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dh_gen.c

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/home/opencoverage/opencoverage/guest-scripts/libressl/src/crypto/dh/dh_gen.c

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1 /* $OpenBSD: dh_gen.c,v 1.16 2017/01/29 17:49:22 beck Exp $ */ -

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 /* NB: These functions have been upgraded - the previous prototypes are in -

60 * dh_depr.c as wrappers to these ones. -

61 * - Geoff -

62 */ -

63 -

64 #include <stdio.h> -

65 -

66 #include <openssl/bn.h> -

67 #include <openssl/dh.h> -

68 #include <openssl/err.h> -

69 -

70 static int dh_builtin_genparams(DH *ret, int prime_len, int generator, -

71 BN_GENCB *cb); -

72 -

73 int -

74 DH_generate_parameters_ex(DH *ret, int prime_len, int generator, BN_GENCB *cb) -

75 { -

if (ret->meth->generate_params)

ret->meth->generate_params	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

return ret->meth->generate_params(ret, prime_len, generator, cb);

never executed: return ret->meth->generate_params(ret, prime_len, generator, cb);

return dh_builtin_genparams(ret, prime_len, generator, cb);

executed 18 times by 2 tests: return dh_builtin_genparams(ret, prime_len, generator, cb);

Executed by:

dhtest
mont

79 } -

80 -

81 /* -

82 * We generate DH parameters as follows: -

83 * find a prime q which is prime_len/2 bits long. -

84 * p=(2*q)+1 or (p-1)/2 = q -

85 * For this case, g is a generator if -

86 * g^((p-1)/q) mod p != 1 for values of q which are the factors of p-1. -

87 * Since the factors of p-1 are q and 2, we just need to check -

88 * g^2 mod p != 1 and g^q mod p != 1. -

89 * -

90 * Having said all that, -

91 * there is another special case method for the generators 2, 3 and 5. -

92 * for 2, p mod 24 == 11 -

93 * for 3, p mod 12 == 5 <<<<< does not work for safe primes. -

94 * for 5, p mod 10 == 3 or 7 -

95 * -

96 * Thanks to Phil Karn <karn@qualcomm.com> for the pointers about the -

97 * special generators and for answering some of my questions. -

98 * -

99 * I've implemented the second simple method :-). -

100 * Since DH should be using a safe prime (both p and q are prime), -

101 * this generator function can take a very very long time to run. -

102 */ -

103 /* Actually there is no reason to insist that 'generator' be a generator. -

104 * It's just as OK (and in some sense better) to use a generator of the -

105 * order-q subgroup. -

106 */ -

107 static int -

108 dh_builtin_genparams(DH *ret, int prime_len, int generator, BN_GENCB *cb) -

109 { -

110 BIGNUM *t1, *t2; -

111 int g, ok = -1; -

112 BN_CTX *ctx = NULL; -

113 -

114 ctx = BN_CTX_new(); -

115

if (ctx == NULL)

ctx == ((void *)0)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

116

goto err;

never executed: goto err;

117 BN_CTX_start(ctx); -

118

if ((t1 = BN_CTX_get(ctx)) == NULL)

(t1 = BN_CTX_g...== ((void *)0)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

119

goto err;

never executed: goto err;

120

if ((t2 = BN_CTX_get(ctx)) == NULL)

(t2 = BN_CTX_g...== ((void *)0)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

121

goto err;

never executed: goto err;

122 -

123 /* Make sure 'ret' has the necessary elements */ -

124

if (!ret->p && ((ret->p = BN_new()) == NULL))

!ret->p	Description
TRUE	evaluated 18 times by 2 tests Evaluated by: dhtest mont
FALSE	never evaluated

((ret->p = BN_... ((void *)0) )	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

125

goto err;

never executed: goto err;

126

if (!ret->g && ((ret->g = BN_new()) == NULL))

!ret->g	Description
TRUE	evaluated 18 times by 2 tests Evaluated by: dhtest mont
FALSE	never evaluated

