projects / thirdparty / openssl.git / blame
| Commit | Line | Data |
|---|---|---|
| d02b48c6 RE |
1 | /* crypto/dh/dh_check.c */ |
| 2 | /* Copyright (C) 1995-1997 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 "cryptlib.h" | |
| 61 | #include "bn.h" | |
| 62 | #include "dh.h" | |
| 63 | ||
| 64 | /* Check that p is a strong prime and | |
| 65 | * if g is 2, 3 or 5, check that is is a suitable generator | |
| 66 | * where | |
| 67 | * for 2, p mod 24 == 11 | |
| 68 | * for 3, p mod 12 == 5 | |
| 69 | * for 5, p mod 10 == 3 or 7 | |
| 70 | * should hold. | |
| 71 | */ | |
| 72 | ||
| 73 | int DH_check(dh,ret) | |
| 74 | DH *dh; | |
| 75 | int *ret; | |
| 76 | { | |
| 77 | int ok=0; | |
| 78 | BN_CTX *ctx=NULL; | |
| 79 | BN_ULONG l; | |
| 80 | BIGNUM *q=NULL; | |
| 81 | ||
| 82 | *ret=0; | |
| 83 | ctx=BN_CTX_new(); | |
| 84 | if (ctx == NULL) goto err; | |
| 85 | q=BN_new(); | |
| 86 | if (q == NULL) goto err; | |
| 87 | ||
| 88 | if (BN_is_word(dh->g,DH_GENERATOR_2)) | |
| 89 | { | |
| 90 | l=BN_mod_word(dh->p,24); | |
| 91 | if (l != 11) *ret|=DH_NOT_SUITABLE_GENERATOR; | |
| 92 | } | |
| 93 | /* else if (BN_is_word(dh->g,DH_GENERATOR_3)) | |
| 94 | { | |
| 95 | l=BN_mod_word(dh->p,12); | |
| 96 | if (l != 5) *ret|=DH_NOT_SUITABLE_GENERATOR; | |
| 97 | }*/ | |
| 98 | else if (BN_is_word(dh->g,DH_GENERATOR_5)) | |
| 99 | { | |
| 100 | l=BN_mod_word(dh->p,10); | |
| 101 | if ((l != 3) && (l != 7)) | |
| 102 | *ret|=DH_NOT_SUITABLE_GENERATOR; | |
| 103 | } | |
| 104 | else | |
| 105 | *ret|=DH_UNABLE_TO_CHECK_GENERATOR; | |
| 106 | ||
| 107 | if (!BN_is_prime(dh->p,BN_prime_checks,NULL,ctx)) | |
| 108 | *ret|=DH_CHECK_P_NOT_PRIME; | |
| 109 | else | |
| 110 | { | |
| 111 | if (!BN_rshift1(q,dh->p)) goto err; | |
| 112 | if (!BN_is_prime(q,BN_prime_checks,NULL,ctx)) | |
| 113 | *ret|=DH_CHECK_P_NOT_STRONG_PRIME; | |
| 114 | } | |
| 115 | ok=1; | |
| 116 | err: | |
| 117 | if (ctx != NULL) BN_CTX_free(ctx); | |
| 118 | if (q != NULL) BN_free(q); | |
| 119 | return(ok); | |
| 120 | } |