1 /*
2 * File imported from FreeBSD, original by Poul-Henning Kamp.
3 *
4 * $FreeBSD: src/lib/libcrypt/crypt-md5.c,v 1.5 1999/12/17 20:21:45 peter Exp $
5 *
6 * contrib/pgcrypto/crypt-md5.c
7 */
8
9 #include "postgres.h"
10
11 #include "px.h"
12 #include "px-crypt.h"
13
14 #define MD5_SIZE 16
15
16 static const char _crypt_a64[] =
17 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
18
19 static void
_crypt_to64(char * s,unsigned long v,int n)20 _crypt_to64(char *s, unsigned long v, int n)
21 {
22 while (--n >= 0)
23 {
24 *s++ = _crypt_a64[v & 0x3f];
25 v >>= 6;
26 }
27 }
28
29 /*
30 * UNIX password
31 */
32
33 char *
px_crypt_md5(const char * pw,const char * salt,char * passwd,unsigned dstlen)34 px_crypt_md5(const char *pw, const char *salt, char *passwd, unsigned dstlen)
35 {
36 static char *magic = "$1$"; /* This string is magic for this algorithm.
37 * Having it this way, we can get better later
38 * on */
39 static char *p;
40 static const char *sp,
41 *ep;
42 unsigned char final[MD5_SIZE];
43 int sl,
44 pl,
45 i;
46 PX_MD *ctx,
47 *ctx1;
48 int err;
49 unsigned long l;
50
51 if (!passwd || dstlen < 120)
52 return NULL;
53
54 /* Refine the Salt first */
55 sp = salt;
56
57 /* If it starts with the magic string, then skip that */
58 if (strncmp(sp, magic, strlen(magic)) == 0)
59 sp += strlen(magic);
60
61 /* It stops at the first '$', max 8 chars */
62 for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
63 continue;
64
65 /* get the length of the true salt */
66 sl = ep - sp;
67
68 /* we need two PX_MD objects */
69 err = px_find_digest("md5", &ctx);
70 if (err)
71 return NULL;
72 err = px_find_digest("md5", &ctx1);
73 if (err)
74 {
75 /* this path is possible under low-memory circumstances */
76 px_md_free(ctx);
77 return NULL;
78 }
79
80 /* The password first, since that is what is most unknown */
81 px_md_update(ctx, (const uint8 *) pw, strlen(pw));
82
83 /* Then our magic string */
84 px_md_update(ctx, (uint8 *) magic, strlen(magic));
85
86 /* Then the raw salt */
87 px_md_update(ctx, (const uint8 *) sp, sl);
88
89 /* Then just as many characters of the MD5(pw,salt,pw) */
90 px_md_update(ctx1, (const uint8 *) pw, strlen(pw));
91 px_md_update(ctx1, (const uint8 *) sp, sl);
92 px_md_update(ctx1, (const uint8 *) pw, strlen(pw));
93 px_md_finish(ctx1, final);
94 for (pl = strlen(pw); pl > 0; pl -= MD5_SIZE)
95 px_md_update(ctx, final, pl > MD5_SIZE ? MD5_SIZE : pl);
96
97 /* Don't leave anything around in vm they could use. */
98 px_memset(final, 0, sizeof final);
99
100 /* Then something really weird... */
101 for (i = strlen(pw); i; i >>= 1)
102 if (i & 1)
103 px_md_update(ctx, final, 1);
104 else
105 px_md_update(ctx, (const uint8 *) pw, 1);
106
107 /* Now make the output string */
108 strcpy(passwd, magic);
109 strncat(passwd, sp, sl);
110 strcat(passwd, "$");
111
112 px_md_finish(ctx, final);
113
114 /*
115 * and now, just to make sure things don't run too fast On a 60 Mhz
116 * Pentium this takes 34 msec, so you would need 30 seconds to build a
117 * 1000 entry dictionary...
118 */
119 for (i = 0; i < 1000; i++)
120 {
121 px_md_reset(ctx1);
122 if (i & 1)
123 px_md_update(ctx1, (const uint8 *) pw, strlen(pw));
124 else
125 px_md_update(ctx1, final, MD5_SIZE);
126
127 if (i % 3)
128 px_md_update(ctx1, (const uint8 *) sp, sl);
129
130 if (i % 7)
131 px_md_update(ctx1, (const uint8 *) pw, strlen(pw));
132
133 if (i & 1)
134 px_md_update(ctx1, final, MD5_SIZE);
135 else
136 px_md_update(ctx1, (const uint8 *) pw, strlen(pw));
137 px_md_finish(ctx1, final);
138 }
139
140 p = passwd + strlen(passwd);
141
142 l = (final[0] << 16) | (final[6] << 8) | final[12];
143 _crypt_to64(p, l, 4);
144 p += 4;
145 l = (final[1] << 16) | (final[7] << 8) | final[13];
146 _crypt_to64(p, l, 4);
147 p += 4;
148 l = (final[2] << 16) | (final[8] << 8) | final[14];
149 _crypt_to64(p, l, 4);
150 p += 4;
151 l = (final[3] << 16) | (final[9] << 8) | final[15];
152 _crypt_to64(p, l, 4);
153 p += 4;
154 l = (final[4] << 16) | (final[10] << 8) | final[5];
155 _crypt_to64(p, l, 4);
156 p += 4;
157 l = final[11];
158 _crypt_to64(p, l, 2);
159 p += 2;
160 *p = '\0';
161
162 /* Don't leave anything around in vm they could use. */
163 px_memset(final, 0, sizeof final);
164
165 px_md_free(ctx1);
166 px_md_free(ctx);
167
168 return passwd;
169 }
170