Bug Summary

File:out/../deps/openssl/openssl/crypto/bn/bn_mod.c
Warning:line 76, column 26
The left operand of '&' is a garbage value

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name bn_mod.c -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 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/home/maurizio/node-v18.6.0/out -resource-dir /usr/local/lib/clang/16.0.0 -D V8_DEPRECATION_WARNINGS -D V8_IMMINENT_DEPRECATION_WARNINGS -D _GLIBCXX_USE_CXX11_ABI=1 -D NODE_OPENSSL_CONF_NAME=nodejs_conf -D NODE_OPENSSL_HAS_QUIC -D __STDC_FORMAT_MACROS -D OPENSSL_NO_PINSHARED -D OPENSSL_THREADS -D OPENSSL_NO_HW -D OPENSSL_API_COMPAT=0x10100001L -D STATIC_LEGACY -D NDEBUG -D OPENSSL_USE_NODELETE -D L_ENDIAN -D OPENSSL_BUILDING_OPENSSL -D AES_ASM -D BSAES_ASM -D CMLL_ASM -D ECP_NISTZ256_ASM -D GHASH_ASM -D KECCAK1600_ASM -D MD5_ASM -D OPENSSL_BN_ASM_GF2m -D OPENSSL_BN_ASM_MONT -D OPENSSL_BN_ASM_MONT5 -D OPENSSL_CPUID_OBJ -D OPENSSL_IA32_SSE2 -D PADLOCK_ASM -D POLY1305_ASM -D SHA1_ASM -D SHA256_ASM -D SHA512_ASM -D VPAES_ASM -D WHIRLPOOL_ASM -D X25519_ASM -D OPENSSL_PIC -D MODULESDIR="/home/maurizio/node-v18.6.0/out/Release/obj.target/deps/openssl/lib/openssl-modules" -D OPENSSLDIR="/home/maurizio/node-v18.6.0/out/Release/obj.target/deps/openssl" -D OPENSSLDIR="/etc/ssl" -D ENGINESDIR="/dev/null" -D TERMIOS -I ../deps/openssl/openssl -I ../deps/openssl/openssl/include -I ../deps/openssl/openssl/crypto -I ../deps/openssl/openssl/crypto/include -I ../deps/openssl/openssl/crypto/modes -I ../deps/openssl/openssl/crypto/ec/curve448 -I ../deps/openssl/openssl/crypto/ec/curve448/arch_32 -I ../deps/openssl/openssl/providers/common/include -I ../deps/openssl/openssl/providers/implementations/include -I ../deps/openssl/config -I ../deps/openssl/config/archs/linux-x86_64/asm -I ../deps/openssl/config/archs/linux-x86_64/asm/include -I ../deps/openssl/config/archs/linux-x86_64/asm/crypto -I ../deps/openssl/config/archs/linux-x86_64/asm/crypto/include/internal -I ../deps/openssl/config/archs/linux-x86_64/asm/providers/common/include -internal-isystem /usr/local/lib/clang/16.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-redhat-linux/8/../../../../x86_64-redhat-linux/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -Wno-unused-parameter -Wno-missing-field-initializers -Wno-old-style-declaration -fdebug-compilation-dir=/home/maurizio/node-v18.6.0/out -ferror-limit 19 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-08-22-142216-507842-1 -x c ../deps/openssl/openssl/crypto/bn/bn_mod.c
1/*
2 * Copyright 1998-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include "internal/cryptlib.h"
11#include "bn_local.h"
12
13int BN_nnmod(BIGNUM *r, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
14{
15 /*
16 * like BN_mod, but returns non-negative remainder (i.e., 0 <= r < |d|
17 * always holds)
18 */
19
20 if (!(BN_mod(r, m, d, ctx)BN_div(((void*)0),(r),(m),(d),(ctx))))
21 return 0;
22 if (!r->neg)
23 return 1;
24 /* now -|d| < r < 0, so we have to set r := r + |d| */
25 return (d->neg ? BN_sub : BN_add) (r, r, d);
26}
27
28int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
29 BN_CTX *ctx)
30{
31 if (!BN_add(r, a, b))
32 return 0;
33 return BN_nnmod(r, r, m, ctx);
34}
35
36/*
37 * BN_mod_add variant that may be used if both a and b are non-negative and
38 * less than m. The original algorithm was
39 *
40 * if (!BN_uadd(r, a, b))
41 * return 0;
42 * if (BN_ucmp(r, m) >= 0)
43 * return BN_usub(r, r, m);
44 *
45 * which is replaced with addition, subtracting modulus, and conditional
46 * move depending on whether or not subtraction borrowed.
