Bug Summary

File:src/lib/libcrypto/bn/bn_exp2.c
Warning:line 282, column 9
3rd function call argument is an uninitialized value

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_exp2.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_exp2.c
1/* $OpenBSD: bn_exp2.c,v 1.12 2017/01/29 17:49:22 beck 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 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
60 *
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
63 * are met:
64 *
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
67 *
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
71 * distribution.
72 *
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
77 *
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
82 *
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
86 *
87 * 6. Redistributions of any form whatsoever must retain the following
88 * acknowledgment:
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
91 *
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
105 *
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
109 *
110 */
111
112#include <stdio.h>
113
114#include <openssl/err.h>
115
116#include "bn_lcl.h"
117
118#define TABLE_SIZE32 32
119
120int
121BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
122 const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m, BN_CTX *ctx,
123 BN_MONT_CTX *in_mont)
124{
125 int i, j, bits, b, bits1, bits2, ret = 0, wpos1, wpos2, window1, window2, wvalue1, wvalue2;
126 int r_is_one = 1;
127 BIGNUM *d, *r;
128 const BIGNUM *a_mod_m;
129 /* Tables of variables obtained from 'ctx' */
130 BIGNUM *val1[TABLE_SIZE32], *val2[TABLE_SIZE32];
131 BN_MONT_CTX *mont = NULL((void *)0);
132
133 bn_check_top(a1);
134 bn_check_top(p1);
135 bn_check_top(a2);
136 bn_check_top(p2);
137 bn_check_top(m);
138
139 if (!(m->d[0] & 1)) {
1
Assuming the condition is false
→
2
←
Taking false branch
→
140 BNerror(BN_R_CALLED_WITH_EVEN_MODULUS)ERR_put_error(3,(0xfff),(102),"/usr/src/lib/libcrypto/bn/bn_exp2.c"
,140);
141 return (0);
142 }
143 bits1 = BN_num_bits(p1);
144 bits2 = BN_num_bits(p2);
145 if ((bits1 == 0) && (bits2 == 0)) {
3
←
Assuming 'bits1' is not equal to 0
→
146 ret = BN_one(rr)BN_set_word((rr), 1);
147 return ret;
148 }
149
150 bits = (bits1 > bits2) ? bits1 : bits2;
4
←
Assuming 'bits1' is <= 'bits2'
→
5
←
'?' condition is false
→
151
152 BN_CTX_start(ctx);
153 if ((d = BN_CTX_get(ctx)) == NULL((void *)0))
6
←
Assuming the condition is false
→
7
←
Taking false branch
→
154 goto err;
155 if ((r = BN_CTX_get(ctx)) == NULL((void *)0))
8
←
Assuming the condition is false
→
9
←
Taking false branch
→
156 goto err;
157 if ((val1[0] = BN_CTX_get(ctx)) == NULL((void *)0))
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
158 goto err;
159 if ((val2[0] = BN_CTX_get(ctx)) == NULL((void *)0))
12
←
Assuming the condition is false
→
13
←
Taking false branch
→
160 goto err;
161
162 if (in_mont != NULL((void *)0))
14
←
Assuming 'in_mont' is equal to NULL
→
15
←
Taking false branch
→
