Bug Summary

File:src/lib/libcrypto/rsa/rsa_gen.c
Warning:line 98, column 7
Although the value stored to 'r3' is used in the enclosing expression, the value is never actually read from 'r3'

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.4 -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name rsa_gen.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 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -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/llvm16/lib/clang/16 -D LIBRESSL_INTERNAL -D HAVE_FUNOPEN -I /usr/src/lib/libcrypto -I /usr/src/lib/libcrypto/arch/amd64 -I /usr/src/lib/libcrypto/asn1 -I /usr/src/lib/libcrypto/bio -I /usr/src/lib/libcrypto/bn -I /usr/src/lib/libcrypto/bn/arch/amd64 -I /usr/src/lib/libcrypto/bytestring -I /usr/src/lib/libcrypto/curve25519 -I /usr/src/lib/libcrypto/dh -I /usr/src/lib/libcrypto/dsa -I /usr/src/lib/libcrypto/ec -I /usr/src/lib/libcrypto/ecdsa -I /usr/src/lib/libcrypto/evp -I /usr/src/lib/libcrypto/hidden -I /usr/src/lib/libcrypto/hmac -I /usr/src/lib/libcrypto/kdf -I /usr/src/lib/libcrypto/modes -I /usr/src/lib/libcrypto/ocsp -I /usr/src/lib/libcrypto/pkcs12 -I /usr/src/lib/libcrypto/rsa -I /usr/src/lib/libcrypto/sha -I /usr/src/lib/libcrypto/ts -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 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 -internal-isystem /usr/local/llvm16/lib/clang/16/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/lib/libcrypto/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fcf-protection=branch -fno-jump-tables -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/scan/2024-01-11-140451-98009-1 -x c /usr/src/lib/libcrypto/rsa/rsa_gen.c
1/* $OpenBSD: rsa_gen.c,v 1.30 2023/07/08 12:26:45 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#include <stdio.h>
60#include <time.h>
61
62#include <openssl/bn.h>
63#include <openssl/err.h>
64#include <openssl/rsa.h>
65
66#include "bn_local.h"
67#include "rsa_local.h"
68
69static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb);
70
71int
72RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
73{
74 if (rsa->meth->rsa_keygen)
75 return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
76 return rsa_builtin_keygen(rsa, bits, e_value, cb);
77}
78LCRYPTO_ALIAS(RSA_generate_key_ex)asm("");
79
80static int
81rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
82{
83 BIGNUM *r0 = NULL((void *)0), *r1 = NULL((void *)0), *r2 = NULL((void *)0), *r3 = NULL((void *)0), *tmp;
84 BIGNUM pr0, d, p;
85 int bitsp, bitsq, ok = -1, n = 0;
86 BN_CTX *ctx = NULL((void *)0);
87
88 ctx = BN_CTX_new();
89 if (ctx == NULL((void *)0))
90 goto err;
91 BN_CTX_start(ctx);
92 if ((r0 = BN_CTX_get(ctx)) == NULL((void *)0))
93 goto err;
94 if ((r1 = BN_CTX_get(ctx)) == NULL((void *)0))
95 goto err;
96 if ((r2 = BN_CTX_get(ctx)) == NULL((void *)0))
97 goto err;
98 if ((r3 = BN_CTX_get(ctx)) == NULL((void *)0))
Although the value stored to 'r3' is used in the enclosing expression, the value is never actually read from 'r3'
99 goto err;
100
101 bitsp = (bits + 1) / 2;
102 bitsq = bits - bitsp;
103
104 /* We need the RSA components non-NULL */
105 if (!rsa->n && ((rsa->n = BN_new()) == NULL((void *)0)))
106 goto err;
107 if (!rsa->d && ((rsa->d = BN_new()) == NULL((void *)0)))
108 goto err;
109 if (!rsa->e && ((rsa->e = BN_new()) == NULL((void *)0)))
110 goto err;
111 if (!rsa->p && ((rsa->p = BN_new()) == NULL((void *)0)))
112 goto err;
113 if (!rsa->q && ((rsa->q = BN_new()) == NULL((void *)0)))
114 goto err;
115 if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL((void *)0)))
116 goto err;
117 if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL((void *)0)))
118 goto err;
119 if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL((void *)0)))
120 goto err;
121
122 if (!bn_copy(rsa->e, e_value))
123 goto err;
124
125 /* generate p and q */
126 for (;;) {
127 if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL((void *)0), NULL((void *)0), cb))
128 goto err;
129 if (!BN_sub(r2, rsa->p, BN_value_one()))
130 goto err;
131 if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
132 goto err;
133 if (BN_is_one(r1))
134 break;
135 if (!BN_GENCB_call(cb, 2, n++))
136 goto err;
137 }
138 if (!BN_GENCB_call(cb, 3, 0))
139 goto err;
140 for (;;) {
141 /*
142 * When generating ridiculously small keys, we can get stuck
143 * continually regenerating the same prime values. Check for
144 * this and bail if it happens 3 times.