47 */
48int bn_mod_add_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
49 const BIGNUM *m)
50{
51 size_t i, ai, bi, mtop = m->top;
52 BN_ULONGunsigned long storage[1024 / BN_BITS2(8 * 8)];
53 BN_ULONGunsigned long carry, temp, mask, *rp, *tp = storage;
54 const BN_ULONGunsigned long *ap, *bp;
55
56 if (bn_wexpand(r, mtop) == NULL((void*)0))
2
←
Assuming the condition is false
→
3
←
Taking false branch
→
57 return 0;
58
59 if (mtop > sizeof(storage) / sizeof(storage[0])) {
4
←
Assuming the condition is false
→
60 tp = OPENSSL_malloc(mtop * sizeof(BN_ULONG))CRYPTO_malloc(mtop * sizeof(unsigned long), "../deps/openssl/openssl/crypto/bn/bn_mod.c"
, 60);
61 if (tp == NULL((void*)0)) {
62 ERR_raise(ERR_LIB_BN, ERR_R_MALLOC_FAILURE)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_mod.c"
,62,__func__), ERR_set_error)((3),((256|((0x1 << 18L)|(
0x2 << 18L)))),((void*)0));
63 return 0;
64 }
65 }
66
67 ap = a->d != NULL((void*)0) ? a->d : tp;
5
←
Taking false branch
→
6
←
Assuming field 'd' is not equal to NULL
→
7
←
'?' condition is true
→
68 bp = b->d != NULL((void*)0) ? b->d : tp;
8
←
Assuming field 'd' is equal to NULL
→
9
←
'?' condition is false
→
69
70 for (i = 0, ai = 0, bi = 0, carry = 0; i < mtop;) {
10
←
The value 0 is assigned to 'bi'
→
11
←
Assuming 'i' is < 'mtop'
→
12
←
Loop condition is true. Entering loop body
→
71 mask = (BN_ULONGunsigned long)0 - ((i - a->top) >> (8 * sizeof(i) - 1));
72 temp = ((ap[ai] & mask) + carry) & BN_MASK2(0xffffffffffffffffL);
73 carry = (temp < carry);
13
←
Assuming 'temp' is >= 'carry'
→
74
75 mask = (BN_ULONGunsigned long)0 - ((i - b->top) >> (8 * sizeof(i) - 1));
76 tp[i] = ((bp[bi] & mask) + temp) & BN_MASK2(0xffffffffffffffffL);
14
←
The left operand of '&' is a garbage value
77 carry += (tp[i] < temp);
78
79 i++;
80 ai += (i - a->dmax) >> (8 * sizeof(i) - 1);
81 bi += (i - b->dmax) >> (8 * sizeof(i) - 1);
82 }
83 rp = r->d;
84 carry -= bn_sub_words(rp, tp, m->d, mtop);
85 for (i = 0; i < mtop; i++) {
86 rp[i] = (carry & tp[i]) | (~carry & rp[i]);
87 ((volatile BN_ULONGunsigned long *)tp)[i] = 0;
88 }
89 r->top = mtop;
90 r->flags |= BN_FLG_FIXED_TOP0;
91 r->neg = 0;
92
93 if (tp != storage)
94 OPENSSL_free(tp)CRYPTO_free(tp, "../deps/openssl/openssl/crypto/bn/bn_mod.c",
94);
95
96 return 1;
97}
98
99int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
100 const BIGNUM *m)
101{
102 int ret = bn_mod_add_fixed_top(r, a, b, m);
1
Calling 'bn_mod_add_fixed_top'
→
103
104 if (ret)
105 bn_correct_top(r);
106
107 return ret;
108}
109
110int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
111 BN_CTX *ctx)
112{
113 if (!BN_sub(r, a, b))
114 return 0;
115 return BN_nnmod(r, r, m, ctx);
116}
117
118/*
119 * BN_mod_sub variant that may be used if both a and b are non-negative,
120 * a is less than m, while b is of same bit width as m. It's implemented
121 * as subtraction followed by two conditional additions.
122 *
123 * 0 <= a < m
124 * 0 <= b < 2^w < 2*m
125 *
126 * after subtraction
127 *
128 * -2*m < r = a - b < m
129 *
130 * Thus it takes up to two conditional additions to make |r| positive.
