 bn_expand_internal(), and NULL should be returned */
374 } else {
375 r = BN_dup(b);
376 }
377
378 bn_check_top(r);
379 return r;
380}
381#endif
382
383/* This is an internal function that should not be used in applications.
384 * It ensures that 'b' has enough room for a 'words' word number
385 * and initialises any unused part of b->d with leading zeros.
386 * It is mostly used by the various BIGNUM routines. If there is an error,
387 * NULL is returned. If not, 'b' is returned. */
388
389BIGNUM *
390bn_expand2(BIGNUM *b, int words)
391{
392 bn_check_top(b);
393
394 if (words > b->dmax) {
395 BN_ULONGunsigned long *a = bn_expand_internal(b, words);
396 if (!a)
397 return NULL((void *)0);
398 if (b->d)
399 freezero(b->d, b->dmax * sizeof(b->d[0]));
400 b->d = a;
401 b->dmax = words;
402 }
403
404/* None of this should be necessary because of what b->top means! */
405#if 0
406 /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
407 if (b->top < b->dmax) {
408 int i;
409 BN_ULONGunsigned long *A = &(b->d[b->top]);
410 for (i = (b->dmax - b->top) >> 3; i > 0; i--, A += 8) {
411 A[0] = 0;
412 A[1] = 0;
413 A[2] = 0;
414 A[3] = 0;
415 A[4] = 0;
416 A[5] = 0;
417 A[6] = 0;
418 A[7] = 0;
419 }
420 for (i = (b->dmax - b->top)&7; i > 0; i--, A++)
421 A[0] = 0;
422 assert(A == &(b->d[b->dmax]))((void)0);
423 }
424#endif
425 bn_check_top(b);
426 return b;
427}
428
429BIGNUM *
430BN_dup(const BIGNUM *a)
431{
432 BIGNUM *t;
433
434 if (a == NULL((void *)0))
435 return NULL((void *)0);
436 bn_check_top(a);
437
438 t = BN_new();
439 if (t == NULL((void *)0))
440 return NULL((void *)0);
441 if (!BN_copy(t, a)) {
442 BN_free(t);
443 return NULL((void *)0);
444 }
445 bn_check_top(t);
446 return t;
447}
448
449BIGNUM *
450BN_copy(BIGNUM *a, const BIGNUM *b)
451{
452 int i;
453 BN_ULONGunsigned long *A;
454 const BN_ULONGunsigned long *B;
455
456 bn_check_top(b);
457
458 if (a == b)
459 return (a);
460 if (bn_wexpand(a, b->top)(((b->top) <= (a)->dmax)?(a):bn_expand2((a),(b->top
))) == NULL((void *)0))
461 return (NULL((void *)0));
462
463#if 1
464 A = a->d;
465 B = b->d;
466 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
467 BN_ULONGunsigned long a0, a1, a2, a3;
468 a0 = B[0];
469 a1 = B[1];
470 a2 = B[2];
471 a3 = B[3];
472 A[0] = a0;
473 A[1] = a1;
474 A[2] = a2;
475 A[3] = a3;
476 }
477 switch (b->top & 3) {
478 case 3:
479 A[2] = B[2];
480 case 2:
481 A[1] = B[1];
482 case 1:
483 A[0] = B[0];
484 }
485#else
486 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
487#endif
488
489 a->top = b->top;
490 a->neg = b->neg;
491 bn_check_top(a);
492 return (a);
493}
494
495void
496BN_swap(BIGNUM *a, BIGNUM *b)
497{
498 int flags_old_a, flags_old_b;
499 BN_ULONGunsigned long *tmp_d;
500 int tmp_top, tmp_dmax, tmp_neg;
501
502 bn_check_top(a);
503 bn_check_top(b);
504
505 flags_old_a = a->flags;
506 flags_old_b = b->flags;
507
508 tmp_d = a->d;
509 tmp_top = a->top;
