1\ Copyright (c) 2016 Thomas Pornin <pornin@bolet.org> 2\ 3\ Permission is hereby granted, free of charge, to any person obtaining 4\ a copy of this software and associated documentation files (the 5\ "Software"), to deal in the Software without restriction, including 6\ without limitation the rights to use, copy, modify, merge, publish, 7\ distribute, sublicense, and/or sell copies of the Software, and to 8\ permit persons to whom the Software is furnished to do so, subject to 9\ the following conditions: 10\ 11\ The above copyright notice and this permission notice shall be 12\ included in all copies or substantial portions of the Software. 13\ 14\ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 15\ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 16\ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 17\ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 18\ BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 19\ ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 20\ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21\ SOFTWARE. 22 23preamble { 24 25#include "inner.h" 26 27#define CTX ((br_pem_decoder_context *)(void *)((unsigned char *)t0ctx - offsetof(br_pem_decoder_context, cpu))) 28 29/* see bearssl_pem.h */ 30void 31br_pem_decoder_init(br_pem_decoder_context *ctx) 32{ 33 memset(ctx, 0, sizeof *ctx); 34 ctx->cpu.dp = &ctx->dp_stack[0]; 35 ctx->cpu.rp = &ctx->rp_stack[0]; 36 br_pem_decoder_init_main(&ctx->cpu); 37 br_pem_decoder_run(&ctx->cpu); 38} 39 40/* see bearssl_pem.h */ 41size_t 42br_pem_decoder_push(br_pem_decoder_context *ctx, 43 const void *data, size_t len) 44{ 45 if (ctx->event) { 46 return 0; 47 } 48 ctx->hbuf = data; 49 ctx->hlen = len; 50 br_pem_decoder_run(&ctx->cpu); 51 return len - ctx->hlen; 52} 53 54/* see bearssl_pem.h */ 55int 56br_pem_decoder_event(br_pem_decoder_context *ctx) 57{ 58 int event; 59 60 event = ctx->event; 61 ctx->event = 0; 62 return event; 63} 64 65} 66 67\ Define a word that evaluates to the address of a field within the 68\ decoder context. 69: addr: 70 next-word { field } 71 "addr-" field + 0 1 define-word 72 0 8191 "offsetof(br_pem_decoder_context, " field + ")" + make-CX 73 postpone literal postpone ; ; 74 75addr: event 76addr: name 77addr: buf 78addr: ptr 79 80\ Set a byte at a specific address (offset within the context). 81cc: set8 ( value addr -- ) { 82 size_t addr = T0_POP(); 83 unsigned x = T0_POP(); 84 *((unsigned char *)CTX + addr) = x; 85} 86 87\ Get a byte at a specific address (offset within the context). 88cc: get8 ( addr -- value ) { 89 size_t addr = T0_POP(); 90 T0_PUSH(*((unsigned char *)CTX + addr)); 91} 92 93\ Send an event. 94: send-event ( event -- ) 95 addr-event set8 co ; 96 97\ Low-level function to read a single byte. Returned value is the byte 98\ (0 to 255), or -1 if there is no available data. 99cc: read8-native ( -- x ) { 100 if (CTX->hlen > 0) { 101 T0_PUSH(*CTX->hbuf ++); 102 CTX->hlen --; 103 } else { 104 T0_PUSHi(-1); 105 } 106} 107 108\ Read next byte. Block until the next byte is available. 109: read8 ( -- x ) 110 begin read8-native dup 0< ifnot ret then drop co again ; 111 112\ Read bytes until next end-of-line. 113: skip-newline ( -- ) 114 begin read8 `\n <> while repeat ; 115 116\ Read bytes until next end-of-line; verify that they are all whitespace. 117\ This returns -1 if they were all whitespace, 0 otherwise. 118: skip-newline-ws ( -- bool ) 119 -1 { r } 120 begin read8 dup `\n <> while ws? ifnot 0 >r then repeat 121 drop r ; 122 123\ Normalise a byte to uppercase (ASCII only). 124: norm-upper ( x -- x ) 125 dup dup `a >= swap `z <= and if 32 - then ; 126 127\ Read bytes and compare with the provided string. On mismatch, the 128\ rest of the line is consumed. Matching is not case sensitive. 129: match-string ( str -- bool ) 130 begin 131 dup data-get8 norm-upper dup ifnot 2drop -1 ret then 132 read8 norm-upper dup `\n = if drop 2drop 0 ret then 133 = ifnot drop skip-newline 0 ret then 134 1+ 135 again ; 136 137\ Read bytes into the provided buffer, but no more than the provided 138\ count. Reading stops when end-of-line is reached. Returned value 139\ is the count of bytes written to the buffer, or 0 if the buffer size 140\ was exceeded. All bytes are normalised to uppercase (ASCII only). 