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\ Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
\
\ Permission is hereby granted, free of charge, to any person obtaining
\ a copy of this software and associated documentation files (the
\ "Software"), to deal in the Software without restriction, including
\ without limitation the rights to use, copy, modify, merge, publish,
\ distribute, sublicense, and/or sell copies of the Software, and to
\ permit persons to whom the Software is furnished to do so, subject to
\ the following conditions:
\
\ The above copyright notice and this permission notice shall be
\ included in all copies or substantial portions of the Software.
\
\ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
\ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
\ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
\ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
\ BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
\ ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
\ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
\ SOFTWARE.
preamble {
#include "inner.h"
#define CTX ((br_pem_decoder_context *)(void *)((unsigned char *)t0ctx - offsetof(br_pem_decoder_context, cpu)))
/* see bearssl_pem.h */
void
br_pem_decoder_init(br_pem_decoder_context *ctx)
{
memset(ctx, 0, sizeof *ctx);
ctx->cpu.dp = &ctx->dp_stack[0];
ctx->cpu.rp = &ctx->rp_stack[0];
br_pem_decoder_init_main(&ctx->cpu);
br_pem_decoder_run(&ctx->cpu);
}
/* see bearssl_pem.h */
size_t
br_pem_decoder_push(br_pem_decoder_context *ctx,
const void *data, size_t len)
{
if (ctx->event) {
return 0;
}
ctx->hbuf = data;
ctx->hlen = len;
br_pem_decoder_run(&ctx->cpu);
return len - ctx->hlen;
}
/* see bearssl_pem.h */
int
br_pem_decoder_event(br_pem_decoder_context *ctx)
{
int event;
event = ctx->event;
ctx->event = 0;
return event;
}
}
\ Define a word that evaluates to the address of a field within the
\ decoder context.
: addr:
next-word { field }
"addr-" field + 0 1 define-word
0 8191 "offsetof(br_pem_decoder_context, " field + ")" + make-CX
postpone literal postpone ; ;
addr: event
addr: name
addr: buf
addr: ptr
\ Set a byte at a specific address (offset within the context).
cc: set8 ( value addr -- ) {
size_t addr = T0_POP();
unsigned x = T0_POP();
*((unsigned char *)CTX + addr) = x;
}
\ Get a byte at a specific address (offset within the context).
cc: get8 ( addr -- value ) {
size_t addr = T0_POP();
T0_PUSH(*((unsigned char *)CTX + addr));
}
\ Send an event.
: send-event ( event -- )
addr-event set8 co ;
\ Low-level function to read a single byte. Returned value is the byte
\ (0 to 255), or -1 if there is no available data.
cc: read8-native ( -- x ) {
if (CTX->hlen > 0) {
T0_PUSH(*CTX->hbuf ++);
CTX->hlen --;
} else {
T0_PUSHi(-1);
}
}
\ Read next byte. Block until the next byte is available.
: read8 ( -- x )
begin read8-native dup 0< ifnot ret then drop co again ;
\ Read bytes until next end-of-line.
: skip-newline ( -- )
begin read8 `\n <> while repeat ;
\ Read bytes until next end-of-line; verify that they are all whitespace.
\ This returns -1 if they were all whitespace, 0 otherwise.
: skip-newline-ws ( -- bool )
-1 { r }
begin read8 dup `\n <> while ws? ifnot 0 >r then repeat
drop r ;
\ Normalise a byte to uppercase (ASCII only).
: norm-upper ( x -- x )
dup dup `a >= swap `z <= and if 32 - then ;
\ Read bytes and compare with the provided string. On mismatch, the
\ rest of the line is consumed. Matching is not case sensitive.
: match-string ( str -- bool )
begin
dup data-get8 norm-upper dup ifnot 2drop -1 ret then
read8 norm-upper dup `\n = if drop 2drop 0 ret then
= ifnot drop skip-newline 0 ret then
1+
again ;
\ Read bytes into the provided buffer, but no more than the provided
\ count. Reading stops when end-of-line is reached. Returned value
\ is the count of bytes written to the buffer, or 0 if the buffer size
\ was exceeded. All bytes are normalised to uppercase (ASCII only).
: read-bytes ( addr len -- len )
dup { orig-len }
swap
begin
over ifnot 2drop skip-newline 0 ret then
read8 dup `\n = if 2drop orig-len swap - ret then
dup `\r = if drop else norm-upper over set8 then
1+ swap 1- swap
again ;
\ Remove trailing dashes from the name buffer.
