1 #include <u.h>
2 #include <libc.h>
3 #include <libsec.h>
4 
5 static void encode(uchar*, u32int*, ulong);
6 
7 extern void _sha1block(uchar*, ulong, u32int*);
8 
9 /*
10  *  we require len to be a multiple of 64 for all but
11  *  the last call.  There must be room in the input buffer
12  *  to pad.
13  */
14 ulong lastlen;
15 
16 SHA1state*
17 sha1(uchar *p, ulong len, uchar *digest, SHA1state *s)
18 {
19 	uchar buf[128];
20 	u32int x[16];
21 	int i;
22 	uchar *e;
23 
24 lastlen = len;
25 	if(s == nil){
26 		s = malloc(sizeof(*s));
27 		if(s == nil)
28 			return nil;
29 		memset(s, 0, sizeof(*s));
30 		s->malloced = 1;
31 		assert(!s->seeded);
32 		assert(!s->blen);
33 	}
34 
35 	if(s->seeded == 0){
36 		/* seed the state, these constants would look nicer big-endian */
37 		s->state[0] = 0x67452301;
38 		s->state[1] = 0xefcdab89;
39 		s->state[2] = 0x98badcfe;
40 		s->state[3] = 0x10325476;
41 		s->state[4] = 0xc3d2e1f0;
42 		s->seeded = 1;
43 	}
44 
45 assert(len < 100000);
46 
47 	/* fill out the partial 64 byte block from previous calls */
48 	if(s->blen){
49 assert(s);
50 		i = 64 - s->blen;
51 		if(len < i)
52 			i = len;
53 		memmove(s->buf + s->blen, p, i);
54 		len -= i;
55 		s->blen += i;
56 		p += i;
57 		if(s->blen == 64){
58 			_sha1block(s->buf, s->blen, s->state);
59 			s->len += s->blen;
60 			s->blen = 0;
61 		}
62 	}
63 
64 assert(len < 1000000);
65 	/* do 64 byte blocks */
66 	i = len & ~0x3f;
67 	if(i){
68 assert(i < 1000000);
69 		_sha1block(p, i, s->state);
70 		s->len += i;
71 		len -= i;
72 		p += i;
73 	}
74 
75 	/* save the left overs if not last call */
76 	if(digest == 0){
77 		if(len){
78 			memmove(s->buf, p, len);
79 			s->blen += len;
80 		}
81 		return s;
82 	}
83 
84 	/*
85 	 *  this is the last time through, pad what's left with 0x80,
86 	 *  0's, and the input count to create a multiple of 64 bytes
87 	 */
88 	if(s->blen){
89 		p = s->buf;
90 		len = s->blen;
91 	} else {
92 		memmove(buf, p, len);
93 		p = buf;
94 	}
95 	s->len += len;
96 	e = p + len;
97 	if(len < 56)
98 		i = 56 - len;
99 	else
100 		i = 120 - len;
101 	memset(e, 0, i);
102 	*e = 0x80;
103 	len += i;
104 
105 	/* append the count */
106 	x[0] = s->len>>29;
107 	x[1] = s->len<<3;
108 	encode(p+len, x, 8);
109 
110 	/* digest the last part */
111 	_sha1block(p, len+8, s->state);
112 	s->len += len+8;
113 
114 	/* return result and free state */
115 	encode(digest, s->state, SHA1dlen);
116 	if(s->malloced == 1)
117 		free(s);
118 	return nil;
119 }
120 
121 /*
122  *	encodes input (ulong) into output (uchar). Assumes len is
123  *	a multiple of 4.
124  */
125 static void
126 encode(uchar *output, u32int *input, ulong len)
127 {
128 	u32int x;
129 	uchar *e;
130 
131 	for(e = output + len; output < e;) {
132 		x = *input++;
133 		*output++ = x >> 24;
134 		*output++ = x >> 16;
135 		*output++ = x >> 8;
136 		*output++ = x;
137 	}
138 }