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libwebsockets/lib/misc/base64-decode.c
Andy Green c9731c5f17 type comparisons: fixes
This is a huge patch that should be a global NOP.

For unix type platforms it enables -Wconversion to issue warnings (-> error)
for all automatic casts that seem less than ideal but are normally concealed
by the toolchain.

This is things like passing an int to a size_t argument.  Once enabled, I
went through all args on my default build (which build most things) and
tried to make the removed default cast explicit.

With that approach it neither change nor bloat the code, since it compiles
to whatever it was doing before, just with the casts made explicit... in a
few cases I changed some length args from int to size_t but largely left
the causes alone.

From now on, new code that is relying on less than ideal casting
will complain and nudge me to improve it by warnings.
2021-01-05 10:56:38 +00:00

273 lines
7 KiB
C

/*
* This code originally came from here
*
* http://base64.sourceforge.net/b64.c
*
* already with MIT license, which is retained.
*
* LICENCE: Copyright (c) 2001 Bob Trower, Trantor Standard Systems Inc.
*
* 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.
*
* VERSION HISTORY:
* Bob Trower 08/04/01 -- Create Version 0.00.00B
*
* I cleaned it up quite a bit to match the (linux kernel) style of the rest
* of libwebsockets
*/
#include "private-lib-core.h"
#include <stdio.h>
#include <string.h>
static const char encode_orig[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz0123456789+/";
static const char encode_url[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz0123456789-_";
static const char decode[] = "|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW"
"$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
static int
_lws_b64_encode_string(const char *encode, const char *in, int in_len,
char *out, int out_size)
{
unsigned char triple[3];
int i, done = 0;
while (in_len) {
int len = 0;
for (i = 0; i < 3; i++) {
if (in_len) {
triple[i] = (unsigned char)*in++;
len++;
in_len--;
} else
triple[i] = 0;
}
if (done + 4 >= out_size)
return -1;
*out++ = encode[triple[0] >> 2];
*out++ = encode[(((triple[0] & 0x03) << 4) & 0x30) |
(((triple[1] & 0xf0) >> 4) & 0x0f)];
*out++ = (len > 1 ? encode[(((triple[1] & 0x0f) << 2) & 0x3c) |
(((triple[2] & 0xc0) >> 6) & 3)] : '=');
*out++ = (len > 2 ? encode[triple[2] & 0x3f] : '=');
done += 4;
}
if (done + 1 >= out_size)
return -1;
*out++ = '\0';
return done;
}
int
lws_b64_encode_string(const char *in, int in_len, char *out, int out_size)
{
return _lws_b64_encode_string(encode_orig, in, in_len, out, out_size);
}
int
lws_b64_encode_string_url(const char *in, int in_len, char *out, int out_size)
{
return _lws_b64_encode_string(encode_url, in, in_len, out, out_size);
}
void
lws_b64_decode_state_init(struct lws_b64state *state)
{
memset(state, 0, sizeof(*state));
}
int
lws_b64_decode_stateful(struct lws_b64state *s, const char *in, size_t *in_len,
uint8_t *out, size_t *out_size, int final)
{
const char *orig_in = in, *end_in = in + *in_len;
uint8_t *orig_out = out, *end_out = out + *out_size;
while (in < end_in && *in && out + 4 < end_out) {
for (; s->i < 4 && in < end_in && *in; s->i++) {