145 */
146 unsigned int degenerate = 0;
147 do {
148 if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL((void *)0), NULL((void *)0),
149 cb))
150 goto err;
151 } while (BN_cmp(rsa->p, rsa->q) == 0 &&
152 ++degenerate < 3);
153 if (degenerate == 3) {
154 ok = 0; /* we set our own err */
155 RSAerror(RSA_R_KEY_SIZE_TOO_SMALL)ERR_put_error(4,(0xfff),(120),"/usr/src/lib/libcrypto/rsa/rsa_gen.c"
,155)
;
156 goto err;
157 }
158 if (!BN_sub(r2, rsa->q, BN_value_one()))
159 goto err;
160 if (!BN_gcd_ct(r1, r2, rsa->e, ctx))
161 goto err;
162 if (BN_is_one(r1))
163 break;
164 if (!BN_GENCB_call(cb, 2, n++))
165 goto err;
166 }
167 if (!BN_GENCB_call(cb, 3, 1))
168 goto err;
169 if (BN_cmp(rsa->p, rsa->q) < 0) {
170 tmp = rsa->p;
171 rsa->p = rsa->q;
172 rsa->q = tmp;
173 }
174
175 /* calculate n */
176 if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
177 goto err;
178
179 /* calculate d */
180 if (!BN_sub(r1, rsa->p, BN_value_one())) /* p-1 */
181 goto err;
182 if (!BN_sub(r2, rsa->q, BN_value_one())) /* q-1 */
183 goto err;
184 if (!BN_mul(r0, r1, r2, ctx)) /* (p-1)(q-1) */
185 goto err;
186
187 BN_init(&pr0);
188 BN_with_flags(&pr0, r0, BN_FLG_CONSTTIME0x04);
189
190 if (BN_mod_inverse_ct(rsa->d, rsa->e, &pr0, ctx) == NULL((void *)0)) /* d */
191 goto err;
192
193 /* set up d for correct BN_FLG_CONSTTIME flag */
194 BN_init(&d);
195 BN_with_flags(&d, rsa->d, BN_FLG_CONSTTIME0x04);
196
197 /* calculate d mod (p-1) */
198 if (!BN_mod_ct(rsa->dmp1, &d, r1, ctx))
199 goto err;
200
201 /* calculate d mod (q-1) */
202 if (!BN_mod_ct(rsa->dmq1, &d, r2, ctx))
203 goto err;
204
205 /* calculate inverse of q mod p */
206 BN_init(&p);
207 BN_with_flags(&p, rsa->p, BN_FLG_CONSTTIME0x04);
208 if (BN_mod_inverse_ct(rsa->iqmp, rsa->q, &p, ctx) == NULL((void *)0))
209 goto err;
210
211 ok = 1;
212err:
213 if (ok == -1) {
214 RSAerror(ERR_LIB_BN)ERR_put_error(4,(0xfff),(3),"/usr/src/lib/libcrypto/rsa/rsa_gen.c"
,214)
;
215 ok = 0;
216 }
217 if (ctx != NULL((void *)0)) {
218 BN_CTX_end(ctx);
219 BN_CTX_free(ctx);
220 }
221
222 return ok;
223}
224
225RSA *
226RSA_generate_key(int bits, unsigned long e_value,
227 void (*callback)(int, int, void *), void *cb_arg)
228{
229 BN_GENCB cb;
230 int i;
231 RSA *rsa = RSA_new();
232 BIGNUM *e = BN_new();
233
234 if (!rsa || !e)
235 goto err;
236
237 /* The problem is when building with 8, 16, or 32 BN_ULONG,
238 * unsigned long can be larger */
239 for (i = 0; i < (int)sizeof(unsigned long) * 8; i++) {
240 if (e_value & (1UL << i))
241 if (BN_set_bit(e, i) == 0)
242 goto err;
243 }
244
245 BN_GENCB_set_old(&cb, callback, cb_arg);
246
247 if (RSA_generate_key_ex(rsa, bits, e, &cb)) {
248 BN_free(e);
249 return rsa;
250 }
251err:
252 BN_free(e);
253 RSA_free(rsa);
254
255 return 0;
256}
257LCRYPTO_ALIAS(RSA_generate_key)asm("");