1*0957b409SSimon J. Gerraty /*
2*0957b409SSimon J. Gerraty * Copyright (c) 2018 Thomas Pornin <pornin@bolet.org>
3*0957b409SSimon J. Gerraty *
4*0957b409SSimon J. Gerraty * Permission is hereby granted, free of charge, to any person obtaining
5*0957b409SSimon J. Gerraty * a copy of this software and associated documentation files (the
6*0957b409SSimon J. Gerraty * "Software"), to deal in the Software without restriction, including
7*0957b409SSimon J. Gerraty * without limitation the rights to use, copy, modify, merge, publish,
8*0957b409SSimon J. Gerraty * distribute, sublicense, and/or sell copies of the Software, and to
9*0957b409SSimon J. Gerraty * permit persons to whom the Software is furnished to do so, subject to
10*0957b409SSimon J. Gerraty * the following conditions:
11*0957b409SSimon J. Gerraty *
12*0957b409SSimon J. Gerraty * The above copyright notice and this permission notice shall be
13*0957b409SSimon J. Gerraty * included in all copies or substantial portions of the Software.
14*0957b409SSimon J. Gerraty *
15*0957b409SSimon J. Gerraty * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16*0957b409SSimon J. Gerraty * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17*0957b409SSimon J. Gerraty * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18*0957b409SSimon J. Gerraty * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19*0957b409SSimon J. Gerraty * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20*0957b409SSimon J. Gerraty * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21*0957b409SSimon J. Gerraty * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22*0957b409SSimon J. Gerraty * SOFTWARE.
23*0957b409SSimon J. Gerraty */
24*0957b409SSimon J. Gerraty
25*0957b409SSimon J. Gerraty #include "inner.h"
26*0957b409SSimon J. Gerraty
27*0957b409SSimon J. Gerraty /*
28*0957b409SSimon J. Gerraty * Get the appropriate Base64 character for a numeric value in the
29*0957b409SSimon J. Gerraty * 0..63 range. This is constant-time.
30*0957b409SSimon J. Gerraty */
31*0957b409SSimon J. Gerraty static char
b64char(uint32_t x)32*0957b409SSimon J. Gerraty b64char(uint32_t x)
33*0957b409SSimon J. Gerraty {
34*0957b409SSimon J. Gerraty /*
35*0957b409SSimon J. Gerraty * Values 0 to 25 map to 0x41..0x5A ('A' to 'Z')
36*0957b409SSimon J. Gerraty * Values 26 to 51 map to 0x61..0x7A ('a' to 'z')
37*0957b409SSimon J. Gerraty * Values 52 to 61 map to 0x30..0x39 ('0' to '9')
38*0957b409SSimon J. Gerraty * Value 62 maps to 0x2B ('+')
39*0957b409SSimon J. Gerraty * Value 63 maps to 0x2F ('/')
40*0957b409SSimon J. Gerraty */
41*0957b409SSimon J. Gerraty uint32_t a, b, c;
42*0957b409SSimon J. Gerraty
43*0957b409SSimon J. Gerraty a = x - 26;
44*0957b409SSimon J. Gerraty b = x - 52;
45*0957b409SSimon J. Gerraty c = x - 62;