510 tmp_dmax = a->dmax;
511 tmp_neg = a->neg;
512
513 a->d = b->d;
514 a->top = b->top;
515 a->dmax = b->dmax;
516 a->neg = b->neg;
517
518 b->d = tmp_d;
519 b->top = tmp_top;
520 b->dmax = tmp_dmax;
521 b->neg = tmp_neg;
522
523 a->flags = (flags_old_a & BN_FLG_MALLOCED0x01) |
524 (flags_old_b & BN_FLG_STATIC_DATA0x02);
525 b->flags = (flags_old_b & BN_FLG_MALLOCED0x01) |
526 (flags_old_a & BN_FLG_STATIC_DATA0x02);
527 bn_check_top(a);
528 bn_check_top(b);
529}
530
531BN_ULONGunsigned long
532BN_get_word(const BIGNUM *a)
533{
534 if (a->top > 1)
535 return BN_MASK2(0xffffffffffffffffL);
536 else if (a->top == 1)
537 return a->d[0];
538 /* a->top == 0 */
539 return 0;
540}
541
542BIGNUM *
543bn_expand(BIGNUM *a, int bits)
544{
545 if (bits > (INT_MAX2147483647 - BN_BITS264 + 1))
546 return (NULL((void *)0));
547
548 if (((bits + BN_BITS264 - 1) / BN_BITS264) <= a->dmax)
549 return (a);
550
551 return bn_expand2(a, (bits + BN_BITS264 - 1) / BN_BITS264);
552}
553
554int
555BN_set_word(BIGNUM *a, BN_ULONGunsigned long w)
556{
557 bn_check_top(a);
558 if (bn_expand(a, (int)sizeof(BN_ULONGunsigned long) * 8) == NULL((void *)0))
559 return (0);
560 a->neg = 0;
561 a->d[0] = w;
562 a->top = (w ? 1 : 0);
563 bn_check_top(a);
564 return (1);
565}
566
567BIGNUM *
568BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
569{
570 unsigned int i, m;
571 unsigned int n;
572 BN_ULONGunsigned long l;
573 BIGNUM *bn = NULL((void *)0);
574
575 if (len < 0)
576 return (NULL((void *)0));
577 if (ret == NULL((void *)0))
578 ret = bn = BN_new();
579 if (ret == NULL((void *)0))
580 return (NULL((void *)0));
581 bn_check_top(ret);
582 l = 0;
583 n = len;
584 if (n == 0) {
585 ret->top = 0;
586 return (ret);
587 }
588 i = ((n - 1) / BN_BYTES8) + 1;
589 m = ((n - 1) % (BN_BYTES8));
590 if (bn_wexpand(ret, (int)i)((((int)i) <= (ret)->dmax)?(ret):bn_expand2((ret),((int
)i))) == NULL((void *)0)) {
591 BN_free(bn);
592 return NULL((void *)0);
593 }
594 ret->top = i;
595 ret->neg = 0;
596 while (n--) {
597 l = (l << 8L) | *(s++);
598 if (m-- == 0) {
599 ret->d[--i] = l;
600 l = 0;
601 m = BN_BYTES8 - 1;
602 }
603 }
604 /* need to call this due to clear byte at top if avoiding
605 * having the top bit set (-ve number) */
606 bn_correct_top(ret){ unsigned long *ftl; int tmp_top = (ret)->top; if (tmp_top
> 0) { for (ftl= &((ret)->d[tmp_top-1]); tmp_top >
0; tmp_top--) if (*(ftl--)) break; (ret)->top = tmp_top; }
; };
607 return (ret);
608}
609
610typedef enum {
611 big,
612 little,
613} endianness_t;
614
615/* ignore negative */
616static int
617bn2binpad(const BIGNUM *a, unsigned char *to, int tolen, endianness_t endianness)
618{
619 int n;
620 size_t i, lasti, j, atop, mask;
621 BN_ULONGunsigned long l;
622
623 /*
624 * In case |a| is fixed-top, BN_num_bytes can return bogus length,
625 * but it's assumed that fixed-top inputs ought to be "nominated"
626 * even for padded output, so it works out...