141: read-bytes ( addr len -- len ) 142 dup { orig-len } 143 swap 144 begin 145 over ifnot 2drop skip-newline 0 ret then 146 read8 dup `\n = if 2drop orig-len swap - ret then 147 dup `\r = if drop else norm-upper over set8 then 148 1+ swap 1- swap 149 again ; 150 151\ Remove trailing dashes from the name buffer. 152: trim-dashes ( len -- ) 153 begin dup while 154 1- 155 dup addr-name + get8 `- <> if 156 addr-name + 1+ 0 swap set8 ret 157 then 158 repeat 159 addr-name set8 ; 160 161\ Scan input for next "begin" banner. 162: next-banner-begin ( -- ) 163 begin 164 "-----BEGIN " match-string if 165 addr-name 127 read-bytes 166 dup if trim-dashes ret then 167 drop 168 then 169 again ; 170 171\ Convert a Base64 character to its numerical value. Returned value is 172\ 0 to 63 for Base64 characters, -1 for '=', and -2 for all other characters. 173cc: from-base64 ( char -- x ) { 174 uint32_t c = T0_POP(); 175 uint32_t p, q, r, z; 176 p = c - 0x41; 177 q = c - 0x61; 178 r = c - 0x30; 179 180 z = ((p + 2) & -LT(p, 26)) 181 | ((q + 28) & -LT(q, 26)) 182 | ((r + 54) & -LT(r, 10)) 183 | (64 & -EQ(c, 0x2B)) 184 | (65 & -EQ(c, 0x2F)) 185 | EQ(c, 0x3D); 186 T0_PUSHi((int32_t)z - 2); 187} 188 189\ Test whether a character is whitespace (but not a newline). 190: ws? ( x -- bool ) 191 dup `\n <> swap 32 <= and ; 192 193\ Read next character, skipping whitespace (except newline). 194: next-nonws ( -- x ) 195 begin 196 read8 dup ws? ifnot ret then 197 drop 198 again ; 199 200\ Write one byte in the output buffer. 201cc: write8 ( x -- ) { 202 unsigned char x = (unsigned char)T0_POP(); 203 CTX->buf[CTX->ptr ++] = x; 204 if (CTX->ptr == sizeof CTX->buf) { 205 if (CTX->dest) { 206 CTX->dest(CTX->dest_ctx, CTX->buf, sizeof CTX->buf); 207 } 208 CTX->ptr = 0; 209 } 210} 211 212\ Flush the output buffer. 213cc: flush-buf ( -- ) { 214 if (CTX->ptr > 0) { 215 if (CTX->dest) { 216 CTX->dest(CTX->dest_ctx, CTX->buf, CTX->ptr); 217 } 218 CTX->ptr = 0; 219 } 220} 221 222\ Decode the four next Base64 characters. Returned value is: 223\ 0 quartet processed, three bytes produced. 224\ -1 dash encountered as first character (no leading whitespace). 225\ 1 quartet processed, one or two bytes produced, terminator reached. 226\ 2 end-of-line reached. 227\ 3 error. 228\ For all positive return values, the remaining of the current line has been 229\ consumed. 230: decode-next-quartet ( -- r ) 231 \ Process first character. It may be a dash. 232 read8 dup `- = if drop -1 ret then 233 dup ws? if drop next-nonws then 234 dup `\n = if drop 2 ret then 235 from-base64 dup 0< if drop skip-newline 3 ret then 236 { acc } 237 238 \ Second character. 239 next-nonws dup `\n = if drop 3 ret then 240 from-base64 dup 0< if drop skip-newline 3 ret then 241 acc 6 << + >acc 242 243 \ Third character: may be an equal sign. 244 next-nonws dup `\n = if drop 3 ret then 245 dup `= = if 246 \ Fourth character must be an equal sign. 247 drop 248 next-nonws dup `\n = if drop 3 ret then 249 skip-newline-ws ifnot drop 3 ret then 250 `= <> if 3 ret then 251 acc 0x0F and if 3 ret then 252 acc 4 >> write8 253 1 ret 254 then 255 from-base64 dup 0< if drop skip-newline 3 ret then 256 acc 6 << + >acc 257 258 \ Fourth character: may be an equal sign. 259 next-nonws dup `\n = if drop 3 ret then 260 dup `= = if 261 drop skip-newline-ws ifnot 3 ret then 262 acc 0x03 and if 3 ret then 263 acc 10 >> write8 264 acc 2 >> write8 265 1 ret 266 then 267 from-base64 dup 0< if drop skip-newline 3 ret then 268 acc 6 << + >acc 269 acc 16 >> write8 270 acc 8 >> write8 271 acc write8 272 0 ; 273 274\ Check trailer line (possibly, the leading dash has been read). This 275\ sends the appropriate event. 276: check-trailer ( bool -- ) 277 ifnot 278 begin read8 dup `\n = while drop repeat 279 `- <> if skip-newline 3 send-event ret then 280 then 281 "----END " match-string ifnot 3 send-event ret then 282 flush-buf 283 skip-newline 2 send-event ; 284 285\ Decode one line worth of characters. Returned value is 0 if the end of the 286\ object is reached, -1 otherwise. The end of object or error event is sent. 287: decode-line ( -- bool ) 288 -1 { first } 289 begin 290 decode-next-quartet 291 case 292 0 of endof 293 -1 of 294 first ifnot 295 skip-newline 3 send-event 296 else 297 -1 check-trailer 298 then 299 0 ret 300 endof 301 1 of 0 check-trailer 0 ret endof 302 2 of -1 ret endof 303 304 \ On decoding error 305 drop 3 send-event 0 ret 306 endcase 307 0 >first 308 again ; 309 310: main ( -- ! ) 311 begin 312 next-banner-begin 1 send-event 313 begin decode-line while repeat 314 again ; 315