1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /*
28 * An aggregate context that is large enough for all supported hash
29 * functions.
30 */
31 typedef union {
32 const br_hash_class *vtable;
33 br_md5_context md5;
34 br_sha1_context sha1;
35 br_sha224_context sha224;
36 br_sha256_context sha256;
37 br_sha384_context sha384;
38 br_sha512_context sha512;
39 } gen_hash_context;
40
41 /*
42 * Get the offset to the state for a specific hash function within the
43 * context structure. This shall be called only for the supported hash
44 * functions,
45 */
46 static size_t
get_state_offset(int id)47 get_state_offset(int id)
48 {
49 if (id >= 5) {
50 /*
51 * SHA-384 has id 5, and SHA-512 has id 6. Both use
52 * eight 64-bit words for their state.
53 */
54 return offsetof(br_multihash_context, val_64)
55 + ((size_t)(id - 5) * (8 * sizeof(uint64_t)));
56 } else {
57 /*
58 * MD5 has id 1, SHA-1 has id 2, SHA-224 has id 3 and
59 * SHA-256 has id 4. They use 32-bit words for their
60 * states (4 words for MD5, 5 for SHA-1, 8 for SHA-224
61 * and 8 for SHA-256).
62 */
63 unsigned x;
64
65 x = id - 1;
66 x = ((x + (x & (x >> 1))) << 2) + (x >> 1);
67 return offsetof(br_multihash_context, val_32)
68 + x * sizeof(uint32_t);
69 }
70 }
71
72 /* see bearssl_hash.h */
73 void
br_multihash_zero(br_multihash_context * ctx)74 br_multihash_zero(br_multihash_context *ctx)
75 {
76 /*
77 * This is not standard, but yields very short and efficient code,
78 * and it works "everywhere".
79 */
80 memset(ctx, 0, sizeof *ctx);
81 }
82
83 /* see bearssl_hash.h */
84 void
br_multihash_init(br_multihash_context * ctx)85 br_multihash_init(br_multihash_context *ctx)
86 {
87 int i;
88
89 ctx->count = 0;
90 for (i = 1; i <= 6; i ++) {
91 const br_hash_class *hc;
92
93 hc = ctx->impl[i - 1];
94 if (hc != NULL) {
95 gen_hash_context g;
96
97 hc->init(&g.vtable);
98 hc->state(&g.vtable,
99 (unsigned char *)ctx + get_state_offset(i));
100 }
101 }
102 }
103
104 /* see bearssl_hash.h */
105 void
br_multihash_update(br_multihash_context * ctx,const void * data,size_t len)106 br_multihash_update(br_multihash_context *ctx, const void *data, size_t len)
107 {
108 const unsigned char *buf;
109 size_t ptr;
110
111 buf = data;
112 ptr = (size_t)ctx->count & 127;
113 while (len > 0) {
114 size_t clen;
115
116 clen = 128 - ptr;
117 if (clen > len) {
118 clen = len;
119 }
120 memcpy(ctx->buf + ptr, buf, clen);
121 ptr += clen;
122 buf += clen;
123 len -= clen;
124 ctx->count += (uint64_t)clen;
125 if (ptr == 128) {
126 int i;
127
128 for (i = 1; i <= 6; i ++) {
129 const br_hash_class *hc;
130
131 hc = ctx->impl[i - 1];
132 if (hc != NULL) {
133 gen_hash_context g;
134 unsigned char *state;
135
136 state = (unsigned char *)ctx
137 + get_state_offset(i);
138 hc->set_state(&g.vtable,
139 state, ctx->count - 128);
140 hc->update(&g.vtable, ctx->buf, 128);
141 hc->state(&g.vtable, state);
142 }
143 }
144 ptr = 0;
145 }
146 }
147 }
148
149 /* see bearssl_hash.h */
150 size_t
br_multihash_out(const br_multihash_context * ctx,int id,void * dst)151 br_multihash_out(const br_multihash_context *ctx, int id, void *dst)
152 {
153 const br_hash_class *hc;
154 gen_hash_context g;
155 const unsigned char *state;
156
157 hc = ctx->impl[id - 1];
158 if (hc == NULL) {
159 return 0;
160 }
161 state = (const unsigned char *)ctx + get_state_offset(id);
162 hc->set_state(&g.vtable, state, ctx->count & ~(uint64_t)127);
163 hc->update(&g.vtable, ctx->buf, ctx->count & (uint64_t)127);
164 hc->out(&g.vtable, dst);
165 return (hc->desc >> BR_HASHDESC_OUT_OFF) & BR_HASHDESC_OUT_MASK;
166 }
167