627 */
628 n = BN_num_bytes(a)((BN_num_bits(a)+7)/8);
629 if (tolen == -1)
630 tolen = n;
631 else if (tolen < n) { /* uncommon/unlike case */
632 BIGNUM temp = *a;
633
634 bn_correct_top(&temp){ unsigned long *ftl; int tmp_top = (&temp)->top; if (
tmp_top > 0) { for (ftl= &((&temp)->d[tmp_top-1
]); tmp_top > 0; tmp_top--) if (*(ftl--)) break; (&temp
)->top = tmp_top; } ; };
635
636 n = BN_num_bytes(&temp)((BN_num_bits(&temp)+7)/8);
637 if (tolen < n)
638 return -1;
639 }
640
641 /* Swipe through whole available data and don't give away padded zero. */
642 atop = a->dmax * BN_BYTES8;
643 if (atop == 0) {
644 explicit_bzero(to, tolen);
645 return tolen;
646 }
647
648 lasti = atop - 1;
649 atop = a->top * BN_BYTES8;
650
651 if (endianness == big)
652 to += tolen; /* start from the end of the buffer */
653
654 for (i = 0, j = 0; j < (size_t)tolen; j++) {
655 unsigned char val;
656
657 l = a->d[i / BN_BYTES8];
658 mask = 0 - ((j - atop) >> (8 * sizeof(i) - 1));
659 val = (unsigned char)(l >> (8 * (i % BN_BYTES8)) & mask);
660
661 if (endianness == big)
662 *--to = val;
663 else
664 *to++ = val;
665
666 i += (i - lasti) >> (8 * sizeof(i) - 1); /* stay on last limb */
667 }
668
669 return tolen;
670}
671
672int
673BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
674{
675 if (tolen < 0)
676 return -1;
677 return bn2binpad(a, to, tolen, big);
678}
679
680int
681BN_bn2bin(const BIGNUM *a, unsigned char *to)
682{
683 return bn2binpad(a, to, -1, big);
684}
685
686BIGNUM *
687BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret)
688{
689 unsigned int i, m, n;
690 BN_ULONGunsigned long l;
691 BIGNUM *bn = NULL((void *)0);
692
693 if (ret == NULL((void *)0))
1
Assuming 'ret' is equal to NULL
→
2
←
Taking true branch
→
694 ret = bn = BN_new();
3
←
Calling 'BN_new'
→
7
←
Returning from 'BN_new'
→
695 if (ret
7.1
'ret' is not equal to NULL
 == NULL((void *)0))
8
←
Taking false branch
→
696 return NULL((void *)0);
697
698 bn_check_top(ret);
699
700 s += len;
701 /* Skip trailing zeroes. */
702 for (; len > 0 && s[-1] == 0; s--, len--)
9
←
Assuming 'len' is <= 0
→
703 continue;
704
705 n = len;
706 if (n == 0) {
10
←
Assuming 'n' is not equal to 0
→
11
←
Taking false branch
→
707 ret->top = 0;
708 return ret;
709 }
710
711 i = ((n - 1) / BN_BYTES8) + 1;
712 m = (n - 1) % BN_BYTES8;
713 if (bn_wexpand(ret, (int)i)((((int)i) <= (ret)->dmax)?(ret):bn_expand2((ret),((int
)i))) == NULL((void *)0)) {
12
←
Assuming 'i' is <= field 'dmax'
→
13
←
'?' condition is true
→
14
←
Taking false branch
→
714 BN_free(bn);
715 return NULL((void *)0);
716 }
717
718 ret->top = i;
719 ret->neg = 0;
720 l = 0;
721 while (n-- > 0) {
15
←
Loop condition is true. Entering loop body
→
722 s--;
723 l = (l << 8L) | *s;
724 if (m-- == 0) {
16
←
Assuming the condition is true
→
17
←
Taking true branch
→
725 ret->d[--i] = l;
18
←
Array access (via field 'd') results in a null pointer dereference
726 l = 0;
727 m = BN_BYTES8 - 1;
728 }
729 }
730
731 /*
732 * need to call this due to clear byte at top if avoiding having the
733 * top bit set (-ve number)
734 */
735 bn_correct_top(ret){ unsigned long *ftl; int tmp_top = (ret)->top; if (tmp_top
> 0) { for (ftl= &((ret)->d[tmp_top-1]); tmp_top >
0; tmp_top--) if (*(ftl--)) break; (ret)->top = tmp_top; }
; };
736
737 return ret;
738}
739
740int
741BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen)
742{
743 if (tolen < 0)
744 return -1;
745
746 return bn2binpad(a, to, tolen, little);
747}
748
749int
750BN_ucmp(const BIGNUM *a, const BIGNUM *b)
751{
752 int i;