((ret->g = BN_... ((void *)0) )	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

127

goto err;

never executed: goto err;

128 -

129

if (generator <= 1) {

generator <= 1	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

130 DHerror(DH_R_BAD_GENERATOR); -

131

goto err;

never executed: goto err;

132 } -

133

if (generator == DH_GENERATOR_2) {

generator == 2	Description
TRUE	evaluated 17 times by 1 test Evaluated by: mont
FALSE	evaluated 1 time by 1 test Evaluated by: dhtest

1-17

134

if (!BN_set_word(t1, 24))

!BN_set_word(t1, 24)	Description
TRUE	never evaluated
FALSE	evaluated 17 times by 1 test Evaluated by: mont

0-17

135

goto err;

never executed: goto err;

136

if (!BN_set_word(t2, 11))

!BN_set_word(t2, 11)	Description
TRUE	never evaluated
FALSE	evaluated 17 times by 1 test Evaluated by: mont

0-17

137

goto err;

never executed: goto err;

138 g = 2; -

139

} else if (generator == DH_GENERATOR_5) {

executed 17 times by 1 test: end of block

Executed by:

mont

generator == 5	Description
TRUE	evaluated 1 time by 1 test Evaluated by: dhtest
FALSE	never evaluated

0-17

140

if (!BN_set_word(t1, 10))

!BN_set_word(t1, 10)	Description
TRUE	never evaluated
FALSE	evaluated 1 time by 1 test Evaluated by: dhtest

0-1

141

goto err;

never executed: goto err;

142

if (!BN_set_word(t2, 3))

!BN_set_word(t2, 3)	Description
TRUE	never evaluated
FALSE	evaluated 1 time by 1 test Evaluated by: dhtest

0-1

143

goto err;

never executed: goto err;

144 /* BN_set_word(t3,7); just have to miss -

145 * out on these ones :-( */ -

146 g = 5; -

147

} else {

executed 1 time by 1 test: end of block

Executed by:

dhtest

148 /* -

149 * in the general case, don't worry if 'generator' is a -

150 * generator or not: since we are using safe primes, -

151 * it will generate either an order-q or an order-2q group, -

152 * which both is OK -

153 */ -

154

if (!BN_set_word(t1, 2))

!BN_set_word(t1, 2)	Description
TRUE	never evaluated
FALSE	never evaluated

155

goto err;

never executed: goto err;

156

if (!BN_set_word(t2, 1))

!BN_set_word(t2, 1)	Description
TRUE	never evaluated
FALSE	never evaluated

157

goto err;

never executed: goto err;

158 g = generator; -

159

}

never executed: end of block

160 -

161

if (!BN_generate_prime_ex(ret->p, prime_len, 1, t1, t2, cb))

!BN_generate_p...1, t1, t2, cb)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

162

goto err;

never executed: goto err;

163

if (!BN_GENCB_call(cb, 3, 0))

!BN_GENCB_call(cb, 3, 0)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

164

goto err;

never executed: goto err;

165

if (!BN_set_word(ret->g, g))

!BN_set_word(ret->g, g)	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

166

goto err;

never executed: goto err;

167 ok = 1; -

168

err:

code before this statement executed 18 times by 2 tests: err:

Executed by:

dhtest
mont

169

if (ok == -1) {

ok == -1	Description
TRUE	never evaluated
FALSE	evaluated 18 times by 2 tests Evaluated by: dhtest mont

0-18

170 DHerror(ERR_R_BN_LIB); -

171 ok = 0; -

172

}

never executed: end of block

173 -

174

if (ctx != NULL) {

ctx != ((void *)0)	Description
TRUE	evaluated 18 times by 2 tests Evaluated by: dhtest mont
FALSE	never evaluated

0-18

175 BN_CTX_end(ctx); -

176 BN_CTX_free(ctx); -

177

}

executed 18 times by 2 tests: end of block

Executed by:

dhtest
mont

178

return ok;

executed 18 times by 2 tests: return ok;

Executed by:

dhtest
mont

179 } -

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