163 mont = in_mont;
164 else {
165 if ((mont = BN_MONT_CTX_new()) == NULL((void *)0))
16
←
Assuming the condition is false
→
17
←
Taking false branch
→
166 goto err;
167 if (!BN_MONT_CTX_set(mont, m, ctx))
18
←
Assuming the condition is false
→
19
←
Taking false branch
→
168 goto err;
169 }
170
171 window1 = BN_window_bits_for_exponent_size(bits1)((bits1) > 671 ? 6 : (bits1) > 239 ? 5 : (bits1) > 79
? 4 : (bits1) > 23 ? 3 : 1);
20
←
Assuming 'bits1' is <= 671
→
21
←
'?' condition is false
→
22
←
Assuming 'bits1' is <= 239
→
23
←
'?' condition is false
→
24
←
Assuming 'bits1' is <= 79
→
25
←
'?' condition is false
→
26
←
Assuming 'bits1' is <= 23
→
27
←
'?' condition is false
→
172 window2 = BN_window_bits_for_exponent_size(bits2)((bits2) > 671 ? 6 : (bits2) > 239 ? 5 : (bits2) > 79
? 4 : (bits2) > 23 ? 3 : 1);
28
←
Assuming 'bits2' is <= 671
→
29
←
'?' condition is false
→
30
←
Assuming 'bits2' is <= 239
→
31
←
'?' condition is false
→
32
←
Assuming 'bits2' is <= 79
→
33
←
'?' condition is false
→
34
←
Assuming 'bits2' is <= 23
→
35
←
'?' condition is false
→
173
174 /*
175 * Build table for a1: val1[i] := a1^(2*i + 1) mod m for i = 0 .. 2^(window1-1)
176 */
177 if (a1->neg || BN_ucmp(a1, m) >= 0) {
36
←
Assuming field 'neg' is 0
→
37
←
Assuming the condition is false
→
38
←
Taking false branch
→
178 if (!BN_mod_ct(val1[0], a1, m, ctx)BN_div_ct(((void *)0),(val1[0]),(a1),(m),(ctx)))
179 goto err;
180 a_mod_m = val1[0];
181 } else
182 a_mod_m = a1;
183 if (BN_is_zero(a_mod_m)) {
39
←
Assuming the condition is false
→
40
←
Taking false branch
→
184 BN_zero(rr)(BN_set_word((rr),0));
185 ret = 1;
186 goto err;
187 }
188
189 if (!BN_to_montgomery(val1[0], a_mod_m, mont, ctx))
41
←
Assuming the condition is false
→
42
←
Taking false branch
→
190 goto err;
191 if (window1
42.1
'window1' is <= 1
 > 1) {
43
←
Taking false branch
→
192 if (!BN_mod_mul_montgomery(d, val1[0], val1[0], mont, ctx))
193 goto err;
194
195 j = 1 << (window1 - 1);
196 for (i = 1; i < j; i++) {
197 if (((val1[i] = BN_CTX_get(ctx)) == NULL((void *)0)) ||
198 !BN_mod_mul_montgomery(val1[i], val1[i - 1],
199 d, mont, ctx))
200 goto err;
201 }
202 }
203
204
205 /*
206 * Build table for a2: val2[i] := a2^(2*i + 1) mod m for i = 0 .. 2^(window2-1)
207 */
208 if (a2->neg || BN_ucmp(a2, m) >= 0) {
44
←
Assuming field 'neg' is 0
→
45
←
Assuming the condition is false
→
46
←
Taking false branch
→
209 if (!BN_mod_ct(val2[0], a2, m, ctx)BN_div_ct(((void *)0),(val2[0]),(a2),(m),(ctx)))
210 goto err;
211 a_mod_m = val2[0];
212 } else
213 a_mod_m = a2;
214 if (BN_is_zero(a_mod_m)) {
47
←
Assuming the condition is false
→
48
←
Taking false branch
→
215 BN_zero(rr)(BN_set_word((rr),0));
216 ret = 1;
217 goto err;
218 }
219 if (!BN_to_montgomery(val2[0], a_mod_m, mont, ctx))
49
←
Assuming the condition is false
→
50
←
Taking false branch
→
220 goto err;
221 if (window2
50.1
'window2' is <= 1
 > 1) {
51
←
Taking false branch
→
222 if (!BN_mod_mul_montgomery(d, val2[0], val2[0], mont, ctx))
223 goto err;
224
