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 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 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