131 */
132int bn_mod_sub_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
133 const BIGNUM *m)
134{
135 size_t i, ai, bi, mtop = m->top;
136 BN_ULONGunsigned long borrow, carry, ta, tb, mask, *rp;
137 const BN_ULONGunsigned long *ap, *bp;
138
139 if (bn_wexpand(r, mtop) == NULL((void*)0))
140 return 0;
141
142 rp = r->d;
143 ap = a->d != NULL((void*)0) ? a->d : rp;
144 bp = b->d != NULL((void*)0) ? b->d : rp;
145
146 for (i = 0, ai = 0, bi = 0, borrow = 0; i < mtop;) {
147 mask = (BN_ULONGunsigned long)0 - ((i - a->top) >> (8 * sizeof(i) - 1));
148 ta = ap[ai] & mask;
149
150 mask = (BN_ULONGunsigned long)0 - ((i - b->top) >> (8 * sizeof(i) - 1));
151 tb = bp[bi] & mask;
152 rp[i] = ta - tb - borrow;
153 if (ta != tb)
154 borrow = (ta < tb);
155
156 i++;
157 ai += (i - a->dmax) >> (8 * sizeof(i) - 1);
158 bi += (i - b->dmax) >> (8 * sizeof(i) - 1);
159 }
160 ap = m->d;
161 for (i = 0, mask = 0 - borrow, carry = 0; i < mtop; i++) {
162 ta = ((ap[i] & mask) + carry) & BN_MASK2(0xffffffffffffffffL);
163 carry = (ta < carry);
164 rp[i] = (rp[i] + ta) & BN_MASK2(0xffffffffffffffffL);
165 carry += (rp[i] < ta);
166 }
167 borrow -= carry;
168 for (i = 0, mask = 0 - borrow, carry = 0; i < mtop; i++) {
169 ta = ((ap[i] & mask) + carry) & BN_MASK2(0xffffffffffffffffL);
170 carry = (ta < carry);
171 rp[i] = (rp[i] + ta) & BN_MASK2(0xffffffffffffffffL);
172 carry += (rp[i] < ta);
173 }
174
175 r->top = mtop;
176 r->flags |= BN_FLG_FIXED_TOP0;
177 r->neg = 0;
178
179 return 1;
180}
181
182/*
183 * BN_mod_sub variant that may be used if both a and b are non-negative and
184 * less than m
185 */
186int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
187 const BIGNUM *m)
188{
189 if (!BN_sub(r, a, b))
190 return 0;
191 if (r->neg)
192 return BN_add(r, r, m);
193 return 1;
194}
195
196/* slow but works */
197int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,
198 BN_CTX *ctx)
199{
200 BIGNUM *t;
201 int ret = 0;
202
203 bn_check_top(a);
204 bn_check_top(b);
205 bn_check_top(m);
206
207 BN_CTX_start(ctx);
208 if ((t = BN_CTX_get(ctx)) == NULL((void*)0))
209 goto err;
210 if (a == b) {
211 if (!BN_sqr(t, a, ctx))
212 goto err;
213 } else {
214 if (!BN_mul(t, a, b, ctx))
215 goto err;
216 }
217 if (!BN_nnmod(r, t, m, ctx))
218 goto err;
219 bn_check_top(r);
220 ret = 1;
221 err:
222 BN_CTX_end(ctx);
223 return ret;
224}
225
226int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
227{
228 if (!BN_sqr(r, a, ctx))
229 return 0;
230 /* r->neg == 0, thus we don't need BN_nnmod */
231 return BN_mod(r, r, m, ctx)BN_div(((void*)0),(r),(r),(m),(ctx));
232}
233
234int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
235{
236 if (!BN_lshift1(r, a))
237 return 0;
238 bn_check_top(r);
239 return BN_nnmod(r, r, m, ctx);
240}
241
242/*
243 * BN_mod_lshift1 variant that may be used if a is non-negative and less than
244 * m
245 */
246int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m)
247{
248 if (!BN_lshift1(r, a))
249 return 0;
250 bn_check_top(r);
251 if (BN_cmp(r, m) >= 0)
252 return BN_sub(r, r, m);
253 return 1;
254}
255
256int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m,
257 BN_CTX *ctx)
258{
259 BIGNUM *abs_m = NULL((void*)0);
260 int ret;
261
262 if (!BN_nnmod(r, a, m, ctx))
263 return 0;
264
265 if (m->neg) {
266 abs_m = BN_dup(m);
267 if (abs_m == NULL((void*)0))
268 return 0;
269 abs_m->neg = 0;
270 }
271
272 ret = BN_mod_lshift_quick(r, r, n, (abs_m ? abs_m : m));
273 bn_check_top(r);
274
275 BN_free(abs_m);
276 return ret;
277}
278
279/*
280 * BN_mod_lshift variant that may be used if a is non-negative and less than
281 * m
282 */
283int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m)
284{
285 if (r != a) {
286 if (BN_copy(r, a) == NULL((void*)0))
287 return 0;
288 }
289
290 while (n > 0) {
291 int max_shift;
292
293 /* 0 < r < m */
294 max_shift = BN_num_bits(m) - BN_num_bits(r);
295 /* max_shift >= 0 */
296
297 if (max_shift < 0) {
298 ERR_raise(ERR_LIB_BN, BN_R_INPUT_NOT_REDUCED)(ERR_new(), ERR_set_debug("../deps/openssl/openssl/crypto/bn/bn_mod.c"
,298,__func__), ERR_set_error)((3),(110),((void*)0));
299 return 0;
300 }
301
302 if (max_shift > n)
303 max_shift = n;
304
305 if (max_shift) {
306 if (!BN_lshift(r, r, max_shift))
307 return 0;
308 n -= max_shift;
309 } else {
310 if (!BN_lshift1(r, r))
311 return 0;
312 --n;
313 }
314
315 /* BN_num_bits(r) <= BN_num_bits(m) */
316
317 if (BN_cmp(r, m) >= 0) {
318 if (!BN_sub(r, r, m))
319 return 0;
320 }
321 }
322 bn_check_top(r);
323
324 return 1;
325}