225 j = 1 << (window2 - 1);
226 for (i = 1; i < j; i++) {
227 if (((val2[i] = BN_CTX_get(ctx)) == NULL((void *)0)) ||
228 !BN_mod_mul_montgomery(val2[i], val2[i - 1],
229 d, mont, ctx))
230 goto err;
231 }
232 }
233
234
235 /* Now compute the power product, using independent windows. */
236 r_is_one = 1;
237 wvalue1 = 0; /* The 'value' of the first window */
238 wvalue2 = 0; /* The 'value' of the second window */
239 wpos1 = 0; /* If wvalue1 > 0, the bottom bit of the first window */
240 wpos2 = 0; /* If wvalue2 > 0, the bottom bit of the second window */
241
242 if (!BN_to_montgomery(r, BN_value_one(), mont, ctx))
52
←
Assuming the condition is false
→
53
←
Taking false branch
→
243 goto err;
244 for (b = bits - 1; b >= 0; b--) {
54
←
Assuming 'b' is >= 0
→
55
←
Loop condition is true. Entering loop body
→
245 if (!r_is_one
55.1
'r_is_one' is 1
) {
56
←
Taking false branch
→
246 if (!BN_mod_mul_montgomery(r, r,r, mont, ctx))
247 goto err;
248 }
249
250 if (!wvalue1
56.1
'wvalue1' is 0
)
57
←
Taking true branch
→
251 if (BN_is_bit_set(p1, b)) {
58
←
Assuming the condition is true
→
59
←
Taking true branch
→
252 /* consider bits b-window1+1 .. b for this window */
253 i = b - window1 + 1;
254 while (!BN_is_bit_set(p1, i)) /* works for i<0 */
60
←
Assuming the condition is false
→
61
←
Loop condition is false. Execution continues on line 256
→
255 i++;
256 wpos1 = i;
257 wvalue1 = 1;
258 for (i = b - 1; i >= wpos1; i--) {
62
←
Assuming 'i' is >= 'wpos1'
→
63
←
Loop condition is true. Entering loop body
→
66
←
Assuming 'i' is < 'wpos1'
→
67
←
Loop condition is false. Execution continues on line 265
→
259 wvalue1 <<= 1;
260 if (BN_is_bit_set(p1, i))
64
←
Assuming the condition is false
→
65
←
Taking false branch
→
261 wvalue1++;
262 }
263 }
264
265 if (!wvalue2
67.1
'wvalue2' is 0
)
68
←
Taking true branch
→
266 if (BN_is_bit_set(p2, b)) {
69
←
Assuming the condition is false
→
70
←
Taking false branch
→
267 /* consider bits b-window2+1 .. b for this window */
268 i = b - window2 + 1;
269 while (!BN_is_bit_set(p2, i))
270 i++;
271 wpos2 = i;
272 wvalue2 = 1;
273 for (i = b - 1; i >= wpos2; i--) {
274 wvalue2 <<= 1;
275 if (BN_is_bit_set(p2, i))
276 wvalue2++;
277 }
278 }
279
280 if (wvalue1
70.1
'wvalue1' is 2
 && b
70.2
'b' is equal to 'wpos1'
 == wpos1) {
71
←
Taking true branch
→
281 /* wvalue1 is odd and < 2^window1 */
282 if (!BN_mod_mul_montgomery(r, r, val1[wvalue1 >> 1],
72
←
3rd function call argument is an uninitialized value
283 mont, ctx))
284 goto err;
285 wvalue1 = 0;
286 r_is_one = 0;
287 }
288
289 if (wvalue2 && b == wpos2) {
290 /* wvalue2 is odd and < 2^window2 */
291 if (!BN_mod_mul_montgomery(r, r, val2[wvalue2 >> 1],
292 mont, ctx))
293 goto err;
294 wvalue2 = 0;
295 r_is_one = 0;
296 }
297 }
298 if (!BN_from_montgomery(rr, r,mont, ctx))
299 goto err;
300 ret = 1;
301
302err:
303 if ((in_mont == NULL((void *)0)) && (mont != NULL((void *)0)))
304 BN_MONT_CTX_free(mont);
305 BN_CTX_end(ctx);
306 bn_check_top(rr);
307 return (ret);
308}