: trim-dashes ( len -- )
begin dup while
1-
dup addr-name + get8 `- <> if
addr-name + 1+ 0 swap set8 ret
then
repeat
addr-name set8 ;
\ Scan input for next "begin" banner.
: next-banner-begin ( -- )
begin
"-----BEGIN " match-string if
addr-name 127 read-bytes
dup if trim-dashes ret then
drop
then
again ;
\ Convert a Base64 character to its numerical value. Returned value is
\ 0 to 63 for Base64 characters, -1 for '=', and -2 for all other characters.
cc: from-base64 ( char -- x ) {
uint32_t c = T0_POP();
uint32_t p, q, r, z;
p = c - 0x41;
q = c - 0x61;
r = c - 0x30;
z = ((p + 2) & -LT(p, 26))
| ((q + 28) & -LT(q, 26))
| ((r + 54) & -LT(r, 10))
| (64 & -EQ(c, 0x2B))
| (65 & -EQ(c, 0x2F))
| EQ(c, 0x3D);
T0_PUSHi((int32_t)z - 2);
}
\ Test whether a character is whitespace (but not a newline).
: ws? ( x -- bool )
dup `\n <> swap 32 <= and ;
\ Read next character, skipping whitespace (except newline).
: next-nonws ( -- x )
begin
read8 dup ws? ifnot ret then
drop
again ;
\ Write one byte in the output buffer.
cc: write8 ( x -- ) {
unsigned char x = (unsigned char)T0_POP();
CTX->buf[CTX->ptr ++] = x;
if (CTX->ptr == sizeof CTX->buf) {
if (CTX->dest) {
CTX->dest(CTX->dest_ctx, CTX->buf, sizeof CTX->buf);
}
CTX->ptr = 0;
}
}
\ Flush the output buffer.
cc: flush-buf ( -- ) {
if (CTX->ptr > 0) {
if (CTX->dest) {
CTX->dest(CTX->dest_ctx, CTX->buf, CTX->ptr);
}
CTX->ptr = 0;
}
}
\ Decode the four next Base64 characters. Returned value is:
\ 0 quartet processed, three bytes produced.
\ -1 dash encountered as first character (no leading whitespace).
\ 1 quartet processed, one or two bytes produced, terminator reached.
\ 2 end-of-line reached.
\ 3 error.
\ For all positive return values, the remaining of the current line has been
\ consumed.
: decode-next-quartet ( -- r )
\ Process first character. It may be a dash.
read8 dup `- = if drop -1 ret then
dup ws? if drop next-nonws then
dup `\n = if drop 2 ret then
from-base64 dup 0< if drop skip-newline 3 ret then
{ acc }
\ Second character.
next-nonws dup `\n = if drop 3 ret then
from-base64 dup 0< if drop skip-newline 3 ret then
acc 6 << + >acc
\ Third character: may be an equal sign.
next-nonws dup `\n = if drop 3 ret then
dup `= = if
\ Fourth character must be an equal sign.
drop
next-nonws dup `\n = if drop 3 ret then
skip-newline-ws ifnot drop 3 ret then
`= <> if 3 ret then
acc 0x0F and if 3 ret then
acc 4 >> write8
1 ret
then
from-base64 dup 0< if drop skip-newline 3 ret then
acc 6 << + >acc
\ Fourth character: may be an equal sign.
next-nonws dup `\n = if drop 3 ret then
dup `= = if
drop skip-newline-ws ifnot 3 ret then
acc 0x03 and if 3 ret then
acc 10 >> write8
acc 2 >> write8
1 ret
then
from-base64 dup 0< if drop skip-newline 3 ret then
acc 6 << + >acc
acc 16 >> write8
acc 8 >> write8
acc write8
0 ;
\ Check trailer line (possibly, the leading dash has been read). This
\ sends the appropriate event.
: check-trailer ( bool -- )
ifnot
begin read8 dup `\n = while drop repeat
`- <> if skip-newline 3 send-event ret then
then
"----END " match-string ifnot 3 send-event ret then
flush-buf
skip-newline 2 send-event ;
\ Decode one line worth of characters. Returned value is 0 if the end of the
\ object is reached, -1 otherwise. The end of object or error event is sent.
: decode-line ( -- bool )
-1 { first }
begin
decode-next-quartet
case
0 of endof
-1 of
first ifnot
skip-newline 3 send-event
else
-1 check-trailer
then
0 ret
endof
1 of 0 check-trailer 0 ret endof
2 of -1 ret endof
\ On decoding error
drop 3 send-event 0 ret
endcase
0 >first
again ;
: main ( -- ! )
begin
next-banner-begin 1 send-event
begin decode-line while repeat
again ;
|