uint8_t v;
v = 0;
s->c = 0;
while (in < end_in && *in && !v) {
s->c = v = (unsigned char)*in++;
/* support the url base64 variant too */
if (v == '-')
s->c = v = '+';
if (v == '_')
s->c = v = '/';
v = (uint8_t)((v < 43 || v > 122) ? 0 : decode[v - 43]);
if (v)
v = (uint8_t)((v == '$') ? 0 : v - 61);
}
if (s->c) {
s->len++;
if (v)
s->quad[s->i] = (uint8_t)(v - 1);
} else
s->quad[s->i] = 0;
}
if (s->i != 4 && !final)
continue;
s->i = 0;
/*
* "The '==' sequence indicates that the last group contained
* only one byte, and '=' indicates that it contained two
* bytes." (wikipedia)
*/
if ((in >= end_in || !*in) && s->c == '=')
s->len--;
if (s->len >= 2)
*out++ = (uint8_t)(s->quad[0] << 2 | s->quad[1] >> 4);
if (s->len >= 3)
*out++ = (uint8_t)(s->quad[1] << 4 | s->quad[2] >> 2);
if (s->len >= 4)
*out++ = (uint8_t)(((s->quad[2] << 6) & 0xc0) | s->quad[3]);
s->done += s->len - 1;
s->len = 0;
}
*out = '\0';
*in_len = (unsigned int)(in - orig_in);
*out_size = (unsigned int)(out - orig_out);
return 0;
}
/*
* returns length of decoded string in out, or -1 if out was too small
* according to out_size
*
* Only reads up to in_len chars, otherwise if in_len is -1 on entry reads until
* the first NUL in the input.
*/
static size_t
_lws_b64_decode_string(const char *in, int in_len, char *out, size_t out_size)
{
struct lws_b64state state;
size_t il = (size_t)in_len, ol = out_size;
if (in_len == -1)
il = strlen(in);
lws_b64_decode_state_init(&state);
lws_b64_decode_stateful(&state, in, &il, (uint8_t *)out, &ol, 1);
if (!il)
return 0;
return ol;
}
int
lws_b64_decode_string(const char *in, char *out, int out_size)
{
return (int)_lws_b64_decode_string(in, -1, out, (unsigned int)out_size);
}
int
lws_b64_decode_string_len(const char *in, int in_len, char *out, int out_size)
{
return (int)_lws_b64_decode_string(in, in_len, out, (unsigned int)out_size);
}
#if 0
static const char * const plaintext[] = {
"any carnal pleasure.",
"any carnal pleasure",
"any carnal pleasur",
"any carnal pleasu",
"any carnal pleas",
"Admin:kloikloi"
};
static const char * const coded[] = {
"YW55IGNhcm5hbCBwbGVhc3VyZS4=",
"YW55IGNhcm5hbCBwbGVhc3VyZQ==",
"YW55IGNhcm5hbCBwbGVhc3Vy",
"YW55IGNhcm5hbCBwbGVhc3U=",
"YW55IGNhcm5hbCBwbGVhcw==",
"QWRtaW46a2xvaWtsb2k="
};
int
lws_b64_selftest(void)
{
char buf[64];
unsigned int n, r = 0;
unsigned int test;
lwsl_notice("%s\n", __func__);
/* examples from https://en.wikipedia.org/wiki/Base64 */
for (test = 0; test < (int)LWS_ARRAY_SIZE(plaintext); test++) {
buf[sizeof(buf) - 1] = '\0';
n = lws_b64_encode_string(plaintext[test],
strlen(plaintext[test]), buf, sizeof buf);
if (n != strlen(coded[test]) || strcmp(buf, coded[test])) {
lwsl_err("Failed lws_b64 encode selftest "
"%d result '%s' %d\n", test, buf, n);
r = -1;
}
buf[sizeof(buf) - 1] = '\0';
n = lws_b64_decode_string(coded[test], buf, sizeof buf);
if (n != strlen(plaintext[test]) ||
strcmp(buf, plaintext[test])) {
lwsl_err("Failed lws_b64 decode selftest "
"%d result '%s' / '%s', %d / %zu\n",
test, buf, plaintext[test], n,
strlen(plaintext[test]));
lwsl_hexdump_err(buf, n);
r = -1;
}
}
if (!r)
lwsl_notice("Base 64 selftests passed\n");
else
lwsl_notice("Base64 selftests failed\n");
return r;
}
#endif