753 BN_ULONGunsigned long t1, t2, *ap, *bp;
754
755 bn_check_top(a);
756 bn_check_top(b);
757
758 i = a->top - b->top;
759 if (i != 0)
760 return (i);
761 ap = a->d;
762 bp = b->d;
763 for (i = a->top - 1; i >= 0; i--) {
764 t1 = ap[i];
765 t2 = bp[i];
766 if (t1 != t2)
767 return ((t1 > t2) ? 1 : -1);
768 }
769 return (0);
770}
771
772int
773BN_cmp(const BIGNUM *a, const BIGNUM *b)
774{
775 int i;
776 int gt, lt;
777 BN_ULONGunsigned long t1, t2;
778
779 if ((a == NULL((void *)0)) || (b == NULL((void *)0))) {
780 if (a != NULL((void *)0))
781 return (-1);
782 else if (b != NULL((void *)0))
783 return (1);
784 else
785 return (0);
786 }
787
788 bn_check_top(a);
789 bn_check_top(b);
790
791 if (a->neg != b->neg) {
792 if (a->neg)
793 return (-1);
794 else
795 return (1);
796 }
797 if (a->neg == 0) {
798 gt = 1;
799 lt = -1;
800 } else {
801 gt = -1;
802 lt = 1;
803 }
804
805 if (a->top > b->top)
806 return (gt);
807 if (a->top < b->top)
808 return (lt);
809 for (i = a->top - 1; i >= 0; i--) {
810 t1 = a->d[i];
811 t2 = b->d[i];
812 if (t1 > t2)
813 return (gt);
814 if (t1 < t2)
815 return (lt);
816 }
817 return (0);
818}
819
820int
821BN_set_bit(BIGNUM *a, int n)
822{
823 int i, j, k;
824
825 if (n < 0)
826 return 0;
827
828 i = n / BN_BITS264;
829 j = n % BN_BITS264;
830 if (a->top <= i) {
831 if (bn_wexpand(a, i + 1)(((i + 1) <= (a)->dmax)?(a):bn_expand2((a),(i + 1))) == NULL((void *)0))
832 return (0);
833 for (k = a->top; k < i + 1; k++)
834 a->d[k] = 0;
835 a->top = i + 1;
836 }
837
838 a->d[i] |= (((BN_ULONGunsigned long)1) << j);
839 bn_check_top(a);
840 return (1);
841}
842
843int
844BN_clear_bit(BIGNUM *a, int n)
845{
846 int i, j;
847
848 bn_check_top(a);
849 if (n < 0)
850 return 0;
851
852 i = n / BN_BITS264;
853 j = n % BN_BITS264;
854 if (a->top <= i)
855 return (0);
856
857 a->d[i] &= (~(((BN_ULONGunsigned long)1) << j));
858 bn_correct_top(a){ unsigned long *ftl; int tmp_top = (a)->top; if (tmp_top >
0) { for (ftl= &((a)->d[tmp_top-1]); tmp_top > 0; tmp_top
--) if (*(ftl--)) break; (a)->top = tmp_top; } ; };
859 return (1);
860}
861
862int
863BN_is_bit_set(const BIGNUM *a, int n)
864{
865 int i, j;
866
867 bn_check_top(a);
868 if (n < 0)
869 return 0;
870 i = n / BN_BITS264;
871 j = n % BN_BITS264;
872 if (a->top <= i)
873 return 0;
874 return (int)(((a->d[i]) >> j) & ((BN_ULONGunsigned long)1));
875}
876
877int
878BN_mask_bits(BIGNUM *a, int n)
879{
880 int b, w;
881
882 bn_check_top(a);
883 if (n < 0)
884 return 0;
885
886 w = n / BN_BITS264;
887 b = n % BN_BITS264;
888 if (w >= a->top)
889 return 0;
890 if (b == 0)
891 a->top = w;
892 else {
893 a->top = w + 1;
894 a->d[w] &= ~(BN_MASK2(0xffffffffffffffffL) << b);
895 }
896 bn_correct_top(a){ unsigned long *ftl; int tmp_top = (a)->top; if (tmp_top >
0) { for (ftl= &((a)->d[tmp_top-1]); tmp_top > 0; tmp_top
--) if (*(ftl--)) break; (a)->top = tmp_top; } ; };
897 return (1);
898}
899
900void
901BN_set_negative(BIGNUM *a, int b)
902{
903 if (b && !BN_is_zero(a))
904 a->neg = 1;
905 else
906 a->neg = 0;
907}
908
909int
910bn_cmp_words(const BN_ULONGunsigned long *a, const BN_ULONGunsigned long *b, int n)
911{
912 int i;
913 BN_ULONGunsigned long aa, bb;
914
915 aa = a[n - 1];
916 bb = b[n - 1];
917 if (aa != bb)
918 return ((aa > bb) ? 1 : -1);
919 for (i = n - 2; i >= 0; i--) {
920 aa = a[i];
921 bb = b[i];
922 if (aa != bb)
923 return ((aa > bb) ? 1 : -1);
924 }
925 return (0);
926}
927
928/* Here follows a specialised variants of bn_cmp_words(). It has the
929 property of performing the operation on arrays of different sizes.