46*0957b409SSimon J. Gerraty
47*0957b409SSimon J. Gerraty /*
48*0957b409SSimon J. Gerraty * Looking at bits 8..15 of values a, b and c:
49*0957b409SSimon J. Gerraty *
50*0957b409SSimon J. Gerraty * x a b c
51*0957b409SSimon J. Gerraty * ---------------------
52*0957b409SSimon J. Gerraty * 0..25 FF FF FF
53*0957b409SSimon J. Gerraty * 26..51 00 FF FF
54*0957b409SSimon J. Gerraty * 52..61 00 00 FF
55*0957b409SSimon J. Gerraty * 62..63 00 00 00
56*0957b409SSimon J. Gerraty */
57*0957b409SSimon J. Gerraty return (char)(((x + 0x41) & ((a & b & c) >> 8))
58*0957b409SSimon J. Gerraty | ((x + (0x61 - 26)) & ((~a & b & c) >> 8))
59*0957b409SSimon J. Gerraty | ((x - (52 - 0x30)) & ((~a & ~b & c) >> 8))
60*0957b409SSimon J. Gerraty | ((0x2B + ((x & 1) << 2)) & (~(a | b | c) >> 8)));
61*0957b409SSimon J. Gerraty }
62*0957b409SSimon J. Gerraty
63*0957b409SSimon J. Gerraty /* see bearssl_pem.h */
64*0957b409SSimon J. Gerraty size_t
br_pem_encode(void * dest,const void * data,size_t len,const char * banner,unsigned flags)65*0957b409SSimon J. Gerraty br_pem_encode(void *dest, const void *data, size_t len,
66*0957b409SSimon J. Gerraty const char *banner, unsigned flags)
67*0957b409SSimon J. Gerraty {
68*0957b409SSimon J. Gerraty size_t dlen, banner_len, lines;
69*0957b409SSimon J. Gerraty char *d;
70*0957b409SSimon J. Gerraty unsigned char *buf;
71*0957b409SSimon J. Gerraty size_t u;
72*0957b409SSimon J. Gerraty int off, lim;
73*0957b409SSimon J. Gerraty
74*0957b409SSimon J. Gerraty banner_len = strlen(banner);
75*0957b409SSimon J. Gerraty /* FIXME: try to avoid divisions here, as they may pull
76*0957b409SSimon J. Gerraty an extra libc function. */
77*0957b409SSimon J. Gerraty if ((flags & BR_PEM_LINE64) != 0) {
78*0957b409SSimon J. Gerraty lines = (len + 47) / 48;
79*0957b409SSimon J. Gerraty } else {
80*0957b409SSimon J. Gerraty lines = (len + 56) / 57;
81*0957b409SSimon J. Gerraty }
82*0957b409SSimon J. Gerraty dlen = (banner_len << 1) + 30 + (((len + 2) / 3) << 2)
83*0957b409SSimon J. Gerraty + lines + 2;
84*0957b409SSimon J. Gerraty if ((flags & BR_PEM_CRLF) != 0) {
85*0957b409SSimon J. Gerraty dlen += lines + 2;
86*0957b409SSimon J. Gerraty }
87*0957b409SSimon J. Gerraty
88*0957b409SSimon J. Gerraty if (dest == NULL) {
89*0957b409SSimon J. Gerraty return dlen;
90*0957b409SSimon J. Gerraty }
91*0957b409SSimon J. Gerraty
92*0957b409SSimon J. Gerraty d = dest;
93*0957b409SSimon J. Gerraty
94*0957b409SSimon J. Gerraty /*
95*0957b409SSimon J. Gerraty * We always move the source data to the end of output buffer;
96*0957b409SSimon J. Gerraty * the encoding process never "catches up" except at the very
97*0957b409SSimon J. Gerraty * end. This also handles all conditions of partial or total
98*0957b409SSimon J. Gerraty * overlap.