930 The sizes of those arrays is expressed through cl, which is the
931 common length ( basicall, min(len(a),len(b)) ), and dl, which is the
932 delta between the two lengths, calculated as len(a)-len(b).
933 All lengths are the number of BN_ULONGs... */
934
935int
936bn_cmp_part_words(const BN_ULONGunsigned long *a, const BN_ULONGunsigned long *b, int cl, int dl)
937{
938 int n, i;
939
940 n = cl - 1;
941
942 if (dl < 0) {
943 for (i = dl; i < 0; i++) {
944 if (b[n - i] != 0)
945 return -1; /* a < b */
946 }
947 }
948 if (dl > 0) {
949 for (i = dl; i > 0; i--) {
950 if (a[n + i] != 0)
951 return 1; /* a > b */
952 }
953 }
954 return bn_cmp_words(a, b, cl);
955}
956
957/*
958 * Constant-time conditional swap of a and b.
959 * a and b are swapped if condition is not 0.
960 * The code assumes that at most one bit of condition is set.
961 * nwords is the number of words to swap.
962 * The code assumes that at least nwords are allocated in both a and b,
963 * and that no more than nwords are used by either a or b.
964 * a and b cannot be the same number
965 */
966void
967BN_consttime_swap(BN_ULONGunsigned long condition, BIGNUM *a, BIGNUM *b, int nwords)
968{
969 BN_ULONGunsigned long t;
970 int i;
971
972 bn_wcheck_size(a, nwords);
973 bn_wcheck_size(b, nwords);
974
975 assert(a != b)((void)0);
976 assert((condition & (condition - 1)) == 0)((void)0);
977 assert(sizeof(BN_ULONG) >= sizeof(int))((void)0);
978
979 condition = ((condition - 1) >> (BN_BITS264 - 1)) - 1;
980
981 t = (a->top^b->top) & condition;
982 a->top ^= t;
983 b->top ^= t;
984
985#define BN_CONSTTIME_SWAP(ind) \
986 do { \
987 t = (a->d[ind] ^ b->d[ind]) & condition; \
988 a->d[ind] ^= t; \
989 b->d[ind] ^= t; \
990 } while (0)
991
992
993 switch (nwords) {
994 default:
995 for (i = 10; i < nwords; i++)
996 BN_CONSTTIME_SWAP(i);
997 /* Fallthrough */
998 case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
999 case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
1000 case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
1001 case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
1002 case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
1003 case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
1004 case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
1005 case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
1006 case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
1007 case 1:
1008 BN_CONSTTIME_SWAP(0);
1009 }
1010#undef BN_CONSTTIME_SWAP
1011}
1012
1013/*
1014 * Constant-time conditional swap of a and b.
1015 * a and b are swapped if condition is not 0.
1016 * nwords is the number of words to swap.
1017 */
1018int
1019BN_swap_ct(BN_ULONGunsigned long condition, BIGNUM *a, BIGNUM *b, size_t nwords)
1020{
1021 BN_ULONGunsigned long t;
1022 int i, words;
1023
1024 if (a == b)
1025 return 1;
1026 if (nwords > INT_MAX2147483647)
1027 return 0;
1028 words = (int)nwords;
1029 if (bn_wexpand(a, words)(((words) <= (a)->dmax)?(a):bn_expand2((a),(words))) == NULL((void *)0) || bn_wexpand(b, words)(((words) <= (b)->dmax)?(b):bn_expand2((b),(words))) == NULL((void *)0))
1030 return 0;
1031 if (a->top > words || b->top > words) {
1032 BNerror(BN_R_INVALID_LENGTH)ERR_put_error(3,(0xfff),(106),"/usr/src/lib/libcrypto/bn/bn_lib.c"
,1032);
1033 return 0;
1034 }
1035
1036 /* Set condition to 0 (if it was zero) or all 1s otherwise. */
1037 condition = ((~condition & (condition - 1)) >> (BN_BITS264 - 1)) - 1;
1038
1039 /* swap top field */
1040 t = (a->top ^ b->top) & condition;
1041 a->top ^= t;
1042 b->top ^= t;
1043
1044 /* swap neg field */
1045 t = (a->neg ^ b->neg) & condition;
1046 a->neg ^= t;
1047 b->neg ^= t;
1048
1049 /* swap BN_FLG_CONSTTIME from flag field */
1050 t = ((a->flags ^ b->flags) & BN_FLG_CONSTTIME0x04) & condition;
1051 a->flags ^= t;
1052 b->flags ^= t;
1053
1054 /* swap the data */
1055 for (i = 0; i < words; i++) {
1056 t = (a->d[i] ^ b->d[i]) & condition;
1057 a->d[i] ^= t;
1058 b->d[i] ^= t;
1059 }
1060
1061 return 1;
1062}
1063
1064void
1065BN_zero_ex(BIGNUM *a)
1066{
1067 a->neg = 0;
1068 a->top = 0;
1069 /* XXX: a->flags &= ~BN_FIXED_TOP */
1070}
1071
1072int
1073BN_abs_is_word(const BIGNUM *a, const BN_ULONGunsigned long w)
1074{
1075 return (a->top == 1 && a->d[0] == w) || (w == 0 && a->top == 0);
1076}
1077
1078int
1079BN_is_zero(const BIGNUM *a)
1080{
1081 return a->top == 0;
1082}
1083
1084int
1085BN_is_one(const BIGNUM *a)
1086{
1087 return BN_abs_is_word(a, 1) && !a->neg;
1088}
1089
1090int
1091BN_is_word(const BIGNUM *a, const BN_ULONGunsigned long w)
1092{
1093 return BN_abs_is_word(a, w) && (w == 0 || !a->neg);
1094}
1095
1096int
1097BN_is_odd(const BIGNUM *a)
1098{
1099 return a->top > 0 && (a->d[0] & 1);
1100}
1101
1102int
1103BN_is_negative(const BIGNUM *a)
1104{
1105 return a->neg != 0;
1106}
1107
1108BN_GENCB *
1109BN_GENCB_new(void)
1110{
1111 BN_GENCB *cb;
1112
1113 if ((cb = calloc(1, sizeof(*cb))) == NULL((void *)0))
1114 return NULL((void *)0);
1115
1116 return cb;
1117}
1118
1119void
1120BN_GENCB_free(BN_GENCB *cb)
1121{
1122 if (cb == NULL((void *)0))
1123 return;
1124 free(cb);
1125}
1126
1127/* Populate a BN_GENCB structure with an "old"-style callback */
1128void
1129BN_GENCB_set_old(BN_GENCB *gencb, void (*cb)(int, int, void *), void *cb_arg)
1130{
1131 gencb->ver = 1;
1132 gencb->cb.cb_1 = cb;
1133 gencb->arg = cb_arg;
1134}
1135
1136/* Populate a BN_GENCB structure with a "new"-style callback */
1137void
1138BN_GENCB_set(BN_GENCB *gencb, int (*cb)(int, int, BN_GENCB *), void *cb_arg)
1139{
1140 gencb->ver = 2;
1141 gencb->cb.cb_2 = cb;
1142 gencb->arg = cb_arg;
1143}
1144
1145void *
1146BN_GENCB_get_arg(BN_GENCB *cb)
1147{
1148 return cb->arg;
1149}