99*0957b409SSimon J. Gerraty */
100*0957b409SSimon J. Gerraty buf = (unsigned char *)d + dlen - len;
101*0957b409SSimon J. Gerraty memmove(buf, data, len);
102*0957b409SSimon J. Gerraty
103*0957b409SSimon J. Gerraty memcpy(d, "-----BEGIN ", 11);
104*0957b409SSimon J. Gerraty d += 11;
105*0957b409SSimon J. Gerraty memcpy(d, banner, banner_len);
106*0957b409SSimon J. Gerraty d += banner_len;
107*0957b409SSimon J. Gerraty memcpy(d, "-----", 5);
108*0957b409SSimon J. Gerraty d += 5;
109*0957b409SSimon J. Gerraty if ((flags & BR_PEM_CRLF) != 0) {
110*0957b409SSimon J. Gerraty *d ++ = 0x0D;
111*0957b409SSimon J. Gerraty }
112*0957b409SSimon J. Gerraty *d ++ = 0x0A;
113*0957b409SSimon J. Gerraty
114*0957b409SSimon J. Gerraty off = 0;
115*0957b409SSimon J. Gerraty lim = (flags & BR_PEM_LINE64) != 0 ? 16 : 19;
116*0957b409SSimon J. Gerraty for (u = 0; (u + 2) < len; u += 3) {
117*0957b409SSimon J. Gerraty uint32_t w;
118*0957b409SSimon J. Gerraty
119*0957b409SSimon J. Gerraty w = ((uint32_t)buf[u] << 16)
120*0957b409SSimon J. Gerraty | ((uint32_t)buf[u + 1] << 8)
121*0957b409SSimon J. Gerraty | (uint32_t)buf[u + 2];
122*0957b409SSimon J. Gerraty *d ++ = b64char(w >> 18);
123*0957b409SSimon J. Gerraty *d ++ = b64char((w >> 12) & 0x3F);
124*0957b409SSimon J. Gerraty *d ++ = b64char((w >> 6) & 0x3F);
125*0957b409SSimon J. Gerraty *d ++ = b64char(w & 0x3F);
126*0957b409SSimon J. Gerraty if (++ off == lim) {
127*0957b409SSimon J. Gerraty off = 0;
128*0957b409SSimon J. Gerraty if ((flags & BR_PEM_CRLF) != 0) {
129*0957b409SSimon J. Gerraty *d ++ = 0x0D;
130*0957b409SSimon J. Gerraty }
131*0957b409SSimon J. Gerraty *d ++ = 0x0A;
132*0957b409SSimon J. Gerraty }
133*0957b409SSimon J. Gerraty }
134*0957b409SSimon J. Gerraty if (u < len) {
135*0957b409SSimon J. Gerraty uint32_t w;
136*0957b409SSimon J. Gerraty
137*0957b409SSimon J. Gerraty w = (uint32_t)buf[u] << 16;
138*0957b409SSimon J. Gerraty if (u + 1 < len) {
139*0957b409SSimon J. Gerraty w |= (uint32_t)buf[u + 1] << 8;
140*0957b409SSimon J. Gerraty }
141*0957b409SSimon J. Gerraty *d ++ = b64char(w >> 18);
142*0957b409SSimon J. Gerraty *d ++ = b64char((w >> 12) & 0x3F);
143*0957b409SSimon J. Gerraty if (u + 1 < len) {
144*0957b409SSimon J. Gerraty *d ++ = b64char((w >> 6) & 0x3F);
145*0957b409SSimon J. Gerraty } else {
146*0957b409SSimon J. Gerraty *d ++ = 0x3D;
147*0957b409SSimon J. Gerraty }
148*0957b409SSimon J. Gerraty *d ++ = 0x3D;
149*0957b409SSimon J. Gerraty off ++;
150*0957b409SSimon J. Gerraty }
151*0957b409SSimon J. Gerraty if (off != 0) {
152*0957b409SSimon J. Gerraty if ((flags & BR_PEM_CRLF) != 0) {
153*0957b409SSimon J. Gerraty *d ++ = 0x0D;
154*0957b409SSimon J. Gerraty }
155*0957b409SSimon J. Gerraty *d ++ = 0x0A;
156*0957b409SSimon J. Gerraty }
157*0957b409SSimon J. Gerraty
158*0957b409SSimon J. Gerraty memcpy(d, "-----END ", 9);
159*0957b409SSimon J. Gerraty d += 9;
160*0957b409SSimon J. Gerraty memcpy(d, banner, banner_len);
161*0957b409SSimon J. Gerraty d += banner_len;
162*0957b409SSimon J. Gerraty memcpy(d, "-----", 5);
163*0957b409SSimon J. Gerraty d += 5;
164*0957b409SSimon J. Gerraty if ((flags & BR_PEM_CRLF) != 0) {
165*0957b409SSimon J. Gerraty *d ++ = 0x0D;
166*0957b409SSimon J. Gerraty }
167*0957b409SSimon J. Gerraty *d ++ = 0x0A;
168*0957b409SSimon J. Gerraty
169*0957b409SSimon J. Gerraty /* Final zero, not counted in returned length. */
170*0957b409SSimon J. Gerraty *d ++ = 0x00;
171*0957b409SSimon J. Gerraty
172*0957b409SSimon J. Gerraty return dlen;
173*0957b409SSimon J. Gerraty }
174